Quote Originally Posted by jrthomas View Post
I know the regs state "138mph at sea level"
Look a little deeper, it says that the 138 mph is CAS (calibrated air speed). What is the TAS (true air speed) when doing 138 CAS at 9,999' msl? Depending on the temperature gradient it's generally around 165 mph TAS and perferctly legal for an LSA.

The above has nothing to do with a prop, sorry for the thread creep, but thought you all would appreciate that clarification.