X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from ispmxmta06-srv.windstream.net ([166.102.165.167] verified) by logan.com (CommuniGate Pro SMTP 5.2c2) with ESMTP id 2472624 for flyrotary@lancaironline.net; Wed, 14 Nov 2007 19:44:06 -0500 Received-SPF: pass receiver=logan.com; client-ip=166.102.165.167; envelope-from=montyr2157@alltel.net Received: from ispmxaamta04-gx.windstream.net ([75.88.21.93]) by ispmxmta06-srv.windstream.net with ESMTP id <20071115004326.YTDN29331.ispmxmta06-srv.windstream.net@ispmxaamta04-gx.windstream.net> for ; Wed, 14 Nov 2007 18:43:26 -0600 Received: from Thorstwin ([75.88.21.93]) by ispmxaamta04-gx.windstream.net with SMTP id <20071115004326.KPQD8365.ispmxaamta04-gx.windstream.net@Thorstwin> for ; Wed, 14 Nov 2007 18:43:26 -0600 Message-ID: <003101c82720$88dc39f0$6501a8c0@Thorstwin> From: "M Roberts" To: "Rotary motors in aircraft" Subject: Thick vs. Thin...ED is trying to scramble your brain like an egg Date: Wed, 14 Nov 2007 18:43:26 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002E_01C826EE.3E0B0280" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 This is a multi-part message in MIME format. ------=_NextPart_000_002E_01C826EE.3E0B0280 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable RESIST! It's a sinister plot to keep us all from working on actual airplanes! = There are too many people completing rotary powered airplanes. Ed is = trying to side track us!! Really tried to remain silent, but all those drugs the dentist used have = lowered my resistance...... I've had more thermo and fluid dynamics than I wanted, and have had to = apply it in the real world. You guys are on a great big snipe hunt. The = only way to fairly compare this is take a core that is say 4 units = thick. spread that exact core out so it is only 1 unit thick. Now run = the numbers both ways sizing the inlets, diffusers, and nozzles and core = area, for the same heat rejection rate and hot side mass flow....All = assuming same efficiencies for diffuser and nozzle (not necessarily = valid, but do it anyway). No rigging the efficiencies or saying this = core is better than that one etc. You can't just assume a cold side = DeltaT. You have to calculate it. Both must be a cross-flow exchanger = etc, etc, etc. You will need a heat transfer book, and a thermo 1 and 2 = text. Before you do this you might want to have a little light = background reading in calculus 1, 2, and 3 and probably fluid dynamics, = You will get real familiar with a lot of funny non dimensional numbers = named after dead German guys. On second thought just go get a mechanical = engineering degree because you will already be so deep in this junk by = then.=20 Then if you avoid any math errors you will find out the magic = theoretical advantage one radiator might have over the other.=20 We are flying too slow and reject too little heat to use the black magic = voodoo Meredith effect....so just put that out of your mind if that is = in any way steering your thinking on this matter. If this sort of thing floats your boat you can spend hours and hours = with spread sheets and equations. and in the end........ sailboat = fuel....turd polishing....snipe hunt. Trade studies for both designs for given airframe and mission are all = that matter....and in the end testing. Packaging/weight/structural constraints will trump some minor = theoretical heat transfer advantage every time.=20 I guess you can argue with the pocket protector set in heat transfer lab = after it's all said and done...but it sure won't get you any dates (or = at least not ones you'd want ;-). All the while you toil, earthbound, in vain, Ed will be flying overhead = with a loud buzzing sound overlain with evil, maniacal, laughter. Monty ------=_NextPart_000_002E_01C826EE.3E0B0280 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
RESIST!
 
It's a sinister plot to keep us all = from working on=20 actual airplanes! There are too many people completing rotary powered = airplanes.=20 Ed is trying to side track us!!
 
Really tried to remain silent, but all = those drugs=20 the dentist used have lowered my resistance......
 
I've had more thermo and fluid = dynamics than I=20 wanted, and have had to apply it in the real world. You guys are on a = great big=20 snipe hunt. The only way to fairly compare this is take a core that is = say 4=20 units thick. spread that exact core out so it is only 1 unit thick. = Now run=20 the numbers both ways sizing the inlets, diffusers, and nozzles and core = area, for the same heat rejection rate and hot side mass=20 flow....All assuming same efficiencies for diffuser and nozzle (not = necessarily valid, but do it anyway). No rigging the efficiencies or = saying this=20 core is better than that one etc. You can't just assume a cold side = DeltaT. You=20 have to calculate it. Both must be a cross-flow exchanger etc, etc, etc. = You=20 will need a heat transfer book, and a thermo 1 and 2 text. Before you do = this=20 you might want to have a little light background = reading in=20 calculus 1, 2, and 3 and probably fluid dynamics, You will get real = familiar with a lot of funny non = dimensional numbers named after=20 dead German guys. On second thought just go get a mechanical=20 engineering degree because you will already be so deep in this junk by = then.=20
 
Then if you avoid any math errors = you will=20 find out the magic theoretical advantage one radiator might have = over the=20 other.
 
We are flying too slow and reject too = little heat=20 to use the black magic voodoo Meredith effect....so just put = that out=20 of your mind if that is in any way steering your thinking on this=20 matter.
 
If this sort of thing floats your boat = you can=20 spend hours and hours with spread sheets and equations. and in the = end........=20 sailboat fuel....turd polishing....snipe hunt.
 
Trade studies for both designs for = given airframe=20 and mission are all that matter....and in the end testing.
 
Packaging/weight/structural  constraints will = trump some=20 minor theoretical heat transfer advantage every = time. 
 
I guess you can argue with the pocket = protector set=20 in heat transfer lab after it's all said and done...but it = sure won't=20 get you any dates (or at least not ones you'd want ;-).
 
All the while you toil, earthbound, in = vain, Ed=20 will be flying overhead with a loud buzzing sound overlain = with=20 evil, maniacal, laughter.
 
Monty
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