X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from rg4.comporium.net ([208.104.2.24] verified) by logan.com (CommuniGate Pro SMTP 5.2c1) with ESMTPS id 2503751 for flyrotary@lancaironline.net; Sun, 25 Nov 2007 01:19:24 -0500 Received-SPF: pass receiver=logan.com; client-ip=208.104.2.24; envelope-from=Jewen@comporium.net Received: from 208-104-81-95.lnhe.2wcm.comporium.net (HELO engineer1) ([208.104.81.95]) by rg4.comporium.net (MOS 3.8.4-GA FastPath queued) with SMTP id AGN57362; Sun, 25 Nov 2007 01:18:44 -0500 (EST) Message-ID: <011d01c82f2a$d85a7d40$6505a8c0@cooleygroup.local> From: "Joe Ewen" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] what are they Date: Sun, 25 Nov 2007 01:17:24 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_011A_01C82F00.EF6EF170" 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 X-Junkmail-Status: score=10/70, host=rg4.comporium.net X-Junkmail-SD-Raw: score=unknown, refid=str=0001.0A090209.474911A4.003F,ss=1,fgs=0, ip=208.104.81.95, so=2007-03-13 10:31:19, dmn=5.4.3/2007-10-18 This is a multi-part message in MIME format. ------=_NextPart_000_011A_01C82F00.EF6EF170 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Not sure if this is the right answer. My understanding is the fins on = most radiators have a slight bend at the leading edge designed to cause = turbulence and improve cooling efficiency. The radiators made for dirt = track racing that do not have the bend in the fin and might be = considered flat plate. I believe the rads for dirt racing are such so = they have a lower tendency to plug up with the track media, at a = sacrifice in cooling efficiency. Joe ----- Original Message -----=20 From: Ed Klepeis=20 To: Rotary motors in aircraft=20 Sent: Sunday, November 25, 2007 12:30 AM Subject: [FlyRotary] what are they Dear Tracy I'm with you what are these special flat plate rads. I have = built many systems but haven't come across these flat plate rads. I will = stand corrected if someone comes up with something. I think what = everyone is talking about is a flat plate cooler that is put in the = bottom tank on rads to cool trans fluid. I think fluidyne is using them = as oil to water oil coolers. I looked into that but didn't like the = sealing system they used around the oil inlet/outlet good enough for = cars but not safe for aircraft. If anyone has anything to add to this I = would be happy to hear about it. = Regards = Ed Klepeis ----- Original Message -----=20 From: Tracy Crook=20 To: Rotary motors in aircraft=20 Sent: Saturday, November 24, 2007 9:39 PM Subject: [FlyRotary] Re: Naca Report on Radiator Thickness OK Steve, I'll bite. Do pusher airplane builders hang their rads = out in the breeze? Do radiator companies make special flat plate style = radiators for them? What am I missing? =20 Tracy On Nov 24, 2007 1:05 PM, Steve Brooks wrote: Tracy, Maybe not relevant for an RV, but pretty relevant if you are = cooling a pusher. Steve Brooks -----Original Message----- From: Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net ]On Behalf Of Tracy Crook Sent: Saturday, November 24, 2007 11:53 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Naca Report on Radiator Thickness This NACA paper discussion is interesting but has almost nothing = to do with our installations using standard automotive rads rather than = the flat plate rads in the paper. Radiator frontal area is almost = irrelavant in our installations because they are totally enclosed within = a streamlined body. Too bad, because if frontal area was a significant = factor, it would end the argument about thick vs thin :-) The thin rad = would look terrible in this respect.=20 Keep everything in perspective! Note that the NACA paper indicates that the rads we use (tube & = fin type) have no application in aircraft. If that were true it would = mean all our discussions and work on installations so far have been a = total waste of time! =20 Tracy (should be working on RV-8) On Nov 21, 2007 9:20 PM, Ron Springer = wrote: Well, engineering judgement tells me that your drag increase is still too low. Now I'll just have to prove=20 it by looking at that report, or elsewhere. Sounds like a good project for the long holiday weekend, or I could just work on my Cozy ... it will be a tough call! Ron --- Ed Anderson wrote: > > Ok, Ron, I went back and looked at the drag aspects > again. It looks like > the calculation was accurate, however, I think this > will put it into a > better perspective than before. > > The frontal drag at 120 mph for the 1 square foot > radiator (using just the > frontal area - no drag coefficient) was > > 37.63 lbf/ft^2, the "internal skin" drag of the 4" > thick radiator was 6.7 > lbf/ft^2. The skin drag for the 1" thick rad was=20 > 4.28 lbf/ft^2. So > comparing the 6.7 with the 4.28 was where I came up > with the 58% increase in > skin drag. > > However, adding the frontal and skin drag factors > for the "total" drag, I=20 > get 37.62 lbf/ft^2 + 4.28 lbf/ft^2 =3D 40.98 lbf/ft^2 > total drag for the 1" > rad. For the 4" rad 37.62 + 6.7 =3D 44.32 lbf/ft^2, > so based on that it > appears that the total drag was increased by=20 > 41.90/44.32 =3D 5.5% more total > drag for the 4" radiator than for the 1" radiator. > It might be a tad bit > less than that due to the 5% decrease in mass flow > on the frontal area of > the thicker rad. > > At least that is the way it appears to me. > > Ed > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html ------=_NextPart_000_011A_01C82F00.EF6EF170 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Not sure if this is the right = answer.  My=20 understanding is the fins on most radiators have a slight bend at the = leading=20 edge designed to cause turbulence and improve cooling efficiency.  = The=20 radiators made for dirt track racing that do not have the bend in the = fin and=20 might be considered flat plate.  I believe the rads for dirt racing = are=20 such so they have a lower tendency to plug up with the track media, at a = sacrifice in cooling efficiency.
 
Joe
 
 
----- Original Message -----
From:=20 Ed=20 Klepeis
Sent: Sunday, November 25, 2007 = 12:30=20 AM
Subject: [FlyRotary] what are = they

Dear Tracy
        I'm=20 with you what are these special flat plate rads. I have built many = systems but=20 haven't come across these flat plate rads. I will stand corrected = if=20 someone comes up with something. I think what everyone is talking = about is a=20 flat plate cooler that is put in the bottom tank on rads to cool trans = fluid.=20 I think fluidyne is using them as oil to water oil coolers. I looked = into that=20 but didn't like the sealing system they used around the oil = inlet/outlet good=20 enough for cars but not safe for aircraft. If anyone has anything to = add to=20 this I would be happy to hear about it.
          &nbs= p;            = ;            =             &= nbsp;           &n= bsp;           &nb= sp;           &nbs= p;            = ;            =          =20 Regards
          &nbs= p;            = ;            =             &= nbsp;           &n= bsp;           &nb= sp;           &nbs= p;            = ;            =      =20 Ed Klepeis
----- Original Message -----
From:=20 Tracy Crook
To: Rotary motors in = aircraft=20
Sent: Saturday, November 24, = 2007 9:39=20 PM
Subject: [FlyRotary] Re: Naca = Report on=20 Radiator Thickness

OK Steve, I'll bite.  Do pusher airplane = builders hang their=20 rads out in the breeze?  Do radiator companies make special = flat plate=20 style radiators for them?    What am I missing?  =
 
Tracy

On Nov 24, 2007 1:05 PM, Steve Brooks = <cozy4pilot@gmail.com> = wrote:
Tracy,
 Maybe = not relevant=20 for an RV, but pretty relevant if you are cooling a=20 pusher.
 
Steve=20 Brooks
 
-----Original=20 Message-----
From: Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net ]On Behalf Of = Tracy=20 Crook
Sent: Saturday, November 24, 2007 11:53 = AM
To:=20 Rotary motors in aircraft
Subject: [FlyRotary] Re: = Naca Report=20 on Radiator Thickness

This NACA paper discussion is interesting but has almost = nothing to=20 do with our installations using standard automotive rads rather = than the=20 flat plate rads in the paper.   Radiator frontal area = is=20 almost irrelavant in our installations because they are totally = enclosed=20 within a streamlined body.  Too bad, because if frontal = area was a=20 significant factor, it would end the argument about thick vs = thin=20 :-)  The thin rad would look terrible in this respect. =
 
Keep everything in perspective!
 
Note that the NACA paper indicates that the rads we use = (tube &=20 fin type) have no application in aircraft.  If that were = true it=20 would mean all our discussions and work on installations so far = have=20 been a total waste of time! 
 
Tracy (should be working on RV-8)

On Nov 21, 2007 9:20 PM, Ron Springer = <ron2369@sbcglobal.net> wrote:
Well,=20 engineering judgement tells me that your drag
increase is = still too=20 low. Now I'll just have to prove
it by looking at that = report, or=20 elsewhere.
Sounds like a good project for the long=20 holiday
weekend, or I could just work on my Cozy ... it = will
be=20 a tough call!

Ron

--- Ed Anderson <eanderson@carolina.rr.com>=20 wrote:

>
>  Ok, Ron, I went back = and looked=20 at the drag aspects
> again.  It looks like
> = the=20 calculation was accurate, however, I think this
> will = put it=20 into a
> better perspective than before.
>
> = The=20 frontal drag at 120 mph for the 1 square foot
> radiator = (using=20 just the
> frontal area - no drag coefficient)=20 was
>
> 37.63 lbf/ft^2,  the "internal skin" = drag of=20 the 4"
> thick radiator was 6.7
> lbf/ft^2. =  The skin=20 drag for the 1" thick rad was
> 4.28 lbf/ft^2. =  So
>=20 comparing the 6.7 with the 4.28 was where I came up
> = with the=20 58% increase in
> skin drag.
>
> =  However,=20 adding  the frontal and skin drag factors
> for the = "total"=20 drag, I
> get 37.62 lbf/ft^2 + 4.28 lbf/ft^2 =3D 40.98=20 lbf/ft^2
> total drag for the 1"
> rad. For the 4" = rad=20  37.62 + 6.7 =3D 44.32 lbf/ft^2,
> so based on that = it
> appears that the total drag was increased by =
>=20 41.90/44.32 =3D 5.5% more total
> drag for the 4" = radiator than=20 for the 1" radiator.
> It might be a tad bit
> = less than=20 that due to the 5% decrease in mass flow
> on the frontal area of
> the thicker=20 rad.
>
> At least that is the way it appears to=20 me.
>
> Ed
>
>
> --
> Homepage:  http://www.flyrotary.com/
> Archive = and=20 UnSub:
>
http://mail.lancaironline.net:81/lists/flyrotary/List.htm= l
>


--
Homepage:=20  http://www.flyrotary.com/
Archive and = UnSub:=20   http://mail.lancaironline.net:81/lists/flyrotary/List.htm= l


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