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 5.2.0) with ESMTP id 2771335 for flyrotary@lancaironline.net; Fri, 29 Feb 2008 15:17:22 -0500 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.121; envelope-from=eanderson@carolina.rr.com Received: from edward2 ([75.191.186.236]) by cdptpa-omta02.mail.rr.com with SMTP id <20080229201642.XSJJ15790.cdptpa-omta02.mail.rr.com@edward2> for ; Fri, 29 Feb 2008 20:16:42 +0000 Message-ID: <000701c87b10$0854d690$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: New (old) guy on list Date: Fri, 29 Feb 2008 15:16:56 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0004_01C87AE6.1F328350" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 This is a multi-part message in MIME format. ------=_NextPart_000_0004_01C87AE6.1F328350 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageGreg, there has been a lot of debate among heat exchange = professionals about whether the P-51 cooling system resulted in any net = thrust( Meredith effect ). There are numerous web sites you can read = about the debate if interested.=20 http://yarchive.net/mil/laminar_flow.html http://yarchive.net/mil/p51.html It appears to me that what can be said about the P-51 cooling system is = that at high airspeeds and high power settings it was very effective and = provided a good (minimum) drag factor. However, be aware that on the = ground it was less effective and care had to be paid to coolant temps = when taxing in warm weather. However, the P-51 style design requires some very specific attention to = certain factors (even the North American P-51 engineers didn't get it = right the first time {:>)). Two of the highest factors on the priority = list is to: 1. Make certain your cooling inlet is outside the fuselage boundary = layer - note that the mouth of the P-51 intake appears 3-4" away from = the fuselage. If you do not stand-off the opening then you may need to = put guide vanes between inlet and core. I am sending a NACA report = direct to your e mails as it is too large for a Rotary Posting. I would = think it easier to stand it off - if you have that option. 2. Make certain you have minimum flow separation near the entrance. = Easy to say, harder to implement. Drop me a line off the list and I = will give you my viewpoint of what it takes. Some interesting viewpoints here on cooling in general http://groups.google.com/group/rec.aviation.homebuilt/browse_thread/threa= d/aa11e7e47621e34b/eac8082eecac905b%23eac8082eecac905b Another source that appears to have good information http://glasairproject.com/AirSig/CoolingSystems/cooling2/CoolingSystems2.= htm Ed ----- Original Message -----=20 From: Greg Ward=20 To: Rotary motors in aircraft=20 Sent: Friday, February 29, 2008 11:50 AM Subject: [FlyRotary] Re: New (old) guy on list I would also be really interested in seeing some others cooling = solutions. I was told that 40% of the Lancair's drag is in the cooling = drag, and I am contemplating a belly scoop A la' P-51, and have created = controversy about how much that configuration will add to the drag = factor. In other words, I might get great cooling at a slower speed? = Supposedly the P-51 configuration creates enough thrust to overcome = around 90% of the drag created, but I would like to confirm that before = I go through the process of designing and building the damn = thing.......(:-) Call me lazy... Greg Ward 20B Lancair in Progress ----- Original Message -----=20 From: Mike Wills=20 To: Rotary motors in aircraft=20 Sent: Friday, February 29, 2008 7:26 AM Subject: [FlyRotary] Re: New (old) guy on list Well, it's not as beautiful as it once was. Had to add some ugly = bumps for exhaust clearance. Finally threw in the towel on a clean oil = cooler install and added a second scoop and stock RX7 cooler below the = rad inlet. Can I attach pictures here? At the moment it appears during full power ground runs that I have = excess cooling capacity, both oil and water. Never been over 180 on = either. Which brings me to thinking (again) about oil/water heat = exchangers. Has anyone successfully implemented one? If so what are you = using? I may eventually be able to get rid of that second scoop. Mike ----- Original Message -----=20 From: Russell Duffy=20 To: Rotary motors in aircraft=20 Sent: Thursday, February 28, 2008 8:57 PM Subject: [FlyRotary] Re: New (old) guy on list I was on this list years ago when it first started up. Job change = and other issues slowed progress on my project and I unsubscribed.=20 Hey, Mike's Back :-) Good to hear from you again. Can't wait until all the new folks = see that beautiful cowl :-) Cheers, Rusty ------=_NextPart_000_0004_01C87AE6.1F328350 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
Greg, there has been a lot of debate among heat = exchange=20 professionals about whether the P-51 cooling system resulted in any net=20  thrust( Meredith effect = ).  There are numerous  web sites you can read about = the debate=20 if interested. 
 
http://yarchive.net/mi= l/laminar_flow.html
  http://yarchive.net/mil/p51.htm= l
 
 
 It appears to me that what can be said = about the=20 P-51 cooling system is that at high airspeeds and high power settings it = was=20 very effective and provided a good (minimum) drag factor.  However, = be=20 aware that  on the ground it was less effective and care had to be = paid to=20 coolant temps when taxing in warm weather.
 
However, the P-51 style design requires some = very specific=20 attention to certain factors (even the North American P-51 engineers = didn't get=20 it right the first time {:>)).  Two of the highest factors on = the=20 priority list is to:
 
1.   Make certain your cooling = inlet is=20 outside the fuselage boundary layer - note that the mouth of the P-51 = intake=20 appears 3-4" away from the fuselage.  If you do not stand-off the = opening=20 then you may need to put guide vanes between inlet and core.  I am = sending=20 a NACA report direct to your e mails as it is too large for a Rotary=20 Posting.  I would think it easier to stand it off - if you have = that=20 option.
 
2.  Make certain you have minimum flow = separation=20 near the entrance.  Easy to say, harder to implement.  Drop me = a line=20 off the list and I will give you my viewpoint of what it = takes.
 
Some interesting viewpoints here on cooling in=20 general
http://grou= ps.google.com/group/rec.aviation.homebuilt/browse_thread/thread/aa11e7e47= 621e34b/eac8082eecac905b%23eac8082eecac905b
 
Another source that appears to have good=20 information
 
http://glasairproject.com/AirSig/CoolingSystems/cooling2/Coo= lingSystems2.htm
 
 
Ed
 
 
----- Original Message -----
From:=20 Greg=20 Ward
Sent: Friday, February 29, 2008 = 11:50=20 AM
Subject: [FlyRotary] Re: New = (old) guy on=20 list

I would also be really interested in seeing = some others=20 cooling solutions.  I was told that 40% of the Lancair's = drag is in=20 the cooling drag, and I am contemplating a belly scoop A la' P-51, and = have=20 created controversy about how much that configuration will add to the = drag=20 factor.  In other words, I might get great cooling at a slower=20 speed?  Supposedly the P-51 configuration creates enough thrust = to=20 overcome around 90% of the drag created, but I would like to confirm = that=20 before I go through the process of designing and building the damn=20 thing.......(:-)  Call me lazy...
Greg Ward
20B Lancair in Progress
----- Original Message -----
From:=20 Mike = Wills=20
To: Rotary motors in = aircraft=20
Sent: Friday, February 29, = 2008 7:26=20 AM
Subject: [FlyRotary] Re: New = (old) guy=20 on list

Well, it's not as beautiful as it = once was. Had=20 to add some ugly bumps for exhaust clearance. Finally threw in the = towel on=20 a clean oil cooler install and added a second scoop and stock RX7 = cooler=20 below the rad inlet.
 
 Can I attach pictures = here?
 
 At the moment it appears = during full=20 power ground runs that I have excess cooling capacity, both oil and = water.=20 Never been over 180 on either. Which brings me to thinking (again) = about=20 oil/water heat exchangers. Has anyone successfully implemented one? = If so=20 what are you using? I may eventually be able to get rid of that = second=20 scoop.
 
Mike
----- Original Message ----- =
From:=20 Russell=20 Duffy
To: Rotary motors in = aircraft=20
Sent: Thursday, February = 28, 2008=20 8:57 PM
Subject: [FlyRotary] Re: = New (old)=20 guy on list

 I was on this list = years ago when=20 it first started up. Job change and other issues slowed progress = on my=20 project and I unsubscribed. 
 
Hey, Mike's Back =20 :-)
 
Good to hear from you again.  = Can't wait=20 until all the new folks see that beautiful cowl=20 :-)
 
Cheers,
Rusty  
=
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