Hi Guys,
I`m using 10% and a11/7 MA prop on os60 FSR best tach on the gound about 12,400 . How does that sound for a 60?
Regards,
Frank

Frank, try an APC 11x7 and tach it again - you'll get a more valid comparison with the many other .60 readings guys have reported with the APC 11x7.

If you get mid to high 12s with an APC 11x7, you're in the .60 performance ballpark.

OS 61FSR Special Edition (gold head) 14200 tuned to fly on 5th tank of fuel 15% nitro Jett sport muffler 11x7 apc broken in using Dar Zeelons method

not bad for a late 70s early 80s motor

Edit this was tached in the shade....will tach it again at field in sunlight to get another comparison