Paul There is the Mercedes coupler i talked to you before ,they have
      several models on EBAY and very cheap,you can design the shaft without
      spline but only an adapted flange cup to meet the coupler and the
flexwheel
      as safety in case the rubber fail.I do have an idea of the shaft
design with
      this Mercedes coupler.Ths one is for the 550 model
http://cgi.ebay.com/**

ebaymotors/Mercedes-W116-**450SE-W124-300D-T-300TD-T-**Flex-Disc-Kit-_**



W0QQcmdZViewItemQQitemZ1405639**31332<http://cgi.ebay.com/ebaymotors/Mercede
s-W116-450SE-W124-300D-T-300TD-T-Flex-Disc-Kit-_W0QQcmdZViewItemQQitemZ14056
3931332



      http://tinyurl.com/3fhm24k


      Jean Prudhomme

    Does anyone have dimensions for this type of coupler?  I interested in
the
    OD and the thickness in particular.

    Randy

     used to use own a few bmw 2002's back in the day.  These were used as a
flexible coupling between
  the driveshaft and the output flange on the transmission (called Guibo
joints).  Having broken a few
  and then needed to call a tow truck, I'd never use one on my airplane.

  half of the bolts were on the output flange, half on the driveshaft.  When
the coupling came apart
  it was usually spectacular.

  Am I missing something-- are you gents suggesting using the flex disc in
another manner?
  William Mason                


Yes i know on the car you do have lot of bending action and twisting but it
have one model which
have a steel cage and all bolting are lineup to the same circonference so if
it fail it keep turning
the shaft ,we can use a strongger one similar to the Mercedes 500 and built
a similar cage and will
be stronger and will keep the sungear shaft driven in case it fail.The steel
cage bolted to the
flexwheelIt worth to make one and test it.There is the picture of the one i
am talking and the 500
Mercedes which i am sure is more stronger then the one you had on your car.

Jean Prudhomme

I am with William Mason; do not use the Mercedes coupling, as when they fail
you will have a very dramatic incident, which is why BMW has a metal cadge
to contain and control the flailing drive shafts.
This type of coupling is only rotating at road wheel speed which is no where
near the speed that the engine will be running at appox 7000 rpm, it is
very unlikely to fail concentrically as the outer ring will fail near one of
the moulded in bushes first.
I do not think these moulded rubber couplings are balanced or can be
balanced for the speed required.
If you have ever seen a Hooks type joint on a front engine, rear wheel drive
car prop shaft fail you will know how exciting and spectacular the
failure will be, interest to watch on the road, but not at any height
or even on the ground.

Geoff
Cheshire
England

Beside all that they are not up to the temperature expected.

I keep coming back to this design for that and other reasons.
Also because it can be retrofitted to Tracy's gear box.
The stiffness  of the silicone blocks can be almost anthing.

Not because it is my design :)

Paul Lamar