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Decalage Angle

Posted: Fri Mar 10, 2017 9:40 am
by Skyboy68
Hi all, new member here. Six months ago purchased Skyboy EX with 100 HP Rotax. High wing pusher fabric wing and tail.

Very short version for very long issue -

My instructor didn't like flying characteristics of this airplane at first. Airplane is flying straight in level with a very high angle attack. I am flying by myself now, and I think I am getting used to it, but still don't like it. After doing a lot of homework I and up discovering that my decalage angle is 9 1/2°. another words, when airplane is sitting on the perfectly level ground, which is supposed to be straight and level flying attitude, the wing is pitched up by 4 1/2°, but tail pitched down buy 5° negative. Gives me a total of almost 10° differential between two surfaces. I am Cessna trained pilot. It feels to me like I am flying around with fully extended flaps.
Does anybody have a knowledge in this area?

Re: Decalage Angle

Posted: Wed Mar 15, 2017 9:59 am
by MrMorden
A friend of mine had a 912-powered Skyboy for a long time, he just sold it. It always seemed an odd airplane. It looks slippery and like it should be pretty fast, but it's not. It also didn't have great glide and seemed to need to land faster than you'd think. It was a neat airplane, but with some interesting limitations.

As for the strange deck angle, I wonder how much of that might be necessitated by the pusher configuration and the high thrust line? Just guessing since I have no time in pushers, but do know they are known for odd and sometimes "backward" characteristics compared to tractors.

Re: Decalage Angle

Posted: Wed Mar 15, 2017 11:37 am
by FastEddieB
Andy,

We did go up in the Sky Arrow once, right?

I was surprised how little difference there is in flying characteristics.

"P factor" would call for left rudder in the climb, but with the thrust line so close to the CG it's virtually unnoticeable in my plane.

And nothing unusual about the fuselage angle in flight, either.

So I don't think it's a pusher thing.