X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao03.cox.net ([68.230.241.36] verified) by logan.com (CommuniGate Pro SMTP 5.0) with ESMTP id 811169 for flyrotary@lancaironline.net; Tue, 01 Nov 2005 16:48:11 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.36; envelope-from=ALVentures@cox.net Received: from BigAl ([68.7.14.39]) by fed1rmmtao03.cox.net (InterMail vM.6.01.05.02 201-2131-123-102-20050715) with ESMTP id <20051101214653.GWFD4527.fed1rmmtao03.cox.net@BigAl> for ; Tue, 1 Nov 2005 16:46:53 -0500 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Catto Prop Date: Tue, 1 Nov 2005 13:47:27 -0800 Message-ID: <001301c5df2d$da1811a0$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0014_01C5DEEA.CBF4D1A0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 Importance: Normal In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_0014_01C5DEEA.CBF4D1A0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable David Leonard wrote:=20 =20 I am turning my 68x74 wood prop at 3000 right now in cruise (if it is = cool out) with some room left in the throttle, but usually not a lot of room = left in the cooling department when going that fast. However, as I continue = to improve on cooling I am finding that I am running up against 3000 rpm. = I don't think I should be running it more than that on a regular basis.=20 =20 If I can turn my 2-blade 74" prop at 3000k, will I pick up any speed = from a 3-blade 74" prop turning at the same speed (through reduced slip)? If I make the prop shorter can I turn it faster? I have heard that 900fps = prop tip speed is a good upper limit. Is this a good number to use? Should = I be using that as my cruise tip speed, not max tip speed? =20 =20 David; =20 I'd suggest you direct this info and these questions to Craig Catto, and = get the straight scoop. He knows his props and is very helpful in picking = size and pitch for your application. =20 Al ------=_NextPart_000_0014_01C5DEEA.CBF4D1A0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

David Leonard wrote:

I am turning my 68x74 wood prop at 3000 right = now in cruise (if it is cool out) with some room left in the throttle, but = usually not a lot of room left in the cooling department when going that fast. However, as I continue to improve on cooling I am finding that I am = running up against 3000 rpm. I don't think I should be running it more = than that on a regular basis.

If I can turn my 2-blade 74" prop at = 3000k, will I pick up any speed from a 3-blade 74" prop turning at the same = speed (through reduced slip)? If I make the prop shorter can I turn = it faster? I have heard that 900fps prop tip speed is a good upper limit. Is = this a good number to use? Should I be using that as my cruise tip = speed, not max tip speed?

David;

I’d suggest you direct this = info and these questions to Craig Catto, and get the straight scoop. He = knows his props and is very helpful in picking size and pitch for your = application.

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