Thrust

t On a Sig 4-star 40 kit the fire wall is marked with a thrust line. How important is the horizontal thrust line. I want to know if I can lower the engine about 1/2 inch. Thanks.

Reply to
Stan
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I wouldn't recommend it.... The 4*40 has very little roll coupling in yaw, and changing the thrust line could have a negative effect on this..

Bill

Reply to
Bill Fulmer

Changing the thrust line MIGHT affect the axiality of the rolls, but unless you're doing precision aerobatics, who cares?

On the other hand, if lowering the thrust line may make your engine run better, thus preventing an untimely flame-out, then by all means, go for it! Dr.1 Driver "There's a Hun in the sun!"

Reply to
Dr1Driver

It's an easy enough thing to test out. The plane won't be uncontrollable with the thrust line moved 1/2" down. Try it both ways to see which you like it best.

Wiz

Stan wrote:

Reply to
Mike Wizynajtys

You probably won't notice the difference.

Reply to
Paul McIntosh

Reply to
Stan

On that kind of aircraft, a 1/2" won't make any measurable difference. For the most part, stay with the design parameters (including the thrust line), however, if you have a good reason to change something, well, experimentation is part of the hobby. In this case, flight qualities won't change much.

MJC

Reply to
MJC

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