I measured 90 pounds static thrust with a 20hp 250cc Fuji Polaris engine. 30" diameter and wide chord prop, direct drive.not a sled person......does that 5500 rpm direct drive the track? I might be looking for a 6000 aprox. rpm 20 hp engine direct drive as I am limited in prop size to 32".....
Google 'torsional vibration'
I guess I do not understand it.....all those PPG engines do they have more than just a couple of pulleys and a belt drive?front crank pulleys have a large amount of rubber cast between the inner and outer pulley, to absorb “harmonics”.
=================================not a sled person......does that 5500 rpm direct drive the track? I might be looking for a 6000 aprox. rpm 20 hp engine direct drive as I am limited in prop size to 32".....
========================================Do centrifugal clutches adsorb harmonics? (slippage?)
Like this?Designing a reliable redrive is no simple task. If you think it is, you don't understand what needs to be addressed.
==========================================I guess I do not understand it.....all those PPG engines do they have more than just a couple of pulleys and a belt drive?
I'm not an engineer; am a competent manual machinist, and work with spindles and precision spindles at times.Like this?
===================================I'm not an engineer; am a competent manual machinist, and work with spindles and precision spindles at times.
I find your spindle design more than a little scary.
With rounding error for convenience, there is 10" between the nut centers, with 2 unlikely bearings sandwiched loosely between that length, for preload.
Again in round numbers for quick mental calculation, steel shrinks/expands 6 millionths of an inch per °F. So with a 50F° change, the preload (or your design clearance) will change by .003 inches. That is quite large for the taper bearing.
Typically a long spindle is retained axially at one end only, and floats at the other end to accommodate the stress of constant length variation due to temperature. Facing taper rollers, if necessary for the load, at one end. lighter radial in which the shaft is a snug but not press fit a the other end, or a light press fit and the bearing outer race floats in the housing in a push fit; or in a roller bearing (not tapered). Alternately, an adequate deep row radial to take all the thrust at one end of the shaft, constrained in the housing and between collars on the shaft, and the other end floating in a plain radial.
I would guess for lightness if you want the long shaft that your design would function efficiently with a roller bearing (non-taper) at the prop end, and possibly a single deep row radial at the tail end. That design would take a shoulder on the shaft at the tail end to retain it in the bearing inner cone, and one on the prop end to seat the prop flange.
If your prop radial and thrust loads can be accommodated at the prop end with a single deep or conventional radial ball bearing, and a lighter radial with the shaft floating at the tail end, it could be made even lighter. That would require a shoulder at the prop end behind the bearing. But none at the tail end, and no nut at the tail end.
If you know the typical arrangements and believe your design is adequate anyway, at least put short keyways in the end threaded sections of the shaft that do not intersect the shoulder, use heavy tab washers, & use crennelated nuts with cotter pins.