Return-Path: Received: from imf19aec.mail.bellsouth.net ([205.152.59.67] verified) by logan.com (CommuniGate Pro SMTP 4.3c1) with ESMTP id 742667 for flyrotary@lancaironline.net; Thu, 17 Feb 2005 08:34:49 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.67; envelope-from=sqpilot@bellsouth.net Received: from [209.214.45.56] by imf19aec.mail.bellsouth.net (InterMail vM.5.01.06.11 201-253-122-130-111-20040605) with ESMTP id <20050217133358.JWKK2048.imf19aec.mail.bellsouth.net@[209.214.45.56]> for ; Thu, 17 Feb 2005 08:33:58 -0500 Received: from 127.0.0.1 (AVG SMTP 7.0.300 [265.8.8]); Thu, 17 Feb 2005 07:33:21 -0600 Message-ID: <00e601c514f5$336be820$382dd6d1@paul52u7f5qyav> From: "Paul" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] 3" Duct Was: [FlyRotary] Re: I found the power Date: Thu, 17 Feb 2005 07:23:10 -0600 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 Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="=======AVGMAIL-42149D21242C=======" --=======AVGMAIL-42149D21242C======= Content-Type: multipart/alternative; boundary="----=_NextPart_000_00B8_01C514C1.88DCC2E0" ------=_NextPart_000_00B8_01C514C1.88DCC2E0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable As usual, you came through with the information I was looking for, Ed. = Thanks again....I will bring outside air to my throttlebody one way or = another. It is such a noticeable difference. It might be possible that = two things are coming into play here. Number one, of course is the = temperature difference of the air. The second is that the cowling is = fairly close to the intake of the throttlebody, and perhaps the volume = of air entering the throttlebody is being somewhat restricted. One = thing I do know for sure is that I need to bring in that outside air. = Paul Conner ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Wednesday, February 16, 2005 10:01 PM Subject: [FlyRotary] 3" Duct Was: [FlyRotary] Re: I found the power Paul, I use a 3" dia SCAT tube which undoubtedly causes some loss of = pressure, but much better than sucking in hot air from under the = cowling. I used to know a rule of thumb formula that told you how much = power you lost for each 10F temp rise, I think it was 1% power loss for = each 10F. If correct then with an OAT of say 60F , your under-the-cowl = air temp could easily be 120F. A 60 deg rise of temp =3D 6% loss in = power. So say you are making 162HP at 5600 on a 60F day. You put the = cowl on and the temps go to 120F, 6% of 162 =3D 9.72 HP loss or down to = 150.28HP. . =20 My spreadsheet shows that a 9.72 HP drop to 150.28HP would give you an = rpm of around 5150 - 5200. This sounds fairly consistent with what you = are seeing, I believe. With my cowl off my static might be 5300 rpm - with my cowling on with = SCAT attached to the throttle body I get at least 5600 rpm and perhaps = 5800 on a cooler day. So I think say 7-9 HP is too much to give up to = hot air. Duct that sucker. Ed A ----- Original Message -----=20 From: Paul=20 To: Rotary motors in aircraft=20 Sent: Wednesday, February 16, 2005 8:54 PM Subject: [FlyRotary] Re: I found the power Thanks, Ed....I think the results of my on-again-off-again cowl = experiments pretty well proved this. Do you think that SCAT or SCEET = tubing (the one with the wire reinforcement, whichever that one is) = would create too much drag on the incoming air? Paul Conner ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Wednesday, February 16, 2005 6:07 PM Subject: [FlyRotary] Re: I found the power Paul, If you are not routing outside air to your engine intake, you are = giving up power. The less dense, hot air underneath the cowling will = take 200-400 rpm away from your rotary. The NACA ducts should work well = for this application. Ed A ----- Original Message -----=20 From: Paul=20 To: Rotary motors in aircraft=20 Sent: Wednesday, February 16, 2005 6:26 PM Subject: [FlyRotary] I found the power Today I finished installing the firesleeve on the remaing fuel = lines, made some stand-offs so that the fuel lines would not be right up = against the engine, and finished hooking up and securing a few other = items. With the top cowling off, I ran the pumps for a minute, then = checked for leaks...none found. Then I started the engine and ran it = for 20 or so seconds and shut it down and reinspected for fuel leaks. = None found. I restarted and taxiied away from the hangar a bit so as to = not be as loud for others in and near the hangar and did a full power = runup. I hit 5600 static rpm's. In the past, the best I could hope for = was 5200, most of the time settling for 5100 rpm's. I taxiied back in = and installed the top cowling....max rpm's 5100. Took the top cowling = back off....max rpm's 5600. One more try....5100 with the cowling back = on. It is beginning to become more clear to me, that one of two things = are affecting rpm's. Option one is that with the top cowling on the = engine is ingesting heated air and just cannot develop the same power as = when it ingests outside unheated air. Option two is the muffler bearing = may be worn. I'm kinda leaning toward option one. I was thinking of installing two small NACA ducts on the = bottom of my cowling with two hoses coming up to feed air to my TWM = throttlebody. The NACA ducts I purchased from Van's RV (made for = cowling ventilation) already have a male outlet already molded in the = assembly, so you just slide a hose over it and secure with a clamp. Very = simple installation.(Works well for my cabin ventillation) If I recall = correctly, they are about the same size as my throttle body bore. I = wonder if I will loose much efficiency as the air goes through the = corregated hose, and if the Van's RV ventillation NACA ducts will = provide a sufficient volume of air. Of course while flying, I would have = the advantage of a little bit of ram effect as well as the ability to = suck in fresh outside air that has not been heated inside the cowling = during taxi/takeoff run. Any opinions/suggestions would of course be = much appreciated. I will discuss the vapor lock issue in the next post, = so as to not complicate responses, etc. Thanks to all who reply. Paul = Conner =20 ------------------------------------------------------------------------ No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 265.8.8 - Release Date: = 2/14/2005 ------------------------------------------------------------------------ >> Homepage: http://www.flyrotary.com/ >> Archive: = http://lancaironline.net/lists/flyrotary/List.html -------------------------------------------------------------------------= - No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 265.8.8 - Release Date: = 2/14/2005 -------------------------------------------------------------------------= --- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 265.8.8 - Release Date: 2/14/2005 -------------------------------------------------------------------------= --- >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html -------------------------------------------------------------------------= ----- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 265.8.8 - Release Date: 2/14/2005 ------=_NextPart_000_00B8_01C514C1.88DCC2E0 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
As usual, you came through with the = information I=20 was looking for, Ed.   Thanks again....I will bring outside = air to my=20 throttlebody one way or another.  It is such a noticeable = difference. =20 It might be possible that two things are coming into play here.  = Number=20 one, of course is the temperature difference of the air. The second is = that the=20 cowling is fairly close to the intake of the throttlebody, and perhaps = the=20 volume of air entering the throttlebody is being somewhat = restricted.  One=20 thing I do know for sure is that I need to bring in that outside = air.  Paul=20 Conner
----- Original Message -----
From:=20 Ed=20 Anderson
Sent: Wednesday, February 16, = 2005 10:01=20 PM
Subject: [FlyRotary] 3" Duct = Was:=20 [FlyRotary] Re: I found the power

Paul, I use a 3" dia SCAT tube which = undoubtedly=20 causes some loss of pressure, but much better than sucking in hot air = from=20 under the cowling.  I used to know a rule of thumb formula that = told you=20 how much power you lost for each 10F temp rise, I think it was 1% = power loss=20 for each 10F.  If correct then with an OAT of say 60F , your = under-the-cowl air temp could easily be 120F.  A 60 deg rise of=20 temp =3D  6% loss in power.  So say you are making = 162HP at 5600=20 on a 60F day.  You put the cowl on and the temps go to 120F, 6% = of 162 =3D=20 9.72 HP loss or down to 150.28HP.
 
. 
 
My spreadsheet shows that a 9.72 HP = drop to=20 150.28HP would give you an rpm of  around 5150 - 5200. This = sounds fairly=20 consistent with what you are seeing, I believe.
 
With my cowl off my static might be = 5300 rpm=20 - with my cowling on with SCAT attached to the throttle body I = get at=20 least 5600 rpm and perhaps 5800 on a cooler day. So I think say 7-9 HP = is too=20 much to give up to hot air.  Duct that sucker.
 
Ed A
----- Original Message -----
From:=20 Paul=20
To: Rotary motors in = aircraft=20
Sent: Wednesday, February 16, = 2005 8:54=20 PM
Subject: [FlyRotary] Re: I = found the=20 power

Thanks, Ed....I think the results = of my=20 on-again-off-again cowl experiments pretty well proved this.  = Do you=20 think that SCAT or SCEET tubing (the one with the wire = reinforcement,=20 whichever that one is) would create too much drag on the incoming = air? =20 Paul Conner
----- Original Message ----- =
From:=20 Ed Anderson
To: Rotary motors in = aircraft=20
Sent: Wednesday, February = 16, 2005=20 6:07 PM
Subject: [FlyRotary] Re: I = found the=20 power

Paul,
 
If you are not routing outside = air to your=20 engine intake, you are giving up power.  The less dense, hot = air=20 underneath the cowling will take 200-400 rpm away from your = rotary. =20 The NACA ducts should work well for this application.
 
Ed A
----- Original Message ----- =
From:=20 Paul
To: Rotary motors in = aircraft=20
Sent: Wednesday, February = 16, 2005=20 6:26 PM
Subject: [FlyRotary] I = found the=20 power

Today I finished installing the = firesleeve=20 on the remaing fuel lines, made some stand-offs so that the fuel = lines=20 would not be right up against the engine, and finished hooking = up and=20 securing a few other items. With the top cowling off, =  I ran=20 the pumps for a minute, then checked for leaks...none = found.  Then=20 I started the engine and ran it for 20 or so seconds and shut it = down=20 and reinspected for fuel leaks. None found.  I restarted = and=20 taxiied away from the hangar a bit so as to not be as loud for = others in=20 and near the hangar and did a full power runup.  I hit 5600 = static=20 rpm's. In the past, the best I could hope for was 5200, most of = the time=20 settling for 5100 rpm's.  I taxiied back in and installed = the top=20 cowling....max rpm's 5100.  Took the top cowling back = off....max=20 rpm's 5600.  One more try....5100 with the cowling back = on. =20 It is beginning to become more clear to me, that one of two = things are=20 affecting rpm's.  Option one is that with the top cowling = on the=20 engine is ingesting heated air and just cannot develop the same = power as=20 when it ingests outside unheated air.  Option two is the = muffler=20 bearing may be worn.  I'm kinda leaning toward option=20 one.
     I was = thinking of=20 installing two small NACA ducts on the bottom of my cowling with = two=20 hoses coming up to feed air to my TWM throttlebody.  The = NACA ducts=20 I purchased from Van's RV (made for cowling ventilation) already = have a=20 male outlet already molded in the assembly, so you just slide a = hose=20 over it and secure with a clamp. Very simple installation.(Works = well=20 for my cabin ventillation) If I recall correctly, they are = about=20 the same size as my throttle body bore. I wonder if I will loose = much=20 efficiency as the air goes through the corregated hose, and if = the Van's=20 RV ventillation NACA ducts will provide a sufficient volume of = air. Of=20 course while flying, I would have the advantage of a little bit = of ram=20 effect as well as the ability to suck in fresh outside air that = has not=20 been heated inside the cowling during taxi/takeoff run.  = Any=20 opinions/suggestions would of course be much appreciated.  = I will=20 discuss the vapor lock issue in the next post, so as to not = complicate=20 responses, etc.  Thanks to all who reply.  Paul=20 Conner
    =

No virus found in this outgoing message.
Checked by = AVG=20 Anti-Virus.
Version: 7.0.300 / Virus Database: 265.8.8 - = Release=20 Date: 2/14/2005

>>  Homepage: =20 http://www.flyrotary.com/
>>  Archive:   = = http://lancaironline.net/lists/flyrotary/List.html

No virus found in this incoming message.
Checked by AVG=20 Anti-Virus.
Version: 7.0.300 / Virus Database: 265.8.8 - = Release Date:=20 2/14/2005

No virus found in this outgoing message.
Checked by AVG=20 Anti-Virus.
Version: 7.0.300 / Virus Database: 265.8.8 - Release = Date:=20 2/14/2005

>>  Homepage: =20 http://www.flyrotary.com/
>>  Archive:  =20 http://lancaironline.net/lists/flyrotary/List.html

No virus found in this incoming message.
Checked by AVG=20 Anti-Virus.
Version: 7.0.300 / Virus Database: 265.8.8 - Release = Date:=20 2/14/2005
------=_NextPart_000_00B8_01C514C1.88DCC2E0-- --=======AVGMAIL-42149D21242C======= Content-Type: text/plain; x-avg=cert; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Content-Description: "AVG certification" No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 265.8.8 - Release Date: 2/14/2005 --=======AVGMAIL-42149D21242C=======--