I think what we really need for the torque damper is a fliud
coupling. I was at the Camarillo air show yesterday and they had
an unprecedented collection of war birds. No less than two flying
P38's among many others.

They also had a restored early Northrop flying wing.

I turned the prop both ways  and it rotated freely.
I asked some of the CAF types if it flew in :)
They said yes. They said it had torque converters but
what I really think they meant were fluid couplings.
Maybe they were really torque converters Northrop got in a
junkyard :)

The torque converter is closely related to a fluid coupling
and is widely used in automatic transmission. The stall
speed is about 2000 RPM so the engine can rotate freely
up to about 1500 RPM before a lot of torque is transmitted.

Our problems are not so much torsional resonance but
gear box chatter.

I think a fluid coupling will solve the problem once
and for all.

http://pt.rexnord.com/products/couplings/true_torque_fluid_couplings/fluid-couplings.asp

Falk True Torque Fluid Couplings

A fluid coupling allows the motor to accelerate independently to full speed,
the driven load has been isolated by the fluid coupling.

Paul Lamar



Paul,

I couldn't tell for sure if you were the one who saw the flying wing or you
were responding to someone's email who saw the wing.   But, what a great
concept--fluid coupling.  If that wasn't you're email, do you think it would
work?  Wow.  I think you can build them to set the stall speed about
wherever you want it as per drag racers.  If you could set it as low as
possible and still accomplish the purpose, seems like great solution.  What
say you.


Van

That was me. I took the pic of the flying wing.

Paul Lamar

I was sitting here watching u-tube videos of T-51s and occurred to me--would
a fluid coupling save an engine if you had a prop strike.  I'm all excited
about the fluid coupling thing.  Hurry up and build it Paul.  What do you
see as the problems?  Those drag racer tyranny shops can build torque
converters with various stall speeds.  The whole tyranny is pricey but not
expensive by airplane standards.  Seems like that fluid coupling part itself
would be easy and relatively inexpensive to get built.
You just have to pit your engineering magic to work and pop out the rest of
the set up.  I'm excited.


Van