Made repairs to one of my foam trainers. Failed to balance it after repairs. Plane failed to get more than 15 feet in the air @ full throttle, the tail dragging the entire way, fairly uncontrollable. Tail heavy, right? Just want to be certain. Thanks

Sure sounds tail heavy to me. If you said it wanted to snap out on you, that would really confirm tail heavy...

Tail heavy.

Ken

Tail heavy - pitch (UP-DOWN) control is difficult and are almost impossible to land

Thank you. Was having a bit of a tough time locating the CG. Finger in one place, balanced. Finger a bit forward or backward, completely tail heavy. Questioned whether or not I was getting the CG right. Added a bit over an ounce to the nose. Balances well.


I realize that you guys get the same questions day after day, so I appreciate this.

Instead of using your fingers make yourself a quick and easy CG maching. Drill two holes 2"or 3" apart in a 1"x2" so that you can put two pencils in, one in each hole. Now you have can set the plane on the top of the erasers of the penils to find your balance point.

Ken

Like dis...

A low wing plane has to be balanced upside down

A high wing plane right side up


A biplane can be balanced from the top wing if right side up

neat little trick, I'll have to try that. that plane in the pic turned upside down right?

Yes, you balance a low wing with the plane upside down, a high wing plane right side up. I was testing the balance point (cg) on both sides to see what the difference was. I had the plane perfectly balanced on the "pencil powered CG rig" so I could snap the picture. I used a piece of masking tape to get the forward most, rearward most and recommended marked without drawing all over the plane itself. I used new pencils so I didn't have to accommodate a point on the end that went into the board.

Best thing to do is just fly inverted. You should need a little bit of pressure - not so much a push - of down elevator to keep it flying inverted w/o losing altitude. As mentioned, the CG location in the manual is a starting point. Fly the plane and see what works.

Second test is fly straight and level, and roll into a 90* banked turn. If the tail drops, or the nose suddenly drops, you know you are tail or nose heavy.

These are generally the first things mentioned on trimming charts. You have to get the CG right before you start trimming other parts of the plane, as CG will affect pitching to the gear or canopy in knife edges, etc.