Thanks Keith,

Actually, my custom prop is that same prop that Josh is running on his plane. I'm getting about the same rpm with my 120SP and 12" of pitch that he is getting with his 90SP and 10" of pitch. I had talked to Josh about it a while back and had deduced that the power difference in the two engines was evidenced in our tests of his prop design. What you say tends to coincide with our findings.

Here's the $64,000 question. After seeing Josh's video, do you believe Josh's prop set at 12" pitch will fly my 13 lb. monster? I believe it will, but I'm just worried about generating enough forward speed. But I think I will try a big 2-blade first.