X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mtiwmhc13.worldnet.att.net ([204.127.131.117] verified) by logan.com (CommuniGate Pro SMTP 5.0.3) with ESMTP id 873049 for flyrotary@lancaironline.net; Mon, 12 Dec 2005 18:49:09 -0500 Received-SPF: none receiver=logan.com; client-ip=204.127.131.117; envelope-from=keltro@att.net Received: from 204.127.135.59 ([204.127.135.59]) by worldnet.att.net (mtiwmhc13) with SMTP id <2005121223471111300rulcpe>; Mon, 12 Dec 2005 23:47:11 +0000 Received: from [64.136.27.229] by 204.127.135.59; Mon, 12 Dec 2005 23:47:11 +0000 From: keltro@att.net (Kelly Troyer) To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Spiral Flow Muffler Insert Test Results Date: Mon, 12 Dec 2005 23:47:11 +0000 Message-Id: <121220052347.3842.439E0BFE00068F0A00000F022160280651019D9B040A05@att.net> X-Mailer: AT&T Message Center Version 1 (Nov 10 2005) X-Authenticated-Sender: a2VsdHJvQGF0dC5uZXQ= MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="NextPart_Webmail_9m3u9jl4l_3842_1134431231_0" --NextPart_Webmail_9m3u9jl4l_3842_1134431231_0 Content-Type: text/plain Content-Transfer-Encoding: 8bit Very interesting Mark !!! Have any photos of A/C , Engine installation , Exhaust , Etc that you would like to share with us ?? -- Kelly Troyer Dyke Delta/13B/RD1C/EC2 -------------- Original message from "Mark R Steitle" : -------------- Well, I ran my 20B on Saturday, with and without the spiral-flow muffler insert, and took some sound measurements. It looks like its good for about a 14db reduction at 3-4000 rpm. Keep in mind that the a/c was positioned between two rows of hangars and since I have a prop now, a good part of the db numbers represent prop noise. Measurements were taken at the front, rear, and at the wing tips, which is about 16’ from the exhaust for the left wing and 18’ for the right wing. Never the less, I am pleased with the results. After we finished the initial runs, I removed the insert and inspected it for damage… there was none. I have 10 hours of easy running on it at this point. The real test is yet to come. Test data below… Mark S. R Wing RPMSMode AMode CMuffler Insert 12008190Y 16008493Y 400097102Y Front RPMSMode AMode CMuffler Insert 12008092Y 16008394Y 300096100Y 4000100100Y 16009490N 4000111114N Left Wing RPMSMode AMode CMuffler Insert 12008292Y 16008393Y 300090102Y 400096104Y 4000111114N Rear RPMSMode AMode CMuffler Insert 12008293Y 160083104Y 300096112Y --NextPart_Webmail_9m3u9jl4l_3842_1134431231_0 Content-Type: text/html Content-Transfer-Encoding: 8bit

Very interesting Mark !!! Have any photos of A/C , Engine installation , Exhaust , Etc

that you would like to share with us ??

--
Kelly Troyer
Dyke Delta/13B/RD1C/EC2

-------------- Original message from "Mark R Steitle" <mark.steitle@austin.utexas.edu>: --------------

Well, I ran my 20B on Saturday, with and without the spiral-flow muffler insert, and took some sound measurements. It looks like its good for about a 14db reduction at 3-4000 rpm. Keep in mind that the a/c was positioned between two rows of hangars and since I have a prop now, a good part of the db numbers represent prop noise. Measurements were taken at the front, rear, and at the wing tips, which is about 16’ from the exhaust for the left wing and 18’ for the right wing. Never the less, I am pleased with the results. After we finished the initial runs, I removed the insert and inspected it for damage… there was none. I have 10 hours of easy running on it at this point. The real test is yet to come.

Test data below…

Mark S.

R Wing

RPMS

Mode A

Mode C

Muffler Insert

1200

81

90

Y

1600

84

93

Y

4000

97

102

Y

Front

RPMS

Mode A

Mode C

Muffler Insert

1200

80

92

Y

1600

83

94

Y

3000

96

100

Y

4000

100

100

Y

1600

94

90

N

4000

111

114

N

Left Wing

RPMS

Mode A

Mode C

Muffler Insert

1200

82

92

Y

1600

83

93

Y

3000

90

102

Y

4000

96

104

Y

4000

111

114

N

Rear

RPMS

Mode A

Mode C

Muffler Insert

1200

82

93

Y

1600

83

104

Y

3000

96

112

Y

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