X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from eastrmmtao05.cox.net ([68.230.240.34] verified) by logan.com (CommuniGate Pro SMTP 5.0.8) with ESMTP id 1033250 for flyrotary@lancaironline.net; Mon, 13 Mar 2006 21:56:20 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.240.34; envelope-from=candtmallory@cox.net Received: from mallorydesktop ([68.1.92.51]) by eastrmmtao05.cox.net (InterMail vM.6.01.05.02 201-2131-123-102-20050715) with SMTP id <20060314025530.VDCW3108.eastrmmtao05.cox.net@mallorydesktop> for ; Mon, 13 Mar 2006 21:55:30 -0500 Message-ID: <001201c64712$c41fce40$335c0144@mallorydesktop> From: "the mallorys" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: finding a radiator Date: Mon, 13 Mar 2006 20:55:34 -0600 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 Looks like there will be some experimenting in my future. Ed, Do you have any more info on the exponential horn? I would need coordinates, formulas, drawing, or something, then I could make a trial run of all three and see which is most efficient. Chris ----- Original Message ----- From: "Ed Anderson" To: "Rotary motors in aircraft" Sent: Monday, March 13, 2006 8:11 PM Subject: [FlyRotary] Re: finding a radiator >I could never find any information on the efficiency of the Wedge diffuser >at subsonic speeds. However, you are correct about the streamline duct. >Measure from the core forward then truncate where you have to. Here is the >way it appears to me, approx 1/2 of the streamline ducts pressure recover >is due to the length of the duct walls the other 1/2 is due to the trumpet >style flair near the core. So say you completely eliminated the duct and >just had the flair then you would get approx 42% pressure recovery (not >terrible good). So if you could incorporate 1/2 of the duct length then >you would be closer to a 62% pressure recovery (getting better). These >are just rough estimates, but I have been please with the truncated >streamline duct. > > There is another similar duct coordinate system call the exponential horn > that is easier to scale for shorter duct lengths. It appears to be based > on the same concept of the streamline of keeping the air velocity rather > high until the a last minute flair of the duct to get pressure recovery. > It would appear that it's efficiency would be close to the streamline and > its ease of calculation might make it worth the effort alone. But, again > I have not been able to find any actually data on pressure recovery. > > If I do another cooling duct experiment, it will be using the exponential > horn duct just to see how it works. But, not today {:>) > > Ed > > Ed Anderson > Rv-6A N494BW Rotary Powered > Matthews, NC > eanderson@carolina.rr.com > ----- Original Message ----- > From: "rijakits" > To: "Rotary motors in aircraft" > Sent: Monday, March 13, 2006 8:43 PM > Subject: [FlyRotary] Re: finding a radiator > > >> If I got the idea right, to use the Streamline you would want to sketch >> the >> "perfect" streamline for your radiator and then measure FROM the radiator >> towards the intake - whatever length you can do, and cut it there. >> That will be your intake area..... >> >> Wedge should be simple: Whatever your opening is - constant cross-area to >> the radiator - as big a radius at the bottom near end as you can >> justify - >> same point top surface, start a tapper to the end of the radiator to end >> about 1/2" above the far end and radius it down. >> >> Which one is better? No idea! >> Generally I would guess streamline, but in your case it will not be >> perfect, >> so you might want to do some mockup from plywood/cardboard/etc. and try >> some >> watermanometer tests/kitchenscale on the rooftop on top of your car - >> tests..... >> >> Thomas J. >> >> PS: PL over at the "other" site was lofting both systems together, looks >> good but results are anyones guess.... >> >> ----- Original Message ----- >> From: "the mallorys" >> To: "Rotary motors in aircraft" >> Sent: Monday, March 13, 2006 10:25 AM >> Subject: [FlyRotary] Re: finding a radiator >> >> >>> Dennis, >>> >>> You seem to be at the same point in installation as I. I'm putting the >>> Renesis in an RV-8 using the James cowl. I'm trying to fit the radiator >>> verticaly under the engine mount. That gives me space of about 8 1/2 by >> 19 >>> 1/2. Make the radiator 3.75 to 4 inches thick, and I should have enough >>> cooling. Since I don't have about 50 inches in front of the radiator >>> for >>> the perfect streamlined diffuser, the question for me is which will be >> less >>> drag, a shorter (about 20 inches) streamline, or tipping the radiator at >> an >>> angle and using a wedge shape diffuser? In any case, I plan on having >>> an >>> exit duct also with a controllable exit. >>> >>> Does anyone know the answer? >>> >>> Chris >>> ----- Original Message ----- >>> From: "Ernest Christley" >>> To: "Rotary motors in aircraft" >>> Sent: Sunday, March 12, 2006 10:37 PM >>> Subject: [FlyRotary] Re: finding a radiator >>> >>> >>> > Dennis Haverlah wrote: >>> > >>> >> My question is - will the air make the 75 degree turn and flow >>> >> through >>> >> the fins? If not - would turning vanes below the radiator make this >>> >> configuration possible? >>> > >>> > Dennis, a section in K&W book discusses this very issue. The short >> answer >>> > is "Yes". The long answer is that you have to be very careful how you >>> > design the duct face in front of the radiator. If you have their >>> > book, >>> > it's figure 12-12 on page 277. >>> > >>> > -- >>> > This is by far the hardest lesson about freedom. It goes against >>> > instinct, and morality, to just sit back and watch people make >>> > mistakes. We want to help them, which means control them and their >>> > decisions, but in doing so we actually hurt them (and ourselves)." >>> > >>> > >>> > -- >>> > 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/