X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.121] verified) by logan.com (CommuniGate Pro SMTP 5.1.12) with ESMTP id 2373945 for flyrotary@lancaironline.net; Sun, 07 Oct 2007 12:58:35 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.121; envelope-from=eanderson@carolina.rr.com Received: from edward2 ([24.74.103.61]) by cdptpa-omta03.mail.rr.com with SMTP id <20071007165757.YUNJ3971.cdptpa-omta03.mail.rr.com@edward2> for ; Sun, 7 Oct 2007 16:57:57 +0000 Message-ID: <005201c80903$40b402b0$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" Subject: New Spreadsheet Details Date: Sun, 7 Oct 2007 12:58:15 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_004F_01C808E1.B972C730" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 This is a multi-part message in MIME format. ------=_NextPart_000_004F_01C808E1.B972C730 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I attempted 3 times to post the new spreadsheet to the list, but it is a = few KB too large. So those of you who may want it, send me an e mail to = eanderson@carolina.rr.com with the subject : Spreadsheet . I will send = you a copy. Details of latest revisions. In the past, I have provided a spreadsheet to aid in determining power, = fuel flow, heat produced, etc, and have also attempt to provide some = rudimentary cooling calculations. You can entertain yourself with it as = well with your dream engine {:>) Since there was no engine load component in earlier spreadsheets, I had = provided % throttle opening factor as a substitute. However, that was = never satisfactory because who of us know exactly what % throttle = opening we have at any point and besides that throttle opening does not = necessarily correspond to load. In any case, I recent revised the spreadsheet, so that a user may now = put in his manifold pressure. That is generally a parameter available = to most folks. It also eliminates potential errors from altitude, air = density, temperature etc. It and rpm also provide a better indicator of = LOAD than does throttle position. It will also works for N/A and = turbo engines. =20 All you do is enter your manifold pressure (and the other engine = operating parameters) and the calculations will use that to calculate = the air density in the intake and from that the power, flow rates,BTU, = etc. So now the manifold air density is separate from the cooling air = density which is dependent on altitude. So manifold pressure and = altitude (ambient pressure) are now separate for engine operation and = cooling operations. So in the cooling section you must now enter your altitude for cooling = calculations. Also, I have now provided for the user to enter the = dimensions of his cooling cores and the number rather than the default = Gm cores and RX-7 oil cooler I had been using. You can change these = parameters on the second sheet titled "Cooling Calculations", it shows = recommended default values (the GM cores and Stock Rx-7 cooler) just to = get you started or if your project is still in the dream stage. Also there is provision on the cooling calculations sheet to have your = coolant flow rate proportional to engine rpm (more realistic). The flow = rate is based on Racing Beat information for 1974 and later coolant pump = flow rate. If you have changed the pulley ratio to non-stock then = these flow rates may be off a bit - but still more realistic than = assuming a 40 gpm flow rate at idle and at 6000 rpm {:>). =20 So these changes mean you can now simulate a partial throttle operation = say at 19" Hg and a cooling altitude at 7500 MS. You can now see if = your system should be cooling at that power setting and then you could = change the power setting to 22" Hg and see if you installation should = still cool at that selected air speed and altitude and power setting. = Manifold pressure and Air Fuel Ratio can make a considerable difference = in the amount of heat produced. So pay attention to the values you are = using. Now here is the potential problem I can see. If you tell the = spreadsheet you are flying at 7500 MSL in the cooling data input, but = you decide to use WOT for your engine, you must realize that the ambient = pressure (and therefore your manifold pressure) at that altitude will = not be 29.92 " HG. Your manifold pressure (for N/A engine) would never = be that high for an N/A engine at that altitude - but, it could be for = a turbo engine. So unless you selected YES for turbocharged in the data = entry area, an error message will be displayed "Manifold Pressure = exceeds ambient". It can also happen if you have already selected a = manifold pressure say 29" while at sea level, but then you enter 2000 = MSL for altitude in the cooling section. The warming message will = inform you that your manifold pressure now exceeds the ambient pressure = at 2000 MSL ( unless you enter=20 turbo charged =3D "yes"). If you select an RPM value for the cooling section and it is outside the = limits of the rpm values in your calculated data table, then an error = message "Invalid RPM" will be shown in the cooling data entry area. So = that would mean either change the rpm OR change the range of rpm in the = table by adjusting the rpm start value or the rpm step value. As always, if anyone finds an error or problem please let me know. Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.dmack.net/mazda/index.html Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.dmack.net/mazda/index.html ------=_NextPart_000_004F_01C808E1.B972C730 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
I attempted 3 times to post the new spreadsheet = to the=20 list, but it is a few KB too large.  So those of you who may want = it, send=20 me an e mail to eanderson@carolina.rr.com = with the=20 subject :  Spreadsheet .  I will send you a copy.
 
Details of latest revisions.
 
In the past, I have provided a spreadsheet to = aid in=20 determining power, fuel flow, heat produced, etc, and have also attempt = to=20 provide some rudimentary cooling calculations.  You can entertain = yourself=20 with it as well with your dream engine {:>)
 
Since there was no engine load component in = earlier=20 spreadsheets, I had provided % throttle opening factor as a=20 substitute.  However, that was never  satisfactory because who = of=20 us know exactly what % throttle opening we have at any point and = besides=20 that throttle opening does not necessarily correspond to = load.
 
In any case, I recent revised the spreadsheet, = so that a=20 user may now put in his manifold pressure.  That is generally a = parameter=20 available to most folks.  It also eliminates  potential errors = from=20 altitude, air density, temperature etc. It and rpm also = provide a=20 better indicator of LOAD than does throttle position.   It = will also=20 works for  N/A and turbo engines. 
 
 
All you do is enter your  manifold = pressure (and=20 the other engine operating parameters)  and the calculations = will use=20 that to calculate the air density in the intake and from that the power, = flow=20 rates,BTU, etc.  So now the manifold air density is separate from = the=20 cooling air density which is dependent on altitude.  So manifold = pressure=20 and altitude (ambient pressure) are now separate for engine operation = and=20 cooling operations.
 
So in the cooling section you must now enter = your altitude=20 for cooling calculations.  Also, I have now provided for the user = to enter=20 the dimensions of his cooling cores and the number rather than the = default Gm=20 cores and RX-7 oil cooler I had been using.  You can change these=20 parameters on the second sheet titled "Cooling Calculations", it  = shows=20 recommended default values (the GM cores and Stock Rx-7 cooler) just to = get you=20 started or if your project is still in the dream stage.
 
Also there is provision on the cooling = calculations sheet=20 to have your coolant flow rate proportional to engine rpm (more=20 realistic).  The flow rate is based on Racing Beat information for = 1974 and=20 later coolant pump  flow rate.  If you have changed the pulley = ratio=20 to non-stock then these flow rates may be off a bit - but still more = realistic=20 than assuming a 40 gpm flow rate at idle and at 6000 rpm {:>). =20
 
So these changes mean you can now simulate a = partial=20 throttle operation say at 19" Hg and a cooling altitude at 7500 = MS.  You=20 can now see if your system should be cooling at that power setting and = then you=20 could change the power setting to 22" Hg and see if you = installation should=20 still cool at that selected air speed and altitude and power = setting. =20 Manifold pressure and Air Fuel Ratio can make a considerable difference = in the=20 amount of heat produced.  So pay attention to the values you are=20 using.
 
Now here is the potential problem I can = see.  If you=20 tell the spreadsheet you are flying at 7500 MSL in the cooling data = input, but=20 you decide to use WOT for your engine, you must realize that the ambient = pressure (and therefore your manifold pressure) at that altitude =  will not=20 be 29.92 " HG.  Your  manifold pressure (for N/A engine) = would=20 never be that high for an N/A engine at that altitude  - = but, it=20 could be for a turbo engine.  So unless you selected YES for turbocharged in the data entry = area, an=20 error message will be displayed "Manifold = Pressure=20 exceeds ambient".  It can also happen if you have = already=20 selected a manifold pressure say 29" while at sea level, but then you = enter 2000=20 MSL for altitude in the cooling section.  The warming message = will=20 inform you that your manifold pressure now exceeds the ambient = pressure at=20 2000 MSL ( unless you enter
turbo charged =3D "yes").
 
If you select an RPM value for the cooling = section and it=20 is outside the limits of the rpm values in  your calculated = data=20  table, then an error message "Invalid=20 RPM" will be shown in the cooling data entry area.  = So that=20 would mean either change the rpm OR change the range of rpm in the table = by=20 adjusting the rpm start value or the rpm step value.
 
As always, if anyone finds an error or problem = please let=20 me know.
 
Ed
 
Ed Anderson
Rv-6A N494BW Rotary = Powered
Matthews,=20 NC
eanderson@carolina.rr.com
http://www.andersonee.com
http://members.cox.net/rogersda/rotary/configs.htm#N494BWhttp://www.dmack.net/mazda/index.html
Ed Anderson
Rv-6A N494BW Rotary = Powered
Matthews,=20 NC
eanderson@carolina.rr.comhttp://www.andersonee.com
http:/= /members.cox.net/rogersda/rotary/configs.htm#N494BW
http://www.dmack.net/mazda= /index.html
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