I fly a Katana T30 stuntplane, wingspan 85 inch. All my settings are set to 0 degrees. The plane flies well, but when I'am slowing down speed to get ready for landing my plane starts to go up ogf its own. I' always have to force it down. My center of gravity is OK.
Can I help it by using the ailerons as flaps (a little bit up or down)
I've already tried this at high altitude, either way my plane goes up.
Does anyone know how to solve this, I already have broken my landinggears three times because of it.

Cool place Belgium...I was there this month doing the tourist thing. Try moving your C.G. one inch forward of that recomended on the plans, and get your fuel tank as close to the C.G. as you can to avoid trim changes. this shound quiet down your ships balloning tendacies.

corsair01,

What is the thrust angle of your engine? If your plane is ballooning on drop of the throttle, you may have too much down thrust. If you have down thrust, try cutting it in half.

If you can dial in some up in your ailerons for landing you may get a little bennefit. Small reduction in lift, a little less tendancy to drop a wing near stall (don't know your airframe and whether it has barn door ailerons, or tip stall tendancy) ... just some thoughts. The down side is that it will increase your landing speed a touch.

Let us know how it goes.

Bedford

Thank you all for the replies.

My thrust angle is 0 degrees. At first I'm going to put the C.G. a bit forward, maybe now its too much to the rear.

The weather is not very good at the time (winter) so it will take a while before I can trie it out.

Moving the center of gravity may make the model to sensitive in pitch to speed changes.

I'd check the balance by doing the dive test thing. Dive the model at about a 45 degree angle with the engine at idle. With the controls at neutral the model should show do a very slow pull up to level over about 150 to 200 feet of altitude. That's about as close to neutral as I'd like to get. If you really want it neutral then sneak it back in very small amounts until the dive is dead straight so you have to pull it out yourself. Any sign of the dive steepening toward vertical is a sign that you're behind the neutral setup and that could be causing the nose up.

Once it seems good try the same test with the engine running at cruise to full throttle. That should point out any thrust angle problems. The pull out should be the same or just very slightly more positive with the higher speeds.