X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [24.25.9.103] (HELO ms-smtp-04-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.3c5) with ESMTP id 912892 for flyrotary@lancaironline.net; Sun, 24 Apr 2005 09:06:07 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.103; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-185-127.carolina.res.rr.com [24.74.185.127]) by ms-smtp-04-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j3OD5KL5013024 for ; Sun, 24 Apr 2005 09:05:21 -0400 (EDT) Message-ID: <002301c548ce$4aad9580$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Chuck Dunlap (was: All Parts have arrived, Whew!) Date: Sun, 24 Apr 2005 09:05:30 -0400 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Virus-Scanned: Symantec AntiVirus Scan Engine Right, Dale, it was a pin rather than a bolt (my mistake) - my point was that his apex seal failure we know was caused by a Foreign object rather than perhaps a "V" slot failure. Ed ----- Original Message ----- From: "Dale Rogers" To: "Rotary motors in aircraft" Sent: Sunday, April 24, 2005 1:28 AM Subject: [FlyRotary] Re: Chuck Dunlap (was: All Parts have arrived, Whew!) >A relatively minor nit, but IIRC, Chuck's engine didn't > ingest a *bolt* but, rather, a pin. The builder had left > the pin(s) in the secondary "boost" sleeves. With no > actuators attached (which would dampen vibration of the > pins) one pin managed to rattle around enough to wallow > out the holes until it came completely loose. > > Lesson learned: throw away the secondary sleeves. > > Regards, (__ > Dale R. |----==(__)==----| > COZY MkIV-R13B #1254 o/ \o > Ch's 4, 5, 16 & 23 in progress > > >> From: "Ed Anderson" >> Date: 2005/04/23 Sat PM 01:05:33 EDT >> To: "Rotary motors in aircraft" >> Subject: [FlyRotary] Re: All Parts have arrived, Whew! >> >> Believe me, I understand, Finn. >> >> NO ONE wants to know the reason more than yours truly. I mean I missed >> the only tail wind I ever had to Florida. It would be easy to say >> "foreign object , poor Ed should have used a filter" {:>) (and I'm going >> to), however, I can find no evidence of a foreign object - no nut/bolt >> heads impressed into the rotor/housing, etc. The only scrape on the >> rotor looks to me as if something the size of a piece of apex seal got >> slid along the rotor as that area was being compressed. It actually >> plowed up a small ridge of metal ahead of it - I'm convinced that was >> caused by the broken seal. Now even if I'm correct about that does not >> mean that the seal could not have been originally broken by a small >> foreign object - long departed. >> >> But lacking evidence of a foreign object and finding both the apex seals >> and the slots worn past the specification limit - I lean to an apex seal >> which broke under stress and angles of forces that it was not designed >> for. >> >> If you believe it was foreign object damage, my suggestion is put a >> filter on your intake and sleep well - I certainly can't prove it wasn't. >> Certainly the fact that I seem to be the first/only flying rotary to have >> tried to digest an apex seal (Chuck Dunlap tried to digest a bolt - >> doesn't count), then its not something that seems to be ready to happen >> everywhere. Could have been just the right circumstances all occurring >> at the same time that caused my failure. >> >> >> >> Ed >> >> >> ----- Original Message ----- >> From: Finn Lassen >> To: Rotary motors in aircraft >> Sent: Saturday, April 23, 2005 10:13 AM >> Subject: [FlyRotary] Re: All Parts have arrived, Whew! >> >> >> Thanks Ed. >> >> Well, if it were the brittle seals breaking then we should be safe with >> Bruce's & RWS's seals, even with excessive wear. >> >> I just hate a major failure like that without a positively identified >> cause. >> >> Finn >> >> Ed Anderson wrote: >> >> Well, a bit of wobble can indeed break apex seals - that is one of >> the failure modes. Its just I didn't think my seal slots were that >> worn - however after finding the were in some cases past the 0.15mm limit >> set by Mazda, I think it possible that the stresses from the "leaned >> over" profile broke the brittle seal. I had not measured the compression >> since last year at the annual inspection - so don't know what it was, but >> I agree it seemed good based on the rpm and power. However, a slop apex >> seal slot will not necessarily show up as low compression - it may still >> seal - but under more stress due to the angle. >> >> However, it could have been an foreign object, don't know what it >> would have been at 7000 msl. Don't see where anything could have laid >> around in the intake through my max power take off and then break loose. >> Besides, there is nothing missing. The things it could have been was a >> chunk of my plastic manifold - no pieces missing, the epoxy shaping the >> secondary intake ports in the lower manifold - inspected and all there. >> >> I could find not scrape mark or impression on the rotor housing with >> the broken seal - which surprised me. I will inspect the rotor housings >> more carefully after I get the engine back together in case I missed it. >> >> I looked at the four spark plugs again yesterday for missing pieces >> of ceramic cone, chunks of electrode, etc. These are Racing plugs and >> seem fairly well constructed and nothing was missing. I will be >> sticking them back in the new engine - after I found their electrode is >> at least 5mm from the combustion chamber. Just a coincident that the >> engine broke right after I put the new spark plugs in - perhaps I was >> generating more power with the new unshrouded plugs and broke the seals >> {:>). >> >> So may never know for certain - could have been just a combination of >> things adding up, weak fractured seal, sloppy apex slot, etc. could have >> been the dust. >> >> Ed >> ----- Original Message ----- >> From: Finn Lassen >> To: Rotary motors in aircraft >> Sent: Friday, April 22, 2005 11:27 PM >> Subject: [FlyRotary] Re: All Parts have arrived, Whew! >> >> >> You all have to remember that Ed has a knack for finding and >> exploring all possible failure modes - known, unknown, and yes, even the >> impossible :) >> >> Something that no one has memtioned is the gears (end >> housings/rotors). >> Also rotor bearings/e-shaft clearance. >> What's the consequences of out-of tolerances here? >> I just can't see that a bit of wobble of the apex seals in their >> grooves could cause a seal to break. >> Also, how could you have such excellent compression with worn >> seals/grooves? >> Sounds more like a fluke or foreign object to me. Any chance that >> some carbon build-up near exhaust ports could break loose and get jammed >> between seal and edge of exhaust port? >> Any telltale on the rotor housing as to where the seal broke? >> Did you *thoroughly* inspect the four sparkplugs? Any piece of >> metal or porcelain missing at all? >> >> Finn >> >> Ed Anderson wrote: >> >> Well, George, I would not take the conclusion that far. We have >> folks flying with several hundred more hours than I have with no apex >> seal failures. In fact to the best of my knowledge, I am the only one I >> am aware of other than Chuck Dunlap who's rotary engine swallowed a 1/4" >> dia steel bolt (it was retained - so we know) to have an apex seal >> failure in an aircraft. However, I do believe that folks need to be more >> aware of the true condition of their used engine components - I know all >> probably did was look at it and not seeing any obviously defects or dings >> said - "good to go!" >> >> As you know, Leon is convinced my apex seal failure was also due >> to foreign object ingestion - I certainly can not prove it was something >> else (like the apex seal slop) although I don't believe a foreign object >> to be the case - belief is not a fact {:>). >> >> >> Ed >> > > >>> Homepage: http://www.flyrotary.com/ >>> Archive: http://lancaironline.net/lists/flyrotary/List.html