Bill Freeman wrote:

Perry,

 Many years ago, I looked at what would be a good, safe
and least cost method of using any car motor in direct
drive mode.  Since the primary issue is to only have torque
load of the crank ( no thrust, no bending) , the method that I
came up with was very simple, and after looking at your new
mount pix, it is something that you can easily do yourself.

What I had envisioned was a steel tube truss coming off of
available mnt points on the engine block (much like your
mount) and supporting a steel mounting plate (perhaps 1/8th
to 1/4 inch ) which has a large central hole and has a machined
(aluminum?) bearing housing bolted to it.  This would have
a pair of large diameter (2.5" ID?)  tapered rollers back to back
supporting a short prop shaft (steel, much like Tracy's output shaft)
and driven by a thinwall tubular driveshaft with either two auto U-joints
or at least one CV joint to avoid alignment issues.  The driveshaft
could be alum or carbon, too.  If you use a single universal
there are bad things put into the shaft due to the inherent design
of a Hooke-type (cross) Ujoint.  Two Hooke joints cancel
it out, so are OK.  One constant velocity joint (outboard car
front wheel drive driveshaft) is ok - the "constant velocity" is
the key point.  Two CVs would work fine by are heavy.

This could be either grease lubed or oil fed and is much like
what Charlie Airesman is using on his VariEze.  I think
this might be reasonably easy to add to your system and would
be an improvement in reliability as you take the motor
back to a being a torque generator, which is what it was
designed to do.  I suspect that his could weigh in at about
25 lbs or possibly less.   I can help you design it if you want.

I don't know enough about the Mazda construction details
to assess the commentary from the Australian dude, but
he could be right.  Of course, torsional vibrations are possible,
with any shaft system but your very light prop helps this a lot.

Bill
Long EZ builder & pilot
mechanical engineer

 
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