Hey man, easy on my cheap Hitec servo. Actually 5% more gain had it right. The 4 stroke Rappy flies fairly well and has no running issues. I dont know why but it does not siphon fuel, may be the header tank. Running is flawless, will Idle all day with good transition and has clean top end. It is a stock 49bb .30 with .50 gearing. has a top head speed of 1630 which computes to 14200+ engine rpm. I have been told by a long time fourstroker that these .52 engines are purposely underated by the manufacturers and indeed they are capable of 14000+ rpms. It has run two 20min timed sessions on one tank and had a full header a a little left in the main. It aint no home sick angel but has reasonable climb authority. All in all I am very pleased with my experiment it has worked very well from the first flight.