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

I would be  more concerned about being able to feather in the event of an
engine  failure, assymetric thrust would have a 50% chance of being an
issue,
it  would just depend on which engine failed but the drag from the dead
engine  would be huge. Of course you could always fly under the assumption
that if  one failed you just shut both down and fly like a single engine
brick  :)

John

With counterrotating props, there is no critical engine. (or each one is a
critical one). The engine out situation is real and feathering is a  must.

There are various electric C/S--Variable props available which have a
feathering feature.

The ones of which I am aware are AIRMASTER AND VESTA.  there are  others.

Make sure that you have a strong rudder trim mechanism as if you loose one,
you may not be able to hold "good engine" rudder for long before your leg
muscles tire.

Rich