Return-Path: Received: from [65.54.169.95] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 3050066 for flyrotary@lancaironline.net; Sat, 28 Feb 2004 17:29:24 -0500 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Sat, 28 Feb 2004 14:29:23 -0800 Received: from 67.243.77.205 by bay3-dav65.bay3.hotmail.com with DAV; Sat, 28 Feb 2004 22:29:23 +0000 X-Originating-IP: [67.243.77.205] X-Originating-Email: [kerrjb@msn.com] X-Sender: kerrjb@msn.com From: "WALTER KERR" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: FW: [VAF Mailing List] Engine Choice (windmilling drag) Date: Sat, 28 Feb 2004 17:29:50 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0036_01C3FE20.78DF1400" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 8.5 X-MimeOLE: Produced By MSN MimeOLE V8.50.0017.1202 Seal-Send-Time: Sat, 28 Feb 2004 17:29:51 -0500 Message-ID: X-OriginalArrivalTime: 28 Feb 2004 22:29:23.0992 (UTC) FILETIME=[51344180:01C3FE4A] This is a multi-part message in MIME format. ------=_NextPart_000_0036_01C3FE20.78DF1400 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Dale, Did the 123's windmilling engine have the blades at flat pitch? I did engine off testing in my RV6A 160 lyc with 80 inch pitch metal = sensenich prop. The glide slope was not measured to be any difference = whether I windmilled the prop at best L/D speed or whether I pulled up = slowed enough to stop the prop turning and then returned to same speed. Bernie Kerr, 6A sold, 9A rotary getting close ----- Original Message -----=20 From: Dale Smith=20 To: Rotary motors in aircraft=20 Sent: Saturday, February 28, 2004 12:45 PM Subject: [FlyRotary] Re: FW: [VAF Mailing List] Engine Choice Jim Sower wrote: Yeah. Also, I believe Tracy has answered all of his "questions" = around tortionals and props and dynos. Additionally, if there were = problems, Tracy would have encountered one in 1500 hrs.=20 The guy's statement around "... sprag clutches cause the prop to = freewheel in the event of engine failure putting the equivalent of a = barn door (HUGE drag compared to stopped prop) behind the airplane ..." = is so preposterous that it calls ALL of his other engineering into = question. =20 Not so fast, Jim .... A widmilling prop DOES have hugh drag compared to a stopped one. An = unfeatherable, windmilling prop almost had me swimming in the Pacific = Ocean near Wake Island many years ago. The fact that the engine seized = when a piston could no longer reciprocate inside a missing cylinder = ..was what saved my bacon. Once it stopped, even though the props' = blade angle was nowhere near feathered, the drag reduction was so = dramatic that we were able to level off from a forced descent and keep = the ship (a C-123B) in the air long enough to make it to destination on = the other engine. When you think windmilling drag ... think prop circle area, not just = the blades cross section themselves. Square yards of drag, not square = ft. His article sounds authoritative, but has all the intellectual = allure of Lamar's rantings that NACA ducts and Electric Water Pumps "... = cannot possibly work ...". Stick with Tracy. He has something flying. = This guy has nada. I tend to like Tracy's solution also. His hours in the air give him a = lot of credibility. Just a theory .... Jim S.=20 David Leonard wrote: Dale Smith ------=_NextPart_000_0036_01C3FE20.78DF1400 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Hi Dale,

Did the 123's windmilling engine have the blades at flat = pitch?

I did engine off testing in my RV6A 160 lyc with 80 inch pitch = metal=20 sensenich prop. The glide slope was not measured to be any difference = whether I=20 windmilled the prop at best L/D speed or whether I pulled up slowed = enough to=20 stop the prop turning and then returned to same speed.

Bernie Kerr, 6A sold, 9A rotary getting close

----- Original Message -----

From: Dale Smith

To: Rotary motors in = aircraft

Sent: Saturday, February 28, = 2004 12:45=20 PM

Subject: [FlyRotary] Re: FW: = [VAF Mailing=20 List] Engine Choice

Jim Sower wrote:

Yeah. = Also, I=20 believe Tracy has answered all of his "questions" around tortionals = and=20 props and dynos. Additionally, if there were problems, Tracy = would=20 have encountered one in 1500 hrs.=20
The guy's statement around "... sprag clutches cause the prop to=20 freewheel in the event of engine failure putting the equivalent of a = barn=20 door (HUGE drag compared to stopped prop) behind the airplane ..." = is so=20 preposterous that it calls ALL of his other engineering into = question. =20

Not so fast, Jim ....

A widmilling prop DOES = have hugh=20 drag compared to a stopped one. An unfeatherable, windmilling = prop=20 almost had me swimming in the Pacific Ocean near Wake Island many = years=20 ago. The fact that the engine seized when a piston could no = longer=20 reciprocate inside a missing cylinder ...was what saved my = bacon. Once=20 it stopped, even though the props' blade angle was nowhere near = feathered, the=20 drag reduction was so dramatic that we were able to level off from a = forced=20 descent and keep the ship (a C-123B) in the air long enough to make it = to=20 destination on the other engine.

When you think windmilling = drag ...=20 think prop circle area, not just the blades cross section themselves. = Square=20 yards of drag, not square ft.

His article sounds authoritative, but has all the intellectual = allure of=20 Lamar's rantings that NACA ducts and Electric Water Pumps "... = cannot=20 possibly work ...". Stick with Tracy. He has = something=20 flying. This guy has nada.

I tend to = like Tracy's=20 solution also. His hours in the air give him a lot of = credibility.

Just a theory .... Jim S.

David Leonard wrote:

Dale=20 Smith

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