yes that was my original concern as most of the gas powered sport hydros etc weigh from 11 pound to 20 pound and as i mentioned with an engined developing approx 8 horsepower at 20 plus rpms swinging a high pitched 67 to 72 mm prop is a big ask for such a small shaft.
yes for smaller craft like electrics and glow power up to 11 cc might be ok. why doesn,t all r/c craft use this type of shaft ?