Bill,
   When you simulate an engine failure with an IO550, all you need to do is pull the mixture out.  You can, or should be able to, pull the prop all the way back too and see how dramatic the difference is in sink rate.  I've done this many times simulating an engine failure and I've been asked the question; "ok, fine but what's it really like when you lose the engine".   Well, when you pull the mixture out, look at the EGT's.   They are ZERO.   Your engine is not developing any power.   Your engine will still be spinning fast enough to have enough oil pressure to operate the prop.  I would suggest you do this with an experienced instructor.  

Yes, your prop will go to max fine pitch if you lose oil pressure, just like having the prop control all the way forward.  The prop governor's for feathering props operate "backwards" from a standard governor, and the prop hub is totally different.

Ron

A few points to consider:

1. With my IO-550 I can't exercise the (Hartzell) prop below roughly 1900
RPM. Nothing happens. If the engine is out there may not be any oil pressure
unless it's windmilling enough to drive the pump and governor. Without high
pressure oil from the governor, my understanding is that the prop is
designed to go to fine pitch unless it's a feathering or aerobatic prop.
I've been intending to test by setting the prop to coarse pitch then
shutting down to see where it ended up.

2. My Navion was originally equipped with a 165-HP engine. The IO-550 near
idle probably is comparable to the old E-165 at cruise. I discovered this
one time when I practiced an engine-out for the Commercial test and found
the plane was not descending. We just kept going round and round. Turned out
I hadn't pulled the last fraction of an inch on the throttle.
How many HP are required to keep a Lancair in the air? The wing loading is
high so speed needs to be kept up but the airframes are very clean. A little
bit of extra power may make a big difference in perceived results.

I think the only way to really know how a plane will fly engine out is to
actually shut it down. This is one of those things I haven't gotten to yet
but one of these days when I'm feeling brave I'll climb to 10K over my
airport, shut the engine down and see what glide ratio I can get.

One question: what would be the better way to shut down for easy restart?
Mags or mixture? -Bill Wade


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