I am really fascinated with Steve's design. I think it could
be a major breakthrough in the cost of PSRU's.
His use of low cost off the shelf two inch hollow shaft was a
brilliant idea.
For those of you not familiar with the QD coupling here are a couple
of pictures. The coupling works by friction alone. I think the torque
capacity of the this coupling could perhaps be enhanced with three
more bolts.

I think you could sell a kit Steve. You could save people money by
offering such things as thick wall aluminum tubing cut to the
proper length for the housing. Also perhaps other machined parts.

"Rosine, Steve" wrote:

I really don't have a lot of time to produce and distribute a kit.  I have
talked to my machine shop about making the case, which has the critical
shrink fits for the case halves and the bearing cups.  As for plans, well,
to be honest, that drawing I posted was my plans.  I will try to produce an
exploded and fully dimensioned drawing in a few days, and I can assemble my
list of Motion Industries part numbers. I can also answer questions for
anyone really interested in building it. The design goal, though, was that
there be as few critical dimensions as possible, in order to make this as
easy for the hobbist machinist to produce. The big issue here is welding the
ring gear to the modified sprocket.  I did it with TIG, and I'm aware of the
difficulties of weld high carbon steel to mild steel.  It also has to be
centered perfectly.   This is probably hte part to contract out, but I doubt
anyone would guarantee this weld.  I was even afraid to stress relieve the
weld for fear of de-hardening the gear.

The place where I got my large dia. aluminum tube, Metals Express, sells by
the inch, no quantity discount listed.

For what its worth, I backed up the QD bushing with Loctite retaining
compound.  It'll have great strength, but it's gonna be a PITA to separate.
Soaking in methylene chloride may help, but loctite recommends heating to
300 deg. F to remove.  RIght now, the prop flange does not have the loctite
on it, since I think its likely that I will have to remove it at some point.
Of course it's probably the part that needs it most (sigh).

Steve ROsine

Mustang II / 13B

Do what you can Steve and I will work on them some more when you get them done.
I can almost dimension it from what you have called out in the way of bearings
and QD couplings so far. I might make a few changes like screwing the stock Ford 
ring gear bulkhead to the shaft such as shown in my original drawing. Everett 
Hatch did that on his original design and it worked well.

This should help a lot of people on a budget.

I might get a QD and see if the torque can be enhanced for the prop flange end
with extra bolts. 

Paul Lamar
 
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