Ok, I just bought and put together a new Extra 330l complete with new engine. I ran a tank of fuel through it for break-in and everything sounded great. So i decide to take it for a test run. As soon as it gets in the air it starts almost like glitching out of control (going up, down, side to side) at its own will. What can cause this?

Here are the specs:
-Extra 330l 50 size
-engine - ttpro.46 (it calls for a .40 - .46 size engine) with MS airscrew 11x7
- radio - Spektrum dx7 (never had problems with it yet), still did a range check and it was fine
- CG is fine
- Gas tank is centered and solid
- No loose wires
- Everything mounted securely and centered including battery and receiver
- Everything trimmed preflight
- servos, horns, etc. secure
- omega fuel 15%

I'm baffled, please help...

I would check the CG again.

I agree with yeeti831 and maybe tone down the rates if they are to high.............[8D]

Sounds tail heavy to me. When you cut the power to land does it settle down?

David

yeah , when i cut the power the nose tilts up and is still uncontrollable..but the cg seemed fine..checked it twice

yeah maybe ill add some weight to the front and see what happens

swap out the receiver and crystal with one from another one of your planes

set elevator and ailerons to 1/2" throw

I have one......did the same thing....takes the elev rates out...these planes need very little elev....mine is set at 1/4 in. I think the book said 3/4 on low rates....WRONG.....and I would put 6oz of weight in the front just to be safe....they love nose heavy..just like warbirds Terry

He mentioned he's got a 2.4 - No Crystal. I'm sticking with Terry. Reduce the throws a lot and maybe add some expo in the radio. Recheck the C.G and don't always believe the instructions. On an Extra, use the wing tube as a guide. Mark the wings on the top at the forward edge of where the wing tube is. Balance the plane upside down on the marks and when you hit the sweet spot (plane level or just a tad nose down) it will fly. Do this with the tank empty. Dont add any excess weight - move the battery around. Good luck.

Either there is too much downthrust in the engine, which you compensated for with up trim, so that when you cut the throttle the trim forced the nose back up... or... and more likely... the C.G. is too far back.

Disregard the manual and put the C.G. another 1/2" forward by moving the battery pack to the front of the plane... then as everyone else has said, tone down your rates and add expo.


When the plane is tail heavy it will be extremely responsive and difficult to control so you have two problems you have to deal with at once.
Any movement of the elevator causes the nose to bob up and down as you attempt to compensate. Letting off on the throttle will seem to improve things a bit, but as you've mentioned the nose will come up until the wing starts to stall, then the plane is difficult to land.

Bring the C.G. forward. It will fly this way ( probably far more easily too ). You can always adjust it back to your liking later.