X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [65.54.250.79] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 5.0.4) with ESMTP id 888922 for flyrotary@lancaironline.net; Mon, 19 Dec 2005 17:30:39 -0500 Received-SPF: pass receiver=logan.com; client-ip=65.54.250.79; envelope-from=lors01@msn.com Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Mon, 19 Dec 2005 14:29:54 -0800 Message-ID: Received: from 4.171.150.151 by BAY115-DAV7.phx.gbl with DAV; Mon, 19 Dec 2005 22:29:53 +0000 X-Originating-IP: [4.171.150.151] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Props Date: Mon, 19 Dec 2005 17:29:49 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0090_01C604C1.D04156A0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 X-MimeOLE: Produced By MSN MimeOLE V9.10.0011.1703 Seal-Send-Time: Mon, 19 Dec 2005 17:29:49 -0500 X-OriginalArrivalTime: 19 Dec 2005 22:29:54.0133 (UTC) FILETIME=[BBCE6850:01C604EB] This is a multi-part message in MIME format. ------=_NextPart_000_0090_01C604C1.D04156A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable These numbers don't sanity check Buly. I turned my engine 6400 with 68" = prop and 2.17 drive when racing and never had the characteristic = snapping prop noise that accompanies supersonic tip speeds.=20 Monty's "one empirical test is worth more than 1000 calcs ....." seems = appropriate here : ) Tracy ----- Original Message -----=20 From: Buly=20 To: Rotary motors in aircraft=20 Sent: Monday, December 19, 2005 1:13 PM Subject: [FlyRotary] Props Yesterday somebody gave me the formulas to calculate the prop tip =20 speed. I did some calculations and looks like us with the 2.17 =20 redrives are kind of painted in the corner. Hope I'm wrong, but if I =20 want to keep the tips from going supersonic, I have to cut down the =20 prop to 64" or keep the engine below 5500 RPM. The choice is either =20 inefficient prop and adequate power, or efficient long prop and not =20 getting all the power from the engine? Am I wrong? Buly atlasyts@bellsouth.net -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net/lists/flyrotary/ ------=_NextPart_000_0090_01C604C1.D04156A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
These numbers don't sanity check Buly.  I turned my engine = 6400 with=20 68" prop and 2.17 drive when racing and never had the = characteristic=20 snapping prop noise that accompanies supersonic tip speeds. 
 
Monty's "one empirical test is worth more than 1000 calcs ....." = seems=20 appropriate here : )
 
Tracy
----- Original Message -----
From: Buly
To: Rotary motors in = aircraft
Sent: Monday, December 19, 2005 = 1:13=20 PM
Subject: [FlyRotary] = Props

Yesterday somebody gave me the formulas to calculate = the prop=20 tip 
speed. I did some calculations and looks like us with = the=20 2.17 
redrives are kind of painted in the corner. Hope I'm = wrong, but=20 if I 
want to keep the tips from going supersonic, I have to = cut down=20 the 
prop to 64" or keep the engine below 5500 RPM. The = choice is=20 either 
inefficient prop and adequate power, or efficient = long prop=20 and not 
getting all the power from the engine? Am I=20 wrong?
Buly
atlasyts@bellsouth.net

=


--
Homepage: =20 http://www.flyrotary.com/
Archi= ve and=20 UnSub:   http://mail.lanca= ironline.net/lists/flyrotary/
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