- Jul 24, 2002
You and Charles are right for sure, if I was running an electric motor my setup might work but I guess the crank whips around way more than I thought throwing that big clutch unit out of whack. I was thinking a tight fit between the male/female parts of the ball joint would support it but guess I was wrong. I'll need the clutch/one way bearing more when I run this as a dyno, it's not really needed now but I'm getting some good testing in with the fan.Terry your test stand/dyno is well constructed to run dead true. Your test motor is mounted to align perfectly with it and everything is rock solid. The only thing is, that any single cyld. 2 stroke engs.' crank, is trying to move all over the place. The motor should be constructed to have slight end play, they vibrate/harmonic at various RPM, and good RC engine brgs. have internal clearances that don't hold the crank at dead zero as they run; they are not suppose to. It's great to have everything within a tenth, but from the motor to the stand, you need to allow some "give". This will also allow the motor to operate closer to an "as in the boat" configuration, and not have it fighting the stand. Rubber isolation motor mounts, slightly flexible joiner, or both. I'm not sure that clutch is doing anything, as the fan seems to be rotating even as the starter motor is spinning over. I'm sure the idle RPM has that clutch fully locked up. You may be able to lighten the centrifical OD of the "shoes" to raise the engagement, or change to a more adjustable clutch if you need one.
I checked the shaft balance, seems pretty good. I'm not completely convinced if I just put a flex shaft or rubber mounts in there it will solve my problem, I think I might need another pillow block to support the other side of the clutch. Or another bearing in the clutch housing, the way it is now the shaft is only supported by the one way bearing.
Rome wasn't built in day I guess, lol.