X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.120] verified) by logan.com (CommuniGate Pro SMTP 5.2.0) with ESMTP id 2772473 for flyrotary@lancaironline.net; Sat, 01 Mar 2008 10:02:49 -0500 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.120; envelope-from=eanderson@carolina.rr.com Received: from edward2 ([75.191.186.236]) by cdptpa-omta03.mail.rr.com with SMTP id <20080301150208.UKOB20983.cdptpa-omta03.mail.rr.com@edward2> for ; Sat, 1 Mar 2008 15:02:08 +0000 Message-ID: <001401c87bad$42899290$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Boundary Layer and Inlets was Re: New (old) guy on list Date: Sat, 1 Mar 2008 10:02:25 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0011_01C87B83.596E6B40" 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_0011_01C87B83.596E6B40 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageIndeed there is more than one way. However, without the inlet = moved out of the boundary layer, this NACA study would indicate that you = may need internal guide vans to overcome the detrimental effect of = ingesting the boundary layer. http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930093223_19930932= 23.pdf Ed ----- Original Message -----=20 From: Mike Wills=20 To: Rotary motors in aircraft=20 Sent: Friday, February 29, 2008 10:34 PM Subject: [FlyRotary] Re: New (old) guy on list Just 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_0011_01C87B83.596E6B40 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
Indeed there is more than one way.  = However, without=20 the inlet moved out of the boundary layer, this NACA study would = indicate that=20 you may need internal guide vans to overcome the detrimental effect of = ingesting=20 the boundary layer.
 
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1993= 0093223_1993093223.pdf
 
Ed
----- Original Message -----
From:=20 Mike = Wills
Sent: Friday, February 29, 2008 = 10:34=20 PM
Subject: [FlyRotary] Re: New = (old) guy on=20 list

Just a comment on the boundary layer = splitter.=20 Take a look at Strega and Voodoo, two of the fastest 51s around and = you'll see=20 there 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=20 go that far. Also, I'd actually like to taxi without having to shut = down to=20 let the 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=20 than a good RV cheek cowl but it will stand out in a = crowd.
 
Mike 
----- Original Message -----
From:=20 Ed Anderson
To: Rotary motors in = aircraft=20
Sent: Friday, February 29, = 2008 12:16=20 PM
Subject: [FlyRotary] Re: New = (old) guy=20 on list

Greg, there has been a lot of debate among = heat=20 exchange professionals about whether the P-51 cooling system = resulted in any=20 net  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=20 engineers didn't get it right the first time {:>)).  Two of = the=20 highest factors 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=20 opening then you may need to put guide vanes between inlet and = core.  I=20 am sending a NACA report direct to your e mails as it is too large = for a=20 Rotary Posting.  I would think it easier to stand it off - if = you have=20 that 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=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 Ward
To: Rotary motors in = aircraft=20
Sent: Friday, February 29, = 2008 11:50=20 AM
Subject: [FlyRotary] Re: = New (old)=20 guy 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=20 a slower speed?  Supposedly the P-51 configuration creates = enough=20 thrust to overcome around 90% of the drag created, but I would = like to=20 confirm that before I go through the process of designing and = building the=20 damn 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=20 7:26 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=20 RX7 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=20 water. Never been over 180 on either. Which brings me to = thinking=20 (again) about oil/water heat exchangers. Has anyone successfully = implemented one? If so what are you using? I may eventually be = able to=20 get rid of that second scoop.
 
Mike
----- Original Message ----- =
From:=20 Russell=20 Duffy
To: Rotary motors in=20 aircraft
Sent: Thursday, = February 28, 2008=20 8:57 PM
Subject: [FlyRotary] = Re: New=20 (old) guy on list

 I was on this = list years ago=20 when it first started up. Job change and other issues slowed = progress=20 on my project and I unsubscribed. 
 
Hey, = Mike's=20 Back  :-)
 
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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