X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fmailhost04.isp.att.net ([207.115.11.54] verified) by logan.com (CommuniGate Pro SMTP 5.3.9) with ESMTP id 4480946 for flyrotary@lancaironline.net; Sat, 25 Sep 2010 14:06:13 -0400 Received-SPF: none receiver=logan.com; client-ip=207.115.11.54; envelope-from=bbradburry@bellsouth.net Received: from desktop (adsl-85-189-64.mco.bellsouth.net[98.85.189.64]) by isp.att.net (frfwmhc04) with SMTP id <20100925180538H0400oceo9e>; Sat, 25 Sep 2010 18:05:38 +0000 X-Originating-IP: [98.85.189.64] From: "Bill Bradburry" To: "'Rotary motors in aircraft'" References: In-Reply-To: Subject: RE: [FlyRotary] simple dyno Date: Sat, 25 Sep 2010 14:05:38 -0400 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0039_01CB5CBA.BBF09610" X-Mailer: Microsoft Office Outlook 11 Thread-Index: ActcykdT9sGK85rgSAmIotAY6l8EEgAEXZQw X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6001.18049 This is a multi-part message in MIME format. ------=_NextPart_000_0039_01CB5CBA.BBF09610 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Over my head! A 75 inch log that is 5 inches square swinging at 7000 rpm??? If 191 HP can do that I will be surprised, but would not want to be close enough to witness it! [:

Over my = head!

A 75 inch log that is 5 inches = square swinging at 7000 rpm??? If 191 HP can do that I will be surprised, = but would not want to be close enough to witness it! = [:<O

Bill B

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Andrew Martin
Sent: Saturday, September = 25, 2010 11:56 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] = simple dyno

Whilst researching propellers, I came across this gem of info = from www.jcpropellerdesign.com<= /p>

Gustave Eiffel (1832-1923) came up with a simple solution for measuring = HP without complex apparatus, By using a balanced wood bar instead of a propeller with a square cross section = of 1/15th of the length of the bar, you can measure the rpm and = calculate the HP available.

Power in HP =3D 0.0532 (diameter/450)5 (RPM/1000)3

As I need a = load on the engine when I run it I’m going to give this a go, 1350 x 90mm at = 7000 rpm will give me 191hp, that’ll do if I can get = it.
--
Regards

Andrew Martin
Renesis RD1c

West = Australia

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