Dynamometer, affordable

[Parmer]

> From: steveb at newkla.kla.com (Steven Buchholz)
> 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.  

There are lots of limitation/problems with this type of setup, but
as long as you're brainstorming....

A 3:1 ratio rearend (or tranny config) will increase your max RPM
from 3100 to 9300, but you will have divided your power consumption
by 3 also.  On a more positive note however, if you had 2 matched
props you could put one on each end of that rearend and not have the
problem of it trying to fly off...while getting twice the power sink. 
Sounds like one helluva dangerous and loud contraption.

I had figured that an irrigation pump would be as good a compromise
as anything. Some people would be grateful to have you blast a stream
of water into the air and aerate (sp?) their pond. Lack of O2 in the
water is a common summertime problem for small ponds.

I'd kinda like to see that mega leaf blower if anyone tries it.

Greg Parmer                   gparmer at acenet.auburn.edu