Today's Message Index:
----------------------
1. 12:34 AM - Occasional engine anomally 912S - water? (graeme bird)
2. 01:12 AM - Re: Occasional engine anomally 912S - water? (Brian Davies)
3. 01:47 AM - Re: Occasional engine anomally 912S - water? (zwakie)
4. 01:52 AM - Re: Occasional engine anomally 912S - water? (ami-mcfadyean@talktalk.net)
5. 02:13 AM - Re: Occasional engine anomally 912S - water? (JonathanMilbank)
6. 02:43 AM - Re: Occasional engine anomally 912S - water? (graeme bird)
7. 03:01 AM - Re: Re: Occasional engine anomally 912S - water? (Alan Burrill)
8. 11:13 AM - Re: Occasional engine anomally 912S - water? (graeme bird)
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Subject: | Occasional engine anomally 912S - water? |
On several occasions now, after some time flying (40+ minutes) the engine has had
a minor episode, like one mag has been turned off for half a second. It then
continues as normal (with me looking for a field). It seems unrelated to temperature
or phase of flight, icing conditions, or turbulence, except perhaps
initiating a slow descent.
I have had a good think around the possible causes and why just these last few
months; one thing I did was change to using Essso Supreme (no ethanol) from ordinary
Shell unleased; the other was to change the long filler tube to aluminium
(classic style).
Recently using the tank drain plugs I have noticed a small amount of water in the
fuel (I'm not in the habit of checking this regularly as there was never an
issue).
So my current theory is, air is filling the long aluminium tube via the breather
and is trapped, when the temperature drops in the hangar condensation forms
on the inside of the tube and enters the fuel, either that or the Esso S+ garage
supplies it with water in.
It would fall into the starboard side of the tank but after 40 minutes or so the
fuel return to the bottom of the starboard side and roll/pitch changes may have
mixed the water and fuel sufficient that it is sucked into the port fuel line,
into the carb bowl and eventually into the engine at which point the mixture
refuses to burn for a beat or two. Once good fuel is back it carries on.
The old tube was rubber so this wouldn't have happened.
--------
Graeme Bird
G-UMPY - Mono Classic/XS FFW 912S, Woodcomp SR3000/3W CS, trutrak Gemini 2 axis
AP, PAW, PFLARM core, ads-b out, 8.33khz, mode S, FP-5, Aera500, SD on Nexus,
Smart A3
350 hours & 6 years on the Mono, 930 total
g(at)gdbmk.co.uk
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=483747#483747
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Subject: | Occasional engine anomally 912S - water? |
Hi Graeme,
A couple of things come to mind.
First, whenever you disturb the fuel system there is a high possibility of
debris moving and temporarily blocking a jet.
Secondly, there is always a danger when you mix fuel containing ethanol with
non-ethanol fuel. Fuel containing 5% ethanol will absorb water until it
reaches its limit and will then undergo phase separation, creating a layer
of pure water. If your 5% ethanol fuel has already absorbed a fair amount
of water and you then fill up with non- ethanol fuel you lower the overall
ethanol percentage of the fuel in your tank and hence its ability to contain
the absorbed water. Phase separation can then take place, probably in
relatively small quantities of water, so this may explain why you are now
getting water out of the drains. The solution is to drain all of the fuel
out of the tank and fill up with Esso Supreme.
This is all theory of course, but worth doing I would suggest.
Regards
Brian Davies
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of graeme bird
Sent: 10 October 2018 08:33
Subject: Europa-List: Occasional engine anomally 912S - water?
On several occasions now, after some time flying (40+ minutes) the engine
has had a minor episode, like one mag has been turned off for half a second.
It then continues as normal (with me looking for a field). It seems
unrelated to temperature or phase of flight, icing conditions, or
turbulence, except perhaps initiating a slow descent.
I have had a good think around the possible causes and why just these last
few months; one thing I did was change to using Essso Supreme (no ethanol)
from ordinary Shell unleased; the other was to change the long filler tube
to aluminium (classic style).
Recently using the tank drain plugs I have noticed a small amount of water
in the fuel (I'm not in the habit of checking this regularly as there was
never an issue).
So my current theory is, air is filling the long aluminium tube via the
breather and is trapped, when the temperature drops in the hangar
condensation forms on the inside of the tube and enters the fuel, either
that or the Esso S+ garage supplies it with water in.
It would fall into the starboard side of the tank but after 40 minutes or so
the fuel return to the bottom of the starboard side and roll/pitch changes
may have mixed the water and fuel sufficient that it is sucked into the port
fuel line, into the carb bowl and eventually into the engine at which point
the mixture refuses to burn for a beat or two. Once good fuel is back it
carries on. The old tube was rubber so this wouldn't have happened.
--------
Graeme Bird
G-UMPY - Mono Classic/XS FFW 912S, Woodcomp SR3000/3W CS, trutrak Gemini 2
axis AP, PAW, PFLARM core, ads-b out, 8.33khz, mode S, FP-5, Aera500, SD on
Nexus, Smart A3
350 hours & 6 years on the Mono, 930 total
g(at)gdbmk.co.uk
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=483747#483747
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Subject: | Re: Occasional engine anomally 912S - water? |
Suggestion of a by-no-means-expert:
graeme bird wrote:
> [...] like one mag has been turned off for half a second. It then continues
as normal [...]
Are you saying this 'coughing' only happens once during flight?
If so, then your theory:
graeme bird wrote:
> [...] starboard side of the tank but after 40 minutes or so the fuel return
to the bottom of the starboard side and roll/pitch changes may have mixed the
water and fuel sufficient [...]
will not hold as if that is the case one would expect it to happen more than once
a flight.
Also, if this happens only once each flight, Brian's suggestion of debris in the
fuel seems unlikely as this does not line up with your description that it always
happens about 40 mins. into the flight.
As you were indicating it seems to only happen on initiating a small descend, e.g.
reducing power after a prolonged period of non-adjusting the power, I would
suspect the carb jet has slowly been building up a minor bit of contaminiation
or is getting slightly out of alignment (early stages of it getting stuck
completely).
--------
Marcel Zwakenberg
XS TG || 912ULS || PH-SBR
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=483749#483749
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Subject: | Occasional engine anomally 912S - water? |
The other variable (which is consistent with your original theory) is change of
season. The temperature differential between warm humid days and cold nights
is relatively high at the moment.
I never saw water in the plastic tank either, but have a 'plastic' filler pipe.
Duncan McF.
----Original Message----
From: brian.davies44@gmail.com
Subj: RE: Europa-List: Occasional engine anomally 912S - water?
Hi Graeme,
A couple of things come to mind.
First, whenever you disturb the fuel system there is a high possibility of
debris moving and temporarily blocking a jet.
Secondly, there is always a danger when you mix fuel containing ethanol with
non-ethanol fuel. Fuel containing 5% ethanol will absorb water until it
reaches its limit and will then undergo phase separation, creating a layer
of pure water. If your 5% ethanol fuel has already absorbed a fair amount
of water and you then fill up with non- ethanol fuel you lower the overall
ethanol percentage of the fuel in your tank and hence its ability to contain
the absorbed water. Phase separation can then take place, probably in
relatively small quantities of water, so this may explain why you are now
getting water out of the drains. The solution is to drain all of the fuel
out of the tank and fill up with Esso Supreme.
This is all theory of course, but worth doing I would suggest.
Regards
Brian Davies
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of graeme bird
Sent: 10 October 2018 08:33
Subject: Europa-List: Occasional engine anomally 912S - water?
On several occasions now, after some time flying (40+ minutes) the engine
has had a minor episode, like one mag has been turned off for half a second.
It then continues as normal (with me looking for a field). It seems
unrelated to temperature or phase of flight, icing conditions, or
turbulence, except perhaps initiating a slow descent.
I have had a good think around the possible causes and why just these last
few months; one thing I did was change to using Essso Supreme (no ethanol)
from ordinary Shell unleased; the other was to change the long filler tube
to aluminium (classic style).
Recently using the tank drain plugs I have noticed a small amount of water
in the fuel (I'm not in the habit of checking this regularly as there was
never an issue).
So my current theory is, air is filling the long aluminium tube via the
breather and is trapped, when the temperature drops in the hangar
condensation forms on the inside of the tube and enters the fuel, either
that or the Esso S+ garage supplies it with water in.
It would fall into the starboard side of the tank but after 40 minutes or so
the fuel return to the bottom of the starboard side and roll/pitch changes
may have mixed the water and fuel sufficient that it is sucked into the port
fuel line, into the carb bowl and eventually into the engine at which point
the mixture refuses to burn for a beat or two. Once good fuel is back it
carries on. The old tube was rubber so this wouldn't have happened.
--------
Graeme Bird
G-UMPY - Mono Classic/XS FFW 912S, Woodcomp SR3000/3W CS, trutrak Gemini 2
axis AP, PAW, PFLARM core, ads-b out, 8.33khz, mode S, FP-5, Aera500, SD on
Nexus, Smart A3
350 hours & 6 years on the Mono, 930 total
g(at)gdbmk.co.uk
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=483747#483747
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Subject: | Re: Occasional engine anomally 912S - water? |
My aircraft is a Classic with the long aluminium filler tube, which was installed
several years ago and I continue to use ordinary unleaded fuel obtained from
any large turnover local garage or supermarket. I have changed all my hoses
and continued to check the tank bottom outlet coarse filters annually since the
introduction of ethanol. No significant dirt nor any water was ever found and
all hoses remain in good condition even after 5 years since the last replacement.
By the way, the prescribed method of tested for ethanol employing a glass tube
etc never shows ethanol to me, although someone who used to use the chemical testing
kit when it was obtainable did detect ethanol. However I take comfort that
pilots in at least one South American country are using fuel with 20% or higher
ethanol content and seemingly don't report problems.
Since the introduction of ethanol I've never found so much as a drop of water in
fuel samples, probably because ethanol "mops it up". Prior to that I did very
rarely find a drop or two, usually when the fuel tank hadn't been filled after
flight and I'd waited a few days until refilling the tank before going flying
again. Consequently I strive to ensure that the tank is filled completely up
to an inch or so below the cap immediately after flying, keeping the aircraft
tilted slightly to the left when filling to get maximum into the tank. My aircraft's
been converted to nose wheel, so possibly more fuel can be accommodated
than is normal for a mono and maybe less likely for an empty space in the aluminium
filler tube due to deck angle.
It seems to me that condensation droplets which might accumulate in the starboard
side of the tank would normally remain in the bottom and wouldn't be able to
cross over the tunnel to the port side in most circumstances. The port side
is what I have selected for all flights except for the annual permit renewal test
flight. Having said all of this, your theory seems plausible in the absence
of any other explanation.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=483751#483751
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Subject: | Re: Occasional engine anomally 912S - water? |
Interesting that a bit of ethanol could gobble up the water; I rarely fill up after
flying; so I could do that while cold nights persist. I doubt the jet block
debris thing as it would be much more pervasive and random; though I did change
all the pipes (didn't really twig it would need such a shakedown again).
Never thought of tilting the plan to get more fuel/less air; good tip.
I couldn't say that it only happens once per flight I think it might have been
more on an occasion.
I always test the fuel for using the water tube thing but have never seen anything
and also never had an issue with ordinary unleaded shell for 5 years.
--------
Graeme Bird
G-UMPY - Mono Classic/XS FFW 912S, Woodcomp SR3000/3W CS, trutrak Gemini 2 axis
AP, PAW, PFLARM core, ads-b out, 8.33khz, mode S, FP-5, Aera500, SD on Nexus,
Smart A3
350 hours & 6 years on the Mono, 930 total
g(at)gdbmk.co.uk
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=483752#483752
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Subject: | Re: Occasional engine anomally 912S - water? |
Probable not related to change in fuel.
Hows the fuel pressure and how old is the Fuel Pump. State of the fuel carb bowls
and general health of the fuel system including the carbs?
Alan
Sent from my iPad
> On 10 Oct 2018, at 10:41, graeme bird <graeme@gdbmk.co.uk> wrote:
>
>
> Interesting that a bit of ethanol could gobble up the water; I rarely fill up
after flying; so I could do that while cold nights persist. I doubt the jet block
debris thing as it would be much more pervasive and random; though I did
change all the pipes (didn't really twig it would need such a shakedown again).
> Never thought of tilting the plan to get more fuel/less air; good tip.
>
> I couldn't say that it only happens once per flight I think it might have been
more on an occasion.
>
> I always test the fuel for using the water tube thing but have never seen anything
and also never had an issue with ordinary unleaded shell for 5 years.
>
> --------
> Graeme Bird
> G-UMPY - Mono Classic/XS FFW 912S, Woodcomp SR3000/3W CS, trutrak Gemini 2 axis
AP, PAW, PFLARM core, ads-b out, 8.33khz, mode S, FP-5, Aera500, SD on Nexus,
Smart A3
> 350 hours & 6 years on the Mono, 930 total
> g(at)gdbmk.co.uk
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=483752#483752
>
>
>
>
>
>
>
>
>
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Subject: | Re: Occasional engine anomally 912S - water? |
Thanks for the response.
The carb bowls are clean, I think there was a small bubble in one when I checked.
Re the pump, this would have to be the mechanical pump and I'd expect it to
be more likely evident at high power (TO, climb), for the effect of fuel starvation
to last longer, for it not to recover so quickly/at all and to show up
as low or fluctuating pressure on the fuel pressure gauge.
It was changed last as a result of the rotax SB maybe 3 years ago/ 180hrs.
--------
Graeme Bird
G-UMPY - Mono Classic/XS FFW 912S, Woodcomp SR3000/3W CS, trutrak Gemini 2 axis
AP, PAW, PFLARM core, ads-b out, 8.33khz, mode S, FP-5, Aera500, SD on Nexus,
Smart A3
350 hours & 6 years on the Mono, 930 total
g(at)gdbmk.co.uk
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=483757#483757
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