RE: P-51 stuff
I can't say for sure, but I saw John's (flyanything) Corsair fly with the 4130-16, and it appeared to be a good setup. The P-51s are about the same size...weight and wing area. It definietly had the power. In fact the torque is what did him in. My best guess for a 4130-16 setup would be a Jeti 70 (or better), 6S3P and a 15x10 APC Thin Electric.
I have a 4130-20 (17x10) that I fly in an 11 pound 90" Cub that flies great. The biggest drawback with the 4130-20 is that it takes a large battery pack (20+ sub Cs or 8SxP). As for my P-51s, they won't see a 4130-xx because of the weight issue. The 4120-18 has plenty of power and is about a half pound or so lighter.
geach