ORIGINAL: hogflyer
ORIGINAL: mxaexm
...I know that .46 is a little bit too much for the Avistar but I really like this setup...I usually fly it 1/2 throttle anyway however when I add full power...it climbs like crazy......I will fly it today and make the adjustments tomorrow.
Thanks guys.
What is happening is you have the plane trimmed out to fly at one airspeed, which in your case is about 1/2 throttle. As you add power you increase the speed, but to the plane it wants to stay at the airspeed to which it was trimmed out. To find that airspeed, which is now slower than it is being flown, it wants to climb to slow down. If you decrease power from the trimmed airspeed the plane will want to still maintain that trimmed airspeed, so it'll dive to try to speed back up to it. This is basic aerodynamics and applies to full scale aircraft as well as models.
To properly set-up and trim out a plane, I was taught you fly the plane and use the trim's on the radio to get it flying straight and level. When you land you look at the control surfaces to see how much deflection they have in what direction. Then you want to center the radio trims and, using adjustments by turning the clevis for each control surface, mechanically put the surfaces back to the position they where at when the plane landed. For example, if the elevator was 1/8'' up after you landed, then you want to turn the clevis so the elevator is 1/8'' up with the transmitter trim now centered.
How is your balance? Since you are running a heavier engine than the plane was initially designed for, is it properly balanced? Nose heavy planes will carry some up-elevator trim and give the same response to what you're experiencing.
As far as shimming the engine mount - try mechanically adjusting the plane first, and expect it will climb when you give it power. If its excessive, then you'll have to look at other factors involved in flight trimming similar to what patter flyers do, but that's a topic for another day. Get it set up properly first.
Hogflyer