Paddy
I wonder if that is a sticking valve? It would be evident from a low
compression on one of the cyls.
Willie
G-BZNY - got its Permit back yesterday...
On 10 Jun 2008, at 21:36, Paddy Clarke wrote:
> <paddyclarke@lineone.net>
>
> Hi Folks,
> Firstly an apology to all those good souls who made the DOTH to
> Andrewsfield today, that I didn't.
> The reason I didn't was that my engine decided to misbehave on
> takeoff. Run-up was normal and I got my normal max RPM on power
> application, but after approx 50m the RPM dropped to 5400. I
> abandoned T/O suspecting the prop controller - 5400 is the
> Airmaster climb power setting. However having exercised the
> controller, I did another power run and the engine was definitely
> unhappy. It was very rough above 4000 RPM and couldn't reach the
> normal max and the EGT reading was right up. Trying the separate
> ignition circuits certainly made it run rougher, but neither side
> much worse than the other.
> I taxied back suspecting a plug lead off - I've had that before-
> but on removing the cowlings all leads were in place. I then took
> out all the plugs, they looked pristine and all identical. I took
> off the carb bowls and gascolator - absolutely no sign of anything
> other than clean, clear fuel.
> I put it all back together and it ran perfectly, giving max RPM
> with stable fuel flow and moderate EGT for a good 2 mins.
> I decided to bite the bullet and do a couple of short flights,
> again no problems.
> One thing that springs to mind is fuel vaporization, but it was the
> first flight of the day and not particularly warm. I am using mogas
> and the aircraft had been fully fueled but left in a covered hangar
> - recent daytime temperatures up to 24 deg C, nighttime probably no
> lower than 15. However I have done approx 750 hrs, many times in
> much higher temperatures, (though it has to be said that the
> highest temperatures would have been on the continent using Avgas),
> and I have never had this problem before. The aircraft was standing
> out in full sun on a warm day before my 2 short flights, but here
> was no hint of a reoccurrence.
> Has anyone had anything similar, or got any suggestions?
> All the best, Paddy
>
>
> Paddy Clarke
>
> Europa XS - 404 G-KIMM
>
>
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