Return-Path: Received: from [24.25.9.102] (HELO ms-smtp-03-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.2b8) with ESMTP id 324928 for flyrotary@lancaironline.net; Sat, 17 Jul 2004 15:56:46 -0400 Received-SPF: error receiver=logan.com; client-ip=24.25.9.102; envelope-from=eanderson@carolina.rr.com Received: from EDWARD (clt25-78-058.carolina.rr.com [24.25.78.58]) by ms-smtp-03-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id i6HJtjiB024254 for ; Sat, 17 Jul 2004 15:55:46 -0400 (EDT) Message-ID: <002301c46c38$0f1b1ce0$2402a8c0@EDWARD> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: 11th test flight Date: Sat, 17 Jul 2004 15:55:49 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0020_01C46C16.87D4FF60" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1409 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0020_01C46C16.87D4FF60 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Dale, Not being a rotary engine mechanic, I only know that one of things = that you were to check for after a case of "overheating" was "shrinkage" = of the aluminum rotor housing. I never heard an explanation for why = this supposedly happened but the thing you were to check for was the = width of the housing. There were minimum specs which if below = supposedly rendered the rotor housing "Bad". I do know that when I took = my first engine apart after overheating it to the point that the inner = coolant seals failed, I measured and found one of my housings right at = the limit - now it may well have been at that point before I ever ran = the engine as I did not measure it before hand. The only thing I could ever think of that might cause this (assuming it = was caused by overheating) is that we have 17 of those big bolts holding = that pancake together which compress the rotor housing between the iron = housings. If it go hot enough supposedly that clamping pressure could = cause the aluminum to weaken sufficiently to partially collapse the = housings coolant chambers and reduce the width of the housing. But, = that was just my take on it. =20 Now with the later engines I have not heard about this shrinkage problem = - so whether it was an "old wives tale" or there was some substance to = it that has been overcome by better castings/alloy , I really do not = know. Ed Thanks Ed, I value your insights. I know that seal chatter was an early development problem with the = wankel, but thought that Mazda had pretty much made it a thing of the = past with modern materials, geometry, and springs. I did not realize = that this was a temperature dependent problem, that we still had to deal = with. Also, not quite sure what you mean re: "shrinkage of the aluminum = rotor housings"? It can't shrink with heat. By this do you mean that, = that having exceeded some elasticity limit, the aluminum cannot return = to it's original specs upon shutdown once it has been overheated? = Wouldn't it thus be oversize? Please explain ... this sure sounds like = an "engine killer". Thanks, Dale Smith ------=_NextPart_000_0020_01C46C16.87D4FF60 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 Dale,
 
    Not being a rotary = engine=20 mechanic, I only know that one of things that you were to check for = after a case=20 of "overheating" was "shrinkage" of the aluminum rotor housing.  I = never=20 heard an explanation for why this supposedly  happened but the = thing you=20 were to check for was the width of the housing.  There were minimum = specs=20 which if below supposedly rendered the rotor housing "Bad".  I do = know that=20 when I took my first engine apart after overheating it to the point that = the=20 inner coolant seals failed, I measured and found one of my housings = right at the=20 limit - now it may well have been at that point before I ever ran the = engine as=20 I did not measure it before hand.
 
The only thing I could ever think of = that might=20 cause this (assuming it was caused by overheating) is that we have 17 of = those=20 big bolts holding that pancake together which compress the rotor housing = between=20 the iron housings.  If it go hot enough supposedly that clamping = pressure=20 could cause the aluminum to weaken sufficiently to partially collapse = the=20 housings coolant chambers and reduce the width of the housing.  = But, that=20 was just my take on it. 
 
Now with the later engines I have not = heard about=20 this shrinkage problem - so whether it was an "old wives tale" or there = was some=20 substance to it that has been overcome by better castings/alloy , I = really do=20 not know.
 
Ed
 

Thanks Ed,  I value your insights.

I know that = seal=20 chatter was an early development problem with the wankel, but thought = that=20 Mazda had pretty much made it a thing of the past with modern = materials,=20 geometry, and springs.  I did not realize that this was a = temperature=20 dependent problem, that we still had to deal with.

Also, not = quite sure=20 what you mean re: "shrinkage of the aluminum rotor = housings"?   It=20 can't shrink with heat.  By this do you mean that, that having = exceeded=20 some elasticity limit, the aluminum cannot return to it's original = specs upon=20 shutdown once it has been overheated?   Wouldn't it thus be=20 oversize?   Please explain ... this sure sounds like an = "engine=20 killer".

Thanks,

Dale = Smith
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