It seems to me that the prop reduction options we're seeing are
unnecessarily complex.
If I wanted complexity for the sake of complexity, I'd just run a
reciprosaur!
A 2-gear reduction would be lighter and simpler than the Ford planetary
units. For that matter a Notax C box only weighs 18 lbs and might be a
good solution for 1-rotor setups.
To build your own reduction, gears are readily available from a number
of sources. The engine-mount side would be an aluminum plate, that
would not only attach to the engine but also mount the gears.
A lightweight gear housing (and contour fills around the output shaft of
the engine) can be made of fiberglass or carbon fiber. Lubrication
would be simple -- tap off a small line from the flow back from the oil
cooler, squirt it at the gears where they mesh, and drain that to the
oil sump.
With a little design work, you can also scrap the flywheel and starter
ring, hooking the starter up to the larger gear and getting even more
weight reduction.
Has anyone tried this, or did they just jump to the planetary systems?
Keith Wood
Planetary's have a higher strength to weight ratio than
any other type of gearing. For that reason alone they are the only
kind of gearing used in serious aircraft engines.
The Ford planet gear set we use weighs less than eight pounds.
Torque capacity is over 650 foot pounds.
1)For a given gear width a six pinion planetary is six times
stronger than just two gears.
2)Two gears alone attempt to wedge them
selves apart requiring a very robust gear case.
3)In a planetary all gear separation forces are self
contained in the ring gear.
4) In a two gear system as the light alloy case expands
with heat the gears get further apart causing higher bending
loads on the teeth.
5) The planetary is ideal for a rotary
as the output shaft is coaxial with the e-shaft. It is also
ideal for a horizontal opposed aircraft piston engine.
Do you need any more reasons? :)
Paul Lamar ...No rotor no motor.
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