I fly the LT-40 with the TT46-Pro. I started flying this past spring with the LHS recommended Master Airscrew 11-4. Plane flew fine but engine screamed (It sounded real cool with the prop tips going supersonic!) and experienced guys would invariably recommend different props every time I flew. Last night I changed to APC 11-5 and even this total rookie could see, feel, and hear that this was a much better fit for this setup. Ran alot cooler.