ORIGINAL: rcfury
I just built the superstar 40 with the dihedhrial taken out and decided to go with the .46 AX motor. In order to get the CG anywhere near spec. 3 3/8 inches from leading edge is by putting nearly 6-7 ounces of ballast to the rear of the plane. There is gotta be a easier way.
Ive read many posts with people using the 46 fx in it, with no trouble (im thinking). Since they stopped with the FX line and going to the AX series which is a heavier motor. Inside the fuse there isn't much room for movement of the Battery and Reciever. And I allready have the motor moved as far back as it can go. I kinda dont want to rip the covering off the rear of the plane to add that much weight. Would the composite variety of Motor mount work better, if so what brand is recommended?
rcfury, there is something definately wrong with this picture. I haven't flown my trainer in over a year, but the CG is 3-5/8" (92mm) from the leading edge. Make the CG be 25-30% of the wing chord. I had a 46FX up front also. I had to put only 1 ounce of weight on the tail to balance. Are you checking the CG with a full tank or empty? It should be empty.
The OS 46FX's weight: 16.45 oz w/muffler
The OS 46AX's weight: 17.2 oz w/muffler
The weight of the engine has nothing to do with you having to put 6-7 oz on the tail. Make sure your CG is correct and the tank is completely empty. Was this an ARF? Has it been nosed in before? If so, epoxy does add up if too much has been used in excess.
DTB