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nimbusaviation(at)YAHOO.C
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 Posted: Mon May 09, 2011 2:57 am Post subject: 912 quit |
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07/05/2011 we experienced an engine stop with the 912 in our monowheel - this happened just as the throttle was being advanced at the commencement of the takeoff sequence, so we rolled only a hundred feet or so and coasted to a halt. After less than a minute, a first restart attempt was successful, and we taxied back to the apron uneventfully, tail between legs, where my second action was to put on the kettle for a cup of tea.
Perhaps relevent, I had heard a sharp 'bump' about 10 seconds earlier, as we were turning on the threshold to line up, and thought I had hit a light or something with the outrigger, but nothing was seen. The ambient conditions were about 21°C and some showers were in the area with a convective active frontal system; we had just completed 1 circuit to land after a reasonably expeditious departure, but on backtracking from the first landing, had to hold for about 5-6 minutes on the main apron, then backtrack the second half of the active.
Immediately after parking first action was to pull the top (XS) cowl when we noticed fuel boiling up the vent tubes which run into the airbox, both sides.
My take on this is fuel vaporisation due to high carb temps. Our (second owner) europa is NOT fitted with drip trays under the carbs - now an item of concern, nor is there any exhaust manifold insulation. The more I read the greater my concern about in-cowl temps and comprehensive action to prevent a repeat of this experience.
Fuel pressure indications were normal, and coolant temp was showing about 40°C, although we now suspect the Temp sender is malfunctioning. Oil and CHTs where nominal.
Ours may be just another data point, but while we trawl this archive and worry the problem, any comments would be most welcome. My own last engine quit, also on the ground, was due carb ice in an O-200; but this was much more 'exciting' coming as it did at the moment of truth .. "G-HL, rolling" - phut!
The climb-out to our east is lacking a good escape option.
Glenn Rainey
Cumbernauld, Scotland
G-OJHL
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kheindl(at)msn.com
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| Posted: Mon May 09, 2011 4:09 am Post subject: 912 quit |
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Glenn,
My engine never quit, but I observed identical boilover on a hot day. It was fixed by putting heat shields below the carbs. On the port side I have a plate made of firewall material, attached to the top bolt of the exhaust. On the starboard side I now have a larger and flexible asbestos plate (from ACS), not attached to anything, but firmly wedged into place, and easy to remove for inspections. There is even more heat starboard because of the oil tank etc.
Karl
| Quote: | Date: Mon, 9 May 2011 11:24:13 +0100
From: nimbusaviation(at)YAHOO.COM
Subject: Europa-List: 912 quit
To: europa-list(at)matronics.com
--> Europa-List message posted by: Glenn Rainey <nimbusaviation(at)yahoo.com>
07/05/2011 we experienced an engine stop with the 912 in our monowheel - this happened just as the throttle was being advanced at the commencement of the takeoff sequence, so we rolled only a hundred feet or so and coasted to a halt. After less than a minute, a first restart attempt was successful, and we taxied back to the apron uneventfully, tail between legs, where my second action was to put on the kettle for a cup of tea.
Perhaps relevent, I had heard a sharp 'bump' about 10 seconds earlier, as we were turning on the threshold to line up, and thought I had hit a light or something with the outrigger, but nothing was seen. The ambient conditions were about 21°C and some showers were in the area with a convective active frontal system; we had just completed 1 circuit to land after a reasonably expeditious departure, but on backtracking from the first landing, had to hold for about 5-6 minutes on the main apron, then backtrack the second half of the active.
Immediately after parking first action was to pull the top (XS) cowl when we noticed fuel boiling up the vent tubes which run into the airbox, both sides.
My take on this is fuel vaporisation due to high carb temps. Our (second owner) europa is NOT fitted with drip trays under the carbs - now an item of concern, nor is there any exhaust manifold insulation. The more I read the greater my concern about in-cowl temps and comprehensive action to prevent a repeat of this experience.
Fuel pressure indications were normal, and coolant temp was showing about 40°C, although we now suspect the Temp sender is malfunctioning. Oil and CHTs where nominal.
Ours may be just another data point, but while we trawl this archive and worry the problem, any comments would be most welcome. My own last engine quit, also on the ground, was due carb ice in an O-200; but this was much more 'exciting' coming as it did at the moment of truth .. "G-HL, rolling" - phut!
The climb-out to our east is lacking a good escape option.
Glenn Rainey
Cumbernauld, Scotland
G-OJHL
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terrys(at)cisco.com
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| Posted: Mon May 09, 2011 10:03 am Post subject: 912 quit |
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Hi Glenn,
I had what might be a similar experience a few years ago with our 912S powered XS, which I believe was caused by vapor lock. At about 9,000 feet altitude I shut down the engine to do some glide tests, and when I restarted a few minutes later the engine ran rough. When I turned on the boost pump, the engine quit. I believe that the extra flow created when the boost pump went on forced a 'vapor bubble' into the carbs and killed the engine. It restarted moments later and I made a precautionary landing to check things out. We had noticed rough running on a few other occasions, and came to a few conclusions.
1) This seemed to happen following a start with the engine already hot.
2) It only seemed to happen in the winter when auto fuel has more volatiles in it.
3) It was more likely (but not always) to happen at higher elevation, where the vapor pressure is lower.
We assumed the problem was vapor lock caused by the close proximity of the exhaust to the carbs and associated lines.
We fitted aluminized heat shield material to the bottoms of the carbs and the associated fuel lines and have not had the problem since.
Regards,
Terry Seaver
A135 / N135TD
Monowheel XS with 912S
--
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grahamsingleton(at)btinte
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| Posted: Mon May 09, 2011 6:32 pm Post subject: 912 quit |
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Sounds like vaporization. Check that you have adequate bleed back, the fuel gets hot in the fuel pump which is attached to the gearbox in hot engine oil. Are all the in cowl pipes firesleeved?
fit the carb drip trays if you can, although if you have the water heated carbs (recommended) that might be tricky
Graham
From: Glenn Rainey <nimbusaviation(at)YAHOO.COM>
To: europa-list(at)matronics.com
Sent: Monday, 9 May, 2011 11:24:13
Subject: 912 quit
--> Europa-List message posted by: Glenn Rainey <nimbusaviation(at)yahoo.com (nimbusaviation(at)yahoo.com)>
07/05/2011 we experienced an engine stop with the 912 in our monowheel - this happened just as the throttle was being advanced at the commencement of the takeoff sequence, so we rolled only a hundred feet or so and coasted to a halt. After less than a minute, a first restart attempt was successful, and we taxied back to the apron uneventfully, tail between legs, where my second action was to put on the kettle for a cup of tea.
Perhaps relevent, I had heard a sharp 'bump' about 10 seconds earlier, as we were turning on the threshold to line up, and thought I had hit a light or something with the outrigger, but nothing was seen. The ambient conditions were about 21°C and some showers were in the area with a convective active frontal system; we had just completed 1 circuit to land after a reasonably expeditious departure, but on backtracking from the first landing, had to hold for about 5-6 minutes on the main apron, then backtrack the second half of the active.
Immediately after parking first action was to pull the top (XS) cowl when we noticed fuel boiling up the vent tubes which run into the airbox, both sides.
My take on this is fuel vaporisation due to high carb temps. Our (second owner) europa is NOT fitted with drip trays under the carbs - now an item of concern, nor is there any exhaust manifold insulation. The more I read the greater my concern about in-cowl temps and comprehensive action to prevent a repeat of this experience.
Fuel pressure indications were normal, and coolant temp was showing about 40°C, although we now suspect the Temp sender is malfunctioning. Oil and CHTs where nominal.
Ours may be just another data point, but while we trawl this archive and worry the problem, any comments would be most welcome. My own last engine quit, also on the ground, was due carb ice in an O-200; but this was much more 'exciting' coming as it did at the moment of truth .. "G-HL, rolling" - phut!
The climb-out to our east is lacking a good escape option.
Glenn Ra/www.matronics.com/Navigator?Europa-List" ="http://forums.matronics.com" target="_blank">http://forums.matronics.  tronics.com/contribution" target="_blank">http://www.matronics.com/contri================
[quote][b]
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