Today's Message Index:
----------------------
1. 07:31 AM - Re: Fuel flow (mikeperkins)
2. 08:28 AM - Re: Re: Fuel flow (Guy Buchanan)
3. 09:01 AM - Re: Fuel flow (mikeperkins)
4. 09:40 AM - Re: Re: Fuel flow (Lowell Fitt)
5. 10:24 AM - Re: Re: Fuel flow (Guy Buchanan)
6. 10:53 AM - Re: Re: Fuel flow (Bob & Toodie)
7. 04:23 PM - fuel flow - dual carbs (clemwehner)
8. 06:13 PM - Re: fuel flow - dual carbs (Ted)
9. 06:48 PM - Re: Fuel flow (floran higgins)
10. 07:34 PM - Engine Mischief (Lloyd & Lorrie Cudnohufsky)
11. 08:27 PM - Re: Engine Mischief (James Shumaker)
Message 1
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The Mikuni fuel pump is spec'd to pull fuel against gravity to a height of 24 inches. However, I assume that's at 1 G. When the aircraft is at 2 Gs, so is the fuel. So if the assumption is correct that 24 inches is at 1 G, then the distance at 2 Gs becomes 12 inches. But I'm not sure how the fuel lift distance was specified (if it spec'd at 1 G or if it is spec'd at more than 1 G). Anyway, here's a writeup on the Mikuni fuel pump: http://www.ultralightnews.ca/mikuni/
Also, most Kitfoxes have fuel caps with ram air vents, but I'm not sure how many
inches of fuel pressure they add.
That having been said, I plan to never count on the fuel remaining in the header
tank alone because with a failed fuel pump, the lack of head pressure with empty
wing tanks will create an unpleasant situation.
--------
Mike Perkins
Havana, Illinois
Model I, 532, B gearbox, GSC prop
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=407032#407032
Message 2
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Mike,
Not too many people launch with empty wing tanks, and if you do, I
guess you get what you asked for, eh? Fortunately the head pressure in
level flight is nearly even, with most of the "loss" of pressure
attributable to friction and other mechanical losses. I don't know if
anyone else has done this but when I get to the end of this installation
I'll be testing without the fuel pump to see if the wing tanks will
gravity feed and at what attitude. There's some conjecture that the
vibration of the carbs allows a pure gravity feed in spite of the lack
of 2.5psi static pressure.
Guy Buchanan
Ramona, CA
Kitfox IV-1200 / 912-S / Warp 3cs / 500 hrs. and grounded
Now a glider pilot, too.
On 8/19/2013 7:30 AM, mikeperkins wrote:
> That having been said, I plan to never count on the fuel remaining in the header
tank alone because with a failed fuel pump, the lack of head pressure with
empty wing tanks will create an unpleasant situation.
>
>
Message 3
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Hi Guy,
You're right to say that no one would (or should) launch with empty tanks, but
someone who encountered something unexpected enroute might wind up accidentally
landing with them empty. In that case, a go-around would put the behind-the-seat
header tank pretty dang low.
I once did a differential measurement of my Kiftox I's behind-the-seat header tank
and the carbs. I discovered the aircraft's supply of fuel would depend upon
a working fuel pump. But I don't remember the distance.
--------
Mike Perkins
Havana, Illinois
Model I, 532, B gearbox, GSC prop
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=407039#407039
Message 4
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Interesting discussion. On another forum a guy measured fuel flow beyond the
fuel pump at the carburetors and he found that the flow there didn't come
up to the FAA recommendations. So the fuel will flow past an inop pump.
However I seem to have heard that if the diaphragm has been breached, fuel
will preferably simply flow into the crank case - not sure on this. I would
think an easy fix would be an electric aux pump between the header tank and
the mechanical fuel pump. I have one on mine and the on switch is within
thumbs reach with my hand on the throttle.
Lowell
--------------------------------------------------
From: "mikeperkins" <flybyewire@gmail.com>
Sent: Monday, August 19, 2013 9:00 AM
Subject: Kitfox-List: Re: Fuel flow
>
> Hi Guy,
>
> You're right to say that no one would (or should) launch with empty tanks,
> but someone who encountered something unexpected enroute might wind up
> accidentally landing with them empty. In that case, a go-around would put
> the behind-the-seat header tank pretty dang low.
>
> I once did a differential measurement of my Kiftox I's behind-the-seat
> header tank and the carbs. I discovered the aircraft's supply of fuel
> would depend upon a working fuel pump. But I don't remember the distance.
>
> --------
> Mike Perkins
> Havana, Illinois
> Model I, 532, B gearbox, GSC prop
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=407039#407039
>
>
>
Message 5
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On 8/19/2013 9:39 AM, Lowell Fitt wrote:
> However I seem to have heard that if the diaphragm has been breached,
> fuel will preferably simply flow into the crank case - not sure on
> this. I would think an easy fix would be an electric aux pump between
> the header tank and the mechanical fuel pump. I have one on mine and
> the on switch is within thumbs reach with my hand on the throttle.
'Course if it's true about the diaphragm, the aux pump isn't going to
help you much in /that /failure mode. (I've never /heard /of anyone
pumping fuel into the case, though.)
Guy Buchanan
Ramona, CA
Kitfox IV-1200 / 912-S / Warp 3cs / 500 hrs. and grounded
Now a glider pilot, too.
Message 6
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I agree, the only way to fly, Back up for the mechanical. Bob & Toodie KF
4/1200/ O02, High Sierras.
--------------------------------------------------
From: "Lowell Fitt" <lcfitt@sbcglobal.net>
Sent: Monday, August 19, 2013 9:39 AM
Subject: Re: Kitfox-List: Re: Fuel flow
>
> Interesting discussion. On another forum a guy measured fuel flow beyond
> the fuel pump at the carburetors and he found that the flow there didn't
> come up to the FAA recommendations. So the fuel will flow past an inop
> pump. However I seem to have heard that if the diaphragm has been
> breached, fuel will preferably simply flow into the crank case - not sure
> on this. I would think an easy fix would be an electric aux pump between
> the header tank and the mechanical fuel pump. I have one on mine and the
> on switch is within thumbs reach with my hand on the throttle.
> Lowell
>
> --------------------------------------------------
> From: "mikeperkins" <flybyewire@gmail.com>
> Sent: Monday, August 19, 2013 9:00 AM
> To: <kitfox-list@matronics.com>
> Subject: Kitfox-List: Re: Fuel flow
>
>>
>> Hi Guy,
>>
>> You're right to say that no one would (or should) launch with empty
>> tanks, but someone who encountered something unexpected enroute might
>> wind up accidentally landing with them empty. In that case, a go-around
>> would put the behind-the-seat header tank pretty dang low.
>>
>> I once did a differential measurement of my Kiftox I's behind-the-seat
>> header tank and the carbs. I discovered the aircraft's supply of fuel
>> would depend upon a working fuel pump. But I don't remember the distance.
>>
>> --------
>> Mike Perkins
>> Havana, Illinois
>> Model I, 532, B gearbox, GSC prop
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=407039#407039
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
>
Message 7
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| Subject: | fuel flow - dual carbs |
I watched the webinar on fuel flow testing which stated flow should be 150% of
engine requirements at 25 degree deck angle and measured at the carb. But, what
about a dual carb engine like the 912? With the fuel flow split between the
carbs, would you need 300% to ensure 150% at each carb?
Or, do you just measure it at one carb and assume the engine will run on half the
fuel volume going to each carb? The webinar did not address dual carb engines.
Ideas?
Clem
Lawton, OK
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=407074#407074
Message 8
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| Subject: | fuel flow - dual carbs |
Clem
Fuel flow is 150% of what the engine consumes irrespective of the number of
carbs the engine may have. So fuel flow would be measured prior to splitting
off for each carb.
Ted
Edmonton 912UL/KF4
-----Original Message-----
From: owner-kitfox-list-server@matronics.com
[mailto:owner-kitfox-list-server@matronics.com] On Behalf Of clemwehner
Sent: Monday, August 19, 2013 5:22 PM
Subject: Kitfox-List: fuel flow - dual carbs
I watched the webinar on fuel flow testing which stated flow should be 150%
of engine requirements at 25 degree deck angle and measured at the carb.
But, what about a dual carb engine like the 912? With the fuel flow split
between the carbs, would you need 300% to ensure 150% at each carb?
Or, do you just measure it at one carb and assume the engine will run on
half the fuel volume going to each carb? The webinar did not address dual
carb engines.
Ideas?
Clem
Lawton, OK
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=407074#407074
Message 9
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I had a fuel pump failure last spring.
The engine would only run for less than a minute at full throttle.
Would run fine at cruise setting.
Fkoran Higgins
Helena, Mt.
Speedster
912 ULS
----- Original Message -----
From: "clemwehner" <clemwehner@sbcglobal.net>
Sent: Sunday, August 18, 2013 10:25 AM
Subject: Kitfox-List: Fuel flow
>
> Our KF-IV has the plastic header tank behind the seat. Since the header
> tank is lower than the carbs, how can the engine run from the header tank
> in the event fuel flow stops from the main tanks for some reason? Some
> guys have said that there is about 10 minutes of fuel in the header tank.
> How is that possible with no gravity flow in level flight?
>
> Does the engine fuel pump suck fuel from the header when it's running?
>
> thanks,
> Clem
> Oklahoma
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=406963#406963
>
>
>
Message 10
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List,
I have been enjoying my Model 5 a lot this summer, even managed to squeeze
in a flight into Airventure, but 2 weeks ago my daughter and I dropped into
a small strip north of here to do some Blueberry Picking. When we were
climbing out to leave the engine (912ul) lost power slightly, I pitched the
nose down, pulled the power and pushed it back in and it was fine. Headed
straight home (20 min flight) with no further problems, the change in power
was so slight my daughter never noticed anything was wrong, but I noticed.
Not sure why I did what I did, but it worked. (I also have an electric
booster pump in-line like Lowell described with the switch next to the
throttle, never even thought of using it). Not sure what it was I
experienced, it almost sounded like I fouled a cylinder for a moment or the
throttle slipped, but was a different sound than just reducing the throttle
(not a slip of the throttle, my hand was on it). So last week I pulled the
plugs, 50 hours on them, black sooted in front cylinders, golden brown in
the rear, put in all new plugs, checked all plug wires. Pulled the carb
bowls to look for debris, they were clean, visuals on everything else was
normal. So I put it back together. Then last weekend I was giving my
daughters friend a ride, we were in normal cruise attitude turning about
4500 and it happened again, I repeated the same procedure and it went away,
again, my passenger never noticed anything wrong.
So, thinking it through and replaying the events in my head I am leaning
towards what I actually experienced was dropping one of the ignition systems
and the power loss was the 100 or so rpm drop.
Now trying to troubleshoot, prove / disprove my theory, wondering if anyone
has had any experience troubleshooting intermittent ignition? Where to
start, what NOT to do, Here is my thoughts,
1) Start with a thorough inspection of all ignition wiring, terminals, key
switch remove tie wraps and bundling, chafe wraps etc, look for cracks,
arcing etc.
2) Review manual for any ohm checks I can make on the coils, ignition
systems, etc. Seeing the problem has been intermittent I am doubtful this
will turn up anything. Seems strange that reducing the throttle and then
increasing again cures the problem, broken wire, shaking?
3) If these steps turn up nothing I am considering taking it up, staying in
the pattern at altitude and turning off one ignition to see if that is what
I experienced, has anyone ever turned their ignition from both to one during
flight? Anyone see any concerns?
4) After all that, if I am unable to find or recreate the problem, buy one
ignition and change out one????
Appreciate any direction I can get,
Lloyd C KF 5 Outback
912ul IVO IFA Northern Mi
IMG00144-20120518-1002
Message 11
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| Subject: | Re: Engine Mischief |
I had vapor lock that was like that.- Happened enough that I could predic
t it on a climb out in warm weather.- Shielded the gascolator from the ex
haust with a sheet of aluminum-and have not had the same problem.- =0A
-=0AThere is no problem with turning off one of the ignitions in flight.
- If you turn off both you should pull the throttle to idle before restar
ting.- =0A-=0AJim Shumaker=0AKitfox III- Rotax 912, 1200 hours=0A =0A
=0A________________________________=0A From: Lloyd & Lorrie Cudnohufsky <7s
uds@Chartermi.net>=0ATo: kitfox-list@matronics.com =0ASent: Monday, August
19, 2013 7:32 PM=0ASubject: Kitfox-List: Engine Mischief =0A =0A=0A=0AList
,=0AI have been enjoying my Model 5 a lot this summer, even managed to sque
eze in a flight into Airventure, but 2 weeks ago my daughter and I dropped
into a small strip north of here to do some Blueberry Picking. When we were
climbing out to leave the engine (912ul) lost power slightly, I pitched th
e nose down, pulled the power and pushed it back in and it was fine. Headed
straight home (20 min flight) with no further problems, the change in powe
r was so slight my daughter never noticed anything was wrong, but I noticed
. Not sure why I did what I did, but it worked. (I also have an electric bo
oster pump in-line like Lowell described with the switch next to the thrott
le, never even thought of using it). Not sure what it was I experienced, it
almost sounded like I fouled a cylinder for a moment or the throttle slipp
ed, but was a different sound than just reducing the throttle (not a slip o
f the throttle, my hand was on it). So last week I pulled the plugs, 50
hours on them, black sooted in front cylinders, golden brown in the rear,
put in all new plugs, checked all plug wires. Pulled the carb bowls to look
for debris, they were clean, visuals on everything else was normal. So I p
ut it back together. Then last weekend I was giving my daughters friend a r
ide, we were in normal cruise attitude turning about 4500 and it happened a
gain, I repeated the same procedure and it went away, again, my passenger n
ever noticed anything wrong. =0ASo, thinking it through and replaying the e
vents in my head I am leaning towards what I actually experienced was dropp
ing one of the ignition systems and the power loss was the 100 or so rpm dr
op.=0A-=0ANow trying to troubleshoot, prove / disprove my theory, wonderi
ng if anyone has had any experience troubleshooting intermittent ignition?
Where to start, what NOT to do, Here is my thoughts,=0A-=0A1) Start with
a thorough inspection of all ignition wiring, terminals, key switch remove
tie wraps and bundling, chafe wraps etc, look for cracks, arcing etc.=0A2)
Review manual for any ohm checks I can make on the coils, ignition systems,
etc. Seeing the problem has been intermittent I am doubtful this will turn
up anything. Seems strange that reducing the throttle and then increasing
again cures the problem, broken wire, shaking?=0A3) If these steps turn up
nothing I am considering taking it up, staying in the pattern at altitude a
nd turning off one ignition to see if that is what I experienced, has anyon
e ever turned their ignition from both to one during flight? Anyone see any
concerns? =0A4) After all that, if I am unable to find or recreate the pro
blem, buy one ignition and change out one????=0A-=0AAppreciate any direct
ion I can get,=0A-=0A----- Lloyd C- KF 5 Outback =0A912ul IVO
IFA Northern Mi
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