X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.120] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3817275 for flyrotary@lancaironline.net; Tue, 18 Aug 2009 15:51:10 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.120; envelope-from=eanderson@carolina.rr.com Received: from computername ([75.191.186.236]) by cdptpa-omta02.mail.rr.com with ESMTP id <20090818195034452.WHFZ8845@cdptpa-omta02.mail.rr.com> for ; Tue, 18 Aug 2009 19:50:34 +0000 From: "Ed Anderson" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Swirl pots/box fans Date: Tue, 18 Aug 2009 15:49:11 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook, Build 11.0.5510 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 Thread-Index: AcogOzNXmvb8CoAjRGegVTQgSkT6FwAAUf7g In-Reply-To: Message-Id: <20090818195034452.WHFZ8845@cdptpa-omta02.mail.rr.com> Ah, but, Chris, don't you recall that Confucius says "..Knowledge shall set you free.. but, it won't necessarily help you cool any better" Besides, it's the only way we engineers have of getting back at lawyers {:>) Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Chris Barber Sent: Tuesday, August 18, 2009 3:34 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Swirl pots/box fans Oh Gawd....numbers and symbols in formula's.....my brain just froze. Heck, if I could do calculations, I would have become an engineer.....not an attorney/cop. Hmmmm, seems I can do percentage of award/fee stuff though . All the best, Chris Cpl. Christopher Barber, JD Badge 330 Bellaire Police Department 5110 Jessamine Bellaire, Texas 77401 713-668-0487 713-662-8289 fax CBarber@BellairePolice.com ________________________________ From: Rotary motors in aircraft on behalf of Ed Anderson Sent: Tue 8/18/2009 2:22 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Swirl pots/box fans Here is a formula for a centrifugal pump that clearly? Shows that Tracy and Lynn are correct Energy Usage The energy usage in a pumping installation is determined by the flow required, the height lifted and the length and characteristics of the pipeline. The power required to drive a pump (Pi), is defined simply using SI units by: by: P_i= \cfrac{\rho\ g\ H\ Q}{\eta} where: Pi is the input power required (W) ? is the fluid density (kg/m3) g is the gravitational constant (9.81 m/s2) H is the energy Head added to the flow (m) Q is the flow rate (m3/s) ? is the efficiency of the pump plant as a decimal One can see that if Q the flow rate becomes zero (by blocking the exit) then the power required to drive the pump Pi also becomes zero. So block the pump and lower the flow and the power required drops - or with the same power, the pump can spin faster. There is always some flow around the vanes of a centrifugal pump in reality, so the power does not cause the pump to spin to infinity rpm but it equalizes at a higher rpm than when considerable (unblocked) flow is the condition. Is this fun or what? Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm ________________________________ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Lynn Hanover Sent: Tuesday, August 18, 2009 2:55 PM To: Rotary motors in aircraft Subject: [FlyRotary] Swirl pots/box fans NO! I meant exactly what I wrote. It is admittedly counter-intuitive but true none the less. Did you attempt to prove it to yourself with the suggested test? Only takes a few seconds :>) Tracy On Tue, Aug 18, 2009 at 11:57 AM, Jeff Luckey wrote: Tracy, When a box fan falls over onto its suction side, it revs up as the work it is performing drops off to near zero.....................same idea. Lynn E. 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