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<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


 So would an automotive torque converter be suitable? At least the mass
would
 give you some desirable flywheel effect:) The fluid fly-wheel would have
 more chance of dissipating heat build-up than those poor little bits of
 rubber!
 What about the prop now free-wheeling to give windmill drag with the
engine
 out?:(


 John Evans


 Probably weigh 10 or 12 pounds. On the up side if you used the Mazda auto
tx
 torque converter it would bolt right up to the stock flex plate :)
Ironically the
 Mazda auto tranny is a scaled down version of the Ford C6, A4OD, etc.,
etc. which
 we now use the planetary gears out of.  Made in Japan by Jatco
transmission.

 Paul Lamar

I wonder if something like this could be adapted for our uses...
it is another type of harmonic damper, and is not inserted
directly into the power transmission chain, but rather only
acts to dampen torsional vibrations in the same way that
harmonic balancers do...it consists of an inertial disc inside
a very viscous fluid:

http://www.thedieselpage.com/**features/fluidampr.htm<http://www.thedieselpage.com/features/fluidampr.htm

Gene Kahn

It might work but it is intended to be tuned to damp the
torsional resonant frequency of a crankshaft. E-shafts don't have that
problem.

Paul Lamar

I don't know if this would do anything constructive, but I just remembered
that somebody made commercially for a while a 4-wheel drive viscous coupling
that would only kick in when the wheels spun.  So, you could drive with the
hubs locked in and the front drive shaft would only start to function when
the front wheels began to spin.  It was meant to allow you to drive at
highway speeds on ice patchy roads with hubs locked and only be running in 4
wheel drive when you hit a patch of ice that caused the front wheels to spin
faster.  My decrepit brain can't remember the exact details on how it
worked, but the point is, it used a viscous (I think silicon) fluid to make
the coupling.  It seems to me that we want as little slippage as possible
but still have a coupling that can work back and forth.  I don't know what
RPM limits are on this setup.  But, certainly Fluidamper's turn really high
rpms with no problem.  It would seem one could vary the viscousity of the
silicon to make the coupling instead of using tranny fluid and stall
speeds?????  But, you listening to a guy who punched cows most of his life
and rodeo bucking horses for 10 years.  Not much brains to begin with and
even fewer now.  Oh.  I think that 4-wheel drive product might have been
called "Milage Master".

Van