thanks again for all your help. I ran the motor in on a test in the inverted position and now that I have read these replies realised that the top of the tank was in line with the needle valve,I thought that I would have problems during this but did not, but I installed the tank in the plane as per manufacturers instructions (dumb) I shall have to rebuild my tank mounts in the fuse, but in this balsa usa citabria i have plenty of room to do this, maybe the maiden flight is not so far of as I thought. I'ts nice to be able to bounce things around with like minded folks. again, thanks