Alan Burrows a crit :
>
>This is all good stuff, but has anyone got any advice on my original
>question. Which was; is it necessary (or desirable) to reduce manifold
>pressure gradually in the decent prior to landing AND is it advisable to
>let the engine run for several minutes on the ground before shut down to
>allow the turbo to cool (with an oil supply) and if so how long?
>
>Alan
>
>
Alan,
My previous post answered each point.
I would suggest you read again your Rotax 914 owner manual. The answers
are in it too.
- 1 inch reduction during descent etc.. : this is all hangar tales and
old women stories. While it is always advisable not to reduce power too
abruptly, you may perform a cruise power descent with the 914. You may
descend at any power setting you choose within the book recommendations.
By the way, if your aircraft is reasonably sleek, you'll need to reduce
power to achieve flap speed in the circuit. Not too abruptly though. Say
2 or three second to retard the throttle from cruise.
- 5 minute idle before shutting down : for reasons already stated a
turbo engine needs some idling before shut down. The book sez "a few
minutes". So why five an not 6 or 4 ? It all depends on what you did
with your engine before shut down. If you've just landed and taxied, you
may just shut down when you're parked. Remember approach needs only very
low power, and landing and taxiing can be performed at idle. So it is up
to you : when you think your temperatures are stabilized, you can shut down.
Hope this helps,
Regards,
Gilles Thesee
Grenoble, France
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