If you have that 3 blade prop don't replace it. Get an 11x5 or 11x 6 Master Airscrew. That 3 blade flies it at just above stall speed from what I have heard. Sorry to hear of your misshap your lucky if it does not require stitches. I got six stitches from a much smaller engine and prop. Thread lock is not the answer to keeping the prop nut on. Adequate torque is. Also an engine that is too rich will want to start backwards and sometimes loosen the prop nut. Your off to a rough start already having an injury but you seem to have a good atitude. I expect you will be tossing that Mustang around great by the time I return and getting ready to maiden the Yak.