RE: Selecting an engine for a 4* 40
I had a 4*40 and started with a Saito 50 - flew great! After it got older I used it to break in some other engines; a Saito 65 and a Saito 91. The 65 was a good fit as well - plenty of vertical and it would still slow down. The 91 was ridiculous, but kinda fun. I would go with the 52. Regards, NM