Paul Wrote> I am beginning to believe WE can build a turbo charged Mazda rotary
engine with a 20% decrease in fuel burn and a 20% increase in
power with no increased cooling load. That would put the
Mazda rotary well above ANY other aircraft engine including
the diesels. It would also have an unequaled power to weight
ratio for any intermittent combustion aircraft engine.
All we need to is extend the shaft out of the turbo charger
through the compressor inlet and feed it into one of these
off the shelf small and light weight (2.2 pounds) planetary
gear boxes and thence into the eshaft using a cog or multi
V belt drive. The belt final drive will serve to isolate
the torque pulses.
Using a belt final drive after a planetary reduction to isolate the torque pulses is a great idea
Paul. I kept hanging up on the clutch idea.
Do you have a price list from Thomson? The AccuTrue gearheads advertise 8X the input speed over
straight bevel gear sets, but still only list speeds up to 5000 rpm (with 10000 hour life, and
that is with side loads).
Have you ever pulled out the rotor of a turbo charger? The turbine is shrunk onto the shaft, so it
is not possible to just pull the turbine off and put it on a new shaft with the extension to the
gearbox.
I think Kurt Schreckling has published a book on model turboprops, which should have some useful
info on how those guy do the shaft and gearbox.
Turbo-prop Engine for Home Construction by Kurt Schreckling ISBN 1900371 26 X
Mark Wrathall
The high input RPM could be a problem with the gear box. We would
probably need to test it somehow. Might need a real low viscosity lube oil.
I think one can make a coupling for the turbo charger shaft since the
compressor rotor is held on with a nut and key way. We are going
out through the compressor inlet after all. 50 HP = torque x RPM / 5252
or 5252 X 50 = Torque X 100,000
Or 5252 X 50 / 100,000 = Torque = 2.6 foot pounds = 31 inch
pounds. That is a real small shaft. Say 3/8th of an inch in dia.
Only needs to be five or six inches long.
Another approach is to use the ring gear and another starter pinion gear
for the final drive. That would give us at least a ten to one
gear reduction right there. Perhaps two or three ring gears welded side
by side. To reduce the wear. Starter pinions are about an .75 inch
wide.
Then a very small 2:1 low torque spur gear box (for the required
off set)out of the turbo with a very small, low torque fluid coupling
connecting the final drive. Not that hard to machine a small fluid
coupling on an NC mill.
Paul Lamar
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