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

What is the weight of a"torque converter" and how efficient are they ?

John

Answered.


Paul Lamar

Paul,  I was under the impression that the torque converter case always
turns faster than the transmission shaft by the lock-up RPM. More or less
constant difference after  lockup RPM is reached.  If that is right the 2.85
planetary combined with the right stall speed converter would act like a
3.20 planetary allowing a larger diameter prop.

    Is the gearbox "chatter" a resonant frequency problem which we want to
idle  below the chatter RPM. If it is a resonant frequency I would think it
would also occur at multiples of the frequency and there may be RPM bands we
don't want to run continuously at.

     A mazda torque converter sounds like a lucky find. It  bolts up and
is rated for more RPM than we need. Somebody told me the Miata  transmission
will bolt up to a rotary  which would widen the source pool, and likely have
a different stall speed than the RX8 converter. B&M modifies torque
converters to a stall RPM you specify. Are we basically trying to add 1500
RPM to the engine with the 2.85 or is that too mutch.

george grimes

The case of the torque converter is bolted to the flex plate by the same four holes
Tracy uses. When the two sections of the torque converter are rotating
at different rpm's and increasing the torque the efficiency is horrible.
You can lose up to 40 or 50% of your HP. One does not want to do that.

Paul Lamar