Great Plains Trainner 40 CG
 

I am rebuilding a Great Planes Trainner 40 and need to balance the plane. Does anyone know where the CG is from the leading edge of the wing?

Great Plains Trainner 40 CG
 

If you are referring to the PT-40, you can download the manual from Great Planes at This Location

They have most of their manuals online.

Nuker

cg-pt40
 

The building manual says (the balance point is located 4 7/64 inches back from the leading edge of the wing )After a few flights you may want to move it either forward or back up to 1/4 inch to change flight characteristics,I had to move mine forward as plane wanted to climd,hands off with "A" wing.

Great Plains Trainner 40 CG
 

If it's really a Trainer 40, I believe the CG is right on the spar. It's also not critical. When I was learning, I played with the CG quite a bit, and could never tell the difference 1/2" forward or back from the recommendation.

By the way, while you're rebuilding, beef up the fuse near the tail. The tail will break off if you as much as look at it sideways.

[edited to delete gratuitous comments about the plane's design]

Great Plains Trainner 40 CG
 

it's is now a tail dragger and not much it is original. I am not planning on using it as a trainner just having a little fun. And it is a Tranner 40 not a PT 40.

Thanks David

Trainer 40 CG
 

From the Trainer Series Instruction Manual, page 22, item 10: "Check the center of gravity of the model near the fuselage at the point shown on the plans by balancing the model under the wing on your fingertips. (This position is just behind the wing spars.)"

The plans for the Trainer 40 show the CG at 3 3/8" behind the leading edge.

If I'm not mistaken, the Trainer 20, 40, 60 series is a Joe Bridi design. With all due respect to AMC, it is difficult for me to imagine a Joe Bridi designed airplane being "outdated."

Re: Trainer 40 CG
 

I agree....From what I remember, of this airplane, it flew great.

Joe Bridi
 

I cannot imagine a Joe Bridi plane being outdated myself, Joe taught me to fly in 1969 at the Bird field in Long Beach, California. Does anybody know if that filed or club still exist??

Terry