Side Pull - Engine mount angles

[PilotNumberOne]

Hi,
i'm about to replace the Rotax 582 by a Nissan MA12 engine in my KFIII.
The engine mount is made by myselfe.

I heard that sometimes aircraft engines not mounted exactly 90 deg. to the lateral axis and even not to the vertical axis.

This is because of a "side pull" of the propeller.

Does anybody has some information how this relates to a KFIII
Thanks for your help.
Frank

[jiott]

For some reason, the Kitfox engineers didn't see any pressing reason to angle the engine mount either laterally or vertically, at least for the Rotax engine. I believe it is directly inline with the fuselage flight attitude. Correct me if I am wrong on this. I have always wondered about this because many airplanes employ some degree of off angle to offset P-factor, etc. On the other hand, after flying for 3.5 years, I'll have to say I don't notice any adverse effects.

[PilotNumberOne]

I agree because i wasn't able to find out if the Rotax had angles or not. At least with the tools i have at home.

So i will install the Nissan exactly inline with the fuselage.

Thanks for your reply.

Frank

[PapuaPilot]

The bigger the engine the more important this becomes. It really isn't an issue with the size engines we have in a KF. The offset helps reduce p-factor and the amount of trim needed.

[PilotNumberOne]

Yes, with 55 hp at 1200 ccm the Nissan isn't one of the biggest!:)
https://www.youtube.com/watch?v=6hQfeEyeQiQ