Thanks for the replys. I did some measurements yesterday and it appears that there is some distortion of the molded ring in the back of the 20" props I have. I have three of the 20" APC's and t found one to be DOA as it looked like the engine backfired on a chicken stick. The TE of one blade is cracked mid way to the tip. All the rings are out of round by as much as 0.005" One prop that I would like to salvage had had the center hole drilled 0.046" off center to the ring.

I'm not concerned about the center hub being weakened by opening up the hole to the 1/2" required for the 300FT.The hub diameter is 1.750" so there is plenty of meat around the hole. The two props that were drilled, one being the damaged one, still have quite a bit of thecenter ring left. It's just that the holes are off centere visibally. I'm thinking though that the 1/2 Pilot "and" the six smaller screws in combination may not be a great idea.

Truckracer, you have given me some good ideas. Ilike the bushing in the back of the prop. I handn't thought of going that route, My idea was to bush theentire depth of the prop. I think I like your idea better.

Balancing the props that have been drilled is going to be interesting. The bushing in the back of the prop would be away to center the prop that has been drilled for balanceing.

Last question, Any tips on balancing a prop with the 1/2" pilot or even the10mm hole for the Zenoah?

Thanksagain for your help. Lots and lots to learn. Infact, with the size of the two planes, andthe dificulity in getting them to the field, I'm wondering is I mightbe better sticking to my 1.20 to 1.80 size planes. Maybe when I get oneof these big guys up, I'll be hooked, so I've at least got to try it.

Don