X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao102.cox.net ([68.230.241.44] verified) by logan.com (CommuniGate Pro SMTP 5.2.11) with ESMTP id 3431137 for flyrotary@lancaironline.net; Sat, 17 Jan 2009 11:13:46 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.44; envelope-from=rv-4mike@cox.net Received: from fed1rmimpo02.cox.net ([70.169.32.72]) by fed1rmmtao102.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20090117161303.IJIA2342.fed1rmmtao102.cox.net@fed1rmimpo02.cox.net> for ; Sat, 17 Jan 2009 11:13:03 -0500 Received: from wills ([68.105.85.56]) by fed1rmimpo02.cox.net with bizsmtp id 4gD11b0091CvZmk04gD3PZ; Sat, 17 Jan 2009 11:13:03 -0500 X-Authority-Analysis: v=1.0 c=1 a=7g1VtSJxAAAA:8 a=Ia-xEzejAAAA:8 a=kvzIWNLi2Sb0USUeOhkA:9 a=BrtPqKIm8s3L84mSbO0A:7 a=gyTHIXnMI3ZWQDQM6IWGZmkpCT4A:4 a=nbrB6oW77rQA:10 a=vnAcdZkGXceFn3P4MicA:9 a=2y83Ee6OOn5u1gllIFgA:7 a=7FkuSt5JTri7uu8UcizuIkEKSaQA:4 a=EzXvWhQp4_cA:10 a=AfD3MYMu9mQA:10 X-CM-Score: 0.00 Message-ID: <003901c978be$77f23090$38556944@wills> From: "Mike Wills" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] another Muffler Date: Sat, 17 Jan 2009 08:13:00 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0036_01C9787B.69805B60" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3350 This is a multi-part message in MIME format. ------=_NextPart_000_0036_01C9787B.69805B60 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Quite the opposite Steve. I think the 3 Kt loss and looks (it actually = looks better than most) is a fair price to payfor a relatively light, = easy to construct muffler that works. My current "muffler" isnt a lot = smaller and weighs about the same. Questions: 1) Overall length? 2) Source for the dome and cone used in the construction? Thanks, Mike Wills N144MW ----- Original Message -----=20 From: sboese=20 To: Rotary motors in aircraft=20 Sent: Friday, January 16, 2009 9:57 AM Subject: [FlyRotary] another Muffler The following muffler description is provided purely as another data = point in the muffler discussion. I would suspect that not many of you = would be interested in it due to its large size and external mounting. = I have had good service from it so far and it fits somewhat into my = loosely interpreted Navy F6F Hellcat inverted paint scheme as a bomb. The materials of construction are 0.032" thick 304 SS and the design = is based on data in NACA Report 1192. The weight is 9.6 lb and the = diameter is 6.25 inches. A SS heat shield is also installed between the = muffler and the fuselage belly. I have about 100 hours on this = installation with no signs of deterioration of the muffler. The engine = is NA with exhaust splitters and is operated normally at density = altitudes above 7000 ft which limits max power, although several hours = of max power operation at DA lower than 5000 ft have not damaged this = muffler so far. I have been told that from the ground, the primary source of noise for = my plane is the propeller. I have landed with a C172 following me in = the pattern and observers told me that they did not know I was there = until I taxied in since they only heard the C172. I have no = quantitative data on the noise characteristics of my muffler system. = Inside the cockpit, the noise level goes from reasonable to unbearable = if the muffler is removed. This is purely subjective, of course. =20 Not shown in the "muffler parts" image are three 1" x 1" angles made = from the same material as the shell that connect the rear of the = internal center tube to the front of the rear cone section. The round = flange in the center of the internal tube is a push fit in the shell and = is not fastened directly to the shell. A down turn also has been added = to the outlet of the rear cone section. From data in the "muffler test chart" image, the speed penalty of the = muffler is about 3 kt. The "muffler in flight" photo may be of interest in that it shows the = heat distribution in the muffler with the dark areas being hotter. This = image is not current since the lower cowling has been modified and the = engine cooling air outlet is now much smaller than shown in this photo. Steve Boese RV6A, 1986 13B NA, EC2, RD1A=20 -------------------------------------------------------------------------= ----- -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html ------=_NextPart_000_0036_01C9787B.69805B60 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Quite the opposite Steve. I think the 3 = Kt loss and=20 looks (it actually looks better than most) is a fair price to payfor a=20 relatively light, easy to construct muffler that works. My current=20 "muffler" isnt a lot smaller and weighs about the same.
 
Questions:
 
1) Overall length?
2) Source for the dome and cone used in = the=20 construction?
 
Thanks,
 
Mike Wills
N144MW
----- Original Message -----
From:=20 sboese =
Sent: Friday, January 16, 2009 = 9:57=20 AM
Subject: [FlyRotary] another=20 Muffler

 

The = following muffler=20 description is provided purely as another data point in the muffler=20 discussion.  I would suspect that not many of you would be = interested in=20 it due to its large size and external mounting.  I have had good = service=20 from it so far and it fits somewhat into my loosely interpreted Navy = F6F=20 Hellcat inverted paint scheme as a bomb.

 

The = materials of=20 construction are 0.032=94 thick 304 SS and the design is based on data = in NACA=20 Report 1192.  The weight is 9.6 lb and the diameter is 6.25 = inches. =20 A SS heat shield is also installed between the muffler and the = fuselage=20 belly.  I have about 100 hours on this installation with no signs = of=20 deterioration of the muffler.  The engine is NA with exhaust = splitters=20 and is operated normally at density altitudes above 7000 ft which = limits max=20 power, although several hours of max power operation at DA lower than = 5000 ft=20 have not damaged this muffler so far.

 

I have been = told that=20 from the ground, the primary source of noise for my plane is the=20 propeller.  I have landed with a C172 following me in the pattern = and=20 observers told me that they did not know I was there until I taxied in = since=20 they only heard the C172.  I have no quantitative data on the = noise=20 characteristics of my muffler system.  Inside the cockpit, the = noise=20 level goes from reasonable to unbearable if the muffler is = removed.  This=20 is purely subjective, of course. 

 

Not shown = in the=20 =93muffler parts=94 image are three 1=94 x 1=94 angles made from the = same material as=20 the shell that connect the rear of the internal center tube to the = front of=20 the rear cone section.  The round flange in the center of the = internal=20 tube is a push fit in the shell and is not fastened directly to the=20 shell.  A down turn also has been added to the outlet of the rear = cone=20 section.

 

From data = in the=20 =93muffler test chart=94 image, the speed penalty of the muffler is = about 3=20 kt.

 

The = =93muffler in=20 flight=94 photo may be of interest in that it shows the heat = distribution in the=20 muffler with the dark areas being hotter.  This image is not = current=20 since the lower cowling has been modified and the engine cooling air = outlet is=20 now much smaller than shown in this photo.

 

Steve Boese

RV6A, 1986 13B NA, EC2, = RD1A=20

--
Homepage:  http://www.flyrotary.com/
Archive and=20 UnSub:  =20 = http://mail.lancaironline.net:81/lists/flyrotary/List.html
------=_NextPart_000_0036_01C9787B.69805B60--