Return-Path: Received: from [216.52.245.18] (HELO ispwestemail2.mdeinc.com) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 486521 for flyrotary@lancaironline.net; Mon, 25 Oct 2004 23:10:07 -0400 Received-SPF: none receiver=logan.com; client-ip=216.52.245.18; envelope-from=wschertz@ispwest.com Received: from 7n7z201 (unverified [67.136.146.19]) by ispwestemail2.mdeinc.com (Vircom SMTPRS 3.2.315.0) with SMTP id for ; Mon, 25 Oct 2004 20:09:34 -0700 Message-ID: <001601c4bb09$2f45cd60$13928843@7n7z201> From: "William" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: oil cooler duct suggestion Date: Mon, 25 Oct 2004 22:05:53 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1437 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 We could learn a lot by having Rusty make some pressure and temperature measurements of the air on both sides of the core, as well as the oil delta-T Bill Schertz KIS Cruiser # 4045 ----- Original Message ----- From: "Ed Anderson" To: "Rotary motors in aircraft" Sent: Sunday, October 24, 2004 7:31 PM Subject: [FlyRotary] Re: oil cooler duct suggestion > So right you are, Bill. > > I made the assumption that the core was not the problem - but as you point > out, the Mazda oil cooler does have the turbulators to promote turbulence on > the oil side for better heat exchange. Could be the airflow is not the > main culprit - but, since Rusty is somewhat committed? to the core {:>), I > figure we'd help him work that side of the equation for a bit - then if we > (he) can't get the improvement he would like, he may have to consider other > alternatives (like a stock core). > > Ed > ----- Original Message ----- > From: "William" > To: "Rotary motors in aircraft" > Sent: Sunday, October 24, 2004 5:41 PM > Subject: [FlyRotary] Re: oil cooler duct suggestion > > > > Ed, > > A third part of the equation is that the evaporator core may not function > > very well as an 'oil' cooler, because it lacks the turbulence generators > in > > the oil flow passages. If the air temperature rise is low (20F you > > speculated) I would look at the oil side of the equation. > > > > Bill Schertz > > KIS Cruiser # 4045 > > ----- Original Message ----- > > From: "Ed Anderson" > > To: "Rotary motors in aircraft" > > Sent: Sunday, October 24, 2004 9:03 AM > > Subject: [FlyRotary] Re: oil cooler duct suggestion > > > > > > > All good points, Bernie > > > > > > My impression is that Rusty 1st objective is he would like for the oil > > > temps to be lower. Assuming that the GM core, Rusty is using for an oil > > > cooler provides adequate air/metal contact area, then it would appear to > > me > > > that the problem at this time is getting more cooling effectiveness from > > the > > > airflow. If you have adequate mass flow through the core, you will > cool. > > > However, if you have not adequately slowed the air down (diffusion) then > > > your cooling drag could be higher than necessary. But, it would appear > to > > > me at this point that cooling is the crucial aspect rather than > minimizing > > > cooling drag. Tight 90 deg turns right before the core does not promote > > > more flow through the core (in my opinion). > > > > > > According to K&W (if I understood the math), the more parallel the flow > > is > > > to the core surface at entry to the core the greater the pressure loss > is > > > and the less cooling effectiveness. They mention that in these cases > the > > > use of guide vans to direct the airflow more directly into the core > > passages > > > can result in cooling effectiveness approaching the straight-in duct. > They > > > also point out that staggering the core layers of the heat exchanger can > > > also help (not feasible in this case). > > > > > > There appears to be two situations possible: > > > > > > 1. There is adequate air mass flow to cool - but the system is not > > > transferring the heat to the air with the best efficiency. In this > case, > > > better diffusion offers improvement. > > > > > > 2. There is not have adequate air mass flow to cool - in this case, it > > does > > > not matter how effective you diffuser is, your system will not cool > > > adequately. > > > > > > So either situation could apply in Rusty's case. > > > > > > If the delta T of the cooling air across the core is in the vicinity > of > > > 40-50F then I would estimate that he has adequate diffusion but perhaps > > not > > > adequate air mass flow to cool. In other words, the system is > > transferring > > > the coolant heat to the air with high efficiency - but, simply not > enough > > > air to carry away adequate heat. > > > > > > If the Delta T is closer to 20F then he may have sufficient air mass > flow > > > but inadequate diffusion (does not slow the air down enough for maximum > > heat > > > transfer) > > > > > > Even with the best diffuser a system will not adequately cool if there > is > > > inadequate mass flow through the core. So my focus would be 1st focused > > on > > > increasing the mass flow. Just my opinion, of course. > > > > > > Ed Anderson > > > > > > > > > > > > > > Rusty and Ed, > > > > > > > > Ed, maybe you know more about his configuration than what I can glean > > from > > > his schetches. I think we need to know whether he is trying to almost > > > totally diffuse the air like mine (hopefully :>) ) to minimize the > turning > > > pressure loss and allow the flow to accelerate thru the cooler or > whether > > he > > > is trying to do the Lamar type min height and volume flow path. > > > > > > > > Rusty, what is the x-cross maximum area perpendicular to the cooler > > > compared to the inlet area? > > > > > > > > Boy the weather looks like it should be good on Wed for your flight > down > > > Ed. Rusty, really sorry you aren't going to make it next weekend, I > really > > > want to meet the guy behind all these emails. > > > > > > > > Bernie > > > > > > > > >> Homepage: http://www.flyrotary.com/ > > > > >> Archive: http://lancaironline.net/lists/flyrotary/List.html > > > > > > > > > > > > > > > > >> Homepage: http://www.flyrotary.com/ > > > >> Archive: http://lancaironline.net/lists/flyrotary/List.html > > > > > > >> Homepage: http://www.flyrotary.com/ > > >> Archive: http://lancaironline.net/lists/flyrotary/List.html > > > > >> Homepage: http://www.flyrotary.com/ > >> Archive: http://lancaironline.net/lists/flyrotary/List.html