Return-Path: Received: from [24.25.9.102] (HELO ms-smtp-03-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.2b5) with ESMTP id 150250 for flyrotary@lancaironline.net; Sat, 12 Jun 2004 18:06:19 -0400 Received: from EDWARD (clt25-78-058.carolina.rr.com [24.25.78.58]) by ms-smtp-03-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id i5CM5kLr002280 for ; Sat, 12 Jun 2004 18:05:48 -0400 (EDT) Message-ID: <000a01c450c9$6df81540$2402a8c0@EDWARD> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: New Truncated Streamline Ducts Date: Sat, 12 Jun 2004 18:05:53 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0007_01C450A7.E6AD3CD0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1409 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0007_01C450A7.E6AD3CD0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Saturday, June 12, 2004 7:39 AM Subject: [FlyRotary] New Truncated Streamline Ducts Here are a few photos of my new radiator ducts modeled along the = Streamline Duct profile. The Right radiator duct inlet has been reduced = from 24 sq inch to 14 sq inch and the left one from 24 to 10 sq inches. = Both use a "truncated" version of the Streamline Duct profile described = in K&W Section 12. =20 SNIP The flared entrances are not part of the streamline duct. They are = simply to smooth the airflow from the cowl duct opening to the actual = duct inlet. This could in effect result in more air moving into the = inlet than my previous ducts which had an approx 1/2 -3/4" blunt lip = around the entrance. Also, it may provide more inlet velocity (Bernoulli = effect) which in turn may provide more energy conversion to pressure = increase inside the duct - just speculation. But, at a minimum, the = smoothed transition should produce less drag than the previous blunt = duct entrance. On the other hand, the flares could act like an external = diffuser and slow the air before the entrance. Just too many factors to = analytically account for them and their interactions. I have kept the old ducts and will put them back on when I get some = instrumentation hooked up so we can do a side by side comparison. Best Regards Ed Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC Geeze, Ed..... those look too good to hide underneath a = cowling.....Very nice work. Paul Conner =20 Thanks, Paul, But, you should have seen the first pair I made. I tried using 3 = lb cloth as I thought it would hug the compound curves best. A big = mistake, the cloth was unmanagable once wet. When dry it just wasn't = strong enough. But, then I tried using 4 mil plastic to do the = sandwich job and found that it was too heavy, should have used the 1-2 = mil as advised. . About the only thing I did right was to buy one of those disk = (Pizza type) cutters. Boy, did they make the job easier, I had been = using shears and once my gloves got resin on them trying to cut cloth = was - lets say not my idea of fun. I ended up using 8 lb cloth and it = layed up well. Still have problems on corners {:>). Ed Anderson=20 ------=_NextPart_000_0007_01C450A7.E6AD3CD0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Message -----

From:=20 Ed Anderson
To: Rotary motors in = aircraft=20

Sent: Saturday, June 12, 2004 = 7:39=20 AM

Subject: [FlyRotary] New = Truncated=20 Streamline Ducts

Here are a few photos of my new = radiator ducts=20 modeled along the Streamline Duct profile. The Right radiator = duct=20 inlet has been reduced from 24 sq inch to 14 sq inch and the left = one from=20 24 to 10 sq inches. Both use a "truncated" version of the = Streamline=20 Duct profile described in K&W Section 12.

SNIP

The flared entrances are not part = of the=20 streamline duct. They are simply to smooth the airflow from = the cowl=20 duct opening to the actual duct inlet. This could in effect = result in=20 more air moving into the inlet than my previous ducts which had an = approx=20 1/2 -3/4" blunt lip around the entrance. Also, it may provide more = inlet=20 velocity (Bernoulli effect) which in turn may provide more energy = conversion=20 to pressure increase inside the duct - just speculation. But, = at a=20 minimum, the smoothed transition should produce less drag than=20 the previous blunt duct entrance. On the other hand, = the=20 flares could act like an external diffuser and slow the air before = the=20 entrance. Just too many factors to analytically account for = them and=20 their interactions.

I have kept the old ducts and = will put=20 them back on when I get some instrumentation hooked up so we can do = a side=20 by side comparison.

Best Regards

Ed

Ed Anderson
RV-6A N494BW Rotary=20 Powered
Matthews, NC

Geeze, Ed..... those look too good = to hide=20 underneath a cowling.....Very nice work. Paul Conner =20

Thanks, Paul,

But, you should = have seen=20 the first pair I made. I tried using 3 lb cloth as I thought it = would hug=20 the compound curves best. A big mistake, the cloth was = unmanagable=20 once wet. When dry it just wasn't strong enough. = But, then=20 I tried using 4 mil plastic to do the sandwich job and found that it = was too=20 heavy, should have used the 1-2 mil as advised.

. About the only thing I did = right was to=20 buy one of those disk (Pizza type) cutters. Boy, did they make = the job=20 easier, I had been using shears and once my gloves got resin on them = trying=20 to cut cloth was - lets say not my idea of fun. I ended up = using 8 lb=20 cloth and it layed up well. Still have problems on corners=20 {:>).

Ed Anderson

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