I fitted my Reactor 46 with a 75ax and had one day of flying couple of weeks back without too much balancing. It flew OK but just a bit nose heavy, so I put in some tail weight and packed it away.

Need to fly tomorrow and so took it out for rebalancing.

Lateral balancing:

Tied a piece of rope to the tailwheel and spinner backplate (not enough space on the crank to tie, ensured that the prop turned freely after tying) and held it up with the rope held in a rectangular shape so as not to get stuck on any part. Lateral balance is perfect (Had already balanced it for the 55 this way earlier and added weight to one wing)

CG:

I tried to check the balance holding it at the cg inverted with the thumbs on the cg line (12.1 cm from LE at the fuse) and it was just impossible to check without a helper. Problem with the CG machine is that the two vertical rode twist and add some non-linearity to the system. (Thats the best way to describe it) i.e. one of the rods is slightly behind the other and out of alignment and that causes a mismatch. I cant use the CG machines scale as the uprights intefere with the LG so I am just using the pads on the ball-socket joint.

Secondly, its frustrating to find out whether it is nose heavy or tail heavy- If you hold the nose slightly down it drops and if you hold the tail slightly down it drops. Have had this issue before as well, after balancing on the CG machine, Had to recheck with hand (two people lifting at the tips ) and its either nose or tail heavy but very slightly. (Yes, I have the ceiling fan off even though it madly hot that way)

Thirdly, this is balancing with an empty tank. Once I put in fuel (about 240cc) it will be nose heavy again.

So, after that extensive description of my problem, what do I do? Have been flying this airplane for a year with a 55ax, have just fitted the 75ax and I definately want to do more 3D now

Ameyam