>
    >>> Giffen Marr wrote:
    >>>
    >>>> Paul
    >>>>
    >>>> Am I to understand that the TC Drive is to be driven by a shaft
    >>>> from the
    >>>> Turbo compressor? If so, aren't shaft rotational speeds of 60k to
    >>>> 80k going
    >>>> to present a problem?
    >>>>
    >>>> Giff Marr
    >>>> LIV-P/20B 45%
    >>>>
    >>>>
    >>>
    >>> What problems did you have in mind? This is what I tink I am going
    >>> to use in the 1/2 inch size.
    >>>
    >>
    >> Paul, you are joking right?
    >> Mark W.
    >>
    >>
    >> No Not joking. What problems do you see?
    >> --
    >> Paul Lamar ...No rotor no motor.
    >
    >
    > Lack of balance, lack of strength, a horrible failure mode with
   an easier
    > released projectile.
    >
    > At 80K RPM, any imbalance will be be exciting it with 480KHz (two per
    > rev).
    > At this frequency, you will at least wear out the metal to metal
   contact
    > points in the universal (although as Reeves says, you will be very
    > unlikely
    > to get up to this RPM.). Turbines normally use some sort of splined
    > coupling, a rigid coupling with a floating oil damped bearing, or
   driving
    > lubs these days.
    >
    > Be really careful testing this Paul.
    >
    > Mark
    >
    >
    > Thanks Mark. I think I will test both the bellows type as Reeve
    > suggested and this type if the off the shelf versions are
    > reasonable well made with tight tolerances. The drawback to
    > the bellows type is a somewhat larger OD for a given torque rating.
    > The second web site Reeve mentioned offer balanced bellows
    > type.
    >
    >
   http://www.rw-america.com/PDF-couplings-line-shafts/MK_miniature-bellows-couplings.pdf
    >
    >
    > BTW what are  "lubs" ?
    >
    > Alignment is near perfect when the engine is cool.
    > I am concerned with slight mis-alignment due to temp difference
    > in the various parts as the engine and turbo charger
    > warm up.
    >
    > Paul Lamar ...No rotor no motor.

   Paul,
   Sunday, my Craftsman branded "Moto-Tool" quit suddenly.    The
   yellowish
   cylinder you see lying behind the tool in the picture was apparently a
   silicone rubber splined sleeve that coupled the motor armature to the
   spindle.  The sleeve bears no resemblance to silicone rubber
   now.  It is
   waxy and brittle.  (We had some silicone rubber Razor scooter wheels
   that deteriorated the same way.)  I found a piece of Tygon type vinyl
   tubing that would slip snugly over the splined shafts and topped that
   with heat shrink tubing to make the fix you see in the picture.  It
   works perfectly to 30,000 rpm.  The friction between this type vinyl
   tubing and any clean smooth surface is tenacious.  If the heat shrink
   hose clamps that Tracy uses are available in a small enough size, this
   scheme may work for a couple hours of testing on the turbo compound.
   The mass is low, so, if it self-destructs it won't be a big deal.  Also,
   it will be easy to replace.

   Aubrey

   Good idea Aubrey. I'll give it a try. Tygon you say.

   --
   Paul Lamar ...No rotor no motor.




Wait a minute...  80,000 RPM is 1333Hz or 1.3KHz.  2per rev is 2.67KHz.
Not 480KHz as stated above.  Divide by 60 to get from RPM to Frequency.
Not multiply. I think it would be tough to find a mechanical system that
resonates at 0.5MHz...  Admittedly, 2.67KHz is pretty high frequency.
Though that just tells me it should be easy to damp..


Regards,

Matt-

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