X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 2 [X] Return-Path: Received: from ms-smtp-03.southeast.rr.com ([24.25.9.102] verified) by logan.com (CommuniGate Pro SMTP 5.1.8) with ESMTP id 2049296 for flyrotary@lancaironline.net; Thu, 17 May 2007 06:50:30 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.102; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-103-061.carolina.res.rr.com [24.74.103.61]) by ms-smtp-03.southeast.rr.com (8.13.6/8.13.6) with SMTP id l4GD5FL9003179 for ; Wed, 16 May 2007 09:05:16 -0400 (EDT) Message-ID: <003701c797bb$14bc9410$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Marginal Cooling contributes to Crash. Date: Wed, 16 May 2007 09:06:56 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0034_01C79799.8D507800" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3028 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0034_01C79799.8D507800 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I think we all understand that being rather "smart" ,we all pride = ourselves on our analytical and decision making ability (however = occasionally good/bad it may be). So when we encounter a circumstance = we consider options (pure water does indeed help the cooling - = considerably) I've done it myself in early flights trying to get a temp = decrease. But, like Dave said, there would have been no problem had he 1. Not = flown into the cold temps or 2. Put adequate anti-freeze prior to doing = so. So this does not sound like a marginal cooling system - to me, just = one that was operated outside of the environmental parameters the pilot = expected. I don't care how big the radiator would have been, the lack = of sufficient anti-freeze would have likely had the same results. So at = least in this case, the "marginality" of the cooling system does not = appear to be a factor. Now I have seen marginal cooling systems, one individual who is = thankfully back to a Lycoming would come flying in and upon shut down = would have smoke curling out of his intakes. When this was pointed out = to him, his response was "It always does that". True this individual = did cook at least 2 engines before he even got to a marginal system. = Since his radiator hose burst and resulted in a force landing - That = also might be another indication of a "marginal" system.=20 But, the two instances that I am aware of that resulted in truly = "cooked" engines had again had nothing to do with how "marginal" their = cooling system was. In one case, a loose radiator hose clamp led to = loss of coolant and a cooked engine, in the second a freak incident in = which both water pump belts popped off the pulley and resulted in no = coolant flow. Fortunately, the robust rotary got both aircraft back to = a safe landing. =20 This is not to make small of Al's points. He is certainly correct that = a cooling system that results in degraded operation or excessive = temperature excursions is not desirable and can lead to serious = problems. On the other hand, accepting temporary limited excursions for = limited periods have been done by just about everybody I know flying a = rotary and I've yet to see any evidence that this detrimental.=20 Certainly as someone mentioned all WWII fighters had some regime of = flight where cooling was less than adequate (generally on the ground or = take off) - on the other hand, the designers knew that if they gave = them enough cooling capacity to handle a normally time -limited = situation then the fighter would never have achieved satisfactory combat = performance. Not that we are in the same league {:>), but nice to = pretend. So the point I attempted to make and others seem to think the same, is = that it would be difficult to pick and agree on the parameters and = values that we could use as a criteria. Al indicated that the = "marginal" point was a spot on a curve - does any one know what this = curve's parameters are? I would at least like to be aware of them. =20 Ed ------=_NextPart_000_0034_01C79799.8D507800 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
I think we all understand that being rather = "smart" ,we=20 all pride ourselves on our analytical and decision making ability = (however=20 occasionally  good/bad it may be).  So when we encounter a=20 circumstance we consider options (pure water does indeed help the = cooling -=20 considerably) I've done it myself in early flights trying to get a temp=20 decrease.
 
  But, like Dave said, there would have = been no=20 problem had he 1.  Not flown into the cold temps or 2.  Put = adequate=20 anti-freeze prior to doing so. So this does not sound like a = marginal=20 cooling system - to me, just one that was operated outside of the =20 environmental parameters the pilot expected.  I don't care how big = the=20 radiator would have been, the lack of sufficient anti-freeze would have = likely=20 had the same results.  So at least in this case, the "marginality" = of the=20 cooling system does not appear to be a factor.
 
 Now I have seen marginal cooling systems, = one=20 individual who is thankfully back to a Lycoming would come flying in and = upon=20 shut down would have smoke curling out of his intakes.  When this = was=20 pointed out to him, his response was "It always does that".  True = this=20 individual did cook at least 2 engines before he even got to a marginal=20 system.  Since his radiator hose burst and resulted in a force = landing -=20 That also  might be another indication of a "marginal" system. =
 
But, the  two instances that I am aware of = that=20 resulted in truly "cooked" engines had again had nothing to do with how=20 "marginal" their cooling system was.  In one case, a loose radiator = hose=20 clamp led to loss of coolant and a cooked engine, in the second a freak = incident=20 in which both water pump belts popped off the pulley and resulted in no = coolant=20 flow.  Fortunately, the robust rotary got both aircraft back to a = safe=20 landing. 
 
This is not to make small of Al's points.  = He is=20 certainly correct that a cooling system that results in degraded = operation or=20 excessive temperature excursions is not desirable and can lead to = serious=20 problems.  On the other hand, accepting temporary limited = excursions for=20 limited periods have been done by just about everybody I know flying a = rotary=20 and I've yet to see any evidence that this = detrimental. 
 
 Certainly as someone mentioned all WWII = fighters had=20 some regime of flight where cooling was less than adequate (generally on = the=20 ground or take off)  - on the other hand, the designers knew that = if they=20 gave them enough cooling capacity to handle a normally time -limited = situation=20 then the fighter would never have achieved satisfactory=20 combat performance.   Not that we are in the same league = {:>),=20 but nice to pretend.
 
So the point I attempted to make and others seem = to think=20 the same, is that it would be difficult to pick and agree on the = parameters and=20 values that we could use as a criteria.   Al indicated that = the=20 "marginal" point was a spot on a curve - does any one know what this = curve's=20 parameters are?  I would at least like to be aware of them. =20
 
Ed
 
 
 


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