Mailing List flyrotary@lancaironline.net Message #8092
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Re: [FlyRotary] Detonated! :-(
Date: Thu, 13 May 2004 07:31:20 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Todd, thanks for the Good news Bad News report.  Particularly good to hear the good news side.  Again the robustness and graceful degradation, even with damage, shows the viability of the rotary as an aircraft engine.  Sorry, to hear about the detonation, but Tracy's seals should assist greatly in protecting from seal breakage should it occur again.  Naturally, we want to know what you figure cause the detonation in the first place - boost?. 
 
 
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
From: Haywire
Sent: Thursday, May 13, 2004 1:03 AM
Subject: [FlyRotary] Detonated! :-(

Hi Guys;
    Got some good news and bad news. Bad news first. During a flight on Monday, during climb-out I inadvertently over-boosted and detonated the engine (more on why later), destroying 1 apex seal in each rotor. It also caused some damage at the rotor tip. At first inspection I thought I had no damage to the rest of the engine, but I just discovered a small scuff mark on the rear end housing. The attached picture shows it rather poorly, but due to the shiny reflective surface is it hard to take a pic to show it clearly. I'm uncertain if this means the rotor is now NFG. The apex of the #2 rotor is where the worst detonation occurred and there is a small notch in the rotor at this location. Again, I don't know yet if this is any good. The pic of the seals pretty much says it all. It also shows one of the side seals that broke. There was another side seal broken as well, but with only a small 2mm piece cleanly broken off the end, would have been easy to miss.
    The pic of the rotor apex also clearly shows remnants of the ceramic coating that was applied to the rotor faces. So if anything at least this shows that don't waste your money on this mod.
    Oh yeah, the good news (hey it's my attempt at finding a silver lining). While I knew something was definitely amiss, the engine continued to run and produce good power while I made a circuit (called tower for a precautionary landing... didn't want to see them damn fire trucks come out to meet me) and continued to run until I was on the ground at which time it quietly died. This is one of the aspects of the rotary that initially attracted me to this engine. I just didn't expect to find out first-hand. I really don't doubt that it would have lasted at least a little while longer.
     It actually ran so good that I really didn't believe that there was much if any damage and tried everything yesterday trying to start it in an effort to avoid removing the engine. After no success and a call to Tracy, I finally pulled it and took it home. Tore it down this morning. Viewing the apex seals through the exhaust ports, everything looked fine. The damage was just past the edge of the port. Surprisingly they actually still felt solid and had spring in them with no indication of the true amount of damage. I was beginning to second guess my decision to teardown.
    I'll be using Tracy's new apex seals in the rebuild and am now just trying to decide which other parts I need.

S. Todd Bartrim    (now into beer drinking mode... lots of beer :-(
Turbo 13B RV-9Endurance
C-FSTB
http://www3.telus.net/haywire/RV-9/C-FSTB.htm

   "Whatever you vividly imagine, Ardently desire, Sincerely believe in, Enthusiastically act upon, Must inevitably come to pass".

 


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