I have been working on my RV 4 for several flights now. The plane climbs as soon as the throttle is increased. I have CG in the dead center of recommendation. I have also tipped engine down one washer thickness to try and compensate with no improvement. Can someone give me some ideas as to what may be wrong with this plane.

Could be stab incidence

It's a fat, flat bottom airfoil that produces a lot of lift and the more power you give it the more lift it creates.

I have the Saito 61cc on mine and with the nose weight of that engine it flies really nice... try some nose weight..

Yea, I forgot, its been a while since I fooled with mine.

The CG in the manual is too far aft, might work fine with AS3X but it flew a lot better after we put some weight up front.

Thanks for the suggestions. I'll give it a try with some more weight up front. I have a 40 twin in it so you would think that's enough weight. Batteries are just behind fuel tank. This thing is driving me crazy.

I relocated both batteries to just next to fuel tank. Fly's the same just keeps on climbing. CG is way in front of where it should be now and still has the problem.

What's your elevator trim showing after set for level flight? How's it fly inverted?

I think you need to take that washer out from the bottom and add to the top

Originally Posted by ponyboy082662

I think you need to take that washer out from the bottom and add to the top

Washers are at the top to drive thrust down. Thanks

Originally Posted by joeteresi

Washers are at the top to drive thrust down. Thanks

I miss spoke....if you add washers to the top it causes the thrust to appear downward but it presents the wing angle up which is why your plane climbs. I had this issue on a bipe. It flew like crap and On landing if you blipped the throttle at all it immediately climbed. I put a thin washer under the bottom 2 standoffs and it flew great after that....give it a try ...if it's better then go a bit more till it's not

Thanks to all for the input

Originally Posted by nappyroots2182

What's your elevator trim showing after set for level flight? How's it fly inverted?

Tim at level flight is elevator down many clicks. The way it flies I wouldn't go inverted.

Try more nose weight

Excessive down trim is a sign of a tail heavy plane

It could be totally wrong but I believe it's your engine thrust angle. In level flight your engine is what's actually flying level not the plane. With too much downward thrust it changes the wing angle upward which is why your plane wants to go up and also why you need downward elevator trim to compensate for it. Like I said before I had the same problems your having and altho it sounds counterintuitive ....a little up thrust is what fixed mine. Not being there to examine it for my self means I may be in left field. Hope you get it figured out and good luck