For any belt drive the pulleys should be stradle mounted with robust
bearings.  Plenty of air cooling is suggested.  Driving pully should
also have stradle mounting.  If the driven pully shaft is large DIA then
cantilever with two separated bearings can work but is usually heavier.
Farm machinery used this method so belts could be easily replaced but
weight was not a consideration.  Belt alignment and tensioning are
secret to successful belt life.

At the low revs for prop use a sealed bearing can work well as long as
it is kept cool.
No need for oil bath though I know of a case where supplier went to oil
bath from sealed as there had been problems.  I do not know the details
but there is a Lancair builder in AZ flying a Chevy small block and I
think his PSRU went to oil bath from sealed.  Belted Air Power uses
sealed bearings.

The Lockheed Q Star used belts very successfuly.  There is one at Cable
airport in So CA  being restored that can be looked at.

We Used multiple Vbelts at McCulloch on a large (200 + hp) two stroke
aircraft lab engine and it worked well.  It was so quiet.  McCulloch
even experimented with a multi Vbelt infinitely variable transmission.

Bob Y

Here are some pictures of Ken Welter's set up.

Paul Lamar

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