Return-Path: Received: from [216.52.245.18] (HELO ispwestemail2.mdeinc.com) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 521633 for flyrotary@lancaironline.net; Sun, 07 Nov 2004 13:49:59 -0500 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 4.0.330.8) with SMTP id for ; Sun, 7 Nov 2004 10:49:56 -0800 Message-ID: <004801c4c4fa$958cb070$13928843@7n7z201> From: "William" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: EWP Date: Sun, 7 Nov 2004 12:49:58 -0600 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original 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 Feel free to use it and link it. Bill Schertz KIS Cruiser # 4045 ----- Original Message ----- From: "Bob White" To: "Rotary motors in aircraft" Sent: Sunday, November 07, 2004 10:24 AM Subject: [FlyRotary] Re: EWP > Hi Bill, > > This is an excellent example of how to use the data in your slide > presentation, and seems to clarify the concepts. Can I put this in an > HTML file and link it to the presentation, or maybe you could edit it > into a form that could be added to the PDF? > > BTW for those of you who don't subscribe to the 'other' list, Bill's > slides as presented at the Rotary Round Up can be found at: > > http://www.bob-white.com/ACRE/Water_Cooling_an_Aircraft_Engine.pdf > > Bob White > > > > On Sun, 7 Nov 2004 08:48:50 -0600 > "William" wrote: > >> MessageTodd has provided some very interesting and valuable >> information on the performance of the EWP. >> >> If the pump, flowing through the Ford evaporator coils, flows 9.3 >> gallons/min, we can determine some things about the performance. The >> attached PDF file shows how to calculate flow vs. water temperature >> and air temperature drop as a function of horsepower generated. >> >> At 9 gallons per min, if Todd's engine generates 150 horsepower to the >> prop, and the engine is successfully cooled, then the temperature rise >> across the engine (and drop across the radiators) must be a little >> more than 50 degrees F. In other words, at 180F out of the engine, the >> coolant entering the engine must be below 130F. >> >> At 100 horsepower to the prop, it is about 40 degrees temperature >> drop. >> >> Now, to get 50+ degrees drop on the coolant side, means that the heat >> has to be transferred to the air. In a first approximation, the >> temperature of the air leaving the radiators cannot be hotter than the >> temperature of the water leaving the radiators, so the air can only be >> heated to some-what less than 130F. If we operate on a hot day, >> (100F), we only have 30F available to heat the air. Looking at the >> second chart in the attachment, we can see that at 150 horsepower, we >> will have to be flowing about 8,000 ft^3/min through the radiators. >> >> Is that possible? If we *assume* that he has about 50 in^2 of opening >> in the cowl feeding the two evaporator cores ( a little bigger than >> 3x8 openings x 2) then the area of the opening is 50/144 = 0.347 ft^2. >> To cram 8000 ft^3 of air through this opening the air must be moving >> at 8000-ft^3/min /0.347 ft^2 = 23040 ft/min >> >> (23040 ft/min)/(60 sec/min) = 384 ft/sec. Now, 60 miles per hour = 88 >> ft/sec, so the air moving through the openings must be moving at >> 384*60/88 = 262 miles per hour. This doesn't seem possible in a 150 >> mph plane. >> >> So, does this mean that the EWP does not work? NO, what is means is >> one of several possiblities, maybe in combination. >> >> 1. Todd may be developing less that 150 horsepower >> 2. Todd may be flying in much cooler climate. >> 3. Todd may be letting the water go to a higher temperature than 180F >> >> The combination of the above 3 items, hotter water temperature, cooler >> ambient temperature, and less horsepower would allow the EWP to work >> within the parameters reported by Todd. However, someone considering >> putting an EWP in a 3 rotor engine, generating well over 200 >> horsepower may not be pleased with the result. >> >> Todd, do you have fuel burn or horsepower numbers for your flights? >> >> Bill Schertz >> KIS Cruiser # 4045 >> ----- Original Message ----- >> From: Todd Bartrim >> To: Rotary motors in aircraft >> Sent: Saturday, November 06, 2004 3:27 PM >> Subject: [FlyRotary] Re: EWP >> >> >> Whoaa, before anybody gets worked up over my current draw figures, >> I'd made a mistake in my report and had sent another post correcting >> it the next day. Below is the corrected post.... hmmnn, is there a >> way of going back into the archives to correct erroneous data, as >> this same issue came up once before based on my incorrect data post. >> >> Hi Guy's >> I had a hard time believing the current draw for the pump so >> I brought home my good "Fluke" multimeter from work. The one >> I used last night was a cheap Digital meter from "Canadian >> Tire". I seldom use this one, so I'm not familiar with it >> but since it is very similar in outward appearance to my >> "Fluke 87" I assumed the same functions would apply. They >> don't. >> >> OK,OK, enough excuses, now for the real current draw. >> >> a.. continuous current draw - 4.3 amps >> b.. max inrush current draw at 100mS - 6.8 amps >> c.. max inrush current draw at 250uS - 13 amps >> d.. continuous current draw at minimum controlled flow - .2 amps >> The max inrush current is not really relevant to our concerns, but >> there it is for those that care. This higher current flow is still >> well within acceptable limits for my needs, and I expect that while >> in cruise flight, the controller will be reducing pump speed and >> current draw. >> >> I've reposted the flow measurements along with this post with the >> incorrect current draw deleted. I hope this clears up any confusion >> about EWP current requirements. I >> >> I ran the first test with the Ford evap cores in the system, >> plumbed in parallel. >> a.. Max flow 9.3 usg/m 35 l/m >> b.. 12.07 volt battery supply voltage >> c.. >> Second test had no evap cores in the system. Simply recirced >> water through pump - engine - header tank - pump. >> a.. max flow 13.0 usg/m 49 l/m >> b.. 12.06 volt battery supply voltage >> c.. >> Third test, I plumbed in a set of GM (Harrison) evap cores in >> parallel, into the system. I hung them just below my mounted >> Ford cores, using they same pipe sizes in an effort to have >> comparable test conditions. >> a.. max flow 7.7 usg/m 29 l/m >> b.. 12.4 volts supply voltage (I hooked a trickle charger to the >> battery) c.. >> In each test configuration test results are with heater valve >> closed. Heater core added .5 usg/m in each case. >> >> In all of the above tests the electronic pump controller was >> bypassed to give full battery voltage to the pump. With the >> pump controller in use, as the water was cold well water, >> controller had pump at minimum flow which was measured at .6 >> usg/m - 2.2 l/m. >> >> I've just been lurking since returning from school as I've got >> allot to catch up on around here, so am trying not to get >> distracted with the list, however I needed to jump in on this one. >> I need to head out to the airport today to install my new radio >> and hopefully get out for a flight, as they are calling for 5" of >> snow tonight. >> >> Todd Bartrim >> >> RV9Endurance >> 13B Turbo Rotary >> C-FSTB >> http://www3.telus.net/haywire/RV-9/C-FSTB.htm >> >> "The world will always have a place for those that >> bring hard work and determination to the things they >> do." >> > > > -- > http://www.bob-white.com > N93BD - Rotary Powered BD-4 (soon) > >>> Homepage: http://www.flyrotary.com/ >>> Archive: http://lancaironline.net/lists/flyrotary/List.html