X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao107.cox.net ([68.230.241.39] verified) by logan.com (CommuniGate Pro SMTP 5.2.0) with ESMTP id 2771889 for flyrotary@lancaironline.net; Fri, 29 Feb 2008 22:35:29 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.39; envelope-from=rv-4mike@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao107.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20080301033447.OKIS8249.fed1rmmtao107.cox.net@fed1rmimpo01.cox.net> for ; Fri, 29 Feb 2008 22:34:47 -0500 Received: from wills ([68.105.86.251]) by fed1rmimpo01.cox.net with bizsmtp id vfaa1Y00J5RMxr00000000; Fri, 29 Feb 2008 22:34:36 -0500 Message-ID: <007601c87b4d$32b43bf0$fb566944@wills> From: "Mike Wills" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: New (old) guy on list Date: Fri, 29 Feb 2008 19:34:46 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0073_01C87B0A.244721B0" 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_0073_01C87B0A.244721B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageJust a comment on the boundary layer splitter. Take a look at = Strega and Voodoo, two of the fastest 51s around and you'll see there is = no boundary layer splitter. Obviously more than one way to skin a cat. I looked at all sorts of ways to locate coolers anyplace other than the = cowl because of the (mostly anecdotal or theoretical) evidence on the = web. But for me it was a non-starter. No way to run coolant lines or add = coolers without structural mods to the RV and I wasnt willing to go that = far. Also, I'd actually like to taxi without having to shut down to let = the engine cool. :-) I compromised by mounting coolers below the engine and eliminating the = stock RV cowl. I doubt it'll be any less draggy than a good RV cheek = cowl but it will stand out in a crowd. Mike=20 ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Friday, February 29, 2008 12:16 PM Subject: [FlyRotary] Re: New (old) guy on list Greg, 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_0073_01C87B0A.244721B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
Just a comment on the boundary layer = splitter. Take=20 a look at Strega and Voodoo, two of the fastest 51s around and you'll = see there=20 is no boundary layer splitter. Obviously more than one way to skin a=20 cat.
 
I looked at all sorts of ways to locate = coolers=20 anyplace other than the cowl because of the (mostly anecdotal or = theoretical)=20 evidence on the web. But for me it was a non-starter. No way to run = coolant=20 lines or add coolers without structural mods to the RV and I wasnt = willing to go=20 that far. Also, I'd actually like to taxi without having to shut down to = let the=20 engine cool. :-)
 I compromised by mounting coolers = below the=20 engine and eliminating the stock RV cowl. I doubt it'll be any less = draggy than=20 a good RV cheek cowl but it will stand out in a crowd.
 
Mike 
----- Original Message -----
From:=20 Ed=20 Anderson
Sent: Friday, February 29, 2008 = 12:16=20 PM
Subject: [FlyRotary] Re: New = (old) guy on=20 list

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=20 debate 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=20 to coolant temps when taxing in warm weather.
 
However, the P-51 style design requires some = very=20 specific attention to certain factors (even the North American P-51 = engineers=20 didn't get it right the first time {:>)).  Two of the highest = factors=20 on the 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=20 sending 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=20 line off the list and I will give you my viewpoint of what it=20 takes.
 
Some interesting viewpoints here on cooling in = 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
To: Rotary motors in = aircraft=20
Sent: Friday, February 29, = 2008 11:50=20 AM
Subject: [FlyRotary] Re: New = (old) guy=20 on list

I would also be really interested in seeing = some=20 others cooling solutions.  I was told that 40% of = the Lancair's=20 drag is in the cooling drag, and I am contemplating a belly scoop A = la'=20 P-51, and have created controversy about how much that configuration = will=20 add to the drag factor.  In other words, I might get great = cooling at a=20 slower speed?  Supposedly the P-51 configuration creates enough = thrust=20 to 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)=20 guy on list

Well, it's not as beautiful as it = once was.=20 Had to add some ugly bumps for exhaust clearance. Finally threw in = the=20 towel on a clean oil cooler install and added a second scoop and = stock RX7=20 cooler below the rad inlet.
 
 Can I attach pictures=20 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=20 when it first started up. Job change and other issues slowed = progress on=20 my 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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