propellor dyno

[Frank_Marrone at optilink.optilink.dsccc.com]

I showed the propeller post to a friend of mine.  We have been toying with the
build at home dyno idea for quite some time now.  We were thinking maybe a jet
boat prop in a large swiming pool or lake would make a good load but the
airplane propellor sounds even better.

I thought I'd forward his comments to the list since he had some input both
humorous and technical...

--- Forwarded mail from sdelanty at wco.com

From: sdelanty at wco.com
Date: Thu, 31 Aug 1995 16:38:40 -0500


>
>Hello,
>The local aircraft rebuilder thinks a used aircraft propeller could be
>an excellent power waster.
>Perfectly good propellers, propeller shafts, crankshafts and other
>parts are discarded due to age, hours of use or minor cosmetic damages.

That's a cool idea!
So where do we get 'em?
Next time we go to quinns we should ask around at the airport.

>Beyond the speed of sound the prop might break or just
>be a power (dynamometer) waster.

Wasting power is cool! Breaking would suck! Have to be careful about that.

If you had a prop that used more power than you had available, You could
restrict the inlet air to "unload" it.

>Clubs are like propellers, but intended for engine testing on ground.
>Clubs can be inexpensively made for custom purposes.

I'll bet if one was clever, clubs could be made at home.
Clubs also have the advantage that they don't push tons of air in just one
direction, so the thrust bearing could be less heavy duty.

>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.

How about a tranny (for changing load) and rear end (2.0?) with 2 smaller
props, one on each axle? If the props pointed in opposite direction, the
thing would have less of a tendancy to "fly away".
It would suck to have Your 390 get away and go flying around geyserville!
 Also the thrust load on each would only be half of what one larger prop
would create.
Maybe a set of props or blowers that just bolt up to the rear axles of the
vehicle to be dynoed. Kind of a chassis dyno thing, just jack the rear end up
on yer car, pull the wheels off and bolt yer props on...

>Some calculation of (effect of) thrust to be generated would be in
>order. Also consider tendency of prop to "process" people.

Maybe we could use it to chop a big batch of salsa.

 Steve Delanty
sdelanty at wco.com



---End of forwarded mail from sdelanty at wco.com

-- 
Frank Marrone at marrone at optilink.dsccc.com
1965 Sunbeam Tiger B9471116
1960 Sumbean Pintopine Series I B9009330
1966 Ford LTD 4-door family barge.