X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [24.25.9.101] (HELO ms-smtp-02-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.3c5) with ESMTP id 912250 for flyrotary@lancaironline.net; Sat, 23 Apr 2005 13:06:11 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.101; 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-02-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j3NH5O0W007040 for ; Sat, 23 Apr 2005 13:05:25 -0400 (EDT) Message-ID: <001301c54826$a942eda0$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: All Parts have arrived, Whew! Date: Sat, 23 Apr 2005 13:05:33 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0010_01C54805.21FF4120" 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 This is a multi-part message in MIME format. ------=_NextPart_000_0010_01C54805.21FF4120 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Believe me, I understand, Finn. =20 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.=20 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=20 ----- Original Message -----=20 From: Finn Lassen=20 To: Rotary motors in aircraft=20 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 -----=20 From: Finn Lassen=20 To: Rotary motors in aircraft=20 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 {:>).=20 Ed ------=_NextPart_000_0010_01C54805.21FF4120 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Believe me, I understand, Finn.  =
 
NO ONE wants to know the reason = more than=20 yours truly. I mean I missed the only tail wind I ever had=20 to Florida.    It would be easy to say "foreign object , = poor Ed=20 should have used a filter" {:>) (and I'm going to), however, I = can find=20 no evidence of a foreign object - no nut/bolt heads impressed into the=20 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=20 was being compressed.  It actually plowed up a small ridge of metal = ahead=20 of it - I'm convinced that was caused by the broken seal.  Now even = if I'm=20 correct about that does not mean that the seal could not have been=20 originally broken by a small foreign object - long = departed.
 
But lacking evidence of a foreign = object and=20 finding both the apex seals and the slots worn past the specification = limit - I=20 lean to an apex seal which broke under stress and angles of forces that = it was=20 not designed for.
 
If you believe it was foreign object = damage, my=20 suggestion is put a filter on your intake and sleep well - I certainly = can't=20 prove it wasn't.  Certainly the fact that I seem to be the = first/only=20 flying rotary to have tried to digest an apex seal (Chuck Dunlap tried = to digest=20 a bolt - doesn't count), then its not something that seems to be ready = to happen=20 everywhere.  Could have been just the right circumstances all = occurring at=20 the same time that caused my failure.
 
 
 
Ed
 
 
----- Original Message -----
From:=20 Finn=20 Lassen
Sent: Saturday, April 23, 2005 = 10:13=20 AM
Subject: [FlyRotary] Re: All = Parts have=20 arrived, Whew!

Thanks Ed.

Well, if it were the brittle seals = breaking=20 then we should be safe with Bruce's & RWS's seals, even with = excessive=20 wear.

I just hate a major failure like that without a = positively=20 identified cause.

Finn

Ed Anderson wrote:
Well, a bit of wobble can indeed = break apex=20 seals - that is one of the failure modes.  Its just I didn't = think my=20 seal slots were that worn - however after finding the were in some = cases=20 past the 0.15mm limit set by Mazda, I think it possible that the = stresses=20 from the "leaned over" profile broke the brittle seal.  I had = not=20 measured the compression since last year at the annual inspection - = so don't=20 know what it was, but I agree it seemed good based on the rpm and=20 power.  However, a slop apex seal slot will not necessarily = show up as=20 low compression - it may still seal - but under more stress due to = the=20 angle.
 
However, it could have been an = foreign object,=20 don't know what it would have been at 7000 msl.  Don't see = where=20 anything could have laid around in the intake  through my max = power=20 take off and then break loose.  Besides, there is nothing=20 missing.  The things it could have been was a chunk of my = plastic=20 manifold - no pieces missing, the epoxy shaping the secondary intake = ports=20 in the lower manifold - inspected and all there.
 
I could find not scrape mark or = impression on=20 the rotor housing with the broken seal - which surprised me.  I = will=20 inspect the rotor housings more carefully after I get the engine = back=20 together in case I missed it.
 
I looked at the four spark plugs = again=20 yesterday for missing pieces of ceramic cone, chunks of electrode,=20 etc.  These are Racing plugs and seem fairly well  = constructed and=20 nothing was missing.  I will be sticking them back in the new=20 engine  - after I found their electrode is at least 5mm from = the=20 combustion chamber.  Just a coincident that the engine broke = right=20 after I put the new spark plugs in - perhaps I was generating more = power=20 with the new unshrouded plugs and broke the seals = {:>).
 
So may never know for certain - = could have been=20 just a combination of things adding up, weak fractured seal, sloppy = apex=20 slot, etc. could have been the dust.
 
Ed
-----=20 Original Message ----- From:=20 Finn Lassen To:=20 Rotary motors in = aircraft=20 Sent:=20 Friday, April 22, 2005 11:27 PM Subject:=20 [FlyRotary] Re: All Parts have arrived, Whew!

You all have to remember that Ed has a knack for = finding=20 and exploring all possible failure modes - known,  unknown, = and yes,=20 even the impossible :)

Something that no one has memtioned = is the=20 gears (end housings/rotors).
Also rotor bearings/e-shaft=20 clearance.
What's the consequences of out-of tolerances = here?
I just=20 can't see that a bit of wobble of the apex seals in their grooves = could=20 cause a seal to break.
Also, how could you have such excellent=20 compression with worn seals/grooves?
Sounds more like a fluke = or=20 foreign object to me. Any chance that some carbon build-up near = exhaust=20 ports could break loose and get jammed between seal and edge of = exhaust=20 port?
Any telltale on the rotor housing as to where the seal=20 broke?
Did you *thoroughly* inspect the four sparkplugs? Any = piece of=20 metal or porcelain missing at all?

Finn

Ed Anderson=20 wrote:
Well, George, I would not =  take=20 the conclusion that far.  We have folks flying with several = hundred=20 more hours than I have with no apex seal failures.  In fact = to the=20 best of my knowledge, I am the only one I am aware of other than = Chuck=20 Dunlap who's rotary engine swallowed a 1/4" dia steel bolt (it = was=20 retained - so we know) to have an apex seal failure in an=20 aircraft.  However, I do believe that folks need to be more = aware=20 of the true condition of their used engine components - I know = all=20 probably did was look at it and not seeing any obviously defects = or=20 dings said - "good to go!"
 
As you know, Leon is = convinced my=20 apex seal failure was also due to foreign object ingestion - I = certainly=20 can not prove it was something else (like the apex seal = slop) =20 although I don't believe a foreign object  to be the = case -=20 belief is not a fact {:>). 
 
 
Ed
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