X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [206.46.252.42] (HELO vms042pub.verizon.net) by logan.com (CommuniGate Pro SMTP 4.3c5) with ESMTP id 911965 for flyrotary@lancaironline.net; Fri, 22 Apr 2005 23:27:46 -0400 Received: from verizon.net ([71.99.159.177]) by vms042.mailsrvcs.net (Sun Java System Messaging Server 6.2 HotFix 0.04 (built Dec 24 2004)) with ESMTPA id <0IFD00GXNQY18035@vms042.mailsrvcs.net> for flyrotary@lancaironline.net; Fri, 22 Apr 2005 22:27:38 -0500 (CDT) Date: Fri, 22 Apr 2005 23:27:36 -0400 From: Finn Lassen Subject: Re: [FlyRotary] Re: All Parts have arrived, Whew! In-reply-to: To: Rotary motors in aircraft Message-id: <4269C0A8.80407@verizon.net> MIME-version: 1.0 Content-type: multipart/alternative; boundary=------------070508050309070108050101 X-Accept-Language: en-us, en References: User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 (ax; PROMO) This is a multi-part message in MIME format. --------------070508050309070108050101 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit 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 --------------070508050309070108050101 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit 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

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