On Mon, Apr 27, 2015 at 5:47 PM, bjoenunley via KRnet <krnet at list.krnet.org> wrote: > Building a belt driven psru seems doable. Has anyone here built one or plan > to build one? > > Joe > Florida > > "current available redrives for the vw seem to be heavy and/or > unreliable. most would find the engineering cost to optimise redrives" > >
yes it is but you have to make compromises. if i have to use a belt i would use a standard weight flywheel from the flyhweel end and 1 inch shafts to and from the belt drives. even a couple v belts will do. i would prefer the newer toothed belt in oil and plain bearings myself. i would still prefer a properly designed geared redrive with a fully counterweighted cross plane crank. the gears and flywheel don't need to be as heavy and i can use a turbo. if you don't want the flywheel then its more difficult. you have to handle harmonics between the prop and the large positive and negative torque pulses from the crankshaft. if you take power from the crank nose then thats way too hard already. the belts will self destruct no matter how heavy you make them. same for chains. even the heaviest gears will not survive the chatter from the backlash between the prop and crankshaft torque pulses. people have tried various clutches, viscous drives, rubber balls etc. they all end up heavier. thats why people who drive the prop from the wrong end always use a force 1 bearing and only wood props at normally aspirated, derated rpm tune only.
