Please, some thoughts about counter-rotating props using
 twin Mazda power
 (one on each wing).

 In fantasy land, we turn the rotors around and run the
 Mazda backwards. I
 don't think even Paul could figure that one out.

 By the way, very nice article in June 2009 KITPLANES,
 Paul.

 I've been unable to find a suitable reversing gearbox. So
 far, I've thought
 of putting a "sandwich" gearbox between the engine and the
 PSRU. I know
 this is easier said than done. You could probably use gears
 from an auto
 transmission. As each engine with the accessories has to be
 the twin of each other
 (except for the rotation part), both need the gearbox.
 With a straight-through arrangement you would need 3 gears
 (input, idler,
 output) for original rotation, and input, two idlers,
 output, for reversed
 rotation. For an offset arrangement, one idler can be
 subtracted from each
 gearboxe. Oil squirting barbs at all gear meshing points.

 Initial problems are the input adapters from the engine,
 and the output
 adapter to the PSRU.

 This is as far as I have gotten with my brainstorming, and
 I am sure that
 there is tons of stuff that I am missing, so please feel
 free to critique -
 something I have learned to value in reading your daily
 posts that I get in
 my daily email.

 By the way, the object of all this is a 60% P-38 in which
 rotary engines
 are the only ones that make sense for physical room and
 power. Also, it only
 works if the inside of the cockpit is laid out like a
 sailplane (recumbent).
 Thank you all, I have learned to enjoy your fearless,
 open-minded ways.
 Bernie.


 Why not just connecting the PSRU to the shaft on a modified
 endplate
 on the other side of the engine ?

 Philippe-Pierre DEJEAN


 Bernie,

 Nice part about the planetary gearing is reverse rotation is easily
 done.

 Ring gear, cluster gears, and sun gear.  Change the input and output for
 different gear rotation and ratios.  You want to match rpms on both
 sides, so it would be a different gear cluster.

 The 2.85 is sun to ring ratio. (same rotation).  So you need to
 find a Sun to Planetary gear that is the same ratio, which
 give counter rotation.

 Mind is slipping.... Was it the Ford Transmission that went
 with the six planetary gears (three being most common),
 but for a Diesel truck it went to six.

 Tom

Bernie,

 Nice part about the planetary gearing is reverse rotation is easily
 done.

 Ring gear, cluster gears, and sun gear.  Change the input and output for
 different gear rotation and ratios.  You want to match rpms on both
 sides, so it would be a different gear cluster.

 The 2.85 is sun to ring ratio. (same rotation).  So you need to
 find a Sun to Planetary gear that is the same ratio, which give
 counter rotation.

 Mind is slipping.... Was it the Ford Transmission that went with the six
 planetary gears (three being most common), but for a Diesel truck it
 went to six.

 Tom Walter

 "So you need to
 find a Sun to Planetary gear that is the same
 ratio, which give counter rotation"

 That is the hard part :)

 Paul Lamar


 Just need to find a Sun and Planet gears that have the
 same number of teeth. Forward and Reverse would have
 the same gear reduction. Irony is ratio would be close
 to 3:1 -- it could be built.

 Paul -- you need a good reason to buy a gear hobbing
 machine, correct? <grin

 Tom Walther

 We have been looking for them for 11 years :)

 Paul Lamar


 A sprag clutch will take care of the feathering
 problem, Virg

I don't think so Virg :)

Paul Lamar


You would be far better off adding some method of braking (not
breaking) the prop - much lower drag, even if the blades were pitched
to be streamlined with the flow.  Windmilling props, even if not
driving the engine are terribly draggy.  Also, it seems likely it
would be easy to over-speed the prop if you can't feather or brake it
- if there were a sprag.


Matt-