larorc

That washers I put in the engine mount to obtain the correct incidence?
The engine is a OS 91 FX.

AcroJo

My Feedback: (1)

Hi, the thrust angle on the motor mount is a trial and error thing. You are looking for about 3 degrees +/-. Not knowing how thick the washers are you can't tell how many to put in. You have to adjust it, fly it and see if you need more or less. Quantum Models sells "Earnst" thrust plates. For under $3.00 a pack it gets you three plates.
1-3 degree plate.
1-2 degree plate.
1-1 degree plate.
It doesn't get any more acurate than that and you don't have to worry about the washers compressing into the wood on the firewall and changing the thrust angle. Different engines = different thrust. Trial and error. Good luck, Joe

magic extra 21

how does this effect the plane if you don't do it at all. i just built my ucd and didn't do any of that and it flies good.

AcroJo

My Feedback: (1)

Magic, a .60 or .46 ? What engine and prop? The .60 with a Saito 100 swinging a 15/6 without thrust angle compensation, under full power, will circle the field in a left hand pattern hands free. Forget about up lines. I'm curious as to how you do it. Joe

Kenny R

The engine is set with right thrust to offset the torque of the engine. Does the plane want to pull to the left? Have you had to add rudder trim to keep the plane from pulling left? Here is a test that I use, with a little speed pull the plane up into a vertical climbwiht the canopy facing you, throttle down and right before the plane stops climbing add full power and dont touch the controls. Do this a few times make sure to get the plane good and straight. If it pulls to the left consistently the you need more right thrust. If you get the right thrust set correctly the plane will fly much better.

magic extra 21

mine is a 60 size and i have a ys 110 with a 15x6 prop, and i did notice that when i was going verticle the plane wanted to go left, and i added trim to the rudder and it really didn't help much but i have only flown this plane one time i will add some right thrust and see if that helps. thanks