Correct thrust angle
 

I have a Mini-Edge 540 built from a Hobby Hanger kit. I am using an O.S. 15 engine. The plane wants to hop coming out of a corner. I had to build my own motor mount to fit everything in the cowl. I am sure the plane is not tail heavy. It also tries to go nose up on aproach or into the wind. the plane doesn't take any unusual trim to fly straight and level. Flying into the wind is easily correctable, but landing is tricky. Anyone have an idea what could help?? I thought possibly a touch of downthrust?

RE: Correct thrust angle
 

It's so hard to say with a plane that small. It could simply be that the tail surface is too small to accurately guide the wing. Or maybe your incidences are off. You could try some down thrust. if it doesn't help, or makes things worse, it's easy enough to take out again.

RE: Correct thrust angle
 

I think the control surfaces are large enough. The plane is very aerobatic and does not stall easily. Maybe I didn't get the engine thrust angle correct.

RE: Correct thrust angle
 

Does it need any elevator trim to fly flat under power? There could be an incidence problem between the wing and stab. (too much!) One thing I am looking at on one of my planes is mixing the elevator to the throttle a bit, to add a touch of down elevator at high throttle settings.

Ernie

RE: Correct thrust angle
 

Trim your airplane to fly straight and level with about 60 to 75% throttle; then reduce the power to idle as it passes in front of you, or where you can see it clearly, and watch what happens.
If the plane pitches up, then you have too much downthrust.
If the plane dives or pitches down where you have to hold more than just a little back stick for glide. then you need to add downthrust
If the plane slows down and then pitches down into a gentle glide, then your thrust angle is correct.

feihu

RE: Correct thrust angle
 

Trainer type planes, with their built in incidence, etc., want to climb when the throttle is advanced, even with downthrust! My solution was to mix in a little bit of down elevator as the throttle is opened.

Ernie