Chad, more than likely the cause of the bent plate was caused by some auto mechanic in the past that did not know not to pry on the flex-plate with his giant screwdriver-prybar he just bought from the Mac, Snap-on, Matco, Cornwell, tool truck while trying to get the trans to brake free from the eng. block-to-trans alignment pins that are all corroded because the manufacturer didn't apply a little grease to the pins at assem. Hows that for a short rant. I see this often on all brands in my shop. David R. Cook RV6A Rotary ( I drilled & installed pins in two of the thin single bolt stand-offs on the RWS RD-1B so they could not turn & hit flex-plate if bolt came loose at all, & yes I applied some lube to the stainless steel pins to help prevent corrosion so the technician working on it can actually get it apart without creating more damage. )
From: "Chad Robinson" <crobinson@medialantern.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Friday, August 5, 2011 10:04:51 PM
Subject: [FlyRotary] Re: Fwd: Flex plate cracks
On 8/5/2011 9:08 PM, Charlie England wrote:
> I was moving stuff around in the hangar today& picked up my salvage
> yard flex
> plate. Found two 3/4" cracks: down from 9 o'clock& up from 3 o'clock
> holes in
> the pic. Plate has never flown AFAIK.
The timing of this whole conversation is eerie. Literally 24 hours
before it was first posted I had finally installed my starter and turned
my engine over for the first time. When I did, I noticed visible runout
in my flex plate ring gear (the whole plate had runout - I just noticed
it because I was making sure my starter alignment was good).
I initially contacted Tracy to see if it was acceptable, but the number
he pulled from thin air for what might be acceptable was a small
fraction of what I had - mine was like 3/16". It was very noticeable.
SO, when the whole hoopla erupted on the list that sealed it for me and
I decided to tear it out and put a new one in. I lucked across an eBay
seller with THREE flex plates, and at only $40 each I just said "f---
it" and bought them all. I'm glad I did. One of the three had runout of
its own - not as much as my first plate, but definitely not a choice
part. I ended up installing the best of the three.
Close examination of these three seems to suggest that some stress
during use caused the warp (heat?). They don't appear to be
manufacturing tolerances. I understand Lynn's point about that and don't
disagree, it's just that all of mine have visible indications of wear
and tear to varying degrees. If somebody had a transmission seize or
hydro-locked their engine, this part is right in the chain to take some
abuse there... It might be worth establishing some guidelines for what's
acceptable in this part.
Regards,
Chad
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