X-Virus-Scanned: clean according to Sophos on Logan.com X-PolluStop-Diagnostic: (direct reply)\eX-PolluStop-Score: 0.00\eX-PolluStop: Scanned with Niversoft PolluStop 2.1 RC1, http://www.niversoft.com/pollustop Return-Path: Received: from imf19aec.mail.bellsouth.net ([205.152.59.67] verified) by logan.com (CommuniGate Pro SMTP 4.3c4) with ESMTP id 866056 for flyrotary@lancaironline.net; Tue, 12 Apr 2005 10:18:49 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.67; envelope-from=sqpilot@bellsouth.net Received: from paul52u7f5qyav ([209.214.45.191]) by imf19aec.mail.bellsouth.net (InterMail vM.5.01.06.11 201-253-122-130-111-20040605) with SMTP id <20050412141801.FGQT2054.imf19aec.mail.bellsouth.net@paul52u7f5qyav> for ; Tue, 12 Apr 2005 10:18:01 -0400 Message-ID: <018801c53f6a$483a22e0$1d2dd6d1@paul52u7f5qyav> From: "Paul" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: SQ2000 flying again Date: Tue, 12 Apr 2005 09:15:06 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0185_01C53F40.1E305CF0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0185_01C53F40.1E305CF0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi, Bill...thank you very much for taking the time to go into such = detail regarding the cowling pressurization/ram air scoop scenario. I = hadn't thought of putting a piece of aluminum under the ram air scoop = with a 3 inch tubing plumbed directly to the throttlebody. The only = drawback there is that due to the location of the ram air scoop, the = hose would have to be a very tight "S" configuration and more difficult = to hook up the hose because it is on the top cowling, which is the last = cowling to be installed. By using this NACA duct on the bottom cowling, = I can install the bottom cowling, attach the hose, then simply install = the top cowling without any hoses to try to align or secure, etc. It = will definately be easier installing/removing cowlings with the lower = NACA scoop versus the ram air scoop on the top cowling. It's funny that = you mentioned that there might be some airspeed where no air would enter = the cowling through the radiator. It seemed that as the plane picked up = speed (at the same throttle setting), my temps were rising. Must be my = imagination, I thought. Maybe not. Temps did, however come back down = as I turned base and final, but I'm sure that was because I was at idle = and therefore producing less heat through horsepower. Oh, = well....another lesson learned. Fortunately it was only fiberglassing = labor lost....no damage or injuries. (except maybe to my ego). Because = my cooling was so great prior to the addition of the ram air scoop, I'm = fairly confident that the removal of the scoop and bringing in air = directly to the throttlebody will give me the cool air intake I need = without inhibiting my cooling airflow. Take care, and thanks again for = your valued input. Paul Conner, waiting on NACA duct from UPS.=20 ----- Original Message -----=20 From: WRJJRS@aol.com=20 To: Rotary motors in aircraft=20 Sent: Tuesday, April 12, 2005 12:15 AM Subject: [FlyRotary] Re: SQ2000 flying again In a message dated 4/11/2005 6:49:04 PM Pacific Standard Time, = sqpilot@bellsouth.net writes: Thanks, Tracy....I should be able to find out in a few days. Today I = removed the ram air scoop and fabricated an intake plenum for the 3 inch = scat tubing. As soon as the NACA duct with the 3 inch outlet arrives, I = will install it and be ready for testing. Today I measured the length of = the scat tube that I will need....14 inches. Thanks again for sharing = your experiences. Paul Conner Paul,=20 It is interesting that as you have noted your problem, there was on = the other list comment made about exactly the same phenomenon you are = experiencing. You have found the relationship between the effectiveness = of the cowl outlet, and inlets. The rules of thumb that have been = discussed on the list recently apply to pushers as well. You have some = advantages, extraction assisted by the prop usually, and some = disadvantages, often turbulent air near inlets often making flow paths = difficult to predict. Ask Perry Mick to remind us of the oil cooler = troubles he had.=20 The real problem Paul is that when used without a sealed tube to the = throttle body your ram air scoop pressurizes the cowl. The fact that you = are seeing higher temps isn't so much a supprize, rather it's expected. = The better your "ram air" scoop works the worse your problem. The = pressure increase does help the engine make more power. That heats up = your coolant and the increase in pressure inside the cowl makes it = harder to get air through the radiator, making the engine run hotter. = There is probably a point if you could reach a high enough speed that = the pressure could prevent ANY air from going through the radiator! The = fixes are to re-plumb the scoop as you are doing, or to enlarge the exit = area to prevent pressure build up. Since enlarging the exit may be = impractical, you should fix the problem by replumbing as you are doing. = It is a shame that you can't keep the other scoop easily. The type of = problems you are having would seem to indicate that it is working well! = I've been away for a while and couldn't comment, but my suggestion would = have been to put a sheet of aluminum under the scoop with a 3" exit tube = near the rear plumbed directly into the TB. You would probably see a HP = increase at cruise. The NACA duct will probably solve the problem but = you will lose some of the ram effect you could recover with the other = scoop. Should be less drag though. Hang in there Paul. Bill Jepson -------------------------------------------------------------------------= ----- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.9.6 - Release Date: 4/11/2005 ------=_NextPart_000_0185_01C53F40.1E305CF0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi, Bill...thank you very much for taking the time to go into such = detail=20 regarding the cowling pressurization/ram air scoop scenario.  I = hadn't=20 thought of putting a piece of aluminum under the ram air scoop with a 3 = inch=20 tubing plumbed directly to the throttlebody. The only drawback there is = that due=20 to the location of the ram air scoop, the hose would have to be a very = tight "S"=20 configuration and more difficult to hook up the hose because it is on = the top=20 cowling, which is the last cowling to be installed. By using this NACA = duct on=20 the bottom cowling, I can install the bottom cowling, attach the hose, = then=20 simply install the top cowling without any hoses to try to align or = secure,=20 etc.  It will definately be easier installing/removing cowlings = with the=20 lower NACA scoop versus the ram air scoop on the top cowling.  It's = funny=20 that you mentioned that there might be some airspeed where no air would = enter=20 the cowling through the radiator. It seemed that as the plane picked up = speed=20 (at the same throttle setting), my temps were rising. Must be my = imagination, I=20 thought.  Maybe not.   Temps did, however come back down = as I=20 turned base and final, but I'm sure that was because I was at idle and = therefore=20 producing less heat through horsepower.  Oh, well....another lesson = learned. Fortunately it was only fiberglassing labor lost....no damage = or=20 injuries. (except maybe to my ego). Because my cooling was so great = prior to the=20 addition of the ram air scoop, I'm fairly confident that the removal of = the=20 scoop and bringing in air directly to the throttlebody will give me the = cool air=20 intake I need without inhibiting my cooling airflow.  Take care, = and thanks=20 again for your valued input.  Paul Conner, waiting on NACA duct = from UPS.=20
 
----- Original Message -----
From:=20 WRJJRS@aol.com
Sent: Tuesday, April 12, 2005 = 12:15=20 AM
Subject: [FlyRotary] Re: SQ2000 = flying=20 again

In a message dated 4/11/2005 6:49:04 PM Pacific Standard Time, sqpilot@bellsouth.net = writes:
Thanks, Tracy....I should be able to find = out in a few=20 days. Today I removed the ram air scoop and fabricated an intake = plenum for=20 the 3 inch scat tubing. As soon as the NACA duct with the 3 inch = outlet=20 arrives, I will install it and be ready for testing. Today I = measured the=20 length of the scat tube that I will need....14 inches.  Thanks = again=20 for sharing your experiences.  Paul Conner
 
Paul,
 It is interesting that as you have noted your problem, = there was on=20 the other list comment made about exactly the same phenomenon you = are=20 experiencing. You have found the relationship between the = effectiveness of the=20 cowl outlet, and inlets. The rules of thumb that have been discussed = on the=20 list recently apply to pushers as well. You have some advantages, = extraction=20 assisted by the prop usually, and some disadvantages, often turbulent = air near=20 inlets often making flow paths difficult to predict. Ask Perry Mick to = remind=20 us of the oil cooler troubles he had.
 The real problem Paul is that when used without a sealed = tube to=20 the throttle body your ram air scoop pressurizes the cowl. The fact = that you=20 are seeing higher temps isn't so much a supprize, rather=20 it's expected. The better your "ram air" scoop works the worse = your=20 problem. The pressure increase does help the engine make more power. = That=20 heats up your coolant and the increase in pressure inside the cowl = makes it=20 harder to get air through the radiator, making the engine run hotter. = There is=20 probably a point if you could reach a high enough speed that the = pressure=20 could prevent ANY air from going through the radiator! The fixes = are to=20 re-plumb the scoop as you are doing, or to enlarge the exit area to = prevent=20 pressure build up. Since enlarging the exit may be impractical, you = should fix=20 the problem by replumbing as you are doing.  It is a shame that = you can't=20 keep the other scoop easily. The type of problems you are having would = seem to=20 indicate that it is working well! I've been away for a while and = couldn't=20 comment, but my suggestion would have been to put a sheet of aluminum = under=20 the scoop with a 3" exit tube near the rear plumbed directly into = the TB.=20 You would probably see a HP increase at cruise. The NACA = duct will=20 probably solve the problem but you will lose some of the ram = effect you=20 could recover with the other scoop. Should be less drag though. Hang = in there=20 Paul.
Bill Jepson

No virus found in this incoming message.
Checked by AVG=20 Anti-Virus.
Version: 7.0.308 / Virus Database: 266.9.6 - Release = Date:=20 4/11/2005
------=_NextPart_000_0185_01C53F40.1E305CF0--