Mailing List flyrotary@lancaironline.net Message #55750
From: Tracy <rwstracy@gmail.com>
Subject: Re: [FlyRotary] Re: Flex Plate Failure - Improvements
Date: Sat, 16 Jul 2011 08:37:46 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Interesting !   The failure might have been the same as on the Blanton V6 drives where the flex plate is used only for the ring gear & starter.   That is apparently the worst case scenario for flex plates, I.e., no load (or damping of any kind) at all.   They apparently flutter and self destruct.

Tracy

Sent from my iPad

On Jul 15, 2011, at 11:55 PM, Lehanover@aol.com wrote:

I made up a small steel flywheel to fit the counter-weight, but only big enough to bolt on a 5 1/2" Tilton dual disc clutch pack. I used a flex plate only to carry the starter ring. It did not occur to me to try to transmit torque through the flex plate. I had one of my drivers miss a shift and reved to the moon. The conical shape of the flex plate went dead flat. Bits of ring gear around the welds hug on and nearly cut the bell housing into two pieces. The remaining pieces were dribbled out onto the track for others to deal with. The flange the ring gear sat on was turned to 45 degrees. After that I TIGed the whole gear to the flex plate. They do fail in cars, that is why you can buy one with the cracks already installed. There used to be a doubler plate on top of the bolt circle to spread out the strain of the mounting bolts and reduce cracking. Are those still being used?
 
Probably not a problem for airplanes, but I would not transfer torque with one.
 
Lynn E. Hanover
 
 
 
In a message dated 7/15/2011 2:42:02 P.M. Paraguay Standard Time, rwstracy@gmail.com writes:
I'm still in analysis mode on this myself.

So far the possibilities are:

1. The flex plate may have been warped when installed  ( I bought several that were)  I think the standard should be close to zero runout or wobble on the flexplate in view of this failure.

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