Brenner

Thanks for the info Andrew.

70 mm diameter is still small. The problem is that the gearbox is integrated into the back of the spinner, and it needs almost a 70 mm opening in the front of the plane in order to have the necessary clearance for the soft mount.

If we opened up the hole in the nose as close to the 70 mm diameter as possible, it might work if the fuselage behind the nose widens enough to make room for the motor mount. Currently I need 68 mm minimum clearance for the gearbox portion of the drive. This leaves only 1 mm per side for fuselage wall thickness, but we probably wouldn't have to worry too much about weakening the fuse by opening it up this far, because we have to put a second carbon fiber reinforcing ring about 20 mm back of the nose to mount the drive to anyway.

Does anyone have details about how wide the new Spark fuselage gets behind the spinner? I need measurements of the narrowest width as a function of distance back from the nose.

Another thing I need is the maximum allowable length for a new Spark spinner. If I don't have enough length to fit two props in, then it's a no-go regardless.