Did everybody get 4 copies of the coupling IGES drawing? If so I am
 sorry but it was not me.

 That may have been done by Earthlink They are having a bit of trouble
 with their email.

 Kevin did you get it?

 Paul Lamar

 Hi Paul, I got the coupling IGES Dave Macandless  in Perth

 Just one copy Dave? Earthlink sent me four.

 Paul Lamar

 I have a copy. I need to print this stuff out and take it to Shaun,
 the company is called Tangent in Smyrna TN. I will let you know next
 week.

 Kevin Alderman

 Are you in Tennessee now Kevin?


 Here are some pictures of the welded steel version.

 It needs to be improved.

 Paul Lamar

 The auto flex plate with the pressed and tack welded ring gear has
 been known to fly apart if the assembly starts to resonate, the flex
 plate had the torque converter bolted to the periphery of the
 flywheel this helped to negate the problem of resonance, the pressed
 plate is only 2mm thick, very light but has caused serious damage to
 an aircraft here in NZ.

 Andrew Campbell

 Yes I know about that. That prompted us to design this coupling.

 This design does not rely on the flex plate. The flex plate's  only
 function is to start the engine. With this design the coupling is
 bolted directly to the rear counter weight with six 10 mm socket
 head screws. Very solid and a direct connection to the e-shaft.

 Tracy bolted his to the flex plate and that failed the flex plate in
 several airplanes. Here is the result.

 Paul Lamar.


 Paul do you or any others plan to make this coupling available to
 purchase?  If so, will it be retrofit-able to Tracy's RD units?

 Scott Gettings

 I hope Kevin does it. I will work with him on marketing and design if
 he does. I am getting too old to start another biz.

 Kevin is a lot younger than me. Almost everybody is :-)

 Paul Lamar


 I think I'm catching up in the age category!  It would be great if
 this coupler were available in the near future.

 Paul, you had previously mentioned that there are some aftermarket
 manual transmission flywheels available, even though they are
 somewhat expensive ($350).  It looks like some of these are assembled
 from more than one piece, and still require the counterweight.

 If this new coupler does not come to fruition, would it be feasible
 (and safer) to retrofit Tracy's RD damper to such a manual
 transmission flywheel instead of the flexplate?


 Scott Gettings

 It would work if you have one of Tracy's boxes and couplings. That is
 what Dave Leonard did.

 Kevin was in your neck of the woods

Paul Lamar

This version looks both very strong and heavy. I will pull out my original manual flywheel to study the dimensions. I do have Tracy's reduction drive including the isolator. Tracy's isolator mounts on the flexplate with four, very small purchases on outer parts of the metal. However, I see the flex plates have failed just outside of the center mount.

Some of the aftermarket manual flywheels are aluminum, which should save significant weight. At least one advertised that the counterweight was still necessary with their unit.

Another thought:  The automatic flex plates are only 2 mm in thickness. Would another alternative for Tracy versions perhaps be to combine two flex plates into one just for the load – bearing areas? Another words remove the ring gear and excess outer metal on one, and weld/epoxy or bolt the two together.   The question would then be whether twice as strong is really strong enough?

Scott Gettings

Thats because the gyro stresses  are applied where the 10mm bolts attach  to the counter weights.
Tracy's coupling adds to the gyroscopic loads for the very reason the rubber bushing are
out near the OD.

We tried all sorts of things including beefing up thr plates with bonded on fiberglass.

Paul Lamar