Today's Message Index:
----------------------
1. 01:13 AM - Re: fuel heedful heedful feed (Bruce Thomas)
2. 04:18 AM - Re: fuel heedful heedful feed (cjpilot710@aol.com)
3. 04:25 AM - Re: feul feed (A. Dennis Savarese)
4. 04:28 AM - Re: Fuel feed problem in a YAK-55 (Scott Poehlmann)
5. 04:49 AM - Re: feul feed (Hans Oortman)
6. 05:29 AM - Re: Again : Oil miracle (Roger Kemp M.D.)
7. 06:00 AM - Yak-55 For Sale (Sam Whatmough)
8. 07:40 AM - Re: feul feed (Stephen Morrey)
9. 07:41 AM - Re: feul feed (Stephen Morrey)
10. 08:07 AM - Re: feul feed (Hans Oortman)
11. 08:59 AM - Re: feul feed (Walter Lannon)
12. 09:50 AM - Re: feul feed (A. Dennis Savarese)
13. 11:06 AM - Re: feul feed (T A LEWIS)
14. 02:35 PM - Fuel Feed Yak18T (Phil Gower)
15. 03:03 PM - Re: feul feed (Walter Lannon)
16. 03:18 PM - Oshkosh Dorms (Cpayne)
17. 04:44 PM - Re: feul feed (Chris Wise)
18. 04:45 PM - Re: Fuel Feed Yak18T (Chris Wise)
19. 04:58 PM - Re: Fuel feed problem in a YAK-55 (Javier Carrasco)
20. 05:19 PM - Re: Oshkosh Dorms (Byron Fox)
21. 08:53 PM - Fuel flow (cjpilot710@aol.com)
22. 09:13 PM - Re: Fuel flow (Paul Hamlin)
23. 09:33 PM - Re: feul feed (Walter Lannon)
24. 09:51 PM - Re: Fuel flow (cjpilot710@aol.com)
25. 10:05 PM - Re: fuel feed (William Halverson)
26. 10:07 PM - Re: Fuel flow (Walter Lannon)
27. 10:33 PM - Re: Fuel flow (KingCJ6@aol.com)
Message 1
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| Subject: | Re: fuel heedful heedful feed |
Pappy,
This also happens in a common or garden Cessna 182, it just seems to adjust
itself as you fly along, On landing dip the tanks and they will show more
in the right tank, but leave it stand
With the valve at both, and they balance out, I don't think it's yaw as I
fly it balanced on auto pilot. There was an article on the Cessna web page
explaining it some time ago. C182s have one vent
On the left tank only with a cross over to the right tank, and I believe the
cross over tube fills with fuel and prevents a balanced draw from both
tanks.
Regards Bruce
Message 2
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| Subject: | Re: fuel heedful heedful feed |
The placement of the vent could be a factor, however I understand from old
T34 pilots, they correct imbalance feed by adjusting the rudder trim sinc
e they have cockpit control of rudder trim. Since my tanks have seperate
vents, I don't believe its just a vent problem.
Autopilots may keep you wings level but they don't correct yaw. Now I;m
not totally sure of the dynamics and physics involve here and how to expl
aine it, but its what I observe.
Sometime ago, one contributor here noted how he had eliminated uneven flow
by modifying the flapper valves (i.e. grinding their seats so that the fl
apper it self had a small contact area for sealing.). The explanation at
the time seemed to make sense. I plan to try it on my next "mod program"
.
The note about slots being cut in the flapper valve is interesting too.
I believe its an easier modify the flapper valves than rebuilding the rud
der and adding rudder trim.
Well its 4am here in SMX, and I need to try and get back to sleep. May ne
ed to fly the B-24 come daylight. Had a nice flight up from BUR yesterday
. Took off on rwy 15 and climbed out over the Hollywood hills. Than drop
ped down to stay under the overcast sky. Passed the hills we turned west
to the coast and followed it until we neared the Vanderburg area. We tha
n turned inland skirting the restricted area there. Ran into some rain sh
owers but was able to even see and fall in behind B-17 "909" for what appe
ared to be a perfect planned arrival.
Sorry guys I still having to much fun. Nite nite
Jim "Pappy" Goolsby
-----Original Message-----
From: Bruce Thomas <bvthomas@bigpond.com>
Sent: Tue, May 18, 2010 4:10 am
Subject: Re: Yak-List: fuel heedful heedful feed
Pappy,
This also happens in a common or garden Cessna 182, it just seems to adju
st itself as you fly along, On landing dip the tanks and they will show
more in the right tank, but leave it stand
With the valve at both, and they balance out, I don=99t think it
=99s yaw as I fly it balanced on auto pilot. There was an article on th
e Cessna web page explaining it some time ago. C182s have one vent
On the left tank only with a cross over to the right tank, and I believe
the cross over tube fills with fuel and prevents a balanced draw from bot
h tanks.
Regards Bruce
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Message 3
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Steve,
In the Yak 52, the purpose of stepping on the low side tank is two fold:
in case one of the flapper valves in the fuel junction under the front
seat is stuck closed, forcing the weight of the fuel against the flapper
valve may free the flapper valve thus permitting fuel to flow; secondly
and more likely, there is fuel in the vent line of the tank that is not
feeding and by stepping on the low side you are trying to force the fuel
out of the vent line.
Assuming the airplane is trimmed properly as Pappy says, which
definitely causes fuel imbalance, a vent line with fuel in it will
definitely affect the fuel feed. I didn't realize I was probably
forcing the fuel into the vent lines on the Yak 52 by filling the tanks
all the way up to the lip. Because of the sitting angle of attack, the
vent line at the top, rear, inside corner of the tank can get fuel in it
by filling the tank to the lip. This is particularly true on the right
tank because the vent line sits lower in the fuselage than the left
tank. Remember, the left vent line enters the fuselage and turns down
and connects at the top of the vent junction. The right tank vent line
is attached to the left side of the vent junction which ends up being
lower than the left tank vent line. So when fuel enters the right vent
line by filling to the lip of the filler neck, it may force the fuel
into the vent line and into the vent junction, blocking air back to the
tank through the vent line.
Also when the fuel heats up in the tank it expands and guess where it
expands to? Right into the vent line. Have you ever seen a Yak 52
"puking" fuel overboard on the ramp during hot weather? The reason is
the fuel has expanded in the tank and is forced out of the vent line
through the vent junction and out through the overboard vent line
exiting out the belly of the airplane. Once the siphon has been set up
by the expansion, the siphoning effect can siphon out 5+ gallons. No
kidding.....it happened to me. I filled the airplane and left it on the
ramp in the sun for 2 days. When I came back the fuel instrument no
longer read 60/60. I refilled the tanks and it took over 5 gallons of
fuel to bring the tanks back to 60/60. The telltale sign was the dark,
black spot in the blacktop under the fuselage directly under the vent
line.
Dennis
----- Original Message -----
From: Stephen Morrey
To: yak-list@matronics.com
Sent: Monday, May 17, 2010 9:48 PM
Subject: Re: Yak-List: feul feed
<stephenmorrey@gmail.com>
So just to be sure, am I correct in saying an in flight remidy is to
step on the side showing the lowest fuel level. If this is the case
is it best to simply step on the low side or is it needed to step and
"hold" for an extended period of time on the low side ? Do I have
this backwards? steve "old school"
On Mon, May 17, 2010 at 12:19 PM, <cjpilot710@aol.com> wrote:
> Guys,
>
> The problem has always been aircraft yaw. The T-34 which has the
same fuel
> setup (on one model anyway) has had the same problem. If you do not
apply
> enough rudder on climb out, engine seem to pull out of the left tank
more.
> I have separate tank vent lines that go to the wing tips. I was told
that
> this would cure the uneven flow, when I put in the long range tanks.
It
> didn't. Yaw is the most likely cause of fuel imbalance.
>
> Jim "Pappy" Goolsby
>
> -----Original Message-----
> From: Chris Wise <wise@txc.net.au>
> To: yak-list@matronics.com
> Sent: Mon, May 17, 2010 2:18 am
> Subject: Re: Yak-List: feul feed
>
> G'Day Walt,
>
> We carry a piece of plastic tubing that fits over the vent pipes and
we use
> this to check the vents by blowing into the pipe.
> Every now and then we blow compressed air thru the vent.
> At no time have we ever found a blocked air vent.
> My mate also fitted new fuel cap seals. Did not solve the problem.
>
> The check valves are a simple flapper valve that prevents any X flow
and I
> cannot see how they can be a problem.
> I am not familiar with the check valves on a CJ6
>
> Thanks and cheers,
> Chris.
>
>
>
> Chris Wise
> GT Propellers Australia
> __________________________________________________________
> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>
> Email chris@gtpropellersaustralia.com.au
> Website www.gtpropellersaustralia.com.au
>
> The information transmitted in and with this email is intended only
for the
> person or entity to which it is addressed and may contain
confidential
> and/or privileged material. Any review, retransmission,
dissemination or
> other use of, or taking of any action in reliance upon this
information, by
> persons or entities other than the intended recipients is
prohibited. If you
> received this transmission in error, please contact the sender and
delete
> this e-mail and associated material from all computers and/or
systems. The
> intended recipient of this e-mail may only use, reproduce, disclose
or
> distribute the information contained in this e-mail and any attached
files,
> with the permission of the sender.
>
> ----- Original Message -----
> From: Walter Lannon
> To: yak-list@matronics.com
> Sent: Monday, May 17, 2010 2:05 PM
> Subject: Re: Yak-List: feul feed
> Hi Chris;
>
> The Nanchang exhibits the same fuel feed problem. Typically the RH
tank is
> late and I know of at least one forced landing with a full RH and
empty LH.
> Believe this was in South Africa about 6 or 7 years ago.
>
> The CJ6 has a single point vent system which I don't believe is the
> problem. However the effective length of the vent line and the fuel
feed
> line are both longer for the RH tank. Theoretically that could
induce a lag
> in the RH feed time but I don't belive it is signifigant. Any
blockage of
> the vent by insect nests etc. will definitaly cause a big problem.
>
> Other than the bugs that leaves the feed tank check valves as the
only
> remaining source. SPEAKING FOR THE CJ6 ONLY (since I have no
knowledge of
> the check valves in any of the Yak models) I believe I have solved
that
> problem with a modification to the check valve which, IMHO, was very
poorly
> designed.
>
> If you have the opportunity to take photos of one of your check
valves and
> email to me I will try to determine if the mod is applicable.
>
> Walt
>
>
> ----- Original Message -----
> From: Chris Wise
> To: yak-list@matronics.com
> Sent: Sunday, May 16, 2010 7:18 PM
> Subject: Yak-List: feul feed
> G'Day All,
>
> I and a friend each run a Yak18T.
> We suffer the same problem with both aircraft, re even fuel feed.
> Flying in turbulence seems to help the problem, but still air is bad
news.
>
> The left tank will feed untill almost empty leaving plenty of fuel
in the
> right tank and on my mates 18, the low fuel warning light on the
left tank
> lit up and was fortunate enough to be close to a small country strip
where
> he landed in a hurry.
>
> He has teed both vents into one. This has not helped.
>
> I moved the left tank vent and re located the vent to about 3/4 of a
inch
> next to the right tank vent thinking that it may be the vortex from
the prop
> that is allowing the right tank to feed. Or rather stopping the left
tank to
> feed.
> I have changed the angle of the vent pipe facing the airflow to try
and
> perhaps get more air into the vent to assist the left tank to feed
more.
> This has only marginally helped.
>
> I landed on Saturday with the left tank low fuel warning light
coming on on
> finals.
> The right tank had 65 - 70 litres fuel remaining and about 12 in the
left
> when dipped.
>
> We have removed and carefully checked the check valves. No problem
there.
>
> Any suggestions would be greatly appreciated.
>
> Thanks and cheers,
> Chris.
>
>
> Chris Wise
> GT Propellers Australia
> __________________________________________________________
> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>
> Email chris@gtpropellersaustralia.com.au
> Website www.gtpropellersaustralia.com.au
>
> The information transmitted in and with this email is intended only
for the
> person or entity to which it is addressed and may contain
confidential
> and/or privileged material. Any review, retransmission,
dissemination or
> other use of, or taking of any action in reliance upon this
information, by
> persons or entities other than the intended recipients is
prohibited. If you
> received this transmission in error, please contact the sender and
delete
> this e-mail and associated material from all computers and/or
systems. The
> intended recipient of this e-mail may only use, reproduce, disclose
or
> distribute the information contained in this e-mail and any attached
files,
> with the permission of the sender.
>
>
>
> get=_blank>http://www.matronics.com/Navigator?Yak-List
>
> tp://forums.matronics.com
>
> _blank>http://www.matronics.com/contribution
>
>
>
Message 4
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| Subject: | Re: Fuel feed problem in a YAK-55 |
Hi Bill,
Mine does that all the time too. Except that some times the right drains
faster... Apparently the tanks are plumbed such that they can crossfeed
at the the point they make a common feed to the engine (which is located
at the drain valve behind the oil radiator...). I have the drawing
around here somewhere and will scan it and send it when I next get a few
minutes (which might not be until 2011 at the current rate...<VBG>).
Scott
Yak-55M
N155YK
William Halverson wrote:
>
> The thread on CJ-6 feed problems reminded me ....
>
> The indicator (exteral wing mounted rotating gauge) on my left wing 'drains'
much more quickly than the right one. After I land, and come back a couple of
days later, the two indicators are balanced.
>
> Ideas on the cause/remedy greatly appreciated!
>
> Best to all!
>
> William Halverson
> Vallejo CA
> YAK-55
> N355YK
>
>
>
Message 5
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Dennis,
It can be very scary though..When I ferried my Yak from Estonia via
Lithuania back to Holland I found it to be very scary.
I flew from Palanga (Lithuania) to Gdansk(Poland) over the middle of the
Baltic Sea outside the airspace of Bullarus when the left tank showed only
12 liters and the right hand tank was still at 60 liters. I made a 90 degree
bank turn to the left and a full 360 back to the original course.after a
while I saw the right hand tank indicator flip to 50 ......man I was glad to
see that happening...problem solved..scary though..
Hans
RA3326K
_____
Van: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] Namens A. Dennis Savarese
Verzonden: dinsdag 18 mei 2010 13:24
Aan: yak-list@matronics.com
Onderwerp: Re: Yak-List: feul feed
Steve,
In the Yak 52, the purpose of stepping on the low side tank is two fold: in
case one of the flapper valves in the fuel junction under the front seat is
stuck closed, forcing the weight of the fuel against the flapper valve may
free the flapper valve thus permitting fuel to flow; secondly and more
likely, there is fuel in the vent line of the tank that is not feeding and
by stepping on the low side you are trying to force the fuel out of the vent
line.
Assuming the airplane is trimmed properly as Pappy says, which definitely
causes fuel imbalance, a vent line with fuel in it will definitely affect
the fuel feed. I didn't realize I was probably forcing the fuel into the
vent lines on the Yak 52 by filling the tanks all the way up to the lip.
Because of the sitting angle of attack, the vent line at the top, rear,
inside corner of the tank can get fuel in it by filling the tank to the lip.
This is particularly true on the right tank because the vent line sits lower
in the fuselage than the left tank. Remember, the left vent line enters the
fuselage and turns down and connects at the top of the vent junction. The
right tank vent line is attached to the left side of the vent junction which
ends up being lower than the left tank vent line. So when fuel enters the
right vent line by filling to the lip of the filler neck, it may force the
fuel into the vent line and into the vent junction, blocking air back to the
tank through the vent line.
Also when the fuel heats up in the tank it expands and guess where it
expands to? Right into the vent line. Have you ever seen a Yak 52 "puking"
fuel overboard on the ramp during hot weather? The reason is the fuel has
expanded in the tank and is forced out of the vent line through the vent
junction and out through the overboard vent line exiting out the belly of
the airplane. Once the siphon has been set up by the expansion, the
siphoning effect can siphon out 5+ gallons. No kidding.....it happened to
me. I filled the airplane and left it on the ramp in the sun for 2 days.
When I came back the fuel instrument no longer read 60/60. I refilled the
tanks and it took over 5 gallons of fuel to bring the tanks back to 60/60.
The telltale sign was the dark, black spot in the blacktop under the
fuselage directly under the vent line.
Dennis
----- Original Message -----
From: Stephen <mailto:stephenmorrey@gmail.com> Morrey
Sent: Monday, May 17, 2010 9:48 PM
Subject: Re: Yak-List: feul feed
So just to be sure, am I correct in saying an in flight remidy is to
step on the side showing the lowest fuel level. If this is the case
is it best to simply step on the low side or is it needed to step and
"hold" for an extended period of time on the low side ? Do I have
this backwards? steve "old school"
On Mon, May 17, 2010 at 12:19 PM, <cjpilot710@aol.com> wrote:
> Guys,
>
> The problem has always been aircraft yaw. The T-34 which has the same fuel
> setup (on one model anyway) has had the same problem. If you do not apply
> enough rudder on climb out, engine seem to pull out of the left tank more.
> I have separate tank vent lines that go to the wing tips. I was told that
> this would cure the uneven flow, when I put in the long range tanks. It
> didn't. Yaw is the most likely cause of fuel imbalance.
>
> Jim "Pappy" Goolsby
>
> -----Original Message-----
> From: Chris Wise <wise@txc.net.au>
> To: yak-list@matronics.com
> Sent: Mon, May 17, 2010 2:18 am
> Subject: Re: Yak-List: feul feed
>
> G'Day Walt,
>
> We carry a piece of plastic tubing that fits over the vent pipes and we
use
> this to check the vents by blowing into the pipe.
> Every now and then we blow compressed air thru the vent.
> At no time have we ever found a blocked air vent.
> My mate also fitted new fuel cap seals. Did not solve the problem.
>
> The check valves are a simple flapper valve that prevents any X flow and I
> cannot see how they can be a problem.
> I am not familiar with the check valves on a CJ6
>
> Thanks and cheers,
> Chris.
>
>
> Chris Wise
> GT Propellers Australia
> __________________________________________________________
> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>
> Email chris@gtpropellersaustralia.com.au
> Website www.gtpropellersaustralia.com.au
>
> The information transmitted in and with this email is intended only for
the
> person or entity to which it is addressed and may contain confidential
> and/or privileged material. Any review, retransmission, dissemination or
> other use of, or taking of any action in reliance upon this information,
by
> persons or entities other than the intended recipients is prohibited. If
you
> received this transmission in error, please contact the sender and delete
> this e-mail and associated material from all computers and/or systems. The
> intended recipient of this e-mail may only use, reproduce, disclose or
> distribute the information contained in this e-mail and any attached
files,
> with the permission of the sender.
>
> ----- Original Message -----
> From: Walter Lannon
> To: yak-list@matronics.com
> Sent: Monday, May 17, 2010 2:05 PM
> Subject: Re: Yak-List: feul feed
> Hi Chris;
>
> The Nanchang exhibits the same fuel feed problem. Typically the RH tank is
> late and I know of at least one forced landing with a full RH and empty
LH.
> Believe this was in South Africa about 6 or 7 years ago.
>
> The CJ6 has a single point vent system which I don't believe is the
> problem. However the effective length of the vent line and the fuel feed
> line are both longer for the RH tank. Theoretically that could induce a
lag
> in the RH feed time but I don't belive it is signifigant. Any blockage of
> the vent by insect nests etc. will definitaly cause a big problem.
>
> Other than the bugs that leaves the feed tank check valves as the only
> remaining source. SPEAKING FOR THE CJ6 ONLY (since I have no knowledge of
> the check valves in any of the Yak models) I believe I have solved that
> problem with a modification to the check valve which, IMHO, was very
poorly
> designed.
>
> If you have the opportunity to take photos of one of your check valves and
> email to me I will try to determine if the mod is applicable.
>
> Walt
>
>
> ----- Original Message -----
> From: Chris Wise
> To: yak-list@matronics.com
> Sent: Sunday, May 16, 2010 7:18 PM
> Subject: Yak-List: feul feed
> G'Day All,
>
> I and a friend each run a Yak18T.
> We suffer the same problem with both aircraft, re even fuel feed.
> Flying in turbulence seems to help the problem, but still air is bad news.
>
> The left tank will feed untill almost empty leaving plenty of fuel in the
> right tank and on my mates 18, the low fuel warning light on the left tank
> lit up and was fortunate enough to be close to a small country strip where
> he landed in a hurry.
>
> He has teed both vents into one. This has not helped.
>
> I moved the left tank vent and re located the vent to about 3/4 of a inch
> next to the right tank vent thinking that it may be the vortex from the
prop
> that is allowing the right tank to feed. Or rather stopping the left tank
to
> feed.
> I have changed the angle of the vent pipe facing the airflow to try and
> perhaps get more air into the vent to assist the left tank to feed more.
> This has only marginally helped.
>
> I landed on Saturday with the left tank low fuel warning light coming on
on
> finals.
> The right tank had 65 - 70 litres fuel remaining and about 12 in the left
> when dipped.
>
> We have removed and carefully checked the check valves. No problem there.
>
> Any suggestions would be greatly appreciated.
>
> Thanks and cheers,
> Chris.
>
>
> Chris Wise
> GT Propellers Australia
> __________________________________________________________
> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>
> Email chris@gtpropellersaustralia.com.au
> Website www.gtpropellersaustralia.com.au
>
> The information transmitted in and with this email is intended only for
the
> person or entity to which it is addressed and may contain confidential
> and/or privileged material. Any review, retransmission, dissemination or
> other use of, or taking of any action in reliance upon this information,
by
> persons or entities other than the intended recipients is prohibited. If
you
> received this transmission in error, please contact the sender and delete
> this e-mail and associated material from all computers and/or systems. The
> intended recipient of this e-mail may only use, reproduce, disclose or
> distribute the information contained in this e-mail and any attached
files,
> with the permission of the sender.
>
>
> ==========
> get=_blank>http://www.matronics.com/Navigator?Yak-List
> ==========
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> ==========
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href="http://www.matronics.com/Navigator?Yak-List">http://www.matronics====
===================<; via the Web
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Message 6
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| Subject: | Again : Oil miracle |
Roger.I do.
Doc
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon
Sent: Monday, May 17, 2010 11:12 PM
Subject: Re: Yak-List: Again : Oil miracle
OK. Just do exactly the same every time.
Walt
----- Original Message -----
From: Roger Kemp M.D. <mailto:viperdoc@mindspring.com>
Sent: Monday, May 17, 2010 8:33 PM
Subject: RE: Yak-List: Again : Oil miracle
Walt according to the original translated YAK-52 pilot's manual, the
procedure is to sump the engine at 70% (~1600 RPM) for 30 sec. Pretty close.
Doc
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon
Sent: Monday, May 17, 2010 11:26 AM
Subject: Re: Yak-List: Again : Oil miracle
All dry sump aircraft engines utilize a scavange pump to return oil to the
tank.
After landing and taxi in at idle RPM the scavange pump output is low and
oil accumulates in the sump.
There is a standard operating procedure for these engines that requires a
ground run prior to shut-down for a specific length of time at a specific
RPM.
For a typical small radial I would suggest 1500 RPM for 1 minute.
Do this the same every time and you will get a reliable oil level reading in
the tank.
Walt
----- Original Message -----
From: Didier Blouzard <mailto:didier.blouzard@gmail.com>
Sent: Monday, May 17, 2010 8:32 AM
Subject: Yak-List: Again : Oil miracle
Good day to all,
I have a question regarding a strange behavior on a YAK52.
During my preflight check, I had a look on the oil stick. It shows about 5
liters left.....danger zone. How could this happen.
So I filled the oil with 5 more liters up to ten.
Then I started the motor and had a look after 15mn run. The stick shows 16
liters. This time too much.
So I purge 6 liters.
The time after I had the same phenomenon again. When the motor has not run
the oil is very low but after a few mn it comes back to normal.
This is sort of a problem because I can't check the oil anymore. When will I
know if the oil is low for real.
Does this have happen to one of you???? Is this a known issue and is there
there any solution?
Now another question regarding the Heading Indicator on a Yak18T. Last week
I was flying and I looked at my HI. It shows about 150 to 180 degres
opposite of the real heading. (GPS heading!!!)
I touched some buttons on the control panel (left hand side) I don't know
which one was the good one but after a moment, it comes back to normal.
Is there anyone out there having the modus operandi (sorry....the manual!!!)
of this HI please.
Sorry about the noise on the list and thanks to all
have a good flying day
kind regards
--
Didier BLOUZARD
didier.blouzard@gmail.com
0624243672
href="http://www.matronics.com/Navigator?Yak-List">http://www.matronics.com/
Navigator?Yak-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
Message 7
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It is with regret that I am forced to sell be beloved Yak-55. As you all
know it is a superb Advanced/Unlimited Aerobatic aircraft, with sweet
handling and a lot of character. It is certainly one of the best examples
around.
British Register, Fresh EASA Permit, All SBs and MPDs up to date.
Airframe: 380 Hours
Engine: 28 Hours
Propeller: 53 Hours
Please contact me off list for further details.
Sam
G-OHNO
sam.whatmough@gmail.com
Message 8
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Dennis, Three points of clarification.
1. Say the left side is low and I want to try and get more fuel
flowing from the right side I would step on the left side this would
in effect yaw the fuel junction under the front seat to the right of
center thus having a tendency to open the right side flapper valve
which I believe opens toward the center line of the plane. Am I
picturing this correct.
2. If the most likely issue is fuel in the vent line and over filling
is a likely culprit then what is the effect if the fuel is filled
"below" the lip and then while climbing to altitude the plane is
pitched up. Would this not create the same problem of filling the
vent line, in this case during climb out, especially if the climb is
steep. Or is there some other force in effect after fuel is flowing
such as pulling a vacuum that prevents this from being a problem.
Same question re filling the vent line in flight during acrobatics.
3. As you recall I have the bladders installed with the recommended
added check valve under the front seat..
I am not sure I remember correctly but is this check valve designed to
prevent back flow and the filling of vent lines or does it serve a
different purpose. If I have this check valve am I assured I will not
have a back flow problem?
On Tue, May 18, 2010 at 7:23 AM, A. Dennis Savarese
<dsavarese0812@bellsouth.net> wrote:
> Steve,
> In the Yak 52, the purpose of stepping on the low side tank is two fold: in
> case one of the flapper valves in the fuel junction under the front seatis
> stuck closed, forcing the weight of the fuel against the flapper valve may
> free the flapper valve thus permitting fuel to flow; secondly and more
> likely, there is fuel in the vent line of the tank that is not feeding and
> by stepping on the low side you are trying to force the fuel out of the vent
> line.
>
> Assuming the airplane is trimmed properly as Pappy says, which definitely
> causes fuel imbalance, a vent line with fuel in it will definitely affect
> the fuel feed. I didn't realize I was probablyforcing the fuel into the
> vent lines on the Yak 52 by filling the tanks all the way up to the lip.
> Because of the sitting angle of attack, the vent line at the top, rear,
> inside corner of the tank can get fuel in it by filling the tank to the
> lip. This is particularly true on the right tank because the vent line sits
> lower in the fuselage than the left tank. Remember, the left vent line
> enters the fuselage and turns down and connects at the top ofthe vent
> junction. The right tank vent line is attached to the left side of the vent
> junction which ends up being lower than the left tank vent line. So when
> fuel enters the right vent line by filling to the lip of the filler neck, it
> may force the fuel into the vent line and into the vent junction, blocking
> air back to the tank through the vent line.
>
> Also when the fuel heats up in the tank it expands and guess where it
> expands to? Right into the vent line. Have you ever seen a Yak 52 "puking"
> fuel overboard on the ramp during hot weather? The reason is the fuel has
> expanded in the tank and is forced out of the vent line through the vent
> junction and out through the overboard vent line exitingout the belly of
> the airplane. Once the siphon has been set up by the expansion, the
> siphoning effect can siphon out 5+ gallons. No kidding.....it happened to
> me. I filled the airplane and left it on the ramp in the sun for 2 days.
> When I came back the fuel instrument no longer read 60/60. I refilled the
> tanks and it took over 5 gallons of fuel to bring the tanks back to 60/60.
> The telltale sign was the dark, black spot in the blacktop under the
> fuselage directly under the vent line.
>
> Dennis
>
> ----- Original Message -----
> From: Stephen Morrey
> To: yak-list@matronics.com
> Sent: Monday, May 17, 2010 9:48 PM
> Subject: Re: Yak-List: feul feed
>
> So just to be sure, am I correct in saying an in flight remidy is to
> step on the side showing the lowest fuel level. If this is the case
> is it best to simply step on the low side or is it needed to step and
> "hold" for an extended period of time on the low side ? Do I have
> this backwards? steve "old school"
>
> On Mon, May 17, 2010 at 12:19 PM, <cjpilot710@aol.com> wrote:
>> Guys,
>>
>> The problem has always been aircraft yaw. The T-34 which has the same fuel
>> setup (on one model anyway) has had the same problem. If you do not apply
>> enough rudder on climb out, engine seem to pull out of the left tank more.
>> I have separate tank vent lines that go to the wing tips. I was told that
>> this would cure the uneven flow, when I put in the long range tanks. It
>> didn't. Yaw is the most likely cause of fuel imbalance.
>>
>> Jim "Pappy" Goolsby
>>
>> -----Original Message-----
>> From: Chris Wise <wise@txc.net.au>
>> To: yak-list@matronics.com
>> Sent: Mon, May 17, 2010 2:18 am
>> Subject: Re: Yak-List: feul feed
>>
>> G'Day Walt,
>>
>> We carry a piece of plastic tubing that fits over the vent pipes and we
>> use
>> this to check the vents by blowing into the pipe.
>> Every now and then we blow compressed air thru the vent.
>> At no time have we ever found a blocked air vent.
>> My mate also fitted new fuel cap seals. Did not solve the problem.
>>
>> The check valves are a simple flapper valve that prevents any X flow and I
>> cannot see how they can be a problem.
>> I am not familiar with the check valves on a CJ6
>>
>> Thanks and cheers,
>> Chris.
>>
>>
>>
>> Chris Wise
>> GT Propellers Australia
>> __________________________________________________________
>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>
>> Email chris@gtpropellersaustralia.com.au
>> Website www.gtpropellersaustralia.com.au
>>
>> The information transmitted in and with this email is intended only for
>> the
>> person or entity to which it is addressed and may contain confidential
>> and/or privileged material. Any review, retransmission, dissemination or
>> other use of, or taking of any action in reliance upon this information,
>> by
>> persons or entities other than the intended recipients is prohibited. If
>> you
>> received this transmission in error, please contact the sender and delete
>> this e-mail and associated material from all computers and/or systems. The
>> intended recipient of this e-mail may only use, reproduce, disclose or
>> distribute the information contained in this e-mail and any attached
>> files,
>> with the permission of the sender.
>>
>> ----- Original Message -----
>> From: Walter Lannon
>> To: yak-list@matronics.com
>> Sent: Monday, May 17, 2010 2:05 PM
>> Subject: Re: Yak-List: feul feed
>> Hi Chris;
>>
>> The Nanchang exhibits the same fuel feed problem. Typically the RH tank is
>> late and I know of at least one forced landing with a full RH and empty
>> LH.
>> Believe this was in South Africa about 6 or 7 years ago.
>>
>> The CJ6 has a single point vent system which I don't believe is the
>> problem. However the effective length of the vent line and the fuel feed
>> line are both longer for the RH tank. Theoretically that could induce a
>> lag
>> in the RH feed time but I don't belive it is signifigant. Any blockage of
>> the vent by insect nests etc. will definitaly cause a big problem.
>>
>> Other than the bugs that leaves the feed tank check valves as the only
>> remaining source. SPEAKING FOR THE CJ6 ONLY (since I have no knowledge of
>> the check valves in any of the Yak models) I believe I have solved that
>> problem with a modification to the check valve which, IMHO, was very
>> poorly
>> designed.
>>
>> If you have the opportunity to take photos of one of your check valves and
>> email to me I will try to determine if the mod is applicable.
>>
>> Walt
>>
>>
>> ----- Original Message -----
>> From: Chris Wise
>> To: yak-list@matronics.com
>> Sent: Sunday, May 16, 2010 7:18 PM
>> Subject: Yak-List: feul feed
>> G'Day All,
>>
>> I and a friend each run a Yak18T.
>> We suffer the same problem with both aircraft, re even fuel feed.
>> Flying in turbulence seems to help the problem, but still air is bad news.
>>
>> The left tank will feed untill almost empty leaving plenty of fuel in the
>> right tank and on my mates 18, the low fuel warning light on the left tank
>> lit up and was fortunate enough to be close to a small country strip where
>> he landed in a hurry.
>>
>> He has teed both vents into one. This has not helped.
>>
>> I moved the left tank vent and re located the vent to about 3/4 of a inch
>> next to the right tank vent thinking that it may be the vortex from the
>> prop
>> that is allowing the right tank to feed. Or rather stopping the left tank
>> to
>> feed.
>> I have changed the angle of the vent pipe facing the airflow to try and
>> perhaps get more air into the vent to assist the left tank to feed more.
>> This has only marginally helped.
>>
>> I landed on Saturday with the left tank low fuel warning light coming on
>> on
>> finals.
>> The right tank had 65 - 70 litres fuel remaining and about 12 in the left
>> when dipped.
>>
>> We have removed and carefully checked the check valves. No problem there.
>>
>> Any suggestions would be greatly appreciated.
>>
>> Thanks and cheers,
>> Chris.
>>
>>
>> Chris Wise
>> GT Propellers Australia
>> __________________________________________________________
>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>
>> Email chris@gtpropellersaustralia.com.au
>> Website www.gtpropellersaustralia.com.au
>>
>> The information transmitted in and with this email is intended only for
>> the
>> person or entity to which it is addressed and may contain confidential
>> and/or privileged material. Any review, retransmission, dissemination or
>> other use of, or taking of any action in reliance upon this information,
>> by
>> persons or entities other than the intended recipients is prohibited. If
>> you
>> received this transmission in error, please contact the sender and delete
>> this e-mail and associated material from all computers and/or systems. The
>> intended recipient of this e-mail may only use, reproduce, disclose or
>> distribute the information contained in this e-mail and any attached
>> files,
>> with the permission of the sender.
>>
>>
>> ==========
>> get=_blank>http://www.matronics.com/Navigator?Yak-List
>> ==========
>> tp://forums.matronics.com
>> ==========
>> _blank>http://www.matronics.com/contribution
>> p; Navigator Photoshare, and
>> href="http://www.matronics.com/Navigator?Yak-List">http://www.matronics========================<;
>> via the Web href="http://forums.matronics.com">http://forums.matronics.com
> _p; generous bsp;
> href="http://www.matronics.com/contribution">http://www.matronics.com/c================
>
>
Message 9
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Again I am a little confused on this, it seems if the 360 turn was
coordinated then the turn should have had no effect. Do I understand
this correctly?
On Tue, May 18, 2010 at 7:49 AM, Hans Oortman <pa3arw@euronet.nl> wrote:
> Dennis,
>
>
> It can be very scary though.When I ferried my Yak from Estonia via
> Lithuania back to Holland I found it to be very scary.
>
> I flew from Palanga (Lithuania) to Gdansk(Poland) over the middle of the
> Baltic Sea outside the airspace of Bullarus when the left tank showed only
> 12 liters and the right hand tank was still at 60 liters. I made a 90 degree
> bank turn to the left and a full 360 back to the original courseafter a
> while I saw the right hand tank indicator flip to 50 ......man I was glad to
> see that happening..problem solved.scary though.
>
>
> Hans
>
> RA3326K
>
> ________________________________
>
> Van: owner-yak-list-server@matronics.com
> [mailto:owner-yak-list-server@matronics.com] Namens A. Dennis Savarese
> Verzonden: dinsdag 18 mei 2010 13:24
> Aan: yak-list@matronics.com
> Onderwerp: Re: Yak-List: feul feed
>
>
> Steve,
>
> In the Yak 52, the purpose of stepping on the low side tank is two fold: in
> case one of the flapper valves in the fuel junction under the front seatis
> stuck closed, forcing the weight of the fuel against the flapper valve may
> free the flapper valve thus permitting fuel to flow; secondly and more
> likely, there is fuel in the vent line of the tank that is not feeding and
> by stepping on the low side you are trying to force the fuel out of the vent
> line.
>
>
> Assuming the airplane is trimmed properly as Pappy says, which definitely
> causes fuel imbalance, a vent line with fuel in it will definitely affect
> the fuel feed. I didn't realize I was probablyforcing the fuel into the
> vent lines on the Yak 52 by filling the tanks all the way up to the lip.
> Because of the sitting angle of attack, the vent line at the top, rear,
> inside corner of the tank can get fuel in it by filling the tank to the
> lip. This is particularly true on the right tank because the vent line sits
> lower in the fuselage than the left tank. Remember, the left vent line
> enters the fuselage and turns down and connects at the top ofthe vent
> junction. The right tank vent line is attached to the left side of the vent
> junction which ends up being lower than the left tank vent line. So when
> fuel enters the right vent line by filling to the lip of the filler neck, it
> may force the fuel into the vent line and into the vent junction, blocking
> air back to the tank through the vent line.
>
>
> Also when the fuel heats up in the tank it expands and guess where it
> expands to? Right into the vent line. Have you ever seen a Yak 52 "puking"
> fuel overboard on the ramp during hot weather? The reason is the fuel has
> expanded in the tank and is forced out of the vent line through the vent
> junction and out through the overboard vent line exitingout the belly of
> the airplane. Once the siphon has been set up by the expansion, the
> siphoning effect can siphon out 5+ gallons. No kidding.....it happened to
> me. I filled the airplane and left it on the ramp in the sun for 2 days.
> When I came back the fuel instrument no longer read 60/60. I refilled the
> tanks and it took over 5 gallons of fuel to bring the tanks back to 60/60.
> The telltale sign was the dark, black spot in the blacktop under the
> fuselage directly under the vent line.
>
>
> Dennis
>
> ----- Original Message -----
>
> From: Stephen Morrey
>
> To: yak-list@matronics.com
>
> Sent: Monday, May 17, 2010 9:48 PM
>
> Subject: Re: Yak-List: feul feed
>
>
>
> So just to be sure, am I correct in saying an in flight remidy is to
> step on the side showing the lowest fuel level. If this is the case
> is it best to simply step on the low side or is it needed to step and
> "hold" for an extended period of time on the low side ? Do I have
> this backwards? steve "old school"
>
> On Mon, May 17, 2010 at 12:19 PM, <cjpilot710@aol.com> wrote:
>> Guys,
>>
>> The problem has always been aircraft yaw. The T-34 which has the same fuel
>> setup (on one model anyway) has had the same problem. If you do not apply
>> enough rudder on climb out, engine seem to pull out of the left tank more.
>> I have separate tank vent lines that go to the wing tips. I was told that
>> this would cure the uneven flow, when I put in the long range tanks. It
>> didn't. Yaw is the most likely cause of fuel imbalance.
>>
>> Jim "Pappy" Goolsby
>>
>> -----Original Message-----
>> From: Chris Wise <wise@txc.net.au>
>> To: yak-list@matronics.com
>> Sent: Mon, May 17, 2010 2:18 am
>> Subject: Re: Yak-List: feul feed
>>
>> G'Day Walt,
>>
>> We carry a piece of plastic tubing that fits over the vent pipes and we
>> use
>> this to check the vents by blowing into the pipe.
>> Every now and then we blow compressed air thru the vent.
>> At no time have we ever found a blocked air vent.
>> My mate also fitted new fuel cap seals. Did not solve the problem.
>>
>> The check valves are a simple flapper valve that prevents any X flow and I
>> cannot see how they can be a problem.
>> I am not familiar with the check valves on a CJ6
>>
>> Thanks and cheers,
>> Chris.
>>
>>
>>
>> Chris Wise
>> GT Propellers Australia
>> __________________________________________________________
>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>
>> Email chris@gtpropellersaustralia.com.au
>> Website www.gtpropellersaustralia.com.au
>>
>> The information transmitted in and with this email is intended only for
>> the
>> person or entity to which it is addressed and may contain confidential
>> and/or privileged material. Any review, retransmission, dissemination or
>> other use of, or taking of any action in reliance upon this information,
>> by
>> persons or entities other than the intended recipients is prohibited. If
>> you
>> received this transmission in error, please contact the sender and delete
>> this e-mail and associated material from all computers and/or systems. The
>> intended recipient of this e-mail may only use, reproduce, disclose or
>> distribute the information contained in this e-mail and any attached
>> files,
>> with the permission of the sender.
>>
>> ----- Original Message -----
>> From: Walter Lannon
>> To: yak-list@matronics.com
>> Sent: Monday, May 17, 2010 2:05 PM
>> Subject: Re: Yak-List: feul feed
>> Hi Chris;
>>
>> The Nanchang exhibits the same fuel feed problem. Typically the RH tank is
>> late and I know of at least one forced landing with a full RH and empty
>> LH.
>> Believe this was in South Africa about 6 or 7 years ago.
>>
>> The CJ6 has a single point vent system which I don't believe is the
>> problem. However the effective length of the vent line and the fuel feed
>> line are both longer for the RH tank. Theoretically that could induce a
>> lag
>> in the RH feed time but I don't belive it is signifigant. Any blockage of
>> the vent by insect nests etc. will definitaly cause a big problem.
>>
>> Other than the bugs that leaves the feed tank check valves as the only
>> remaining source. SPEAKING FOR THE CJ6 ONLY (since I have no knowledge of
>> the check valves in any of the Yak models) I believe I have solved that
>> problem with a modification to the check valve which, IMHO, was very
>> poorly
>> designed.
>>
>> If you have the opportunity to take photos of one of your check valves and
>> email to me I will try to determine if the mod is applicable.
>>
>> Walt
>>
>>
>> ----- Original Message -----
>> From: Chris Wise
>> To: yak-list@matronics.com
>> Sent: Sunday, May 16, 2010 7:18 PM
>> Subject: Yak-List: feul feed
>> G'Day All,
>>
>> I and a friend each run a Yak18T.
>> We suffer the same problem with both aircraft, re even fuel feed.
>> Flying in turbulence seems to help the problem, but still air is bad news.
>>
>> The left tank will feed untill almost empty leaving plenty of fuel in the
>> right tank and on my mates 18, the low fuel warning light on the left tank
>> lit up and was fortunate enough to be close to a small country strip where
>> he landed in a hurry.
>>
>> He has teed both vents into one. This has not helped.
>>
>> I moved the left tank vent and re located the vent to about 3/4 of a inch
>> next to the right tank vent thinking that it may be the vortex from the
>> prop
>> that is allowing the right tank to feed. Or rather stopping the left tank
>> to
>> feed.
>> I have changed the angle of the vent pipe facing the airflow to try and
>> perhaps get more air into the vent to assist the left tank to feed more.
>> This has only marginally helped.
>>
>> I landed on Saturday with the left tank low fuel warning light coming on
>> on
>> finals.
>> The right tank had 65 - 70 litres fuel remaining and about 12 in the left
>> when dipped.
>>
>> We have removed and carefully checked the check valves. No problem there.
>>
>> Any suggestions would be greatly appreciated.
>>
>> Thanks and cheers,
>> Chris.
>>
>>
>> Chris Wise
>> GT Propellers Australia
>> __________________________________________________________
>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>
>> Email chris@gtpropellersaustralia.com.au
>> Website www.gtpropellersaustralia.com.au
>>
>> The information transmitted in and with this email is intended only for
>> the
>> person or entity to which it is addressed and may contain confidential
>> and/or privileged material. Any review, retransmission, dissemination or
>> other use of, or taking of any action in reliance upon this information,
>> by
>> persons or entities other than the intended recipients is prohibited. If
>> you
>> received this transmission in error, please contact the sender and delete
>> this e-mail and associated material from all computers and/or systems. The
>> intended recipient of this e-mail may only use, reproduce, disclose or
>> distribute the information contained in this e-mail and any attached
>> files,
>> with the permission of the sender.
>>
>>
>> ==========
>> get=_blank>http://www.matronics.com/Navigator?Yak-List
>> ==========
>> tp://forums.matronics.com
>> ==========
>> _blank>http://www.matronics.com/contribution
>> p; Navigator Photoshare, and
>> href="http://www.matronics.com/Navigator?Yak-List">http://www.matronics========================<;
>> via the Web href="http://forums.matronics.com">http://forums.matronics.com
> _p; generous bsp;
> href="http://www.matronics.com/contribution">http://www.matronics.com/c================
>
>
> http://www.matronics.com/Navigator?Yak-List
>
> http://forums.matronics.com
>
> http://www.matronics.com/contribution
>
>
Message 10
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Stephen,
Negative...it did have an effect...de valve opened.
Left tank empty...right full...bank 60/90 degrees left..it did the trick..
Hans
-----Oorspronkelijk bericht-----
Van: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] Namens Stephen Morrey
Verzonden: dinsdag 18 mei 2010 16:42
Aan: yak-list@matronics.com
Onderwerp: Re: Yak-List: feul feed
Again I am a little confused on this, it seems if the 360 turn was
coordinated then the turn should have had no effect. Do I understand this
correctly?
On Tue, May 18, 2010 at 7:49 AM, Hans Oortman <pa3arw@euronet.nl> wrote:
> Dennis,
>
>
> It can be very scary though.When I ferried my Yak from Estonia via
> Lithuania back to Holland I found it to be very scary.
>
> I flew from Palanga (Lithuania) to Gdansk(Poland) over the middle of
> the Baltic Sea outside the airspace of Bullarus when the left tank
> showed only
> 12 liters and the right hand tank was still at 60 liters. I made a 90
> degree bank turn to the left and a full 360 back to the original
> courseafter a while I saw the right hand tank indicator flip to 50
> ......man I was glad to see that happening..problem solved.scary
though.
>
>
> Hans
>
> RA3326K
>
> ________________________________
>
> Van: owner-yak-list-server@matronics.com
> [mailto:owner-yak-list-server@matronics.com] Namens A. Dennis Savarese
> Verzonden: dinsdag 18 mei 2010 13:24
> Aan: yak-list@matronics.com
> Onderwerp: Re: Yak-List: feul feed
>
>
> Steve,
>
> In the Yak 52, the purpose of stepping on the low side tank is two
> fold: in case one of the flapper valves in the fuel junction under the
> front seatis stuck closed, forcing the weight of the fuel against the
> flapper valve may free the flapper valve thus permitting fuel to flow;
> secondly and more likely, there is fuel in the vent line of the tank
> that is not feeding and by stepping on the low side you are trying to
> force the fuel out of the vent line.
>
>
> Assuming the airplane is trimmed properly as Pappy says, which
> definitely causes fuel imbalance, a vent line with fuel in it will
> definitely affect the fuel feed. I didn't realize I was probably
> forcing the fuel into the vent lines on the Yak 52 by filling the tanks
all the way up to the lip.
> Because of the sitting angle of attack, the vent line at the top,
> rear, inside corner of the tank can get fuel in it by filling the tank
> to the lip. This is particularly true on the right tank because the
> vent line sits lower in the fuselage than the left tank. Remember,
> the left vent line enters the fuselage and turns down and connects at
> the top ofthe vent junction. The right tank vent line is attached to
> the left side of the vent junction which ends up being lower than the
> left tank vent line. So when fuel enters the right vent line by
> filling to the lip of the filler neck, it may force the fuel into the
> vent line and into the vent junction, blocking air back to the tank
through the vent line.
>
>
> Also when the fuel heats up in the tank it expands and guess where it
> expands to? Right into the vent line. Have you ever seen a Yak 52
"puking"
> fuel overboard on the ramp during hot weather? The reason is the fuel
> has expanded in the tank and is forced out of the vent line through
> the vent junction and out through the overboard vent line exitingout
> the belly of the airplane. Once the siphon has been set up by the
> expansion, the siphoning effect can siphon out 5+ gallons. No
> kidding.....it happened to me. I filled the airplane and left it on the
ramp in the sun for 2 days.
> When I came back the fuel instrument no longer read 60/60. I refilled
> the tanks and it took over 5 gallons of fuel to bring the tanks back to
60/60.
> The telltale sign was the dark, black spot in the blacktop under the
> fuselage directly under the vent line.
>
>
> Dennis
>
> ----- Original Message -----
>
> From: Stephen Morrey
>
> To: yak-list@matronics.com
>
> Sent: Monday, May 17, 2010 9:48 PM
>
> Subject: Re: Yak-List: feul feed
>
>
> --> <stephenmorrey@gmail.com>
>
> So just to be sure, am I correct in saying an in flight remidy is to
> step on the side showing the lowest fuel level. If this is the case
> is it best to simply step on the low side or is it needed to step and
> "hold" for an extended period of time on the low side ? Do I have
> this backwards? steve "old school"
>
> On Mon, May 17, 2010 at 12:19 PM, <cjpilot710@aol.com> wrote:
>> Guys,
>>
>> The problem has always been aircraft yaw. The T-34 which has the same
>> fuel setup (on one model anyway) has had the same problem. If you do
>> not apply enough rudder on climb out, engine seem to pull out of the left
tank more.
>> I have separate tank vent lines that go to the wing tips. I was told
>> that this would cure the uneven flow, when I put in the long range
>> tanks. It didn't. Yaw is the most likely cause of fuel imbalance.
>>
>> Jim "Pappy" Goolsby
>>
>> -----Original Message-----
>> From: Chris Wise <wise@txc.net.au>
>> To: yak-list@matronics.com
>> Sent: Mon, May 17, 2010 2:18 am
>> Subject: Re: Yak-List: feul feed
>>
>> G'Day Walt,
>>
>> We carry a piece of plastic tubing that fits over the vent pipes and
>> we use this to check the vents by blowing into the pipe.
>> Every now and then we blow compressed air thru the vent.
>> At no time have we ever found a blocked air vent.
>> My mate also fitted new fuel cap seals. Did not solve the problem.
>>
>> The check valves are a simple flapper valve that prevents any X flow
>> and I cannot see how they can be a problem.
>> I am not familiar with the check valves on a CJ6
>>
>> Thanks and cheers,
>> Chris.
>>
>>
>>
>> Chris Wise
>> GT Propellers Australia
>> __________________________________________________________
>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>
>> Email chris@gtpropellersaustralia.com.au
>> Website www.gtpropellersaustralia.com.au
>>
>> The information transmitted in and with this email is intended only
>> for the person or entity to which it is addressed and may contain
>> confidential and/or privileged material. Any review, retransmission,
>> dissemination or other use of, or taking of any action in reliance
>> upon this information, by persons or entities other than the intended
>> recipients is prohibited. If you received this transmission in error,
>> please contact the sender and delete this e-mail and associated
>> material from all computers and/or systems. The intended recipient of
>> this e-mail may only use, reproduce, disclose or distribute the
>> information contained in this e-mail and any attached files, with the
>> permission of the sender.
>>
>> ----- Original Message -----
>> From: Walter Lannon
>> To: yak-list@matronics.com
>> Sent: Monday, May 17, 2010 2:05 PM
>> Subject: Re: Yak-List: feul feed
>> Hi Chris;
>>
>> The Nanchang exhibits the same fuel feed problem. Typically the RH
>> tank is late and I know of at least one forced landing with a full RH
>> and empty LH.
>> Believe this was in South Africa about 6 or 7 years ago.
>>
>> The CJ6 has a single point vent system which I don't believe is the
>> problem. However the effective length of the vent line and the fuel
>> feed line are both longer for the RH tank. Theoretically that could
>> induce a lag in the RH feed time but I don't belive it is
>> signifigant. Any blockage of the vent by insect nests etc. will
>> definitaly cause a big problem.
>>
>> Other than the bugs that leaves the feed tank check valves as the
>> only remaining source. SPEAKING FOR THE CJ6 ONLY (since I have no
>> knowledge of the check valves in any of the Yak models) I believe I
>> have solved that problem with a modification to the check valve
>> which, IMHO, was very poorly designed.
>>
>> If you have the opportunity to take photos of one of your check
>> valves and email to me I will try to determine if the mod is applicable.
>>
>> Walt
>>
>>
>> ----- Original Message -----
>> From: Chris Wise
>> To: yak-list@matronics.com
>> Sent: Sunday, May 16, 2010 7:18 PM
>> Subject: Yak-List: feul feed
>> G'Day All,
>>
>> I and a friend each run a Yak18T.
>> We suffer the same problem with both aircraft, re even fuel feed.
>> Flying in turbulence seems to help the problem, but still air is bad
news.
>>
>> The left tank will feed untill almost empty leaving plenty of fuel in
>> the right tank and on my mates 18, the low fuel warning light on the
>> left tank lit up and was fortunate enough to be close to a small
>> country strip where he landed in a hurry.
>>
>> He has teed both vents into one. This has not helped.
>>
>> I moved the left tank vent and re located the vent to about 3/4 of a
>> inch next to the right tank vent thinking that it may be the vortex
>> from the prop that is allowing the right tank to feed. Or rather
>> stopping the left tank to feed.
>> I have changed the angle of the vent pipe facing the airflow to try
>> and perhaps get more air into the vent to assist the left tank to feed
more.
>> This has only marginally helped.
>>
>> I landed on Saturday with the left tank low fuel warning light coming
>> on on finals.
>> The right tank had 65 - 70 litres fuel remaining and about 12 in the
>> left when dipped.
>>
>> We have removed and carefully checked the check valves. No problem there.
>>
>> Any suggestions would be greatly appreciated.
>>
>> Thanks and cheers,
>> Chris.
>>
>>
>> Chris Wise
>> GT Propellers Australia
>> __________________________________________________________
>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>
>> Email chris@gtpropellersaustralia.com.au
>> Website www.gtpropellersaustralia.com.au
>>
>> The information transmitted in and with this email is intended only
>> for the person or entity to which it is addressed and may contain
>> confidential and/or privileged material. Any review, retransmission,
>> dissemination or other use of, or taking of any action in reliance
>> upon this information, by persons or entities other than the intended
>> recipients is prohibited. If you received this transmission in error,
>> please contact the sender and delete this e-mail and associated
>> material from all computers and/or systems. The intended recipient of
>> this e-mail may only use, reproduce, disclose or distribute the
>> information contained in this e-mail and any attached files, with the
>> permission of the sender.
>>
>>
>> ==========
>> get=_blank>http://www.matronics.com/Navigator?Yak-List
>> ==========
>> tp://forums.matronics.com
>> ==========
>> _blank>http://www.matronics.com/contribution
>> p; Navigator Photoshare, and
>> href="http://www.matronics.com/Navigator?Yak-List">http://www.matroni
>> cs========================<; via the Web
>> href="http://forums.matronics.com">http://forums.matronics.com
> _p; generous bsp;
> href="http://www.matronics.com/contribution">http://www.matronics.com/
> c================
>
>
> http://www.matronics.com/Navigator?Yak-List
>
> http://forums.matronics.com
>
> http://www.matronics.com/contribution
>
>
Message 11
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If there was zero turbulence and the turn was perfectly co-coordinated
throughout it may not work.
But in the real world it probably will.
If necessary I use a very brief "knife edge" - definitely not
co-coordinated.
I have a problem with the fuel in vent lines being the cause of unequal
feed. If the lines are properly routed in relation to the max. fuel level
in the tanks and are not blocked by some other material the fuel in the
line will flow to wherever the pressure is lower. If the engine is using
fuel that flow will be back to the tank.
The comments I have heard so far lead me to believe the Yak series fuel feed
tank check valves are exactly the same as the Nanchang and are therefore the
primary reason for unequal fuel flow.
The file and/or hacksaw cuts in the flapper used by the PLAAF and others do
not address the problem.
They simply destroy the intended function of the valve
Have at it guys!
Walt
----- Original Message -----
From: "Stephen Morrey" <stephenmorrey@gmail.com>
Sent: Tuesday, May 18, 2010 7:41 AM
Subject: Re: Yak-List: feul feed
>
> Again I am a little confused on this, it seems if the 360 turn was
> coordinated then the turn should have had no effect. Do I understand
> this correctly?
>
> On Tue, May 18, 2010 at 7:49 AM, Hans Oortman <pa3arw@euronet.nl> wrote:
>> Dennis,
>>
>>
>>
>> It can be very scary though.When I ferried my Yak from Estonia via
>> Lithuania back to Holland I found it to be very scary.
>>
>> I flew from Palanga (Lithuania) to Gdansk(Poland) over the middle of the
>> Baltic Sea outside the airspace of Bullarus when the left tank showed
>> only
>> 12 liters and the right hand tank was still at 60 liters. I made a 90
>> degree
>> bank turn to the left and a full 360 back to the original courseafter a
>> while I saw the right hand tank indicator flip to 50 ......man I was glad
>> to
>> see that happening..problem solved.scary though.
>>
>>
>>
>> Hans
>>
>> RA3326K
>>
>> ________________________________
>>
>> Van: owner-yak-list-server@matronics.com
>> [mailto:owner-yak-list-server@matronics.com] Namens A. Dennis Savarese
>> Verzonden: dinsdag 18 mei 2010 13:24
>> Aan: yak-list@matronics.com
>> Onderwerp: Re: Yak-List: feul feed
>>
>>
>>
>> Steve,
>>
>> In the Yak 52, the purpose of stepping on the low side tank is two fold:
>> in
>> case one of the flapper valves in the fuel junction under the front seat
>> is
>> stuck closed, forcing the weight of the fuel against the flapper valve
>> may
>> free the flapper valve thus permitting fuel to flow; secondly and more
>> likely, there is fuel in the vent line of the tank that is not feeding
>> and
>> by stepping on the low side you are trying to force the fuel out of the
>> vent
>> line.
>>
>>
>>
>> Assuming the airplane is trimmed properly as Pappy says, which definitely
>> causes fuel imbalance, a vent line with fuel in it will definitely affect
>> the fuel feed. I didn't realize I was probably forcing the fuel into the
>> vent lines on the Yak 52 by filling the tanks all the way up to the lip.
>> Because of the sitting angle of attack, the vent line at the top, rear,
>> inside corner of the tank can get fuel in it by filling the tank to the
>> lip. This is particularly true on the right tank because the vent line
>> sits
>> lower in the fuselage than the left tank. Remember, the left vent line
>> enters the fuselage and turns down and connects at the top of the vent
>> junction. The right tank vent line is attached to the left side of the
>> vent
>> junction which ends up being lower than the left tank vent line. So when
>> fuel enters the right vent line by filling to the lip of the filler neck,
>> it
>> may force the fuel into the vent line and into the vent junction,
>> blocking
>> air back to the tank through the vent line.
>>
>>
>>
>> Also when the fuel heats up in the tank it expands and guess where it
>> expands to? Right into the vent line. Have you ever seen a Yak 52
>> "puking"
>> fuel overboard on the ramp during hot weather? The reason is the fuel has
>> expanded in the tank and is forced out of the vent line through the vent
>> junction and out through the overboard vent line exiting out the belly of
>> the airplane. Once the siphon has been set up by the expansion, the
>> siphoning effect can siphon out 5+ gallons. No kidding.....it happened to
>> me. I filled the airplane and left it on the ramp in the sun for 2 days.
>> When I came back the fuel instrument no longer read 60/60. I refilled the
>> tanks and it took over 5 gallons of fuel to bring the tanks back to
>> 60/60.
>> The telltale sign was the dark, black spot in the blacktop under the
>> fuselage directly under the vent line.
>>
>>
>>
>> Dennis
>>
>> ----- Original Message -----
>>
>> From: Stephen Morrey
>>
>> To: yak-list@matronics.com
>>
>> Sent: Monday, May 17, 2010 9:48 PM
>>
>> Subject: Re: Yak-List: feul feed
>>
>>
>>
>>
>> So just to be sure, am I correct in saying an in flight remidy is to
>> step on the side showing the lowest fuel level. If this is the case
>> is it best to simply step on the low side or is it needed to step and
>> "hold" for an extended period of time on the low side ? Do I have
>> this backwards? steve "old school"
>>
>> On Mon, May 17, 2010 at 12:19 PM, <cjpilot710@aol.com> wrote:
>>> Guys,
>>>
>>> The problem has always been aircraft yaw. The T-34 which has the same
>>> fuel
>>> setup (on one model anyway) has had the same problem. If you do not
>>> apply
>>> enough rudder on climb out, engine seem to pull out of the left tank
>>> more.
>>> I have separate tank vent lines that go to the wing tips. I was told
>>> that
>>> this would cure the uneven flow, when I put in the long range tanks. It
>>> didn't. Yaw is the most likely cause of fuel imbalance.
>>>
>>> Jim "Pappy" Goolsby
>>>
>>> -----Original Message-----
>>> From: Chris Wise <wise@txc.net.au>
>>> To: yak-list@matronics.com
>>> Sent: Mon, May 17, 2010 2:18 am
>>> Subject: Re: Yak-List: feul feed
>>>
>>> G'Day Walt,
>>>
>>> We carry a piece of plastic tubing that fits over the vent pipes and we
>>> use
>>> this to check the vents by blowing into the pipe.
>>> Every now and then we blow compressed air thru the vent.
>>> At no time have we ever found a blocked air vent.
>>> My mate also fitted new fuel cap seals. Did not solve the problem.
>>>
>>> The check valves are a simple flapper valve that prevents any X flow and
>>> I
>>> cannot see how they can be a problem.
>>> I am not familiar with the check valves on a CJ6
>>>
>>> Thanks and cheers,
>>> Chris.
>>>
>>>
>>>
>>> Chris Wise
>>> GT Propellers Australia
>>> __________________________________________________________
>>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>>
>>> Email chris@gtpropellersaustralia.com.au
>>> Website www.gtpropellersaustralia.com.au
>>>
>>> The information transmitted in and with this email is intended only for
>>> the
>>> person or entity to which it is addressed and may contain confidential
>>> and/or privileged material. Any review, retransmission, dissemination or
>>> other use of, or taking of any action in reliance upon this information,
>>> by
>>> persons or entities other than the intended recipients is prohibited. If
>>> you
>>> received this transmission in error, please contact the sender and
>>> delete
>>> this e-mail and associated material from all computers and/or systems.
>>> The
>>> intended recipient of this e-mail may only use, reproduce, disclose or
>>> distribute the information contained in this e-mail and any attached
>>> files,
>>> with the permission of the sender.
>>>
>>> ----- Original Message -----
>>> From: Walter Lannon
>>> To: yak-list@matronics.com
>>> Sent: Monday, May 17, 2010 2:05 PM
>>> Subject: Re: Yak-List: feul feed
>>> Hi Chris;
>>>
>>> The Nanchang exhibits the same fuel feed problem. Typically the RH tank
>>> is
>>> late and I know of at least one forced landing with a full RH and empty
>>> LH.
>>> Believe this was in South Africa about 6 or 7 years ago.
>>>
>>> The CJ6 has a single point vent system which I don't believe is the
>>> problem. However the effective length of the vent line and the fuel feed
>>> line are both longer for the RH tank. Theoretically that could induce a
>>> lag
>>> in the RH feed time but I don't belive it is signifigant. Any blockage
>>> of
>>> the vent by insect nests etc. will definitaly cause a big problem.
>>>
>>> Other than the bugs that leaves the feed tank check valves as the only
>>> remaining source. SPEAKING FOR THE CJ6 ONLY (since I have no knowledge
>>> of
>>> the check valves in any of the Yak models) I believe I have solved that
>>> problem with a modification to the check valve which, IMHO, was very
>>> poorly
>>> designed.
>>>
>>> If you have the opportunity to take photos of one of your check valves
>>> and
>>> email to me I will try to determine if the mod is applicable.
>>>
>>> Walt
>>>
>>>
>>> ----- Original Message -----
>>> From: Chris Wise
>>> To: yak-list@matronics.com
>>> Sent: Sunday, May 16, 2010 7:18 PM
>>> Subject: Yak-List: feul feed
>>> G'Day All,
>>>
>>> I and a friend each run a Yak18T.
>>> We suffer the same problem with both aircraft, re even fuel feed.
>>> Flying in turbulence seems to help the problem, but still air is bad
>>> news.
>>>
>>> The left tank will feed untill almost empty leaving plenty of fuel in
>>> the
>>> right tank and on my mates 18, the low fuel warning light on the left
>>> tank
>>> lit up and was fortunate enough to be close to a small country strip
>>> where
>>> he landed in a hurry.
>>>
>>> He has teed both vents into one. This has not helped.
>>>
>>> I moved the left tank vent and re located the vent to about 3/4 of a
>>> inch
>>> next to the right tank vent thinking that it may be the vortex from the
>>> prop
>>> that is allowing the right tank to feed. Or rather stopping the left
>>> tank
>>> to
>>> feed.
>>> I have changed the angle of the vent pipe facing the airflow to try and
>>> perhaps get more air into the vent to assist the left tank to feed more.
>>> This has only marginally helped.
>>>
>>> I landed on Saturday with the left tank low fuel warning light coming on
>>> on
>>> finals.
>>> The right tank had 65 - 70 litres fuel remaining and about 12 in the
>>> left
>>> when dipped.
>>>
>>> We have removed and carefully checked the check valves. No problem
>>> there.
>>>
>>> Any suggestions would be greatly appreciated.
>>>
>>> Thanks and cheers,
>>> Chris.
>>>
>>>
>>> Chris Wise
>>> GT Propellers Australia
>>> __________________________________________________________
>>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>>
>>> Email chris@gtpropellersaustralia.com.au
>>> Website www.gtpropellersaustralia.com.au
>>>
>>> The information transmitted in and with this email is intended only for
>>> the
>>> person or entity to which it is addressed and may contain confidential
>>> and/or privileged material. Any review, retransmission, dissemination or
>>> other use of, or taking of any action in reliance upon this information,
>>> by
>>> persons or entities other than the intended recipients is prohibited. If
>>> you
>>> received this transmission in error, please contact the sender and
>>> delete
>>> this e-mail and associated material from all computers and/or systems.
>>> The
>>> intended recipient of this e-mail may only use, reproduce, disclose or
>>> distribute the information contained in this e-mail and any attached
>>> files,
>>> with the permission of the sender.
>>>
>>>
>>> ==========
>>> get=_blank>http://www.matronics.com/Navigator?Yak-List
>>> ==========
>>> tp://forums.matronics.com
>>> ==========
>>> _blank>http://www.matronics.com/contribution
>>> p; Navigator Photoshare, and
>>> href="http://www.matronics.com/Navigator?Yak-List">http://www.matronics========================<;
>>> via the Web
>>> href="http://forums.matronics.com">http://forums.matronics.com
>> _p; generous bsp;
>> href="http://www.matronics.com/contribution">http://www.matronics.com/c================
>>
>>
>>
>>
>>
>> http://www.matronics.com/Navigator?Yak-List
>>
>> http://forums.matronics.com
>>
>> http://www.matronics.com/contribution
>>
>>
>>
>>
>
>
>
Message 12
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Walt,
Although it seems questionable regarding the vent system as the cause of
fuel not feeding from one tank or the other, particularly in the 52, the
Yakovlev design bureau redesigned the vent system in the 89 and up model
years. Two things happen on a pre 1989 Yak 52's which most Yak 52
owners have experienced. When the fuel tanks are close to full and the
temperature builds causing the fuel to expand in the tank, if one were
to remove the fuel caps, you will hear a rather large "whoosh" and the
fuel will spill out of the filler neck all over the wing. This is
caused by pressure building in the tank. The only way the expanded fuel
can exit is via the vent line with the tank cap in place. The second
reason the vent system was redesigned was because of the expansion and
contraction of the very thin aluminum metal of the fuel tanks. This
expansion and contraction of the metal (ie: flexing) created cracks in
many of the fuel tanks as evident of the weld marks on the bottom of the
tanks seen in most pre 1989 Yak 52's.
The post 1989 vent system was far superior to the pre 1989 system. The
fuel tanks had two vent lines; one at the top, rear on the inside (the
same as pre 1989) and one on the top of the tank near the outboard edge.
This second vent line eliminated the expansion of the fuel and the
puking of the fuel overboard because the tank could "breath". There
are 2 separate vent systems on the post 1989 airplanes. One system for
each tank. And here's the most important fact,......no more fuel
feeding imbalance. The tanks are the same size. The flapper valves
are identical. The only thing that changed was the vent system.
Dennis
----- Original Message -----
From: Walter Lannon
To: yak-list@matronics.com
Sent: Tuesday, May 18, 2010 10:59 AM
Subject: Re: Yak-List: feul feed
If there was zero turbulence and the turn was perfectly co-coordinated
throughout it may not work.
But in the real world it probably will.
If necessary I use a very brief "knife edge" - definitely not
co-coordinated.
I have a problem with the fuel in vent lines being the cause of
unequal
feed. If the lines are properly routed in relation to the max. fuel
level
in the tanks and are not blocked by some other material the fuel in
the
line will flow to wherever the pressure is lower. If the engine is
using
fuel that flow will be back to the tank.
The comments I have heard so far lead me to believe the Yak series
fuel feed
tank check valves are exactly the same as the Nanchang and are
therefore the
primary reason for unequal fuel flow.
The file and/or hacksaw cuts in the flapper used by the PLAAF and
others do
not address the problem.
They simply destroy the intended function of the valve
Have at it guys!
Walt
----- Original Message -----
From: "Stephen Morrey" <stephenmorrey@gmail.com>
To: <yak-list@matronics.com>
Sent: Tuesday, May 18, 2010 7:41 AM
Subject: Re: Yak-List: feul feed
<stephenmorrey@gmail.com>
>
> Again I am a little confused on this, it seems if the 360 turn was
> coordinated then the turn should have had no effect. Do I
understand
> this correctly?
>
> On Tue, May 18, 2010 at 7:49 AM, Hans Oortman <pa3arw@euronet.nl>
wrote:
>> Dennis,
>>
>>
>>
>> It can be very scary though=85.When I ferried my Yak from Estonia
via
>> Lithuania back to Holland I found it to be very scary.
>>
>> I flew from Palanga (Lithuania) to Gdansk(Poland) over the middle
of the
>> Baltic Sea outside the airspace of Bullarus when the left tank
showed
>> only
>> 12 liters and the right hand tank was still at 60 liters. I made a
90
>> degree
>> bank turn to the left and a full 360 back to the original
course=85after a
>> while I saw the right hand tank indicator flip to 50 ......man I
was glad
>> to
>> see that happening=85..problem solved=85.scary though=85.
>>
>>
>>
>> Hans
>>
>> RA3326K
>>
>> ________________________________
>>
>> Van: owner-yak-list-server@matronics.com
>> [mailto:owner-yak-list-server@matronics.com] Namens A. Dennis
Savarese
>> Verzonden: dinsdag 18 mei 2010 13:24
>> Aan: yak-list@matronics.com
>> Onderwerp: Re: Yak-List: feul feed
>>
>>
>>
>> Steve,
>>
>> In the Yak 52, the purpose of stepping on the low side tank is two
fold:
>> in
>> case one of the flapper valves in the fuel junction under the front
seat
>> is
>> stuck closed, forcing the weight of the fuel against the flapper
valve
>> may
>> free the flapper valve thus permitting fuel to flow; secondly and
more
>> likely, there is fuel in the vent line of the tank that is not
feeding
>> and
>> by stepping on the low side you are trying to force the fuel out of
the
>> vent
>> line.
>>
>>
>>
>> Assuming the airplane is trimmed properly as Pappy says, which
definitely
>> causes fuel imbalance, a vent line with fuel in it will definitely
affect
>> the fuel feed. I didn't realize I was probably forcing the fuel
into the
>> vent lines on the Yak 52 by filling the tanks all the way up to the
lip.
>> Because of the sitting angle of attack, the vent line at the top,
rear,
>> inside corner of the tank can get fuel in it by filling the tank to
the
>> lip. This is particularly true on the right tank because the vent
line
>> sits
>> lower in the fuselage than the left tank. Remember, the left vent
line
>> enters the fuselage and turns down and connects at the top of the
vent
>> junction. The right tank vent line is attached to the left side of
the
>> vent
>> junction which ends up being lower than the left tank vent line. So
when
>> fuel enters the right vent line by filling to the lip of the filler
neck,
>> it
>> may force the fuel into the vent line and into the vent junction,
>> blocking
>> air back to the tank through the vent line.
>>
>>
>>
>> Also when the fuel heats up in the tank it expands and guess where
it
>> expands to? Right into the vent line. Have you ever seen a Yak 52
>> "puking"
>> fuel overboard on the ramp during hot weather? The reason is the
fuel has
>> expanded in the tank and is forced out of the vent line through the
vent
>> junction and out through the overboard vent line exiting out the
belly of
>> the airplane. Once the siphon has been set up by the expansion, the
>> siphoning effect can siphon out 5+ gallons. No kidding.....it
happened to
>> me. I filled the airplane and left it on the ramp in the sun for 2
days.
>> When I came back the fuel instrument no longer read 60/60. I
refilled the
>> tanks and it took over 5 gallons of fuel to bring the tanks back to
>> 60/60.
>> The telltale sign was the dark, black spot in the blacktop under
the
>> fuselage directly under the vent line.
>>
>>
>>
>> Dennis
>>
>> ----- Original Message -----
>>
>> From: Stephen Morrey
>>
>> To: yak-list@matronics.com
>>
>> Sent: Monday, May 17, 2010 9:48 PM
>>
>> Subject: Re: Yak-List: feul feed
>>
>>
>>
<stephenmorrey@gmail.com>
>>
>> So just to be sure, am I correct in saying an in flight remidy is
to
>> step on the side showing the lowest fuel level. If this is the case
>> is it best to simply step on the low side or is it needed to step
and
>> "hold" for an extended period of time on the low side ? Do I have
>> this backwards? steve "old school"
>>
>> On Mon, May 17, 2010 at 12:19 PM, <cjpilot710@aol.com> wrote:
>>> Guys,
>>>
>>> The problem has always been aircraft yaw. The T-34 which has the
same
>>> fuel
>>> setup (on one model anyway) has had the same problem. If you do
not
>>> apply
>>> enough rudder on climb out, engine seem to pull out of the left
tank
>>> more.
>>> I have separate tank vent lines that go to the wing tips. I was
told
>>> that
>>> this would cure the uneven flow, when I put in the long range
tanks. It
>>> didn't. Yaw is the most likely cause of fuel imbalance.
>>>
>>> Jim "Pappy" Goolsby
>>>
>>> -----Original Message-----
>>> From: Chris Wise <wise@txc.net.au>
>>> To: yak-list@matronics.com
>>> Sent: Mon, May 17, 2010 2:18 am
>>> Subject: Re: Yak-List: feul feed
>>>
>>> G'Day Walt,
>>>
>>> We carry a piece of plastic tubing that fits over the vent pipes
and we
>>> use
>>> this to check the vents by blowing into the pipe.
>>> Every now and then we blow compressed air thru the vent.
>>> At no time have we ever found a blocked air vent.
>>> My mate also fitted new fuel cap seals. Did not solve the problem.
>>>
>>> The check valves are a simple flapper valve that prevents any X
flow and
>>> I
>>> cannot see how they can be a problem.
>>> I am not familiar with the check valves on a CJ6
>>>
>>> Thanks and cheers,
>>> Chris.
>>>
>>>
>>>
>>> Chris Wise
>>> GT Propellers Australia
>>> __________________________________________________________
>>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>>
>>> Email chris@gtpropellersaustralia.com.au
>>> Website www.gtpropellersaustralia.com.au
>>>
>>> The information transmitted in and with this email is intended
only for
>>> the
>>> person or entity to which it is addressed and may contain
confidential
>>> and/or privileged material. Any review, retransmission,
dissemination or
>>> other use of, or taking of any action in reliance upon this
information,
>>> by
>>> persons or entities other than the intended recipients is
prohibited. If
>>> you
>>> received this transmission in error, please contact the sender and
>>> delete
>>> this e-mail and associated material from all computers and/or
systems.
>>> The
>>> intended recipient of this e-mail may only use, reproduce,
disclose or
>>> distribute the information contained in this e-mail and any
attached
>>> files,
>>> with the permission of the sender.
>>>
>>> ----- Original Message -----
>>> From: Walter Lannon
>>> To: yak-list@matronics.com
>>> Sent: Monday, May 17, 2010 2:05 PM
>>> Subject: Re: Yak-List: feul feed
>>> Hi Chris;
>>>
>>> The Nanchang exhibits the same fuel feed problem. Typically the RH
tank
>>> is
>>> late and I know of at least one forced landing with a full RH and
empty
>>> LH.
>>> Believe this was in South Africa about 6 or 7 years ago.
>>>
>>> The CJ6 has a single point vent system which I don't believe is
the
>>> problem. However the effective length of the vent line and the
fuel feed
>>> line are both longer for the RH tank. Theoretically that could
induce a
>>> lag
>>> in the RH feed time but I don't belive it is signifigant. Any
blockage
>>> of
>>> the vent by insect nests etc. will definitaly cause a big problem.
>>>
>>> Other than the bugs that leaves the feed tank check valves as the
only
>>> remaining source. SPEAKING FOR THE CJ6 ONLY (since I have no
knowledge
>>> of
>>> the check valves in any of the Yak models) I believe I have solved
that
>>> problem with a modification to the check valve which, IMHO, was
very
>>> poorly
>>> designed.
>>>
>>> If you have the opportunity to take photos of one of your check
valves
>>> and
>>> email to me I will try to determine if the mod is applicable.
>>>
>>> Walt
>>>
>>>
>>> ----- Original Message -----
>>> From: Chris Wise
>>> To: yak-list@matronics.com
>>> Sent: Sunday, May 16, 2010 7:18 PM
>>> Subject: Yak-List: feul feed
>>> G'Day All,
>>>
>>> I and a friend each run a Yak18T.
>>> We suffer the same problem with both aircraft, re even fuel feed.
>>> Flying in turbulence seems to help the problem, but still air is
bad
>>> news.
>>>
>>> The left tank will feed untill almost empty leaving plenty of fuel
in
>>> the
>>> right tank and on my mates 18, the low fuel warning light on the
left
>>> tank
>>> lit up and was fortunate enough to be close to a small country
strip
>>> where
>>> he landed in a hurry.
>>>
>>> He has teed both vents into one. This has not helped.
>>>
>>> I moved the left tank vent and re located the vent to about 3/4 of
a
>>> inch
>>> next to the right tank vent thinking that it may be the vortex
from the
>>> prop
>>> that is allowing the right tank to feed. Or rather stopping the
left
>>> tank
>>> to
>>> feed.
>>> I have changed the angle of the vent pipe facing the airflow to
try and
>>> perhaps get more air into the vent to assist the left tank to feed
more.
>>> This has only marginally helped.
>>>
>>> I landed on Saturday with the left tank low fuel warning light
coming on
>>> on
>>> finals.
>>> The right tank had 65 - 70 litres fuel remaining and about 12 in
the
>>> left
>>> when dipped.
>>>
>>> We have removed and carefully checked the check valves. No problem
>>> there.
>>>
>>> Any suggestions would be greatly appreciated.
>>>
>>> Thanks and cheers,
>>> Chris.
>>>
>>>
>>> Chris Wise
>>> GT Propellers Australia
>>> __________________________________________________________
>>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>>
>>> Email chris@gtpropellersaustralia.com.au
>>> Website www.gtpropellersaustralia.com.au
>>>
>>> The information transmitted in and with this email is intended
only for
>>> the
>>> person or entity to which it is addressed and may contain
confidential
>>> and/or privileged material. Any review, retransmission,
dissemination or
>>> other use of, or taking of any action in reliance upon this
information,
>>> by
>>> persons or entities other than the intended recipients is
prohibited. If
>>> you
>>> received this transmission in error, please contact the sender and
>>> delete
>>> this e-mail and associated material from all computers and/or
systems.
>>> The
>>> intended recipient of this e-mail may only use, reproduce,
disclose or
>>> distribute the information contained in this e-mail and any
attached
>>> files,
>>> with the permission of the sender.
>>>
>>>
>>> ==========
>>> get=_blank>http://www.matronics.com/Navigator?Yak-List
>>> ==========
>>> tp://forums.matronics.com
>>> ==========
>>> _blank>http://www.matronics.com/contribution
>>> p; Navigator Photoshare, and
>>>
href="http://www.matronics.com/Navigator?Yak-List">http://www.matronics
========================<
;
>>> via the Web
>>> href="http://forums.matronics.com">http://forums.matronics.com
>> _p; generous bsp;
>>
href="http://www.matronics.com/contribution">http://www.matronics.com/c
================
>>
>>
>>
>>
>>
>> http://www.matronics.com/Navigator?Yak-List
>>
>> http://forums.matronics.com
>>
>> http://www.matronics.com/contribution
>>
>>
>>
>>
>
>
>
>
>
>
Message 13
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Think " G load" on the fuel to force the valve to open .
Terry
----- Original Message ----
From: Stephen Morrey <stephenmorrey@gmail.com>
Sent: Tue, May 18, 2010 10:41:39 AM
Subject: Re: Yak-List: feul feed
Again I am a little confused on this, it seems if the 360 turn was
coordinated then the turn should have had no effect. Do I understand
this correctly?
On Tue, May 18, 2010 at 7:49 AM, Hans Oortman <pa3arw@euronet.nl> wrote:
> Dennis,
>
>
> It can be very scary though.When I ferried my Yak from Estonia via
> Lithuania back to Holland I found it to be very scary.
>
> I flew from Palanga (Lithuania) to Gdansk(Poland) over the middle of the
> Baltic Sea outside the airspace of Bullarus when the left tank showed only
> 12 liters and the right hand tank was still at 60 liters. I made a 90 degree
> bank turn to the left and a full 360 back to the original courseafter a
> while I saw the right hand tank indicator flip to 50 ......man I was glad to
> see that happening..problem solved.scary though.
>
>
> Hans
>
> RA3326K
>
> ________________________________
>
> Van: owner-yak-list-server@matronics.com
> [mailto:owner-yak-list-server@matronics.com] Namens A. Dennis Savarese
> Verzonden: dinsdag 18 mei 2010 13:24
> Aan: yak-list@matronics.com
> Onderwerp: Re: Yak-List: feul feed
>
>
> Steve,
>
> In the Yak 52, the purpose of stepping on the low side tank is two fold: in
> case one of the flapper valves in the fuel junction under the front seatis
> stuck closed, forcing the weight of the fuel against the flapper valve may
> free the flapper valve thus permitting fuel to flow; secondly and more
> likely, there is fuel in the vent line of the tank that is not feeding and
> by stepping on the low side you are trying to force the fuel out of the vent
> line.
>
>
> Assuming the airplane is trimmed properly as Pappy says, which definitely
> causes fuel imbalance, a vent line with fuel in it will definitely affect
> the fuel feed. I didn't realize I was probablyforcing the fuel into the
> vent lines on the Yak 52 by filling the tanks all the way up to the lip.
> Because of the sitting angle of attack, the vent line at the top, rear,
> inside corner of the tank can get fuel in it by filling the tank to the
> lip. This is particularly true on the right tank because the vent line sits
> lower in the fuselage than the left tank. Remember, the left vent line
> enters the fuselage and turns down and connects at the top ofthe vent
> junction. The right tank vent line is attached to the left side of the vent
> junction which ends up being lower than the left tank vent line. So when
> fuel enters the right vent line by filling to the lip of the filler neck, it
> may force the fuel into the vent line and into the vent junction, blocking
> air back to the tank through the vent line.
>
>
> Also when the fuel heats up in the tank it expands and guess where it
> expands to? Right into the vent line. Have you ever seen a Yak 52 "puking"
> fuel overboard on the ramp during hot weather? The reason is the fuel has
> expanded in the tank and is forced out of the vent line through the vent
> junction and out through the overboard vent line exitingout the belly of
> the airplane. Once the siphon has been set up by the expansion, the
> siphoning effect can siphon out 5+ gallons. No kidding.....it happened to
> me. I filled the airplane and left it on the ramp in the sun for 2 days.
> When I came back the fuel instrument no longer read 60/60. I refilled the
> tanks and it took over 5 gallons of fuel to bring the tanks back to 60/60.
> The telltale sign was the dark, black spot in the blacktop under the
> fuselage directly under the vent line.
>
>
> Dennis
>
> ----- Original Message -----
>
> From: Stephen Morrey
>
> To: yak-list@matronics.com
>
> Sent: Monday, May 17, 2010 9:48 PM
>
> Subject: Re: Yak-List: feul feed
>
>
>
> So just to be sure, am I correct in saying an in flight remidy is to
> step on the side showing the lowest fuel level. If this is the case
> is it best to simply step on the low side or is it needed to step and
> "hold" for an extended period of time on the low side ? Do I have
> this backwards? steve "old school"
>
> On Mon, May 17, 2010 at 12:19 PM, <cjpilot710@aol.com> wrote:
>> Guys,
>>
>> The problem has always been aircraft yaw. The T-34 which has the same fuel
>> setup (on one model anyway) has had the same problem. If you do not apply
>> enough rudder on climb out, engine seem to pull out of the left tank more.
>> I have separate tank vent lines that go to the wing tips. I was told that
>> this would cure the uneven flow, when I put in the long range tanks. It
>> didn't. Yaw is the most likely cause of fuel imbalance.
>>
>> Jim "Pappy" Goolsby
>>
>> -----Original Message-----
>> From: Chris Wise <wise@txc.net.au>
>> To: yak-list@matronics.com
>> Sent: Mon, May 17, 2010 2:18 am
>> Subject: Re: Yak-List: feul feed
>>
>> G'Day Walt,
>>
>> We carry a piece of plastic tubing that fits over the vent pipes and we
>> use
>> this to check the vents by blowing into the pipe.
>> Every now and then we blow compressed air thru the vent.
>> At no time have we ever found a blocked air vent.
>> My mate also fitted new fuel cap seals. Did not solve the problem.
>>
>> The check valves are a simple flapper valve that prevents any X flow and I
>> cannot see how they can be a problem.
>> I am not familiar with the check valves on a CJ6
>>
>> Thanks and cheers,
>> Chris.
>>
>>
>>
>> Chris Wise
>> GT Propellers Australia
>> __________________________________________________________
>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>
>> Email chris@gtpropellersaustralia.com.au
>> Website www.gtpropellersaustralia.com.au
>>
>> The information transmitted in and with this email is intended only for
>> the
>> person or entity to which it is addressed and may contain confidential
>> and/or privileged material. Any review, retransmission, dissemination or
>> other use of, or taking of any action in reliance upon this information,
>> by
>> persons or entities other than the intended recipients is prohibited. If
>> you
>> received this transmission in error, please contact the sender and delete
>> this e-mail and associated material from all computers and/or systems. The
>> intended recipient of this e-mail may only use, reproduce, disclose or
>> distribute the information contained in this e-mail and any attached
>> files,
>> with the permission of the sender.
>>
>> ----- Original Message -----
>> From: Walter Lannon
>> To: yak-list@matronics.com
>> Sent: Monday, May 17, 2010 2:05 PM
>> Subject: Re: Yak-List: feul feed
>> Hi Chris;
>>
>> The Nanchang exhibits the same fuel feed problem. Typically the RH tank is
>> late and I know of at least one forced landing with a full RH and empty
>> LH.
>> Believe this was in South Africa about 6 or 7 years ago.
>>
>> The CJ6 has a single point vent system which I don't believe is the
>> problem. However the effective length of the vent line and the fuel feed
>> line are both longer for the RH tank. Theoretically that could induce a
>> lag
>> in the RH feed time but I don't belive it is signifigant. Any blockage of
>> the vent by insect nests etc. will definitaly cause a big problem.
>>
>> Other than the bugs that leaves the feed tank check valves as the only
>> remaining source. SPEAKING FOR THE CJ6 ONLY (since I have no knowledge of
>> the check valves in any of the Yak models) I believe I have solved that
>> problem with a modification to the check valve which, IMHO, was very
>> poorly
>> designed.
>>
>> If you have the opportunity to take photos of one of your check valves and
>> email to me I will try to determine if the mod is applicable.
>>
>> Walt
>>
>>
>> ----- Original Message -----
>> From: Chris Wise
>> To: yak-list@matronics.com
>> Sent: Sunday, May 16, 2010 7:18 PM
>> Subject: Yak-List: feul feed
>> G'Day All,
>>
>> I and a friend each run a Yak18T.
>> We suffer the same problem with both aircraft, re even fuel feed.
>> Flying in turbulence seems to help the problem, but still air is bad news.
>>
>> The left tank will feed untill almost empty leaving plenty of fuel in the
>> right tank and on my mates 18, the low fuel warning light on the left tank
>> lit up and was fortunate enough to be close to a small country strip where
>> he landed in a hurry.
>>
>> He has teed both vents into one. This has not helped.
>>
>> I moved the left tank vent and re located the vent to about 3/4 of a inch
>> next to the right tank vent thinking that it may be the vortex from the
>> prop
>> that is allowing the right tank to feed. Or rather stopping the left tank
>> to
>> feed.
>> I have changed the angle of the vent pipe facing the airflow to try and
>> perhaps get more air into the vent to assist the left tank to feed more.
>> This has only marginally helped.
>>
>> I landed on Saturday with the left tank low fuel warning light coming on
>> on
>> finals.
>> The right tank had 65 - 70 litres fuel remaining and about 12 in the left
>> when dipped.
>>
>> We have removed and carefully checked the check valves. No problem there.
>>
>> Any suggestions would be greatly appreciated.
>>
>> Thanks and cheers,
>> Chris.
>>
>>
>> Chris Wise
>> GT Propellers Australia
>> __________________________________________________________
>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>
>> Email chris@gtpropellersaustralia.com.au
>> Website www.gtpropellersaustralia.com.au
>>
>> The information transmitted in and with this email is intended only for
>> the
>> person or entity to which it is addressed and may contain confidential
>> and/or privileged material. Any review, retransmission, dissemination or
>> other use of, or taking of any action in reliance upon this information,
>> by
>> persons or entities other than the intended recipients is prohibited. If
>> you
>> received this transmission in error, please contact the sender and delete
>> this e-mail and associated material from all computers and/or systems. The
>> intended recipient of this e-mail may only use, reproduce, disclose or
>> distribute the information contained in this e-mail and any attached
>> files,
>> with the permission of the sender.
>>
>>
>> ==========
>> get=_blank>http://www.matronics.com/Navigator?Yak-List
>> ==========
>> tp://forums.matronics.com
>> ==========
>> _blank>http://www.matronics.com/contribution
>> p; Navigator Photoshare, and
>> href="http://www.matronics.com/Navigator?Yak-List">http://www.matronics========================<;
>> via the Web href="http://forums.matronics.com">http://forums.matronics.com
> _p; generous bsp;
> href="http://www.matronics.com/contribution">http://www.matronics.com/c================
>
>
> http://www.matronics.com/Navigator?Yak-List
>
> http://forums.matronics.com
>
> http://www.matronics.com/contribution
>
>
Message 14
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| Subject: | Fuel Feed Yak18T |
Chris - I agree with comments about problem being yaw (or slip/skid).
Keep adjusting rudder trim tab after each flight until the ball is
centered without having to apply continually rudder pressure to achieve
the ball in the centre. Works for me with my YAK18t and now fuel
consumption in each tank is even. Make sure the ball is centered
though, in the hangar on even level ground with tyre pressures the same.
If not adjust it and then do the procedure above. Cheers, Phil.
Message 15
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A perfectly coordinated turn should produce the same "G" load on all the
fuel therefore no relative change to the force on each side of the valve.
Walt
----- Original Message -----
From: "T A LEWIS" <talew@bellsouth.net>
Sent: Tuesday, May 18, 2010 11:05 AM
Subject: Re: Yak-List: feul feed
>
> Think " G load" on the fuel to force the valve to open .
> Terry
>
>
> ----- Original Message ----
> From: Stephen Morrey <stephenmorrey@gmail.com>
> To: yak-list@matronics.com
> Sent: Tue, May 18, 2010 10:41:39 AM
> Subject: Re: Yak-List: feul feed
>
>
> Again I am a little confused on this, it seems if the 360 turn was
> coordinated then the turn should have had no effect. Do I understand
> this correctly?
>
> On Tue, May 18, 2010 at 7:49 AM, Hans Oortman <pa3arw@euronet.nl> wrote:
>> Dennis,
>>
>>
>>
>> It can be very scary though.When I ferried my Yak from Estonia via
>> Lithuania back to Holland I found it to be very scary.
>>
>> I flew from Palanga (Lithuania) to Gdansk(Poland) over the middle of the
>> Baltic Sea outside the airspace of Bullarus when the left tank showed
>> only
>> 12 liters and the right hand tank was still at 60 liters. I made a 90
>> degree
>> bank turn to the left and a full 360 back to the original courseafter a
>> while I saw the right hand tank indicator flip to 50 ......man I was glad
>> to
>> see that happening..problem solved.scary though.
>>
>>
>>
>> Hans
>>
>> RA3326K
>>
>> ________________________________
>>
>> Van: owner-yak-list-server@matronics.com
>> [mailto:owner-yak-list-server@matronics.com] Namens A. Dennis Savarese
>> Verzonden: dinsdag 18 mei 2010 13:24
>> Aan: yak-list@matronics.com
>> Onderwerp: Re: Yak-List: feul feed
>>
>>
>>
>> Steve,
>>
>> In the Yak 52, the purpose of stepping on the low side tank is two fold:
>> in
>> case one of the flapper valves in the fuel junction under the front seat
>> is
>> stuck closed, forcing the weight of the fuel against the flapper valve
>> may
>> free the flapper valve thus permitting fuel to flow; secondly and more
>> likely, there is fuel in the vent line of the tank that is not feeding
>> and
>> by stepping on the low side you are trying to force the fuel out of the
>> vent
>> line.
>>
>>
>>
>> Assuming the airplane is trimmed properly as Pappy says, which definitely
>> causes fuel imbalance, a vent line with fuel in it will definitely affect
>> the fuel feed. I didn't realize I was probably forcing the fuel into the
>> vent lines on the Yak 52 by filling the tanks all the way up to the lip.
>> Because of the sitting angle of attack, the vent line at the top, rear,
>> inside corner of the tank can get fuel in it by filling the tank to the
>> lip. This is particularly true on the right tank because the vent line
>> sits
>> lower in the fuselage than the left tank. Remember, the left vent line
>> enters the fuselage and turns down and connects at the top of the vent
>> junction. The right tank vent line is attached to the left side of the
>> vent
>> junction which ends up being lower than the left tank vent line. So when
>> fuel enters the right vent line by filling to the lip of the filler neck,
>> it
>> may force the fuel into the vent line and into the vent junction,
>> blocking
>> air back to the tank through the vent line.
>>
>>
>>
>> Also when the fuel heats up in the tank it expands and guess where it
>> expands to? Right into the vent line. Have you ever seen a Yak 52
>> "puking"
>> fuel overboard on the ramp during hot weather? The reason is the fuel has
>> expanded in the tank and is forced out of the vent line through the vent
>> junction and out through the overboard vent line exiting out the belly of
>> the airplane. Once the siphon has been set up by the expansion, the
>> siphoning effect can siphon out 5+ gallons. No kidding.....it happened to
>> me. I filled the airplane and left it on the ramp in the sun for 2 days.
>> When I came back the fuel instrument no longer read 60/60. I refilled the
>> tanks and it took over 5 gallons of fuel to bring the tanks back to
>> 60/60.
>> The telltale sign was the dark, black spot in the blacktop under the
>> fuselage directly under the vent line.
>>
>>
>>
>> Dennis
>>
>> ----- Original Message -----
>>
>> From: Stephen Morrey
>>
>> To: yak-list@matronics.com
>>
>> Sent: Monday, May 17, 2010 9:48 PM
>>
>> Subject: Re: Yak-List: feul feed
>>
>>
>>
>>
>> So just to be sure, am I correct in saying an in flight remidy is to
>> step on the side showing the lowest fuel level. If this is the case
>> is it best to simply step on the low side or is it needed to step and
>> "hold" for an extended period of time on the low side ? Do I have
>> this backwards? steve "old school"
>>
>> On Mon, May 17, 2010 at 12:19 PM, <cjpilot710@aol.com> wrote:
>>> Guys,
>>>
>>> The problem has always been aircraft yaw. The T-34 which has the same
>>> fuel
>>> setup (on one model anyway) has had the same problem. If you do not
>>> apply
>>> enough rudder on climb out, engine seem to pull out of the left tank
>>> more.
>>> I have separate tank vent lines that go to the wing tips. I was told
>>> that
>>> this would cure the uneven flow, when I put in the long range tanks. It
>>> didn't. Yaw is the most likely cause of fuel imbalance.
>>>
>>> Jim "Pappy" Goolsby
>>>
>>> -----Original Message-----
>>> From: Chris Wise <wise@txc.net.au>
>>> To: yak-list@matronics.com
>>> Sent: Mon, May 17, 2010 2:18 am
>>> Subject: Re: Yak-List: feul feed
>>>
>>> G'Day Walt,
>>>
>>> We carry a piece of plastic tubing that fits over the vent pipes and we
>>> use
>>> this to check the vents by blowing into the pipe.
>>> Every now and then we blow compressed air thru the vent.
>>> At no time have we ever found a blocked air vent.
>>> My mate also fitted new fuel cap seals. Did not solve the problem.
>>>
>>> The check valves are a simple flapper valve that prevents any X flow and
>>> I
>>> cannot see how they can be a problem.
>>> I am not familiar with the check valves on a CJ6
>>>
>>> Thanks and cheers,
>>> Chris.
>>>
>>>
>>>
>>> Chris Wise
>>> GT Propellers Australia
>>> __________________________________________________________
>>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>>
>>> Email chris@gtpropellersaustralia.com.au
>>> Website www.gtpropellersaustralia.com.au
>>>
>>> The information transmitted in and with this email is intended only for
>>> the
>>> person or entity to which it is addressed and may contain confidential
>>> and/or privileged material. Any review, retransmission, dissemination or
>>> other use of, or taking of any action in reliance upon this information,
>>> by
>>> persons or entities other than the intended recipients is prohibited. If
>>> you
>>> received this transmission in error, please contact the sender and
>>> delete
>>> this e-mail and associated material from all computers and/or systems.
>>> The
>>> intended recipient of this e-mail may only use, reproduce, disclose or
>>> distribute the information contained in this e-mail and any attached
>>> files,
>>> with the permission of the sender.
>>>
>>> ----- Original Message -----
>>> From: Walter Lannon
>>> To: yak-list@matronics.com
>>> Sent: Monday, May 17, 2010 2:05 PM
>>> Subject: Re: Yak-List: feul feed
>>> Hi Chris;
>>>
>>> The Nanchang exhibits the same fuel feed problem. Typically the RH tank
>>> is
>>> late and I know of at least one forced landing with a full RH and empty
>>> LH.
>>> Believe this was in South Africa about 6 or 7 years ago.
>>>
>>> The CJ6 has a single point vent system which I don't believe is the
>>> problem. However the effective length of the vent line and the fuel feed
>>> line are both longer for the RH tank. Theoretically that could induce a
>>> lag
>>> in the RH feed time but I don't belive it is signifigant. Any blockage
>>> of
>>> the vent by insect nests etc. will definitaly cause a big problem.
>>>
>>> Other than the bugs that leaves the feed tank check valves as the only
>>> remaining source. SPEAKING FOR THE CJ6 ONLY (since I have no knowledge
>>> of
>>> the check valves in any of the Yak models) I believe I have solved that
>>> problem with a modification to the check valve which, IMHO, was very
>>> poorly
>>> designed.
>>>
>>> If you have the opportunity to take photos of one of your check valves
>>> and
>>> email to me I will try to determine if the mod is applicable.
>>>
>>> Walt
>>>
>>>
>>> ----- Original Message -----
>>> From: Chris Wise
>>> To: yak-list@matronics.com
>>> Sent: Sunday, May 16, 2010 7:18 PM
>>> Subject: Yak-List: feul feed
>>> G'Day All,
>>>
>>> I and a friend each run a Yak18T.
>>> We suffer the same problem with both aircraft, re even fuel feed.
>>> Flying in turbulence seems to help the problem, but still air is bad
>>> news.
>>>
>>> The left tank will feed untill almost empty leaving plenty of fuel in
>>> the
>>> right tank and on my mates 18, the low fuel warning light on the left
>>> tank
>>> lit up and was fortunate enough to be close to a small country strip
>>> where
>>> he landed in a hurry.
>>>
>>> He has teed both vents into one. This has not helped.
>>>
>>> I moved the left tank vent and re located the vent to about 3/4 of a
>>> inch
>>> next to the right tank vent thinking that it may be the vortex from the
>>> prop
>>> that is allowing the right tank to feed. Or rather stopping the left
>>> tank
>>> to
>>> feed.
>>> I have changed the angle of the vent pipe facing the airflow to try and
>>> perhaps get more air into the vent to assist the left tank to feed more.
>>> This has only marginally helped.
>>>
>>> I landed on Saturday with the left tank low fuel warning light coming on
>>> on
>>> finals.
>>> The right tank had 65 - 70 litres fuel remaining and about 12 in the
>>> left
>>> when dipped.
>>>
>>> We have removed and carefully checked the check valves. No problem
>>> there.
>>>
>>> Any suggestions would be greatly appreciated.
>>>
>>> Thanks and cheers,
>>> Chris.
>>>
>>>
>>> Chris Wise
>>> GT Propellers Australia
>>> __________________________________________________________
>>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>>
>>> Email chris@gtpropellersaustralia.com.au
>>> Website www.gtpropellersaustralia.com.au
>>>
>>> The information transmitted in and with this email is intended only for
>>> the
>>> person or entity to which it is addressed and may contain confidential
>>> and/or privileged material. Any review, retransmission, dissemination or
>>> other use of, or taking of any action in reliance upon this information,
>>> by
>>> persons or entities other than the intended recipients is prohibited. If
>>> you
>>> received this transmission in error, please contact the sender and
>>> delete
>>> this e-mail and associated material from all computers and/or systems.
>>> The
>>> intended recipient of this e-mail may only use, reproduce, disclose or
>>> distribute the information contained in this e-mail and any attached
>>> files,
>>> with the permission of the sender.
>>>
>>>
>>> ==========
>>> get=_blank>http://www.matronics.com/Navigator?Yak-List
>>> ==========
>>> tp://forums.matronics.com
>>> ==========
>>> _blank>http://www.matronics.com/contribution
>>> p; Navigator Photoshare, and
>>> href="http://www.matronics.com/Navigator?Yak-List">http://www.matronics========================<;
>>> via the Web
>>> href="http://forums.matronics.com">http://forums.matronics.com
>> _p; generous bsp;
>> href="http://www.matronics.com/contribution">http://www.matronics.com/c================
>>
>>
>>
>>
>>
>> http://www.matronics.com/Navigator?Yak-List
>>
>> http://forums.matronics.com
>>
>> http://www.matronics.com/contribution
>>
>>
>>
>>
>
>
>
Message 16
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Just paid the balance on my dorm room this year. For those with no room...too bad,
some dorms are being demolished, others renovated. End result: 700 less rooms
this summer.
Reservations open for 2011 usually around July 15th.
Craig Payne
Message 17
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G'Day Dennis,
It allways seems to come back to the vents.
Doing some aero's in the 18T one day, we got too slow around a
hesitation roll and sort of hung upside down.
Not a good thing in a 18T as no inverted oil sysyem. What a mess.
The point is that I was not at my home airfield.
So put a splash in each side before departing, then flew on to another
strip and then about 35 min flight home. About 55 min.
The right tank hardly fed at all and the left tank was way down. Blew
the line out with compressed air and it seems to be behaving again.
This sort of indicates that when inverted the feul may have got into the
vent line and stopped the tank from feeding.
It is a huge puzzle to me, as I explained, I relocated the left tank
vent to about 3/4 inch away from the right vent thinking that they are
hence "breathing" from the same locality.
The problem is not consistant. A 3 hour 40 min trip last month with 2
feul stops the tanks were within 10 litres of each other when refeuling.
And yet the feul man at one stop had a spill by overfilling the left
tank and no problems. One would have thought that the feul would have
got into the vent line and caused theleft tank to not feed.
It would seem that when there is a bit of turbulance around the tanks
feed in a more even manner.
There is no doubt that flying the aircraft without the rudder input does
affect it.
Hell, it's got me beat.
By the way, thanks to all for the input.
Cheers,
Chris.
Chris Wise
GT Propellers Australia
__________________________________________________________
Tel. +61 415 195 095 Fax. +61 8 8326 7268
Email chris@gtpropellersaustralia.com.au
Website www.gtpropellersaustralia.com.au
The information transmitted in and with this email is intended only for
the person or entity to which it is addressed and may contain
confidential and/or privileged material. Any review, retransmission,
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this information, by persons or entities other than the intended
recipients is prohibited. If you received this transmission in error,
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the sender.
----- Original Message -----
From: A. Dennis Savarese
To: yak-list@matronics.com
Sent: Wednesday, May 19, 2010 2:20 AM
Subject: Re: Yak-List: feul feed
Walt,
Although it seems questionable regarding the vent system as the cause
of fuel not feeding from one tank or the other, particularly in the 52,
the Yakovlev design bureau redesigned the vent system in the 89 and up
model years. Two things happen on a pre 1989 Yak 52's which most Yak 52
owners have experienced. When the fuel tanks are close to full and the
temperature builds causing the fuel to expand in the tank, if one were
to remove the fuel caps, you will hear a rather large "whoosh" and the
fuel will spill out of the filler neck all over the wing. This is
caused by pressure building in the tank. The only way the expanded fuel
can exit is via the vent line with the tank cap in place. The second
reason the vent system was redesigned was because of the expansion and
contraction of the very thin aluminum metal of the fuel tanks. This
expansion and contraction of the metal (ie: flexing) created cracks in
many of the fuel tanks as evident of the weld marks on the bottom of the
tanks seen in most pre 1989 Yak 52's.
The post 1989 vent system was far superior to the pre 1989 system.
The fuel tanks had two vent lines; one at the top, rear on the inside
(the same as pre 1989) and one on the top of the tank near the outboard
edge. This second vent line eliminated the expansion of the fuel and
the puking of the fuel overboard because the tank could "breath".
There are 2 separate vent systems on the post 1989 airplanes. One
system for each tank. And here's the most important fact,......no more
fuel feeding imbalance. The tanks are the same size. The flapper
valves are identical. The only thing that changed was the vent system.
Dennis
----- Original Message -----
From: Walter Lannon
To: yak-list@matronics.com
Sent: Tuesday, May 18, 2010 10:59 AM
Subject: Re: Yak-List: feul feed
If there was zero turbulence and the turn was perfectly
co-coordinated
throughout it may not work.
But in the real world it probably will.
If necessary I use a very brief "knife edge" - definitely not
co-coordinated.
I have a problem with the fuel in vent lines being the cause of
unequal
feed. If the lines are properly routed in relation to the max. fuel
level
in the tanks and are not blocked by some other material the fuel in
the
line will flow to wherever the pressure is lower. If the engine is
using
fuel that flow will be back to the tank.
The comments I have heard so far lead me to believe the Yak series
fuel feed
tank check valves are exactly the same as the Nanchang and are
therefore the
primary reason for unequal fuel flow.
The file and/or hacksaw cuts in the flapper used by the PLAAF and
others do
not address the problem.
They simply destroy the intended function of the valve
Have at it guys!
Walt
----- Original Message -----
From: "Stephen Morrey" <stephenmorrey@gmail.com>
To: <yak-list@matronics.com>
Sent: Tuesday, May 18, 2010 7:41 AM
Subject: Re: Yak-List: feul feed
<stephenmorrey@gmail.com>
>
> Again I am a little confused on this, it seems if the 360 turn was
> coordinated then the turn should have had no effect. Do I
understand
> this correctly?
>
> On Tue, May 18, 2010 at 7:49 AM, Hans Oortman <pa3arw@euronet.nl>
wrote:
>> Dennis,
>>
>>
>>
>> It can be very scary though=85.When I ferried my Yak from Estonia
via
>> Lithuania back to Holland I found it to be very scary.
>>
>> I flew from Palanga (Lithuania) to Gdansk(Poland) over the middle
of the
>> Baltic Sea outside the airspace of Bullarus when the left tank
showed
>> only
>> 12 liters and the right hand tank was still at 60 liters. I made
a 90
>> degree
>> bank turn to the left and a full 360 back to the original
course=85after a
>> while I saw the right hand tank indicator flip to 50 ......man I
was glad
>> to
>> see that happening=85..problem solved=85.scary though=85.
>>
>>
>>
>> Hans
>>
>> RA3326K
>>
>> ________________________________
>>
>> Van: owner-yak-list-server@matronics.com
>> [mailto:owner-yak-list-server@matronics.com] Namens A. Dennis
Savarese
>> Verzonden: dinsdag 18 mei 2010 13:24
>> Aan: yak-list@matronics.com
>> Onderwerp: Re: Yak-List: feul feed
>>
>>
>>
>> Steve,
>>
>> In the Yak 52, the purpose of stepping on the low side tank is
two fold:
>> in
>> case one of the flapper valves in the fuel junction under the
front seat
>> is
>> stuck closed, forcing the weight of the fuel against the flapper
valve
>> may
>> free the flapper valve thus permitting fuel to flow; secondly and
more
>> likely, there is fuel in the vent line of the tank that is not
feeding
>> and
>> by stepping on the low side you are trying to force the fuel out
of the
>> vent
>> line.
>>
>>
>>
>> Assuming the airplane is trimmed properly as Pappy says, which
definitely
>> causes fuel imbalance, a vent line with fuel in it will
definitely affect
>> the fuel feed. I didn't realize I was probably forcing the fuel
into the
>> vent lines on the Yak 52 by filling the tanks all the way up to
the lip.
>> Because of the sitting angle of attack, the vent line at the top,
rear,
>> inside corner of the tank can get fuel in it by filling the tank
to the
>> lip. This is particularly true on the right tank because the vent
line
>> sits
>> lower in the fuselage than the left tank. Remember, the left vent
line
>> enters the fuselage and turns down and connects at the top of the
vent
>> junction. The right tank vent line is attached to the left side
of the
>> vent
>> junction which ends up being lower than the left tank vent line.
So when
>> fuel enters the right vent line by filling to the lip of the
filler neck,
>> it
>> may force the fuel into the vent line and into the vent junction,
>> blocking
>> air back to the tank through the vent line.
>>
>>
>>
>> Also when the fuel heats up in the tank it expands and guess
where it
>> expands to? Right into the vent line. Have you ever seen a Yak 52
>> "puking"
>> fuel overboard on the ramp during hot weather? The reason is the
fuel has
>> expanded in the tank and is forced out of the vent line through
the vent
>> junction and out through the overboard vent line exiting out the
belly of
>> the airplane. Once the siphon has been set up by the expansion,
the
>> siphoning effect can siphon out 5+ gallons. No kidding.....it
happened to
>> me. I filled the airplane and left it on the ramp in the sun for
2 days.
>> When I came back the fuel instrument no longer read 60/60. I
refilled the
>> tanks and it took over 5 gallons of fuel to bring the tanks back
to
>> 60/60.
>> The telltale sign was the dark, black spot in the blacktop under
the
>> fuselage directly under the vent line.
>>
>>
>>
>> Dennis
>>
>> ----- Original Message -----
>>
>> From: Stephen Morrey
>>
>> To: yak-list@matronics.com
>>
>> Sent: Monday, May 17, 2010 9:48 PM
>>
>> Subject: Re: Yak-List: feul feed
>>
>>
>>
<stephenmorrey@gmail.com>
>>
>> So just to be sure, am I correct in saying an in flight remidy is
to
>> step on the side showing the lowest fuel level. If this is the
case
>> is it best to simply step on the low side or is it needed to step
and
>> "hold" for an extended period of time on the low side ? Do I have
>> this backwards? steve "old school"
>>
>> On Mon, May 17, 2010 at 12:19 PM, <cjpilot710@aol.com> wrote:
>>> Guys,
>>>
>>> The problem has always been aircraft yaw. The T-34 which has the
same
>>> fuel
>>> setup (on one model anyway) has had the same problem. If you do
not
>>> apply
>>> enough rudder on climb out, engine seem to pull out of the left
tank
>>> more.
>>> I have separate tank vent lines that go to the wing tips. I was
told
>>> that
>>> this would cure the uneven flow, when I put in the long range
tanks. It
>>> didn't. Yaw is the most likely cause of fuel imbalance.
>>>
>>> Jim "Pappy" Goolsby
>>>
>>> -----Original Message-----
>>> From: Chris Wise <wise@txc.net.au>
>>> To: yak-list@matronics.com
>>> Sent: Mon, May 17, 2010 2:18 am
>>> Subject: Re: Yak-List: feul feed
>>>
>>> G'Day Walt,
>>>
>>> We carry a piece of plastic tubing that fits over the vent pipes
and we
>>> use
>>> this to check the vents by blowing into the pipe.
>>> Every now and then we blow compressed air thru the vent.
>>> At no time have we ever found a blocked air vent.
>>> My mate also fitted new fuel cap seals. Did not solve the
problem.
>>>
>>> The check valves are a simple flapper valve that prevents any X
flow and
>>> I
>>> cannot see how they can be a problem.
>>> I am not familiar with the check valves on a CJ6
>>>
>>> Thanks and cheers,
>>> Chris.
>>>
>>>
>>>
>>> Chris Wise
>>> GT Propellers Australia
>>> __________________________________________________________
>>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>>
>>> Email chris@gtpropellersaustralia.com.au
>>> Website www.gtpropellersaustralia.com.au
>>>
>>> The information transmitted in and with this email is intended
only for
>>> the
>>> person or entity to which it is addressed and may contain
confidential
>>> and/or privileged material. Any review, retransmission,
dissemination or
>>> other use of, or taking of any action in reliance upon this
information,
>>> by
>>> persons or entities other than the intended recipients is
prohibited. If
>>> you
>>> received this transmission in error, please contact the sender
and
>>> delete
>>> this e-mail and associated material from all computers and/or
systems.
>>> The
>>> intended recipient of this e-mail may only use, reproduce,
disclose or
>>> distribute the information contained in this e-mail and any
attached
>>> files,
>>> with the permission of the sender.
>>>
>>> ----- Original Message -----
>>> From: Walter Lannon
>>> To: yak-list@matronics.com
>>> Sent: Monday, May 17, 2010 2:05 PM
>>> Subject: Re: Yak-List: feul feed
>>> Hi Chris;
>>>
>>> The Nanchang exhibits the same fuel feed problem. Typically the
RH tank
>>> is
>>> late and I know of at least one forced landing with a full RH
and empty
>>> LH.
>>> Believe this was in South Africa about 6 or 7 years ago.
>>>
>>> The CJ6 has a single point vent system which I don't believe is
the
>>> problem. However the effective length of the vent line and the
fuel feed
>>> line are both longer for the RH tank. Theoretically that could
induce a
>>> lag
>>> in the RH feed time but I don't belive it is signifigant. Any
blockage
>>> of
>>> the vent by insect nests etc. will definitaly cause a big
problem.
>>>
>>> Other than the bugs that leaves the feed tank check valves as
the only
>>> remaining source. SPEAKING FOR THE CJ6 ONLY (since I have no
knowledge
>>> of
>>> the check valves in any of the Yak models) I believe I have
solved that
>>> problem with a modification to the check valve which, IMHO, was
very
>>> poorly
>>> designed.
>>>
>>> If you have the opportunity to take photos of one of your check
valves
>>> and
>>> email to me I will try to determine if the mod is applicable.
>>>
>>> Walt
>>>
>>>
>>> ----- Original Message -----
>>> From: Chris Wise
>>> To: yak-list@matronics.com
>>> Sent: Sunday, May 16, 2010 7:18 PM
>>> Subject: Yak-List: feul feed
>>> G'Day All,
>>>
>>> I and a friend each run a Yak18T.
>>> We suffer the same problem with both aircraft, re even fuel
feed.
>>> Flying in turbulence seems to help the problem, but still air is
bad
>>> news.
>>>
>>> The left tank will feed untill almost empty leaving plenty of
fuel in
>>> the
>>> right tank and on my mates 18, the low fuel warning light on the
left
>>> tank
>>> lit up and was fortunate enough to be close to a small country
strip
>>> where
>>> he landed in a hurry.
>>>
>>> He has teed both vents into one. This has not helped.
>>>
>>> I moved the left tank vent and re located the vent to about 3/4
of a
>>> inch
>>> next to the right tank vent thinking that it may be the vortex
from the
>>> prop
>>> that is allowing the right tank to feed. Or rather stopping the
left
>>> tank
>>> to
>>> feed.
>>> I have changed the angle of the vent pipe facing the airflow to
try and
>>> perhaps get more air into the vent to assist the left tank to
feed more.
>>> This has only marginally helped.
>>>
>>> I landed on Saturday with the left tank low fuel warning light
coming on
>>> on
>>> finals.
>>> The right tank had 65 - 70 litres fuel remaining and about 12 in
the
>>> left
>>> when dipped.
>>>
>>> We have removed and carefully checked the check valves. No
problem
>>> there.
>>>
>>> Any suggestions would be greatly appreciated.
>>>
>>> Thanks and cheers,
>>> Chris.
>>>
>>>
>>> Chris Wise
>>> GT Propellers Australia
>>> __________________________________________________________
>>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>>
>>> Email chris@gtpropellersaustralia.com.au
>>> Website www.gtpropellersaustralia.com.au
>>>
>>> The information transmitted in and with this email is intended
only for
>>> the
>>> person or entity to which it is addressed and may contain
confidential
>>> and/or privileged material. Any review, retransmission,
dissemination or
>>> other use of, or taking of any action in reliance upon this
information,
>>> by
>>> persons or entities other than the intended recipients is
prohibited. If
>>> you
>>> received this transmission in error, please contact the sender
and
>>> delete
>>> this e-mail and associated material from all computers and/or
systems.
>>> The
>>> intended recipient of this e-mail may only use, reproduce,
disclose or
>>> distribute the information contained in this e-mail and any
attached
>>> files,
>>> with the permission of the sender.
>>>
>>>
>>> ==========
>>> get=_blank>http://www.matronics.com/Navigator?Yak-List
>>> ==========
>>> tp://forums.matronics.com
>>> ==========
>>> _blank>http://www.matronics.com/contribution
>>> p; Navigator Photoshare, and
>>>
href="http://www.matronics.com/Navigator?Yak-List">http://www.matronics
========================<
;
>>> via the Web
>>> href="http://forums.matronics.com">http://forums.matronics.com
>> _p; generous bsp;
>>
href="http://www.matronics.com/contribution">http://www.matronics.com/c
================
>>
>>
>>
>>
>>
>> http://www.matronics.com/Navigator?Yak-List
>>
>> http://forums.matronics.com
>>
>> http://www.matronics.com/contribution
>>
>>
>>
>>
>
>
>
>
>
> nbsp; Navigator Photoshare, and
href="http://www.matronics.com/Navigator?Yak-List">http://www.matronics
========================<
; via the Web
href="http://forums.matronics.com">http://forums.matronics.com
_p; generous bsp;
href="http://www.matronics.com/contribution">http://www.matronics.com/c
================
Message 18
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| Subject: | Re: Fuel Feed Yak18T |
G'Day Phill,
I shall most certainly give it a go.
Thanks and Cheers,
Chris.
Chris Wise
GT Propellers Australia
__________________________________________________________
Tel. +61 415 195 095 Fax. +61 8 8326 7268
Email chris@gtpropellersaustralia.com.au
Website www.gtpropellersaustralia.com.au
The information transmitted in and with this email is intended only for
the person or entity to which it is addressed and may contain
confidential and/or privileged material. Any review, retransmission,
dissemination or other use of, or taking of any action in reliance upon
this information, by persons or entities other than the intended
recipients is prohibited. If you received this transmission in error,
please contact the sender and delete this e-mail and associated material
from all computers and/or systems. The intended recipient of this e-mail
may only use, reproduce, disclose or distribute the information
contained in this e-mail and any attached files, with the permission of
the sender.
----- Original Message -----
From: Phil Gower
To: yak-list@matronics.com
Sent: Wednesday, May 19, 2010 6:56 AM
Subject: Yak-List: Fuel Feed Yak18T
Chris - I agree with comments about problem being yaw (or slip/skid).
Keep adjusting rudder trim tab after each flight until the ball is
centered without having to apply continually rudder pressure to achieve
the ball in the centre. Works for me with my YAK18t and now fuel
consumption in each tank is even. Make sure the ball is centered
though, in the hangar on even level ground with tyre pressures the same.
If not adjust it and then do the procedure above. Cheers, Phil.
Message 19
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| Subject: | Re: Fuel feed problem in a YAK-55 |
Hi Guys!
My 55 does the same, I fix it by flying uncordinated on the side that needs
to be cross fed for about a minute or 2.
Yak-55
N5245H
JC
--- On Tue, 5/18/10, Scott Poehlmann <scott-p@texas.net> wrote:
From: Scott Poehlmann <scott-p@texas.net>
Subject: Re: Yak-List: Fuel feed problem in a YAK-55
Hi Bill,
Mine does that all the time too. Except that some times the right drains
faster... Apparently the tanks are plumbed such that they can crossfeed
at the the point they make a common feed to the engine (which is located
at the drain valve behind the oil radiator...). I have the drawing
around here somewhere and will scan it and send it when I next get a few
minutes (which might not be until 2011 at the current rate...<VBG>).
Scott
Yak-55M
N155YK
William Halverson wrote:
>
> The thread on CJ-6 feed problems reminded me ....
>
> The indicator (exteral wing mounted rotating gauge) on my left wing 'drai
ns' much more quickly than the right one.- After I land, and come back a
couple of days later, the two indicators are balanced.
>
> Ideas on the cause/remedy greatly appreciated!
>
> Best to all!
>
> William Halverson
> Vallejo CA
> YAK-55
> N355YK
>
>
>---
le, List Admin.
=0A=0A=0A
Message 20
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| Subject: | Re: Oshkosh Dorms |
Never again in this lifetime will I stay in one of those rooms. The
tempurature/humidity index in that airless cubicle never declined
below 90. ...Blitz
Sent from my iPhone
On May 18, 2010, at 2:17 PM, Cpayne <cpayne@joimail.com> wrote:
>
> Just paid the balance on my dorm room this year. For those with no
> room...too bad, some dorms are being demolished, others renovated.
> End result: 700 less rooms this summer.
>
> Reservations open for 2011 usually around July 15th.
>
> Craig Payne
>
>
Message 21
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Let me see if I can elucidate what I think happens.
While a plug vent will definitely cause fuel to flow from just one tank,
I just don't feel that the vent line placed closer to one tank than the
other will cause the problem. If we have two tanks with equal amounts of
fuel in them AND they are level with each other, they both will exert the
same pressure head at the outlets. Hence the fuel in the header tank, whi
ch is full at all times, will have that same pressure. The flop valves wil
l only open when pressure from the tank side is greater than what is in th
e header tank and thus fuel will flow. So it bear to reason that if the ai
rplane is sitting on a slope, fuel from the high side will flow. Since the
head pressure builds up in the header tank the flop valve on the lower si
de will close.
Now lets get the airplane moving. Now both tanks AND the header tank, will
not only have the head pressure but inertia forces acting on them. IF you
make coordinated turns forces are the same in the tank AND the header tan
k.
But lets say you have a slight yaw either in a turn or wings level, the in
ertia forces of the fuel tank will actually increase head pressure will fo
rce one flop valve open and fuel will feed from that tank. Assume you have
yaw left (left rudder peddle down), the inertia in the left tank will eff
ectively increase the head pressure and force open the left flop valve, an
d the left tank will feed fuel. The right tank may have exactly the same
amount of fuel, but its inertia is a way from the flop valve thus its hea
d pressure is effective less.
The inertia of the fuel in the header tank will react the same - helping
keep the opposite flop valve closed.
Anyway that's what I think happens. A engineer type agreed with me, but I
think he was in a hurry to get to the bar. Would appreciate a back up che
ck on my theory.
Jim "Pappy" Goolsby
Message 22
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So are you saying if the right tank is not feeding, step on the right rudde
r.- Others have said apply rudder on the low tank side (left).
--- On Wed, 5/19/10, cjpilot710@aol.com <cjpilot710@aol.com> wrote:
From: cjpilot710@aol.com <cjpilot710@aol.com>
Subject: Yak-List: Fuel flow
Let me see if I can elucidate what I think happens.
-
While a plug vent will definitely cause fuel to flow from just one tank, I
just don't feel that the vent line placed closer to one tank than the other
will cause the problem. If we have two tanks with equal amounts of fuel in
them AND they are level with each other, they both will exert the same pre
ssure head at the outlets. Hence the fuel in the header tank, which is full
at all times, will have that same pressure. The flop valves will only open
when pressure from the tank side is greater than what is in the header tan
k and thus fuel will flow. So it bear to reason that if the airplane is sit
ting on a slope, fuel from the high side will flow. Since the head pressure
builds up in the header tank the flop valve on the lower side will close.
-
Now lets get the airplane moving. Now both tanks AND the header tank, will
not only have the head pressure but inertia forces acting on them. IF you m
ake coordinated turns forces are the same in the tank AND the header tank.
-
But lets say you have a slight yaw either in a turn or wings level, the ine
rtia forces of the fuel tank will actually increase head pressure will forc
e one flop valve open and fuel will feed from that tank. Assume you have ya
w left (left rudder peddle down), the inertia in the left tank will effecti
vely increase the head pressure and force open the left flop valve, and the
left tank will feed fuel. The right tank may have exactly the same amount
of fuel, but its inertia is a way from the flop valve thus its head pressur
e is effective less.
-
The inertia of the fuel in the header tank will react the same - helping ke
ep the opposite flop valve closed.
-
Anyway that's what I think happens. A engineer type agreed with me, but I t
hink he was in a hurry to get to the bar. Would appreciate a back up check
on my theory.
-
Jim "Pappy" Goolsby
=0A=0A=0A
Message 23
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Hi Dennis;
It would be interesting to see the 52 flapper valve. It could very well
be an improved version of the early CJ6 valve which were likely direct
copies from the Yak 18 era.
The Chinese did at some point in time make a minor change that would
improve the flow. I have seen that improved valve in 1980's aircraft
but also the original 1960 type in the same aircraft.
I personally do not like the single point vent system since one leaf
cutter bee (common in this area) can spoil your whole day. If your
aircraft is parked outside here you are well advised to use a pitot
cover AND a vent cover. Lack of airspeed indication is a minor
annoyance. Lack of engine power is a major one.
The CJ has an advantage over the 52 for fuel tank venting in that the
outer wing has a 7 deg dihedral, The filler is at the inboard end and
the vent outlet at the outboard forward corner. This allows a fairly
generous expansion space that cannot be filled. Of course if the
temperature is high enough it can still vent fuel.
If I convert to an individual tank vent system (which I am considering)
I may install Parker MS series fuel vent valves with pin hole bleeds.
Best;
Walt
----- Original Message -----
From: A. Dennis Savarese
To: yak-list@matronics.com
Sent: Tuesday, May 18, 2010 9:50 AM
Subject: Re: Yak-List: feul feed
Walt,
Although it seems questionable regarding the vent system as the cause
of fuel not feeding from one tank or the other, particularly in the 52,
the Yakovlev design bureau redesigned the vent system in the 89 and up
model years. Two things happen on a pre 1989 Yak 52's which most Yak 52
owners have experienced. When the fuel tanks are close to full and the
temperature builds causing the fuel to expand in the tank, if one were
to remove the fuel caps, you will hear a rather large "whoosh" and the
fuel will spill out of the filler neck all over the wing. This is
caused by pressure building in the tank. The only way the expanded fuel
can exit is via the vent line with the tank cap in place. The second
reason the vent system was redesigned was because of the expansion and
contraction of the very thin aluminum metal of the fuel tanks. This
expansion and contraction of the metal (ie: flexing) created cracks in
many of the fuel tanks as evident of the weld marks on the bottom of the
tanks seen in most pre 1989 Yak 52's.
The post 1989 vent system was far superior to the pre 1989 system.
The fuel tanks had two vent lines; one at the top, rear on the inside
(the same as pre 1989) and one on the top of the tank near the outboard
edge. This second vent line eliminated the expansion of the fuel and
the puking of the fuel overboard because the tank could "breath".
There are 2 separate vent systems on the post 1989 airplanes. One
system for each tank. And here's the most important fact,......no more
fuel feeding imbalance. The tanks are the same size. The flapper
valves are identical. The only thing that changed was the vent system.
Dennis
----- Original Message -----
From: Walter Lannon
To: yak-list@matronics.com
Sent: Tuesday, May 18, 2010 10:59 AM
Subject: Re: Yak-List: feul feed
If there was zero turbulence and the turn was perfectly
co-coordinated
throughout it may not work.
But in the real world it probably will.
If necessary I use a very brief "knife edge" - definitely not
co-coordinated.
I have a problem with the fuel in vent lines being the cause of
unequal
feed. If the lines are properly routed in relation to the max. fuel
level
in the tanks and are not blocked by some other material the fuel in
the
line will flow to wherever the pressure is lower. If the engine is
using
fuel that flow will be back to the tank.
The comments I have heard so far lead me to believe the Yak series
fuel feed
tank check valves are exactly the same as the Nanchang and are
therefore the
primary reason for unequal fuel flow.
The file and/or hacksaw cuts in the flapper used by the PLAAF and
others do
not address the problem.
They simply destroy the intended function of the valve
Have at it guys!
Walt
----- Original Message -----
From: "Stephen Morrey" <stephenmorrey@gmail.com>
To: <yak-list@matronics.com>
Sent: Tuesday, May 18, 2010 7:41 AM
Subject: Re: Yak-List: feul feed
<stephenmorrey@gmail.com>
>
> Again I am a little confused on this, it seems if the 360 turn was
> coordinated then the turn should have had no effect. Do I
understand
> this correctly?
>
> On Tue, May 18, 2010 at 7:49 AM, Hans Oortman <pa3arw@euronet.nl>
wrote:
>> Dennis,
>>
>>
>>
>> It can be very scary though=85.When I ferried my Yak from Estonia
via
>> Lithuania back to Holland I found it to be very scary.
>>
>> I flew from Palanga (Lithuania) to Gdansk(Poland) over the middle
of the
>> Baltic Sea outside the airspace of Bullarus when the left tank
showed
>> only
>> 12 liters and the right hand tank was still at 60 liters. I made
a 90
>> degree
>> bank turn to the left and a full 360 back to the original
course=85after a
>> while I saw the right hand tank indicator flip to 50 ......man I
was glad
>> to
>> see that happening=85..problem solved=85.scary though=85.
>>
>>
>>
>> Hans
>>
>> RA3326K
>>
>> ________________________________
>>
>> Van: owner-yak-list-server@matronics.com
>> [mailto:owner-yak-list-server@matronics.com] Namens A. Dennis
Savarese
>> Verzonden: dinsdag 18 mei 2010 13:24
>> Aan: yak-list@matronics.com
>> Onderwerp: Re: Yak-List: feul feed
>>
>>
>>
>> Steve,
>>
>> In the Yak 52, the purpose of stepping on the low side tank is
two fold:
>> in
>> case one of the flapper valves in the fuel junction under the
front seat
>> is
>> stuck closed, forcing the weight of the fuel against the flapper
valve
>> may
>> free the flapper valve thus permitting fuel to flow; secondly and
more
>> likely, there is fuel in the vent line of the tank that is not
feeding
>> and
>> by stepping on the low side you are trying to force the fuel out
of the
>> vent
>> line.
>>
>>
>>
>> Assuming the airplane is trimmed properly as Pappy says, which
definitely
>> causes fuel imbalance, a vent line with fuel in it will
definitely affect
>> the fuel feed. I didn't realize I was probably forcing the fuel
into the
>> vent lines on the Yak 52 by filling the tanks all the way up to
the lip.
>> Because of the sitting angle of attack, the vent line at the top,
rear,
>> inside corner of the tank can get fuel in it by filling the tank
to the
>> lip. This is particularly true on the right tank because the vent
line
>> sits
>> lower in the fuselage than the left tank. Remember, the left vent
line
>> enters the fuselage and turns down and connects at the top of the
vent
>> junction. The right tank vent line is attached to the left side
of the
>> vent
>> junction which ends up being lower than the left tank vent line.
So when
>> fuel enters the right vent line by filling to the lip of the
filler neck,
>> it
>> may force the fuel into the vent line and into the vent junction,
>> blocking
>> air back to the tank through the vent line.
>>
>>
>>
>> Also when the fuel heats up in the tank it expands and guess
where it
>> expands to? Right into the vent line. Have you ever seen a Yak 52
>> "puking"
>> fuel overboard on the ramp during hot weather? The reason is the
fuel has
>> expanded in the tank and is forced out of the vent line through
the vent
>> junction and out through the overboard vent line exiting out the
belly of
>> the airplane. Once the siphon has been set up by the expansion,
the
>> siphoning effect can siphon out 5+ gallons. No kidding.....it
happened to
>> me. I filled the airplane and left it on the ramp in the sun for
2 days.
>> When I came back the fuel instrument no longer read 60/60. I
refilled the
>> tanks and it took over 5 gallons of fuel to bring the tanks back
to
>> 60/60.
>> The telltale sign was the dark, black spot in the blacktop under
the
>> fuselage directly under the vent line.
>>
>>
>>
>> Dennis
>>
>> ----- Original Message -----
>>
>> From: Stephen Morrey
>>
>> To: yak-list@matronics.com
>>
>> Sent: Monday, May 17, 2010 9:48 PM
>>
>> Subject: Re: Yak-List: feul feed
>>
>>
>>
<stephenmorrey@gmail.com>
>>
>> So just to be sure, am I correct in saying an in flight remidy is
to
>> step on the side showing the lowest fuel level. If this is the
case
>> is it best to simply step on the low side or is it needed to step
and
>> "hold" for an extended period of time on the low side ? Do I have
>> this backwards? steve "old school"
>>
>> On Mon, May 17, 2010 at 12:19 PM, <cjpilot710@aol.com> wrote:
>>> Guys,
>>>
>>> The problem has always been aircraft yaw. The T-34 which has the
same
>>> fuel
>>> setup (on one model anyway) has had the same problem. If you do
not
>>> apply
>>> enough rudder on climb out, engine seem to pull out of the left
tank
>>> more.
>>> I have separate tank vent lines that go to the wing tips. I was
told
>>> that
>>> this would cure the uneven flow, when I put in the long range
tanks. It
>>> didn't. Yaw is the most likely cause of fuel imbalance.
>>>
>>> Jim "Pappy" Goolsby
>>>
>>> -----Original Message-----
>>> From: Chris Wise <wise@txc.net.au>
>>> To: yak-list@matronics.com
>>> Sent: Mon, May 17, 2010 2:18 am
>>> Subject: Re: Yak-List: feul feed
>>>
>>> G'Day Walt,
>>>
>>> We carry a piece of plastic tubing that fits over the vent pipes
and we
>>> use
>>> this to check the vents by blowing into the pipe.
>>> Every now and then we blow compressed air thru the vent.
>>> At no time have we ever found a blocked air vent.
>>> My mate also fitted new fuel cap seals. Did not solve the
problem.
>>>
>>> The check valves are a simple flapper valve that prevents any X
flow and
>>> I
>>> cannot see how they can be a problem.
>>> I am not familiar with the check valves on a CJ6
>>>
>>> Thanks and cheers,
>>> Chris.
>>>
>>>
>>>
>>> Chris Wise
>>> GT Propellers Australia
>>> __________________________________________________________
>>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>>
>>> Email chris@gtpropellersaustralia.com.au
>>> Website www.gtpropellersaustralia.com.au
>>>
>>> The information transmitted in and with this email is intended
only for
>>> the
>>> person or entity to which it is addressed and may contain
confidential
>>> and/or privileged material. Any review, retransmission,
dissemination or
>>> other use of, or taking of any action in reliance upon this
information,
>>> by
>>> persons or entities other than the intended recipients is
prohibited. If
>>> you
>>> received this transmission in error, please contact the sender
and
>>> delete
>>> this e-mail and associated material from all computers and/or
systems.
>>> The
>>> intended recipient of this e-mail may only use, reproduce,
disclose or
>>> distribute the information contained in this e-mail and any
attached
>>> files,
>>> with the permission of the sender.
>>>
>>> ----- Original Message -----
>>> From: Walter Lannon
>>> To: yak-list@matronics.com
>>> Sent: Monday, May 17, 2010 2:05 PM
>>> Subject: Re: Yak-List: feul feed
>>> Hi Chris;
>>>
>>> The Nanchang exhibits the same fuel feed problem. Typically the
RH tank
>>> is
>>> late and I know of at least one forced landing with a full RH
and empty
>>> LH.
>>> Believe this was in South Africa about 6 or 7 years ago.
>>>
>>> The CJ6 has a single point vent system which I don't believe is
the
>>> problem. However the effective length of the vent line and the
fuel feed
>>> line are both longer for the RH tank. Theoretically that could
induce a
>>> lag
>>> in the RH feed time but I don't belive it is signifigant. Any
blockage
>>> of
>>> the vent by insect nests etc. will definitaly cause a big
problem.
>>>
>>> Other than the bugs that leaves the feed tank check valves as
the only
>>> remaining source. SPEAKING FOR THE CJ6 ONLY (since I have no
knowledge
>>> of
>>> the check valves in any of the Yak models) I believe I have
solved that
>>> problem with a modification to the check valve which, IMHO, was
very
>>> poorly
>>> designed.
>>>
>>> If you have the opportunity to take photos of one of your check
valves
>>> and
>>> email to me I will try to determine if the mod is applicable.
>>>
>>> Walt
>>>
>>>
>>> ----- Original Message -----
>>> From: Chris Wise
>>> To: yak-list@matronics.com
>>> Sent: Sunday, May 16, 2010 7:18 PM
>>> Subject: Yak-List: feul feed
>>> G'Day All,
>>>
>>> I and a friend each run a Yak18T.
>>> We suffer the same problem with both aircraft, re even fuel
feed.
>>> Flying in turbulence seems to help the problem, but still air is
bad
>>> news.
>>>
>>> The left tank will feed untill almost empty leaving plenty of
fuel in
>>> the
>>> right tank and on my mates 18, the low fuel warning light on the
left
>>> tank
>>> lit up and was fortunate enough to be close to a small country
strip
>>> where
>>> he landed in a hurry.
>>>
>>> He has teed both vents into one. This has not helped.
>>>
>>> I moved the left tank vent and re located the vent to about 3/4
of a
>>> inch
>>> next to the right tank vent thinking that it may be the vortex
from the
>>> prop
>>> that is allowing the right tank to feed. Or rather stopping the
left
>>> tank
>>> to
>>> feed.
>>> I have changed the angle of the vent pipe facing the airflow to
try and
>>> perhaps get more air into the vent to assist the left tank to
feed more.
>>> This has only marginally helped.
>>>
>>> I landed on Saturday with the left tank low fuel warning light
coming on
>>> on
>>> finals.
>>> The right tank had 65 - 70 litres fuel remaining and about 12 in
the
>>> left
>>> when dipped.
>>>
>>> We have removed and carefully checked the check valves. No
problem
>>> there.
>>>
>>> Any suggestions would be greatly appreciated.
>>>
>>> Thanks and cheers,
>>> Chris.
>>>
>>>
>>> Chris Wise
>>> GT Propellers Australia
>>> __________________________________________________________
>>> Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>>
>>> Email chris@gtpropellersaustralia.com.au
>>> Website www.gtpropellersaustralia.com.au
>>>
>>> The information transmitted in and with this email is intended
only for
>>> the
>>> person or entity to which it is addressed and may contain
confidential
>>> and/or privileged material. Any review, retransmission,
dissemination or
>>> other use of, or taking of any action in reliance upon this
information,
>>> by
>>> persons or entities other than the intended recipients is
prohibited. If
>>> you
>>> received this transmission in error, please contact the sender
and
>>> delete
>>> this e-mail and associated material from all computers and/or
systems.
>>> The
>>> intended recipient of this e-mail may only use, reproduce,
disclose or
>>> distribute the information contained in this e-mail and any
attached
>>> files,
>>> with the permission of the sender.
>>>
>>>
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>>
>>
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>>
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Message 24
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In this case the right tank has the most fuel in it. Raise that wing (sti
ck left) while at the same time applying right rudder. You'll do two thin
gs. Increase the head pressure of the right tank and induce a yaw to use
inertia to increase its effective pressure to open the flop valve. - -
- - - - - I think.
Jim "Pappy" Goolsby
-----Original Message-----
From: Paul Hamlin <ph451@yahoo.com>
Sent: Wed, May 19, 2010 12:12 am
Subject: Re: Yak-List: Fuel flow
So are you saying if the right tank is not feeding, step on the right rudd
er. Others have said apply rudder on the low tank side (left).
--- On Wed, 5/19/10, cjpilot710@aol.com <cjpilot710@aol.com> wrote:
From: cjpilot710@aol.com <cjpilot710@aol.com>
Subject: Yak-List: Fuel flow
Let me see if I can elucidate what I think happens.
While a plug vent will definitely cause fuel to flow from just one tank,
I just don't feel that the vent line placed closer to one tank than the
other will cause the problem. If we have two tanks with equal amounts of
fuel in them AND they are level with each other, they both will exert the
same pressure head at the outlets. Hence the fuel in the header tank, whi
ch is full at all times, will have that same pressure. The flop valves wil
l only open when pressure from the tank side is greater than what is in th
e header tank and thus fuel will flow. So it bear to reason that if the ai
rplane is sitting on a slope, fuel from the high side will flow. Since the
head pressure builds up in the header tank the flop valve on the lower si
de will close.
Now lets get the airplane moving. Now both tanks AND the header tank, will
not only have the head pressure but inertia forces acting on them. IF you
make coordinated turns forces are the same in the tank AND the header tan
k.
But lets say you have a slight yaw either in a turn or wings level, the in
ertia forces of the fuel tank will actually increase head pressure will fo
rce one flop valve open and fuel will feed from that tank. Assume you have
yaw left (left rudder peddle down), the inertia in the left tank will eff
ectively increase the head pressure and force open the left flop valve, an
d the left tank will feed fuel. The right tank may have exactly the same
amount of fuel, but its inertia is a way from the flop valve thus its hea
d pressure is effective less.
The inertia of the fuel in the header tank will react the same - helping
keep the opposite flop valve closed.
Anyway that's what I think happens. A engineer type agreed with me, but I
think he was in a hurry to get to the bar. Would appreciate a back up che
ck on my theory.
Jim "Pappy" Goolsby
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Message 25
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Would negative G maneuvers help open the
valve? Specifically an outside loop or turn?
William
At 08:59 AM 5/18/2010, Walter Lannon wrote:
>
>If there was zero turbulence and the turn was
>perfectly co-coordinated throughout it may not work.
>But in the real world it probably will.
>
>If necessary I use a very brief "knife edge" - definitely not co-coordinated.
>
>I have a problem with the fuel in vent lines
>being the cause of unequal feed. If the lines
>are properly routed in relation to the max. fuel
>level in the tanks and are not blocked by some
>other material the fuel in the line will flow to
>wherever the pressure is lower. If the engine
>is using fuel that flow will be back to the tank.
>
>The comments I have heard so far lead me to
>believe the Yak series fuel feed tank check
>valves are exactly the same as the Nanchang and
>are therefore the primary reason for unequal fuel flow.
>
>The file and/or hacksaw cuts in the flapper used
>by the PLAAF and others do not address the problem.
>They simply destroy the intended function of the valve
>
>Have at it guys!
>Walt
>
>
>----- Original Message ----- From: "Stephen Morrey" <stephenmorrey@gmail.com>
>To: <yak-list@matronics.com>
>Sent: Tuesday, May 18, 2010 7:41 AM
>Subject: Re: Yak-List: feul feed
>
>
>>
>>Again I am a little confused on this, it seems if the 360 turn was
>>coordinated then the turn should have had no effect. Do I understand
>>this correctly?
>>
>>On Tue, May 18, 2010 at 7:49 AM, Hans Oortman <pa3arw@euronet.nl> wrote:
>>>Dennis,
>>>
>>>
>>>
>>>It can be very scary though.When I ferried my Yak from Estonia via
>>>Lithuania back to Holland I found it to be very scary.
>>>
>>>I flew from Palanga (Lithuania) to Gdansk(Poland) over the middle of the
>>>Baltic Sea outside the airspace of Bullarus when the left tank showed only
>>>12 liters and the right hand tank was still at 60 liters. I made a 90 degree
>>>bank turn to the left and a full 360 back to the original courseafter a
>>>while I saw the right hand tank indicator flip to 50 ......man I was glad to
>>>see that happening..problem solved.scary though.
>>>
>>>
>>>
>>>Hans
>>>
>>>RA3326K
>>>
>>>________________________________
>>>
>>>Van: owner-yak-list-server@matronics.com
>>>[mailto:owner-yak-list-server@matronics.com] Namens A. Dennis Savarese
>>>Verzonden: dinsdag 18 mei 2010 13:24
>>>Aan: yak-list@matronics.com
>>>Onderwerp: Re: Yak-List: feul feed
>>>
>>>
>>>
>>>Steve,
>>>
>>>In the Yak 52, the purpose of stepping on the low side tank is two fold: in
>>>case one of the flapper valves in the fuel junction under the front seat is
>>>stuck closed, forcing the weight of the fuel against the flapper valve may
>>>free the flapper valve thus permitting fuel to flow; secondly and more
>>>likely, there is fuel in the vent line of the tank that is not feeding and
>>>by stepping on the low side you are trying to force the fuel out of the vent
>>>line.
>>>
>>>
>>>
>>>Assuming the airplane is trimmed properly as Pappy says, which definitely
>>>causes fuel imbalance, a vent line with fuel in it will definitely affect
>>>the fuel feed. I didn't realize I was probably forcing the fuel into the
>>>vent lines on the Yak 52 by filling the tanks all the way up to the lip.
>>>Because of the sitting angle of attack, the vent line at the top, rear,
>>>inside corner of the tank can get fuel in it by filling the tank to the
>>>lip. This is particularly true on the right tank because the vent line sits
>>>lower in the fuselage than the left tank. Remember, the left vent line
>>>enters the fuselage and turns down and connects at the top of the vent
>>>junction. The right tank vent line is attached to the left side of the vent
>>>junction which ends up being lower than the left tank vent line. So when
>>>fuel enters the right vent line by filling to the lip of the filler neck, it
>>>may force the fuel into the vent line and into the vent junction, blocking
>>>air back to the tank through the vent line.
>>>
>>>
>>>
>>>Also when the fuel heats up in the tank it expands and guess where it
>>>expands to? Right into the vent line. Have you ever seen a Yak 52 "puking"
>>>fuel overboard on the ramp during hot weather? The reason is the fuel has
>>>expanded in the tank and is forced out of the vent line through the vent
>>>junction and out through the overboard vent line exiting out the belly of
>>>the airplane. Once the siphon has been set up by the expansion, the
>>>siphoning effect can siphon out 5+ gallons. No kidding.....it happened to
>>>me. I filled the airplane and left it on the ramp in the sun for 2 days.
>>>When I came back the fuel instrument no longer read 60/60. I refilled the
>>>tanks and it took over 5 gallons of fuel to bring the tanks back to 60/60.
>>>The telltale sign was the dark, black spot in the blacktop under the
>>>fuselage directly under the vent line.
>>>
>>>
>>>
>>>Dennis
>>>
>>>----- Original Message -----
>>>
>>>From: Stephen Morrey
>>>
>>>To: yak-list@matronics.com
>>>
>>>Sent: Monday, May 17, 2010 9:48 PM
>>>
>>>Subject: Re: Yak-List: feul feed
>>>
>>>
>>>
>>>
>>>So just to be sure, am I correct in saying an in flight remidy is to
>>>step on the side showing the lowest fuel level. If this is the case
>>>is it best to simply step on the low side or is it needed to step and
>>>"hold" for an extended period of time on the low side ? Do I have
>>>this backwards? steve "old school"
>>>
>>>On Mon, May 17, 2010 at 12:19 PM, <cjpilot710@aol.com> wrote:
>>>>Guys,
>>>>
>>>>The problem has always been aircraft yaw. The T-34 which has the same fuel
>>>>setup (on one model anyway) has had the same problem. If you do not apply
>>>>enough rudder on climb out, engine seem to pull out of the left tank more.
>>>>I have separate tank vent lines that go to the wing tips. I was told that
>>>>this would cure the uneven flow, when I put in the long range tanks. It
>>>>didn't. Yaw is the most likely cause of fuel imbalance.
>>>>
>>>>Jim "Pappy" Goolsby
>>>>
>>>>-----Original Message-----
>>>>From: Chris Wise <wise@txc.net.au>
>>>>To: yak-list@matronics.com
>>>>Sent: Mon, May 17, 2010 2:18 am
>>>>Subject: Re: Yak-List: feul feed
>>>>
>>>>G'Day Walt,
>>>>
>>>>We carry a piece of plastic tubing that fits over the vent pipes and we
>>>>use
>>>>this to check the vents by blowing into the pipe.
>>>>Every now and then we blow compressed air thru the vent.
>>>>At no time have we ever found a blocked air vent.
>>>>My mate also fitted new fuel cap seals. Did not solve the problem.
>>>>
>>>>The check valves are a simple flapper valve that prevents any X flow and I
>>>>cannot see how they can be a problem.
>>>>I am not familiar with the check valves on a CJ6
>>>>
>>>>Thanks and cheers,
>>>>Chris.
>>>>
>>>>
>>>>
>>>>Chris Wise
>>>>GT Propellers Australia
>>>>__________________________________________________________
>>>>Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>>>
>>>>Email chris@gtpropellersaustralia.com.au
>>>>Website www.gtpropellersaustralia.com.au
>>>>
>>>>The information transmitted in and with this email is intended only for
>>>>the
>>>>person or entity to which it is addressed and may contain confidential
>>>>and/or privileged material. Any review, retransmission, dissemination or
>>>>other use of, or taking of any action in reliance upon this information,
>>>>by
>>>>persons or entities other than the intended recipients is prohibited. If
>>>>you
>>>>received this transmission in error, please contact the sender and delete
>>>>this e-mail and associated material from all computers and/or systems. The
>>>>intended recipient of this e-mail may only use, reproduce, disclose or
>>>>distribute the information contained in this e-mail and any attached
>>>>files,
>>>>with the permission of the sender.
>>>>
>>>>----- Original Message -----
>>>>From: Walter Lannon
>>>>To: yak-list@matronics.com
>>>>Sent: Monday, May 17, 2010 2:05 PM
>>>>Subject: Re: Yak-List: feul feed
>>>>Hi Chris;
>>>>
>>>>The Nanchang exhibits the same fuel feed problem. Typically the RH tank is
>>>>late and I know of at least one forced landing with a full RH and empty
>>>>LH.
>>>>Believe this was in South Africa about 6 or 7 years ago.
>>>>
>>>>The CJ6 has a single point vent system which I don't believe is the
>>>>problem. However the effective length of the vent line and the fuel feed
>>>>line are both longer for the RH tank. Theoretically that could induce a
>>>>lag
>>>>in the RH feed time but I don't belive it is signifigant. Any blockage of
>>>>the vent by insect nests etc. will definitaly cause a big problem.
>>>>
>>>>Other than the bugs that leaves the feed tank check valves as the only
>>>>remaining source. SPEAKING FOR THE CJ6 ONLY (since I have no knowledge of
>>>>the check valves in any of the Yak models) I believe I have solved that
>>>>problem with a modification to the check valve which, IMHO, was very
>>>>poorly
>>>>designed.
>>>>
>>>>If you have the opportunity to take photos of one of your check valves and
>>>>email to me I will try to determine if the mod is applicable.
>>>>
>>>>Walt
>>>>
>>>>
>>>>----- Original Message -----
>>>>From: Chris Wise
>>>>To: yak-list@matronics.com
>>>>Sent: Sunday, May 16, 2010 7:18 PM
>>>>Subject: Yak-List: feul feed
>>>>G'Day All,
>>>>
>>>>I and a friend each run a Yak18T.
>>>>We suffer the same problem with both aircraft, re even fuel feed.
>>>>Flying in turbulence seems to help the problem, but still air is bad news.
>>>>
>>>>The left tank will feed untill almost empty leaving plenty of fuel in the
>>>>right tank and on my mates 18, the low fuel warning light on the left tank
>>>>lit up and was fortunate enough to be close to a small country strip where
>>>>he landed in a hurry.
>>>>
>>>>He has teed both vents into one. This has not helped.
>>>>
>>>>I moved the left tank vent and re located the vent to about 3/4 of a inch
>>>>next to the right tank vent thinking that it may be the vortex from the
>>>>prop
>>>>that is allowing the right tank to feed. Or rather stopping the left tank
>>>>to
>>>>feed.
>>>>I have changed the angle of the vent pipe facing the airflow to try and
>>>>perhaps get more air into the vent to assist the left tank to feed more.
>>>>This has only marginally helped.
>>>>
>>>>I landed on Saturday with the left tank low fuel warning light coming on
>>>>on
>>>>finals.
>>>>The right tank had 65 - 70 litres fuel remaining and about 12 in the left
>>>>when dipped.
>>>>
>>>>We have removed and carefully checked the check valves. No problem there.
>>>>
>>>>Any suggestions would be greatly appreciated.
>>>>
>>>>Thanks and cheers,
>>>>Chris.
>>>>
>>>>
>>>>Chris Wise
>>>>GT Propellers Australia
>>>>__________________________________________________________
>>>>Tel. +61 415 195 095 Fax. +61 8 8326 7268
>>>>
>>>>Email chris@gtpropellersaustralia.com.au
>>>>Website www.gtpropellersaustralia.com.au
>>>>
>>>>The information transmitted in and with this email is intended only for
>>>>the
>>>>person or entity to which it is addressed and may contain confidential
>>>>and/or privileged material. Any review, retransmission, dissemination or
>>>>other use of, or taking of any action in reliance upon this information,
>>>>by
>>>>persons or entities other than the intended recipients is prohibited. If
>>>>you
>>>>received this transmission in error, please contact the sender and delete
>>>>this e-mail and associated material from all computers and/or systems. The
>>>>intended recipient of this e-mail may only use, reproduce, disclose or
>>>>distribute the information contained in this e-mail and any attached
>>>>files,
>>>>with the permission of the sender.
>>>>
>>>>
>>>>==========
>>>>get=_blank>http://www.matronics.com/Navigator?Yak-List
>>>>==========
>>>>tp://forums.matronics.com
>>>>==========
>>>>_blank>http://www.matronics.com/contribution
>>>>p; Navigator Photoshare, and
>>>>href="http://www.matronics.com/Navigator?Yak-List">http://www.matronics========================<;
>>>>via the Web href="http://forums.matronics.com">http://forums.matronics.com
>>>_p; generous bsp;
>>>href="http://www.matronics.com/contribution">http://www.matronics.com/c================
>>>
>>>
>>>
>>>
>>>
>>>http://www.matronics.com/Navigator?Yak-List
>>>
>>>http://forums.matronics.com
>>>
>>>http://www.matronics.com/contribution
>>>
>>>
>>>
>>
>>
>>
>>
>>
>
>
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Message 26
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Jim;
I agree with you as well - but this engineer type just came FROM the bar.
Yes the same quantities of fuel in both tanks will result in the same pressure
being applied to both sides of the flapper valve.
But that same pressure does not translate into the same force being applied on
each side of the valve.
Pressure, whether described in pounds per sq. ft, grams per sq. cm. or whatever
produces equal force only when applied to an equal area.
That is precisely the problem with the CJ flapper valve. The closing force is actually
3 to 4 times the opening force with equal pressure.
In fact with absolutely no fuel sloshing (ie: no yaw, no turbulence, perfect condition
vents, etc.) it will take an imbalance of about 50 liters to open.
Fortunately we rarely ever find a day, or a pilot, that can deliver a non fuel
sloshing flight.
That it is invariably the right side hung up is I believe a result of the vent
system design. The left side vents much more directly than the right.
Walt
----- Original Message -----
From: cjpilot710@aol.com
To: yak-list@matronics.com
Sent: Tuesday, May 18, 2010 8:44 PM
Subject: Yak-List: Fuel flow
Let me see if I can elucidate what I think happens.
While a plug vent will definitely cause fuel to flow from just one tank, I just
don't feel that the vent line placed closer to one tank than the other will
cause the problem. If we have two tanks with equal amounts of fuel in them AND
they are level with each other, they both will exert the same pressure head
at the outlets. Hence the fuel in the header tank, which is full at all times,
will have that same pressure. The flop valves will only open when pressure from
the tank side is greater than what is in the header tank and thus fuel will
flow. So it bear to reason that if the airplane is sitting on a slope, fuel from
the high side will flow. Since the head pressure builds up in the header tank
the flop valve on the lower side will close.
Now lets get the airplane moving. Now both tanks AND the header tank, will not
only have the head pressure but inertia forces acting on them. IF you make coordinated
turns forces are the same in the tank AND the header tank.
But lets say you have a slight yaw either in a turn or wings level, the inertia
forces of the fuel tank will actually increase head pressure will force one
flop valve open and fuel will feed from that tank. Assume you have yaw left (left
rudder peddle down), the inertia in the left tank will effectively increase
the head pressure and force open the left flop valve, and the left tank will
feed fuel. The right tank may have exactly the same amount of fuel, but its
inertia is a way from the flop valve thus its head pressure is effective less.
The inertia of the fuel in the header tank will react the same - helping keep
the opposite flop valve closed.
Anyway that's what I think happens. A engineer type agreed with me, but I think
he was in a hurry to get to the bar. Would appreciate a back up check on my
theory.
Jim "Pappy" Goolsby
Message 27
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All =93 I think there have been 50+ posts on this subject in the la
st few
days, not counting the 100+ in years past. Bill Blackwell sells a simple,
very inexpensive kit consisting of some PVC tubing, two manual cockpit
mounted toggle shut-off valves and a few T-fittings that takes about 3-4
hours
for a novice A&P wana-be to install. Simply flip the non-venting tank swi
tch
off for 5-10 minutes in-flight, and problem solved.
The beauty of our =9Cexperimental=9D class!
Dave
In a message dated 5/18/2010 10:07:46 P.M. Pacific Daylight Time,
wlannon@persona.ca writes:
Jim;
I agree with you as well - but this engineer type just came FROM the bar.
Yes the same quantities of fuel in both tanks will result in the same
pressure being applied to both sides of the flapper valve.
But that same pressure does not translate into the same force being
applied on each side of the valve.
Pressure, whether described in pounds per sq. ft, grams per sq. cm. or
whatever produces equal force only when applied to an equal area.
That is precisely the problem with the CJ flapper valve. The closing forc
e
is actually 3 to 4 times the opening force with equal pressure.
In fact with absolutely no fuel sloshing (ie: no yaw, no turbulence,
perfect condition vents, etc.) it will take an imbalance of about 50 lite
rs to
open.
Fortunately we rarely ever find a day, or a pilot, that can deliver a non
fuel sloshing flight.
That it is invariably the right side hung up is I believe a result of the
vent system design. The left side vents much more directly than the righ
t.
Walt
----- Original Message -----
From: _cjpilot710@aol.com_ (mailto:cjpilot710@aol.com)
Sent: Tuesday, May 18, 2010 8:44 PM
Subject: Yak-List: Fuel flow
Let me see if I can elucidate what I think happens.
While a plug vent will definitely cause fuel to flow from just one tank,
I
just don't feel that the vent line placed closer to one tank than the
other will cause the problem. If we have two tanks with equal amounts of
fuel
in them AND they are level with each other, they both will exert the same
pressure head at the outlets. Hence the fuel in the header tank, which is
full at all times, will have that same pressure. The flop valves will onl
y
open when pressure from the tank side is greater than what is in the head
er
tank and thus fuel will flow. So it bear to reason that if the airplane
is si
tting on a slope, fuel from the high side will flow. Since the head
pressure builds up in the header tank the flop valve on the lower side wi
ll close.
Now lets get the airplane moving. Now both tanks AND the header tank, wil
l
not only have the head pressure but inertia forces acting on them. IF you
make coordinated turns forces are the same in the tank AND the header tan
k.
But lets say you have a slight yaw either in a turn or wings level, the
inertia forces of the fuel tank will actually increase head pressure will
force one flop valve open and fuel will feed from that tank. Assume you ha
ve
yaw left (left rudder peddle down), the inertia in the left tank will
effectively increase the head pressure and force open the left flop valve,
and
the left tank will feed fuel. The right tank may have exactly the same am
ount
of fuel, but its inertia is a way from the flop valve thus its head
pressure is effective less.
The inertia of the fuel in the header tank will react the same - helping
keep the opposite flop valve closed.
Anyway that's what I think happens. A engineer type agreed with me, but
I
think he was in a hurry to get to the bar. Would appreciate a back up che
ck
on my theory.
Jim "Pappy" Goolsby
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