DT,

I'd suggest you look into how Vampire installed new retract mounts. He seems to have cured his retract mount problems.

Slightly OT but RB related : What brand/size prop are you runnning and what engine, YS110 or something larger ??

I'm installing an ASP 1.08 Redhead, this is the old high compression ABC engine designed for FAI fuel. It easily swings a 15-8 @ close to 10K RPM running 10 % Ducted Fan Fuel, IIRC the mfg recommends a 16-6 2 blader. I'm thinking of starting with an APC but I'm not certain where to start for sizing. The APC site lists some LARGE props, 15-13.5 sort of things. I also see thay have a 13.4x13.5 listed for 1.20 4-cycle engines. My 1.08 will pull most props suited for the 1.20 4-cycle. I do have a Graupner 14x7 3 blader that I've never mounted on the engine so I have no idea what the RPM or thrust is like on this engine. I'm wondering if I should try one of the big 15" APC props and trim it down in length to achieve a proper load based on RPM. The downside of the APC props is the cost, $24 bucks for test purposes is kind of pricey. I'm also wondering what effect the HUGE cowling and the shrouding of the prop will have on prop selection. I know 3 bladed props are less efficient but they also load the engine more. I also think the so called rule of thumb (go down 1" in pitch and diameter or something like that) for prop sizing a 3 blader is suspect.

Since I know I can pull typical 1.20 4 cycle sizes, what prop size in a 3 blader would be a good starting point ??

Rich