"PAW" wrote in message ...
"Bob Kuykendall" wrote in message
om...
Hydraulic power was the only way I could think of to use one engine with
two drives in an in-line thrust design. Some of these motors are very
lightweight (IMO) and,as you said, are not the $150.00 cast-iron jobs from
Graingers. These are $2300.00 each. They're piston motors. They ( Eaton )
carry several that are rated from 2000 RPM, up to 3600 RPM... several models
to choose from. And, they have a ton of torque! :

Phil (on his way to the patent office) J/K

But what was the original reason you wanted an in-line thrust design?
I've been keen on that layout (in-line) for fail-soft/reliability
benefits. I didn't like the idea of a single point failure in the
most likely place to have a failure (engine) meaning a forced landing.
If you use a single engine to drive 2 props, you don't get that
benefit.

There are some other bene's I could see though such as
1) Engine located at center of gravity perhaps on main spar
carry-through. So you could save some structural weight.

From an efficiency standpoint I think you're better off turning a
single big prop rather than 2 smaller ones.