X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 08 Jun 2011 08:25:10 -0400 Message-ID: X-Original-Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.122] verified) by logan.com (CommuniGate Pro SMTP 5.4.0) with ESMTP id 5012586 for lml@lancaironline.net; Tue, 07 Jun 2011 18:48:03 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.122; envelope-from=tednoel@cfl.rr.com X-Original-Return-Path: X-Authority-Analysis: v=1.1 cv=8mDY8c80ZOa76EOwICuS+E2YRQjxDgO9xqUnRMONc7w= c=1 sm=0 a=9TeGTiT7SGcA:10 a=Jhy8mP4OLzYA:10 a=5zEv8FOEouFFTgTFH6HffA==:17 a=qQ3xTZYr87HXaaYLJqgA:9 a=wPNLvfGTeEIA:10 a=4PR2P7QzAAAA:8 a=RjFPcendtxrbINqmhVYA:9 a=djSSOgbfo6cA:10 a=5zEv8FOEouFFTgTFH6HffA==:117 X-Cloudmark-Score: 0 X-Originating-IP: 97.101.50.108 Received: from [97.101.50.108] ([97.101.50.108:62167] helo=[192.168.0.102]) by cdptpa-oedge03.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id 8F/D6-00666-E7AAEED4; Tue, 07 Jun 2011 22:47:26 +0000 X-Original-Message-ID: <4DEEAA80.6010808@cfl.rr.com> X-Original-Date: Tue, 07 Jun 2011 18:47:28 -0400 From: Ted Noel User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.17) Gecko/20110414 Lightning/1.0b2 Thunderbird/3.1.10 MIME-Version: 1.0 X-Original-To: Lancair Mailing List Subject: Re: [LML] Re: L-IV Choice of Engine References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------060507090508030405060203" This is a multi-part message in MIME format. --------------060507090508030405060203 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Brent, Well said, but in need of a small correction. My gearbox is helical, not spur. That means that I have 3.4 tooth engagement, not 1. That obviously reduces the individual tooth load. Also, the character of the sliding along those teeth is somewhat different from the sliding of spur gears. The loading is somewhat oblique as opposed to direct face loading. Is it good enough? Time will tell. Ted > NOW you want to transfer 800 horsepower from one vibrating system to > the other but that power is not in the form of a smooth torque. It is > a product of hammer blows on the end of a lever arm. So you have big > pulses, lots of little pulses and lots of energy that is going back > and forth between the two big vibrating systems (engine and > propeller). And what is all this energy passing through?*_Two_ little > chunks of steel that together are about the size of a pencil (gear > teeth). * > > > How do you accomplish the filtering of the forces that will invariably > tear your little gears to shreds? > The problem defies analysis. You can have armchair debates as to > whether composite is better than metal or if three blades are better > than four but being a "better" choice does not address the critical > question. Are ANY of the choices presented good enough? Only time and > testing will tell. > > Regards > Brent Regan > --------------060507090508030405060203 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Brent,

Well said, but in need of a small correction. My gearbox is helical, not spur. That means that I have 3.4 tooth engagement, not 1. That obviously reduces the individual tooth load. Also, the character of the sliding along those teeth is somewhat different from the sliding of spur gears. The loading is somewhat oblique as opposed to direct face loading.

Is it good enough? Time will tell.

Ted


NOW you want to transfer 800 horsepower from one vibrating system to the other but that power is not in the form of a smooth torque. It is a product of hammer blows on the end of a lever arm. So you have big pulses, lots of little pulses and lots of energy that is going back and forth between the two big vibrating systems (engine and propeller). And what is all this energy passing through? Two little chunks of steel that together are about the size of a pencil (gear teeth).


How do you accomplish the filtering of the forces that will invariably tear your little gears to shreds?

The problem defies analysis. You can have armchair debates as to whether composite is better than metal or if three blades are better than four but being a "better" choice does not address the critical question. Are ANY of the choices presented good enough?  Only time and testing will tell.

Regards
Brent Regan

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