Paul
As per today all major cars are  built with front drive and almost built
with a wheel bearing hub integrated with double ball bearing who act as
trust in both sides and as been proof since lot of years..

I found one who can be use to match the prop stubs by machining those
hole stubs between the original wheel stubs and remove the existing
stubs and enlarge them to remove excess weight'.

The wheel flange have to be reduce in diameter to standard prop shaft
size flange.

The attaché triangular flange can be machined to .200" thickness to
reduce weight and all these parts are soft enough to be machined.

The hub can be hold on pressure fit and  with 3 long bolts from the
inside aluminum casing and the head seal with orings to hold the oil
pressure inside the gears chamber, or 3 long treaded studs.

The aluminum casing can be machined from solid bar or get it  cast from
foundry, it can also be added some ribs for more stiffeness

You can find the wheel hub bearing in Ebay at $40.00 and up depends on
quality.

The both shaft are about $80.00 from Slauson Transmission Parts,all
other parts as sun gear ,planet.ring gear,front ring,drum forward
,bearings less then $200 from Slauson few years ago

I am sending you several sketch showing  how to built this gear box and
it might be a few more pounds of Tracy one , much cheaper and fast to
built with almost available parts.



JEAN PRUDHOMME


That link did not work. Jean. Send the sketches as attachments.

Paul Lamar


Paul,
I had mentioned a front wheel drive hub as thrust bearings previously. I
looked at several the cheapest being a Hyundai elantra at about $40.00.
There are several Audi quattro bearings that would do nicely. Don't
mention that you want to use them in an airplane though as many dealers
won't sell to you.
Bill Jepson


These hubs weigh a lot compared to a prop flange and 2 inch needle bearing as used
in the Ross design. The ball bearings are way over kill being designed to take a 1000
pound continuous radial load. The radial load on a Ross front needle bearing is zero
unless the airplane stalls or spins. The Ross needle thrust bearings weigh next to nothing.

Assume for the moment you are going to use a stock outer constant velocity
U joint and shaft to connect this hub to the planet carrier. That forces the 10 pound planet carrier
assemble (ring gear, planets and sun gear) about 8 or 10 inches forward compared to the Ross.

 Now you have a lot of weight just behind the prop. Unless you move the engine back
to compensate you are going to have a CG problem for a lot of airplanes. If you do
move the engine back the whole firewall forward package will become much longer
and it won't fit in most cowls. The fire wall forward weight will also increase.

Most cowls are 35 to 39 inches long. The Ross design is about right
for most cowls and the planet carrier CG is close to the engine. The prop flange is about
14 inches in front of the engine. This yields a reasonable engine package CG position
and over all length.

In effect you have saved only a few dollars for an increase in FWF weight.

Paul Lamar

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