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


Paul,

If I understand correctly, the gear box chatter is at low RPM and possibly
under low load coming in to land. If that is the case, a high stall automotive
torque could work. A 9" Ford with the matching transmission pump to circulate
the oil and charge the converter. The PSRU drive could go into the torque. You
could even use a lockup converter with a switch on the panel to lock it up. I
do not think that would be necessary as the RPM in flight would not give a lot
of slip. Then it is just to decide on the correct oil.

Dale Davies