Dynamometer, affordable

[Bill Lewis]

> 
> Eric Elliott wrote: [excerpted]
> > A prop on a rear axle could be cheap and avoid the 3100 RPM limit via 
> > hypoid gear ratio. The differential could be locked for <$5, via 
> > addition of 2 spider gears. A thrust bearing might not be needed as 
> > ring gear axial thrust might exceed prop thrust.
> > Some calculation of (effect of) thrust to be generated would be in 
> > order. Also consider tendency of prop to "process" people.
> 
> Just a quick $0.02 ... if you chose the rear differential from an Audi
> Quattro you would find that the diff locking mechanism was built in.
> I don't know how many different reduction ratios are available in these
> diffs.  
> 
> Steve Buchholz
> s_buchho at kla.com
> 

I've considered building a light dyno using a VW Type I transaxle, connecting
a torque measuring device (like a torque wrench) to the output flange on
one side, and a water spray cooled disk brake on the other.  I'm afraid
my scheme has the spider gears in the differential constantly spinning
under load, and a quick look in the shop manual shows no ball or roller
bearings used in the stub output shafts.  I dropped the idea assuming the
simple bushings would burn up.  Having the transmission in a low gear would
keep the brake rotor speed within reason.

/Bill

-- 
Bill Lewis - wrl at access.digex.net