Return-Path: Received: from mail.tsisp.com ([65.23.108.44] verified) by logan.com (CommuniGate Pro SMTP 4.2b8) with ESMTP-TLS id 321456 for flyrotary@lancaironline.net; Wed, 14 Jul 2004 15:08:35 -0400 Received-SPF: error receiver=logan.com; client-ip=65.23.108.44; envelope-from=steve@tsisp.com Received: from stevehome by mail.tsisp.com (Technical Support Inc.) with SMTP id CQA74584 for ; Wed, 14 Jul 2004 15:07:57 -0400 Reply-To: From: "Steve Brooks" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: New Scoop Date: Wed, 14 Jul 2004 15:09:58 -0400 Message-ID: <02d501c469d6$28685320$6400a8c0@WORKGROUP.local> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_02D6_01C469B4.A156B320" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook CWS, Build 9.0.2416 (9.0.2910.0) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 In-Reply-To: Importance: Normal This is a multi-part message in MIME format. ------=_NextPart_000_02D6_01C469B4.A156B320 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Al, Its been hard to get good photos of this, because the lower cowling makes up a good portion of the airflow path. Basically I have a standard Cozy NACA scoop, with the oil cooler and radiator sitting flat, end-to-end beneath the engine mount. I have a curved deflector on the oil cooler to help the air make the turn up and through the oil cooler. I have another one of those deflectors on the radiator about half way back. The downside to this design, is that it takes pressure to make the air turn, and go up through the radiators. The NACA does not work well that way. What I'm trying to do is augment the existing scoop, with a "bolt on" scoop ahead of it, which will capture air outside of the boundary layer, i.e. high speed air, to improve cooling. I made a scoop first, that while it worked somewhat, does not exclude the boundary layer air. Also it's kind of like a funnel, with the largest are at the opening and tapering down into the existing scoop. I hope that makes some sense. Steve Brooks -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On Behalf Of Joseph M Berki Sent: Wednesday, July 14, 2004 2:45 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: New Scoop Al, Do you have any photos of your oil cooler install showing the airflow path? Joe Berki Limo EZ At 10:57 AM 7/14/2004 -0700, Al Gietzen wrote: Subject: [FlyRotary] New Scoop Steve; There are all kinds of things one could say about trying to make the scoop ideal, effective, low drag, etc; and then when you face the reality of fitting to your plane, you can t do it. So it s what works for you. I ll add a few comments for whatever it s worth. The intake area of the scoop should be fine. One would like to slow (expand) and turn the air entering the scoop in a manner that maintains surface attachment for max pressure recovery and minimum drag. This takes a much longer scoop throat than you have. The air entering will trip to turbulent at the abrupt corner behind the B.L dam. This will result in poor flow and pressure distribution, with most of the air going toward the back of the scoop. I don t know what happens in your installation downstream from the actual scoop, but you might consider some internal baffles but get a more uniform distribution if the rad is close to the scoop. The boundary layer dam that you have is high drag, and may be close enough to the entrance lip that backup of the B.L. flow will be ingested into the scoop or it could result in some external diffusion (pressure recovery) and allow the scoop to work just fine. The idea in the B.L. bleed is to try to divert that flow somewhere else, generally off to the sides. That would require a much more gradual diverter angle. I made a much more gradual bend in the wall of my scoop (pic) attached. Still, in doing flow tests, I found flow separation and turbulence which lead uneven flow distribution. I added to baffles in the scoop get it fairly uniform. It could be that some of the turbulence was a result of the test rig setup, although I thought I had a long enough duct from the blower to straighten things out. The squared off internal corners will add frictional drag, but probably not significant in overall picture. But, hey try it. If it gives you the cooling you need, you ve got 90% of the battle won. If you feel you need to reduce drag, you can consider that at your leisure. Al Ed, and others - Attached are some photos of the new scoop I'm building to replace my old new scoop. As you can see the new one actually has less intake area, but extends further in order to get outside of the boundary layer. I don't want the intake any larger than it has to be, but I want to make sure also that it is sufficient to allow for enough air flow. My old new scoop did improve cooling, but as I found out, it was only marginal. The new scoop, which is patterned after a P51 style scoop, not only gets outside of the boundary layer air, but also excludes it, with the dam that you see at the bottom. Well, actually it will be at the top, once it is mounted under the belly. It also gives me an expansion area once inside the scoop. Using the program that Al sent me, the boundary area calculated out to about 1.625-1.75 inches +/- depending on speed. The scoop intake measures 10.75" inside at the top (narrowest) and 14.75" at the widest point average = 12.75" Height of the inside of the scoop measures 4.25" This should equal about 54.18 sq in of area. The inside of the scoop sits exactly 2" from the bottom of the fuselage, and overall height to the outside of the scoop is about 6.6" again, measured from the fuselage bottom. I haven't glassed the scoop yet, other than on one side to help with gluing it together. I am interested in any feedback concerning the size of the intake area. Regards, Steve Brooks Cozy MKIV N75CZ Turbo Rotary >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_02D6_01C469B4.A156B320 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Al= ,

It= s been hard to get good photos of this, because the lower cowling makes up a = good portion of the airflow path.  Basically I have a standard Cozy NACA scoop, with the oil cooler = and radiator sitting flat, end-to-end beneath the engine = mount.

 

I = have a curved deflector on the oil cooler to help the air make the turn up and = through the oil cooler.  I have = another one of those deflectors on the radiator about half way back.  =

 

Th= e downside to this design, is that it takes pressure to make the air turn, = and go up through the radiators.  = The NACA does not work well that way.

 

Wh= at I’m trying to do is augment the existing scoop, with a “bolt on” = scoop ahead of it, which will capture air outside of the boundary layer, i.e. high speed = air, to improve cooling.

 

I = made a scoop first, that while it worked somewhat, does not exclude the = boundary layer air.  Also it’s kind = of like a funnel, with the largest are at the opening and tapering down into the = existing scoop.

 

I = hope that makes some sense.

 

St= eve Brooks

 

-----Original Message-----
From: Rotary motors in = aircraft [mailto:flyrotary@lancaironline.net]On Behalf Of Joseph M Berki
Sent: Wednesday, July 14, = 2004 2:45 PM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Re: = New Scoop

 

Al,
        Do you = have any photos of your oil cooler install showing the airflow path?

Joe Berki
Limo EZ


At 10:57 AM 7/14/2004 -0700, Al Gietzen wrote:


Subject: [FlyRotary] New Scoop =

 

Steve;

 

There are all kinds of things = one could say about trying to make the scoop ideal, effective, low drag, etc; and = then when you face the reality of fitting to your plane, you can t do = it.  So it s what works for you.  I ll add a few comments for whatever it s = worth.

 

The intake area of the scoop = should be fine.

 

One would like to slow (expand) = and turn the air entering the scoop in a manner that maintains surface = attachment for max pressure recovery and minimum drag.  This takes a much = longer scoop throat than you have.  The air entering will trip to = turbulent at the abrupt corner behind the B.L dam.  This will result in poor = flow and pressure distribution, with most of the air going toward the back of the scoop.  I don t know what happens in your installation downstream = from the actual scoop, but you might consider some internal baffles but get a = more uniform distribution if the rad is close to the scoop.

 

The boundary layer dam that you = have is high drag, and may be close enough to the entrance lip that backup of = the B.L. flow will be ingested into the scoop or it could result in some external diffusion (pressure recovery) and allow the scoop to work just = fine.  The idea in the B.L. bleed is to try to divert that flow somewhere else, generally  off to the sides.  That would require a much more = gradual diverter angle.

 

I made a much more gradual bend = in the wall of my scoop (pic) attached.  Still, in doing flow tests, I = found flow separation and turbulence which lead uneven flow distribution.  I = added to baffles in the scoop get it fairly uniform.  It could be that some = of the turbulence was a result of the test rig setup, although I thought I had = a long enough duct from the blower to straighten things out.

 

The squared off internal corners = will add frictional drag, but probably not significant in overall = picture.

 

But, hey try it. If it gives you = the cooling you need, you ve got 90% of the battle won.  If you feel = you need to reduce drag, you can consider that at your leisure.

 

Al

 

 

Ed, and others -

 

Attached are some photos of the new scoop I'm building to = replace my old new

scoop.  As you can see the new one actually has less = intake area, but

extends further in order to get outside of the boundary = layer.

 

I don't want the intake any larger than it has to be, but I = want to make

sure also that it is sufficient to allow for enough air flow.  My old new

scoop did improve cooling, but as I found out, it was only marginal.

 

The new scoop, which is patterned after a P51 style scoop, = not only gets

outside of the boundary layer air, but also excludes it, = with the dam that

you see at the bottom.  Well, actually it will be at = the top, once it is

mounted under the belly.  It also gives me an = expansion area once inside the

scoop.

 

Using the program that Al sent me, the boundary area = calculated out to about

1.625-1.75 inches +/- depending on speed.

 

The scoop intake measures 10.75" inside at the top (narrowest) and 14.75" at

the widest point average =3D 12.75"

Height of the inside of the scoop measures 4.25"

This should equal about 54.18 sq in of area.

 

The inside of the scoop sits exactly 2" from the = bottom of the fuselage, and

overall height to the outside of the scoop is about 6.6"  again, measured

from the fuselage bottom.

 

I haven't glassed the scoop yet, other than on one side to = help with gluing

it together.

 

I am interested in any feedback concerning the size of the = intake area.

 

Regards,

 

Steve Brooks

Cozy MKIV N75CZ

Turbo Rotary




>>  Homepage:  http://www.flyrotary.com/
>>  Archive:   http://lancaironline.net/lists/flyrotary/List.html<= /p>

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