Mailing List flyrotary@lancaironline.net Message #20698
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Attn: Finn -Shattered Apex seal Was "V" Groove
Date: Sat, 23 Apr 2005 21:07:25 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Finn, regarding the possibility of the apex seal simply shattering rather than FOD.  I also found in the overhaul supplemental instructions about the parts in the basic overhaul kit this sentence from Bruce:
 
".... The apex seal will rock in their grooves, wearing the groove to a V and eventually shatter due to the excessive clearance...."
 
Sooooo, I am more convinced than ever that I did not encounter a necessarily rare condition - that excessive seal clearance and shatter seals do happen.  Does not take a foreign object.  I strongly suspect that there are probably several conditions that play a role in when the seal shatters (if ever) and if they all play the wrong way at the same time, the seal shatters sooner.  On the otherhand, the engine might possibly wear out before the seal shatters if those factors never converge.
 
 
Ed
 
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
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