Help Balancing My Plane
 

I am new to the RC world and I am finished building my trainer plane. The plane has tricycle gear, a .46 engine and an 8oz. fuel tank (just to give you an idea). The planes give no procedure on balancing the plane on the CG. Am I to hang the plane from the wings at the point of the CG and then balance the plane accordingly? What about the fuel tank, do I fill it up or leave it empty for the balancing procedure? Can somebody please outline some simple steps on balancing a plane? I think that I could get it right but I want to be sure before I get it to the field and have to go home because I am not ready.

Thanks, Wayne M.

RE: Help Balancing My Plane
 

Wayne,
I assume the plane is a high winger - wing on top of fuselage... Most CG set ups are measured at the point where the bottom of the wing meets the fuselage (at either side).

Determining the CG requires determining a variety of measuerements of different parts of the wing: root, tip, MAC, etc...

Most high wing trainers I have seen are set up so that the CG is at a point normally at the bottom spar. (where the D-box sheeting of the leading edge ends).

Place a finger from each hand at the point where the spar meets the fuslage on the bottom of the wing and lift slightly. With the fuel tank EMPTY, the plane should balance evenly such that neither the front or tail assembly drags down. HOWEVER, THIS METHOD RELIES ON THE CG BEING AT THE POINT I HAVE MENTIONED. IT DOES NOT MEAN THAT ALL CG POINTS ARE AT THAT POINT. IT WILL BE NECESSARY FOR YOU TO OBTAIN THE RECOMMENDED CG POINT FROM THE MANUFACTURER OR ANOTHER PERSON WHO HAS THIS TYPE OF PLANE.

Also check the lateral balance by turning plane upside down and holding by the spinner and the rear. If one wing drops it is heavy and appropriate weight will need to be added to the high side to balance.

Hope this helps and as I stated, it would be best to get in writing from someone what the recommended manufacturers CG is before trying to fly.

Regards
Flapper

RE: Help Balancing My Plane
 

Just lift the wing at the tips, or next to the fuse with your fingers on the CG (This will require a helper if you're doing it at the wingtips - Unless you have REALLY long arms) and with the tank EMPTY.

It should sit level, or slightly nose down.

RE: Help Balancing My Plane
 

Measure on the under side of the wing, and put a mark 1/3 back from the
leading edge on both sides. If the wing (includinding the aileron) is say 9 inches,
your marks would be at the 3" mark. Now with the plane upright put a finger
on each mark and lift the plane up off the wheels with the tank empty. It should
balance, or be slightly nose heavy....never tail heavy.

If it is nose heavy you don't need to worry about it, unless it is insanely
nose heavy. ;)

FBD. :D

RE: Help Balancing My Plane
 

Hey, thanks for the help guys! I don't know what I'd do if I didn't have forums like this!!! I'll be able to get it ballanced tonight!

Thanks Again,

Wayne M.