Mailing List flyrotary@lancaironline.net Message #15953
From: Dale Rogers <dale.r@cox.net>
Subject: [FlyRotary] Re: Flex plate <> Flywheel
Date: Mon, 24 Jan 2005 20:42:06 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Ummm, Guys?

  I can't address how Tracy's adapter is fastened to the flexplate, but from the appearance of mine, it follows the customs of other automatic transmissions: [1]  The torque converter (the *real* flywheel in an automatic) is equipped with threaded studs matching the hole placement in the flexplate; it is then secured to the flexplate with locking nuts.

or [2]  The torque converter is equiped with threaded bosses matching the hole placement in the flexplate; cap screws go through the back of the flexplate and into the bosses.

In neither case is any attempt made to thread into the thin metal of the flexplate - it is simply clamped between the fasteners and the torque converter.

Hope this is some help,
Dale R.
COZY MkIV #1254

From: "Ed Anderson" <eanderson@carolina.rr.com>
Date: 2005/01/24 Mon PM 06:24:45 EST
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: Flex plate <> Flywheel [FlyRotary] Re: flex
 plate

> I've read this several times, and still not quite sure I can believe
> it.  The flex plate I have is thin.  In the .040" range thin.  I realize
> that it will all be shear forces, but can 9 threaded holes be expected
> to take the 800ft/lb of reaction forces that a typical NA engine is
> expected to put out?
> (I believe I got the 800ft/lb number out of the discussion of the
> Schwertz beam motor mount on PL website).  Just doesn't seem like it
> could hold up.

For crimmney sakes, Ernest - not so loud.  If we never tell it, it won't
know it can't handle it.

Ernest, I think the flex plate is more like .092 - 0.125 " thick or more.
In any case, I have never heard of a flex plate failing.
It will would also take a bit less stress without the gear shifting going on
as in the automobile.  Also, not certain but I think the flywheel torque is
on the order of 150-200 ft/lb for an NA engine.

Ed A


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