Mailing List flyrotary@lancaironline.net Message #20153
From: George Lendich <lendich@optusnet.com.au>
Subject: Re: [FlyRotary] The Final? Story on the Engine problem
Date: Wed, 13 Apr 2005 08:43:20 +1000
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Ed,
That was me who suggester RX8 rotors, I would like to hear what Bruce T says as well. I will use one in a single rotor.
Question - did you say those were Hurley apex seals?
I would use Tracy/Bruce's apex seals and the RX8 rotors.
George ( down under)
Tried to send the below message with 4 photos and it was rejected as 307K which exceeded the lists 300K limit.  So here it is again with  two photos with this e mail and two photos to follow with the next e mail.
 
Ed
 
 
 
Well, folks the Mystery of my apex seal failure may never be solved completely.  But, I can now eliminate the spark plugs as well as the plastic plenum.  The end of the spark plug clears the combustion chamber even with the washer removed - and no pieces of the porcelain appear to missing from  the plugs.
 
So just don't know what caused the initial seal failure, but the sequence of events after that is fairly evident.
 
Photos 3 piece Apex shows what remained of one apex seal from rotor #1, clearly a rather large chuck is missing and could not be found. But evidence of its passage through the combustion chamber was left behind.   The other two pieces of the broken apex were still in their slot.
 
Photo  Apex Departing Slot clearly shows where the missing piece of the apex seal bent over the straight edge of its slot when it departed. Apparently when it left the clearance was getting less and the departing edge was apparently caught between the lip of the slot and the rotor housing forming a flatten corner.
 
Photo Apex Scrapes shows that the ejected apex seal piece probably  made it around the chamber a couple of times, one impression looks to be smaller than the width of the ejected piece - so perhaps it broke up further in its round.
 
Photo Apex Slot Peened shows that the 2nd apex seal of #1 rotor that would not move up and down - clear why, now.  The departing piece peened over the slot and froze the seal in its slot.  I had to pry the opposite end of the seal up to the position you see.
 
Overall rotor #1 is shot, although I guess one could have the slot milled out to 3mm but I'm not inclined to do so.
 
Surprisingly, I could find no damage to either the side housing or the rotor housing.  The rotor housings were used (came with the core) and looks the same as when I put them on in 2001.  The side housings are new and minimal wear - could not even catch the tip of a dentist took pick on any of the marks.
 
So what was the initial cause of the apex seal to fail - no evidence I could find.  No indication of FOD other than the broken apex seal imprints in the rotor.  Could have been some thing that just failed the seal and did no other damage before departing. Before this intake I had a SS screen mesh placed over the Mazda throttle body I had been using.  Had not yet mounted one to the new Mustang TB as it was not as easy to do.  Don't know if that would have made a difference.
 
I am still puzzled why it took so long if it were a foreign object to cause the damage.  Just one of those things I'll likely never know.
 
Now the question is what to do next.  Someone suggested the 10:1 rotors of the new Rensis as cheaper and higher compression - I like both of those features {:>).  I'll need to check with Bruce T and see if there is any merit to that idea.
 
Surprisingly little carbon on the rotors and most was soft not hard baked - may have been caused a bit by the gobs of fuel I was forcing through the chambers with no good combustion taking place.  But, certainly no where near as bad as a car engine.
 
That's it for now.
 
Best Regards
 
Ed
 
 
 
 
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com


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