Today's Message Index:
----------------------
1. 04:50 AM - New to Carb Synch in 912. Should Carbs behave the same at all rpms? (Godo Barrenechea)
2. 06:09 AM - in-line fuel filters - can you recommend any? (MacDonald Doug)
3. 06:43 AM - Re: in-line fuel filters - can you recommend any? (Bob Harrison)
4. 07:05 AM - Re: air entering fuel system on suction side - or is my Pierburg electrical pump broken? (Bob Harrison)
5. 08:47 AM - Re: in-line fuel filters - can you recommend any? (Don Hudgeon)
Message 1
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| Subject: | New to Carb Synch in 912. Should Carbs behave the same |
at all rpms?
Hi,
After attending a couple of seminars and watching the videos, I felt I
could run my firts Carb Synch...
I followed the manual and run first the mechanical adjustment followed by
the pneumatic ones at 3000 rpm. All good here.
Issue came when, out of curiosity, I wanted to check if carbs would be
balanced also at the high rpms when I would be flying, so I started
adjusting, not for 3000 as per the manual, but playing up and down.
The thing is that, no matter which rpm I would synchronise for, the results
would not be the same all way in the rest of the rpm, so I started to
believe that I had a different behaviour in the carbs. I asked the shop
that does usually my maintenance and both carbs were cleaned and needles
changed 10 h ago.
So here I am, doubting if my readings are wrong, If I need to check again
carbs or if I'm only good to build airframes, but unable to tune engines...
For those of you with more experience, any suggestion/comments pls
Thanks in advance
Godo
RV12 in Barcelona, Spain
Last data:
Rigth vs Left Carb mmH reading
4500 rpm +0.5 mm
4000 rpm +0.0 mm
3500 rpm -1.5 mm
3000 rpm -2.5 mm
2500 rpm -2.5 mm
Message 2
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| Subject: | in-line fuel filters - can you recommend any? |
I was figuratively biting my tongue, hoping this topic would go away withou
t killing anyone but seeing so many responses in the Daily Digest I decided
to add my two cents.- Forgive me if I come across as a bit pushy on this
topic as fuel filters and aircraft fuel system design are a bit of a pet p
eeve of mine.=0A=0ABased on standard aircraft design, there should be a coa
rse finger screen on the outlet of each tank, this is filter number one whi
ch keeps large chunks of debris from entering the fuel delivery system.-
Each tank should have a sediment drain to check for and eliminate debris an
d water which can accumulate in the tank.- At the lowest point in the fue
l system there needs to be another sediment drain as this is also where wat
er can accumulate.- A properly designed gascolator should be installed in
the system, often at the lowest point in lieu of a low point drain.- The
gascolator should be the type which has a sediment bowl with drain and a f
airly fine mesh screen in the top which acts as filter number two.- Final
ly, the fuel pumps used on Rotax engines have a fine mesh screen in them (a
ccording to Phil Lockwood) which acts as a final filter before the fuel ent
ers the carburetors.- If particulate can get through these three filters,
then it will go
through the engine without hurting anything.=0A=0A=0ASo essentially, a pro
perly designed fuel system has three stages of filtration.- Why would you
want to add another level of filtration to your fuel system?- =0A=0A=0AI
n his talk on 912 maintenance, Phil Lockwood tells an entertaining story ab
out getting a bad batch of fuel in his older carburated car.- The fuel ha
d some kind of very fine particulate suspended in it which plugged his fuel
filter and made for very poor performance, eventually killing the engine.
- Phil replaced the fuel filter and the new one plugged again within a fe
w minutes as he still had the bad fuel in his fuel tank.- Since he was in
the middle of nowhere and did not have another fuel filter, Phil removed t
he fuel filter all together until he reached his destination and the car ra
n fine for the remainder of the trip.- As long as the particulate is smal
l enough to not plug the carburetor jets, it is not going to hurt anything
in the engine.- However, if a fine particulate accumulates on a too fine
of filtration media, the particulate could interrupt fuel flow to the engin
e.=0A=0AFuel systems in homebuilts/ultralights/LSAs are one place where we
need to pay close attention to what has been done in the certified world.
- Adding components into the fuel system where they should not be can be
dangerous and should be done only with extreme caution. If your aircraft fu
el system is not set up according to standard design, that should be your g
oal, not adding fuel filters for the sake of =0Aadding fuel filters.- Of
course, fuel injection systems like that on the 912iS is another issue but
I am not experienced with the iS installation so cannot comment on its filt
ration requirements.=0A=0A=0AThere, I will get down off my soapbox.- I ho
pe I have given you guys something to think about without coming across as
too preachy.=0A=0ADoug M=0ACH-701, Rotax 912UL- =0A
Message 3
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| Subject: | in-line fuel filters - can you recommend any? |
................and don't forget the thimble filter in the electric Pierburg
fuel pumps x 2 on the 914 engine.
Regards
Bob Harrison Europa /Rotax 914
From: owner-rotaxengines-list-server@matronics.com
[mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of MacDonald
Doug
Sent: 29 June 2014 14:08
Subject: RotaxEngines-List: in-line fuel filters - can you recommend any?
I was figuratively biting my tongue, hoping this topic would go away without
killing anyone but seeing so many responses in the Daily Digest I decided to
add my two cents. Forgive me if I come across as a bit pushy on this topic
as fuel filters and aircraft fuel system design are a bit of a pet peeve of
mine.
Based on standard aircraft design, there should be a coarse finger screen on
the outlet of each tank, this is filter number one which keeps large chunks
of debris from entering the fuel delivery system. Each tank should have a
sediment drain to check for and eliminate debris and water which can
accumulate in the tank. At the lowest point in the fuel system there needs
to be another sediment drain as this is also where water can accumulate. A
properly designed gascolator should be installed in the system, often at the
lowest point in lieu of a low point drain. The gascolator should be the
type which has a sediment bowl with drain and a fairly fine mesh screen in
the top which acts as filter number two. Finally, the fuel pumps used on
Rotax engines have a fine mesh screen in them (according to Phil Lockwood)
which acts as a final filter before the fuel enters the carburetors. If
particulate can get through these three filters, then it will go through the
engine without hurting anything.
So essentially, a properly designed fuel system has three stages of
filtration. Why would you want to add another level of filtration to your
fuel system?
In his talk on 912 maintenance, Phil Lockwood tells an entertaining story
about getting a bad batch of fuel in his older carburated car. The fuel had
some kind of very fine particulate suspended in it which plugged his fuel
filter and made for very poor performance, eventually killing the engine.
Phil replaced the fuel filter and the new one plugged again within a few
minutes as he still had the bad fuel in his fuel tank. Since he was in the
middle of nowhere and did not have another fuel filter, Phil removed the
fuel filter all together until he reached his destination and the car ran
fine for the remainder of the trip. As long as the particulate is small
enough to not plug the carburetor jets, it is not going to hurt anything in
the engine. However, if a fine particulate accumulates on a too fine of
filtration media, the particulate could interrupt fuel flow to the engine.
Fuel systems in homebuilts/ultralights/LSAs are one place where we need to
pay close attention to what has been done in the certified world. Adding
components into the fuel system where they should not be can be dangerous
and should be done only with extreme caution. If your aircraft fuel system
is not set up according to standard design, that should be your goal, not
adding fuel filters for the sake of adding fuel filters. Of course, fuel
injection systems like that on the 912iS is another issue but I am not
experienced with the iS installation so cannot comment on its filtration
requirements.
There, I will get down off my soapbox. I hope I have given you guys
something to think about without coming across as too preachy.
Doug M
CH-701, Rotax 912UL
Message 4
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| Subject: | air entering fuel system on suction side - or is |
my Pierburg electrical pump broken?
I recommend you use HYLOMAR sealant made in the USA under licence and
developed by Rolls Royce Aero Engines for all fuel and oil related joints.
But use it very sparingly and especially as mentioned on the instructions.
I would never make any oil or fuel related joint without it.
Regards
Bob Harrison Rolls Royce Aero Engine trained .Europa G-PTAG Rotax 914
-----Original Message-----
From: owner-rotaxengines-list-server@matronics.com
[mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of John
Hauck
Sent: 28 June 2014 23:11
Subject: RE: RotaxEngines-List: air entering fuel system on suction side -
or is my Pierburg electrical pump broken?
--> <jhauck@elmore.rr.com>
I would definitely keep silicon sealant away from any fuel system.
Your silicone coated cork gasket is trash. Silicone seal causes the gasket
to squeeze out and leak.
You can get several fuel tank sealant cartridges from Aircraft Spruce that
work well. Also cut your own gasket.
john h
Kolb MKIII
Boise, Idaho
-----Original Message-----
From: owner-rotaxengines-list-server@matronics.com
[mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Sacha
Sent: Saturday, June 28, 2014 3:38 PM
Subject: Re: RotaxEngines-List: air entering fuel system on suction side -
or is my Pierburg electrical pump broken?
<uuccio@gmail.com>
Ok so I got rid of all the silicone sealant and cleaned the cork gasket
which seals the VDO sender (it's quite a big gasket with a 40mm diameter
hole in the centre and five 5mm holes for the screws around the perimeter).
Well guess what? The cork seal leaks badly. So I'm back to square one, I
need to find a way to seal the VDO sender on the top of my header tank. I
have some silicone rubber which I thought of cutting to size and using. What
do folks think?
Another solution would be to use the same red silicone sealant as I used
before but only to apply it on the exterior of the tank. I'm concerned it
might eat into the cork though as someone (John?) mentioned.
=
Photoshare, and much much more:
http://www.matronics.com/Navigator?RotaxEngines-List
=
=
=
Message 5
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| Subject: | Re: in-line fuel filters - can you recommend any? |
I fly a kitfox 912 ul and have the exact fuel system you describe.
in 400 hours never had a problem.
take care
Don
On Jun 29, 2014 6:14 AM, "MacDonald Doug" <dougsnash@yahoo.com> wrote:
> I was figuratively biting my tongue, hoping this topic would go away
> without killing anyone but seeing so many responses in the Daily Digest I
> decided to add my two cents. Forgive me if I come across as a bit pushy on
> this topic as fuel filters and aircraft fuel system design are a bit of a
> pet peeve of mine.
>
> Based on standard aircraft design, there should be a coarse finger screen
> on the outlet of each tank, this is filter number one which keeps large
> chunks of debris from entering the fuel delivery system. Each tank should
> have a sediment drain to check for and eliminate debris and water which can
> accumulate in the tank. At the lowest point in the fuel system there needs
> to be another sediment drain as this is also where water can accumulate. A
> properly designed gascolator should be installed in the system, often at
> the lowest point in lieu of a low point drain. The gascolator should be
> the type which has a sediment bowl with drain and a fairly fine mesh screen
> in the top which acts as filter number two. Finally, the fuel pumps used
> on Rotax engines have a fine mesh screen in them (according to Phil
> Lockwood) which acts as a final filter before the fuel enters the
> carburetors. If particulate can get through these three filters, then it
> will go through the engine without hurting anything.
>
> So essentially, a properly designed fuel system has three stages of
> filtration. Why would you want to add another level of filtration to your
> fuel system?
>
> In his talk on 912 maintenance, Phil Lockwood tells an entertaining story
> about getting a bad batch of fuel in his older carburated car. The fuel
> had some kind of very fine particulate suspended in it which plugged his
> fuel filter and made for very poor performance, eventually killing the
> engine. Phil replaced the fuel filter and the new one plugged again within
> a few minutes as he still had the bad fuel in his fuel tank. Since he was
> in the middle of nowhere and did not have another fuel filter, Phil removed
> the fuel filter all together until he reached his destination and the car
> ran fine for the remainder of the trip. As long as the particulate is
> small enough to not plug the carburetor jets, it is not going to hurt
> anything in the engine. However, if a fine particulate accumulates on a
> too fine of filtration media, the particulate could interrupt fuel flow to
> the engine.
>
> Fuel systems in homebuilts/ultralights/LSAs are one place where we need to
> pay close attention to what has been done in the certified world. Adding
> components into the fuel system where they should not be can be dangerous
> and should be done only with extreme caution. If your aircraft fuel system
> is not set up according to standard design, that should be your goal, not
> adding fuel filters for the sake of adding fuel filters. Of course, fuel
> injection systems like that on the 912iS is another issue but I am not
> experienced with the iS installation so cannot comment on its filtration
> requirements.
>
> There, I will get down off my soapbox. I hope I have given you guys
> something to think about without coming across as too preachy.
>
> Doug M
> CH-701, Rotax 912UL
>
> *
>
>
> *
>
>
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