X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail846.megamailservers.com ([69.49.106.56] verified) by logan.com (CommuniGate Pro SMTP 5.0.8) with ESMTPS id 1029869 for flyrotary@lancaironline.net; Fri, 10 Mar 2006 16:22:46 -0500 Received-SPF: none receiver=logan.com; client-ip=69.49.106.56; envelope-from=MadScientist@covad.net X-POP-User: madscientist.covad.net Received: from [67.101.98.110] (h-67-101-98-110.snfccasy.dynamic.covad.net [67.101.98.110]) by mail846.megamailservers.com (8.13.1/8.13.1) with ESMTP id k2ALLwSC031556 for ; Fri, 10 Mar 2006 16:21:59 -0500 Message-ID: <4411EDF4.9060904@covad.net> Date: Fri, 10 Mar 2006 13:21:56 -0800 From: James User-Agent: Mozilla Thunderbird 1.0 (X11/20050203) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: NACA's, Cooling and Sport Aviation Mag.. References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit The vortex generator article I read had a photograph with the NACA scoop on top much like a velocity... must have been a velocity. Regards; James Freeman al p Wick wrote: >I have totally stock Naca on Cozy. Just added the vortex generators as >John describes (I think it's 40 deg included angle). > > I found air flowed in wrong direction often upon takeoff. It would both >take time and playing around with aircraft attitude to get it to flow in >correct direction. There after, it did ok. Adding erics vg's increased >total pressure differential and totally eliminated that initial flow >problem. In hind sight, this makes sense. The cozy has long flat bottom. >NACA at rear of craft. Thick boundary layer at that location. So the vg's >break thru the boundary layer allowing the NACA to do it's thing. I >measure air pressure differential with PC and atmospheric sensors. Log >info every few moments. > >I have huge safety margin with my cooling. Lucked out and learned from >others. Didn't allow myself to make any design assumptions. > > >-al wick >Artificial intelligence in cockpit, Cozy IV powered by stock Subaru 2.5 >N9032U 200+ hours on engine/airframe from Portland, Oregon >Prop construct, Subaru install, Risk assessment, Glass panel design info: >http://www.maddyhome.com/canardpages/pages/alwick/index.html > > > >On Fri, 10 Mar 2006 14:50:55 -0500 john slade >writes: > > >>This would be Eric Westland. He did some oil trail tests and ended >>up >>with much improved cooling using vortex generators 1" * 4" vortex >>generators at 45 degrees to the airstream ahead of the NACA (or >>whatever >>you want to call the plans Cozy scoop). The results are up on a web >>site >>somewhere. >> >>Based on his results I installed the same generators from day one. >>I >>have no measurements with them not in place. >>John Slade >> >> >> >> >>aheaJames wrote: >> >> >> >>>I read an article (don't remember where) about a fellow who placed >>> >>> >>two >> >> >>>vortex generator tabs just in front of the NACA ducts. This >>> >>> >>improved >> >> >>>efficiency quite a lot. He had to experiment a while to get it >>> >>> >>right; >> >> >>>but, liked the results. I think it was on a Velocity or Cozy. >>> >>>This makes perfect sense. As I remember when I read the initial >>> >>> >>NACA >> >> >>>report. The paper indicated that the duct was efficient for >>> >>> >>large >> >> >>>volume flows which created little back pressure. >>>Thus, my analysis of the operation is that the efficiency of the >>> >>> >>duct >> >> >>>depends on a bit of local turbulence at the duct to break the >>> >>> >>local >> >> >>>boundary layer. A high flow rate, as the original paper >>> >>> >>indicated >> >> >>>and/or required, would do that. Also a set of vortex generators >>> >>> >>in >> >> >>>front of the duct would also do the same. >>> >>>Second point: I believe that a reversed direction NACA scoop >>> >>> >>would >> >> >>>make an excellent low drag exit port for the cooling air stream. >>> >>> >>>Such a scoop design would tend to form a small low- drag partial >>>vacuum at that point, allowing the exit scoop to literally help >>> >>> >>suck >> >> >>>the air out. This would improve cooling efficiency I.E. NACA in, >>> >>> >>and >> >> >>>ACAN out. >>>I hold several patents, but I am not going to pursue this idea on >>> >>> >>that >> >> >>>basis. I think it has a good possibility of being a very >>> >>> >>efficient >> >> >>>low drag cooling system. >>> >>> >>>If anyone tries it, please let us know your findings. >>> >>>Best Regards; >>> >>>James Freeman >>> >>> >>> >>>David Staten wrote: >>> >>> >>> >>>>I skimmed it.. Chris and I are actually considering armpit scoops >>>> >>>> >>for >> >> >>>>cooling, but we still have this nagging urge to minimize >>>> >>>> >>deviations >> >> >>>>from plans. I will go back and do more than just skim.. >>>> >>>>All I saw was NACA's, Cooling and immediately thought of PL.. >>>> >>>>Dave >>>> >>>>Bulent Aliev wrote: >>>> >>>> >>>> >>>>>You are right Bill. David did not read the whole article. Or he >>>>> >>>>> >>>>>didn't want to hear it? :) >>>>>Buly >>>>> >>>>> >>>>> >>>>>On Mar 9, 2006, at 8:58 PM, Bill Dube wrote: >>>>> >>>>> >>>>> >>>>>>I read that article as well. I had the same skepticism about >>>>>> >>>>>> >>the >> >> >>>>>>NACA intake for cooling. My understanding is that with an NACA >>>>>> >>>>>> >>>>>>inlet, you don't get the ram pressure you need to force air >>>>>>through a high fin-count radiator. Am I wrong about this? >>>>>> >>>>>>Bill Dube' >>>>>> >>>>>>David Staten wrote: >>>>>> >>>>>> >>>>>> >>>>>>>At the risk of invoking PL's name, anyone else read this >>>>>>> >>>>>>> >>months >> >> >>>>>>>Sport Aviation mag from EAA, and notice an article on cooling >>>>>>>that seems to indicate that NACA's are acceptable and >>>>>>> >>>>>>> >>adequate >> >> >>>>>>>for aircraft cooling needs? I have no idea regarding the >>>>>>> >>>>>>> >>authors >> >> >>>>>>>credentials, and I no longer monitor PL's "newsletter".. I was >>>>>>> >>>>>>> >>>>>>>curious more than anything else... Pauls reaction, others >>>>>>>reactions, etc. >>>>>>> >>>>>>>Translation.. yes.. I'm stirring the pot/Trolling... I figure >>>>>>> >>>>>>> >>if >> >> >>>>>>>we are using NACA's on the Velocity, that makes us somewhat of >>>>>>> >>>>>>> >>a >> >> >>>>>>>NACA supporter.. >>>>>>> >>>>>>>Dave >>>>>>> >>>>>>>-- >>>>>>>Homepage: http://www.flyrotary.com/ >>>>>>>Archive and UnSub: >>>>>>> >>>>>>> >>http://mail.lancaironline.net/lists/flyrotary/ >> >> >>>>>>-- >>>>>>Homepage: http://www.flyrotary.com/ >>>>>>Archive and UnSub: >>>>>> >>>>>> >>http://mail.lancaironline.net/lists/flyrotary/ >> >> >>>>> >>>>> >>>>> >>>>>-- >>>>>Homepage: http://www.flyrotary.com/ >>>>>Archive and UnSub: >>>>> >>>>> >>http://mail.lancaironline.net/lists/flyrotary/ >> >> >>>>-- >>>>Homepage: http://www.flyrotary.com/ >>>>Archive and UnSub: >>>> >>>> >>http://mail.lancaironline.net/lists/flyrotary/ >> >> >>>>. >>>> >>>> >>>> >>>-- >>>Homepage: http://www.flyrotary.com/ >>>Archive and UnSub: >>> >>> >>http://mail.lancaironline.net/lists/flyrotary/ >> >> >>-- >>Homepage: http://www.flyrotary.com/ >>Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ >> >> >> >> > > >-al wick >Artificial intelligence in cockpit, Cozy IV powered by stock Subaru 2.5 >N9032U 200+ hours on engine/airframe from Portland, Oregon >Prop construct, Subaru install, Risk assessment, Glass panel design info: >http://www.maddyhome.com/canardpages/pages/alwick/index.html > >-- >Homepage: http://www.flyrotary.com/ >Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ > >. > > >