> >  > George Lendich wrote:

 >>
 >>  Paul,
 >>  I'm out of my depth here mate - as usual but my flexplate has a counter
 >>  weight it's bolted to and weighs 3879 grams all up
 >>  or 8.5 lbs.
 >>
 >>  However having seen the BMW type dampers they do seem heavy
but very robust.
 >>
 >>  I'm wondering  what the all up weight of Tracy's Flexplate and
damper is,
 >>  perhaps there isn't much between Tracy's and Ken's 16
 >>  lbs.
 >>
 >>  I'm now wondering what an ideal all up flex-plate and damper
might be !!?
 >>  George (down under)

 >Here is something Power Sport came up with.
 >Sorry about the out of focus pic. Don Dunbar is using a rubber
 >coupling that looks
 >real interesting. I would wait and see how it idles however :)
Might be a bit
 >too stiff. One can always drill holes in the rubber to soften it up a bit.
 >Freeze it first.
 >
 >The real advantage of a rubber coupling is there is no spline
hence there is
 >no slop to wear out the spline.
 >
 >Paul Lamar

    Hey George maybe you missed my point that I would run the 16 lb
 flywheel and a damper similar to Tracy's or something else so I would
 be adding the 16 lbs as I am just replacing the flex plate, this is
 what I did with the Ross setup when I was blowing the dampers.
   When I get by the airport I will shot a photo of the busted damper I
 have there from the Ross redrive.
   Also I think that if anyone is still running a Ross with the spring
 damper it may be worth trying one of those PYI dampers as the spring
 damper has is known to fail and the PYI should be a direct
 replacement.

   Hey Paul I would love to get rid of the spline on the damper but I
 don't see how to make it work as if there is a flange on the sun gear
 shaft to bolt to the damper you won't be able to get that flange
 through the thrust bearings, oil seal or the housing.
   Also while we are in the that aria what is the best way to attach
 the sun gear to the pilot shaft, Ross said that he made it a press
 fit and then pined it but I don't recall seeing any pins and I don't
 have the Ross redrive back to him and of corse I never got it back.

    Ken

I have a shot of Ken's busted damper :) So far we have had no other reports
of busted Ross dampers but then very few people are routinely
running nitrous through
their engines like Ken does and use an 18 pound prop :) So far Tom Parkes is
reporting no problems with his damper and he is feeding a turbo 3
rotor through
it. I will admit they rattle the heck out of the gear box if you let them
idle below 2000 engine RPM.

Damper is a misnomer with these things as the springs give back all the  pulse
energy put in them. Rubber on the other hand heats up and dissipates some of
the energy. Tracy claims he keeps making the bushings softer and softer
and it keeps working better and better. I don't know how long ago he stopped
doing that and settled on a final hardness :)

The helical gear thrust bearing ID and seal ID must be larger than
the sun gear OD
unlike that shown on this drawing. Then you use a split keeper.
Something like a
valve stem keeper to feed the gear thrust load into the bearing. I am sure Don
Dunbar found that out already when he first tried to put his together :)

I'll do a 3D of this trick if you need one.

I had Tracy just press fit my sun gear on the shaft. My theory (to
be tried on the dyno
and not in the air) is if it slips it will friction weld itself to the shaft.

Here too is a picture of me and Ken getting ready to go down and
land in the river.

Paul Lamar

    I think I will stick with the spline as it sounds to complicated.

    In theory the press fit should work as transmissions that I have
been around just press the engagement dogs on but for high hp we weld
them on but they don't have nearly the surface aria that we have and
if you set it up with about .002 interference and heat the gear and
cool the shaft it should hold.

   Atkins did have some dampers crack on him and like I said the
flywheel he added stopped the cracking, also I will mention that even
with the damper that came apart and went through the prop I still
flew home with it as there was enough pieces to keep the engine
engaged to the gearbox.

  I know exactly when it let go as there was a rattling noise and then
it went away, I was about 80 miles from home but had water under me
all the way so no big deal if the windmill stopped turning.
  The other two that I had cracks in I spotted during inspections as I
started inspecting them more often after the one cracked.

  Also the first one that busted to pieces was before I put the
nitrous in the coot, it was like in the first 50 hrs of flying that I
had on it and I put the nitrous on at about 100 hrs and I cracked
three in the first 150 hrs and then I put over 200 hrs on it without
any cracks after I installed the flywheel.

   I had thought about sticking with the spring damper with a flywheel
but now I think I may try that damper made by PYI.

  Ken

I don't know Ken My spline eliminator might take all of 20 minutes to make
on a lathe.

Paul Lamar
 
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