For a 40-5 on 10s Lipo APCE are not strong enough, i had big trubbel during acceleration and max RPM on the 20" APCE, now there are RASA carbon props avalibul with simular chape as APCE but much stronger, best prop for 3D and still have very high % is 20x8" on the 40-5. To swing bigger props the 40-6 is better, but i belive the best mixed performance u get from the 40-5, i have tesded that motor alot, i love it...very powerfull, fast trotteling, stays cooool and much power. I belive the only motor that can beat it is the awsome new Xtra 30 but that is abit havier and lotts of more $, for fast trotteling and nice startup the Jeti advance works very good with all Actro motors, from C to 60 sice.