Do I really need to balance my plane? How?

While the balance of your plane does not have to be perfect, it does need to be balanced so that it flys.

Quick answer: Yes.

Necessary information:
There are two directions that need to be balanced. First you need to balance the plane for the correct CG (center of gravity). The instructions that came with the plane should give a range (distance from the leading edge of the wing). If you don't do this and the plane is "tail heavy" then you could loose the plane. A tail heavy plane will be very sensitive to elevator inputs. Normally the plane (trainer type) will balance about 25% back from the leading edge with the fuel tank empty. Normally moving the battery will accomplish this. Second you need to check for lateral balance. This from tip to tip on the wing. One easy method is to take the wing off the plane and suspend it from the leading and trailing edges at the center inverted. If there is a heavy wing panel it will drop. Add weight to the light wing. I was helping a new modeler early last year with a new trainer. I took the wing off to check the controls. When I placed the wing on the bench one wing panel dropped immediately. After checking one panel was really heavy. Before balancing the wing we flew the plane to see how much this would make. In the air the plane needed more than a reasonable amount of aileron trim to fly level. At every throttle setting the trim would change (lift changes with speed). I was aware that the landing might be a bit tricky. An approach was made and the plane was coming in nicely and then as expected the heavy wing made a real dip (about 30 degrees). Throttle was added and the low wing was brought back to level. If you don't add throttle the plane will go into an almost immediate stall. When the wing rolls the effective wing area is greatly reduced. It took quite a few large fender washers glued to the light wing panel to balance this situation. Once done the plane flew as expected and is still flying. None of the above flight tests would be possible for the novice pilot. It is difficult enough to learn with a properly set up plane. Don't add to that equation.

EXCAP232

I've heard that you have to balance a low wing plane inverted. Is it true even if the low wing has a dihidral? The plane is a 4* 60. Thanks. Hope you do not mind me adding to question nmtr13

Nah no prob.

This forum is for asking and answering questions. It is easier to balance a low wing plane inverted as the fuselage serves as a pendulum just as it does for the high wing model upright. Two pencil erasers on the the end of dowels that are embedded in wood plates will help with this.

EXCAP232

I can very definitely tell you balancing is important. I recently flew my trainer without balancing it and no amount of trim would help. After a little lead in the front and a little on the left wing panel, it balances perfectly. Don't overlook this important step in setting up your plane as it might very well save it.

balacing is important, but unless you REALLY know what your doing, leave it to a pro

OK, I see repeated mention of balancing the wing and fuse separately.

I have always balanced GC and lateral with the wing attached to the fuse. My thought on this is that you don't fly the fuse without the wing and you don't fly the wing without the fuse, so they should be balanced together, as a unit.

Also, wouldn't this give a truer flight balance doing it as a unit? If the wing is not perfectly centered on the fuse, the lateral balance would be off if they were balanced separately, yes?

Anyway, I've got to balance a new one for my grandson tomorrow, and if I've been doing it wrong all these years, I need to straighten-up!

Let me know!