I Have a 61" WS biplane powered by a YS140. I want to do a bit of kit bashing on it and change the cowl to a fiberglass one I already have. To use the new cowl, I will need to move the engine 1/2" higher than the thrustline shown on the plans. No changes are being made to any thrust angles, just a pure offset in the mounting of the engine. What effect will I likely see, or is it minor enough not to have any effect. TIA

John Hayes
[email protected]

There won't be any change to anything.. that's a minor shift in the thrustline.
MOF, any change could only be observable if you made it to a flying airplane. The flight characteristics -might- be influenced, but only by comparing a no-change condition to the changed condition could you find out for sure.

Generally if you raise the thrust line, you will need less down thrust.

If you lower the thrust line you will need more down thrust.

Enjoy,

Jim