Message-ID: <3C430030.8010403@regandesigns.com>
Date: Mon, 14 Jan 2002 07:58:40 -0800
From: Brent Regan <Brent@regandesigns.com>
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To: Lancair List <lancair.list@olsusa.com>
Subject: Re: Physics and props
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Gary, thanks for keeping me honest.

Regarding your question of static thrust, good luck. You can perform a 
detailed series of calculations which use simplifications and 
assumptions to arrive at an answer that is an estimation for a case that 
almost never happens and is transient OR you can do what I do......Guess.

For variable pitch propellers in the diameter we are interested (74-80") 
a rough guess of 3 pounds per horsepower will get you close to the 
manufacturers published (and wispered) emperical figures. The larger the 
diameter the more static thrust you get per horsepower (think of a 
helicopter). Acording to MT, if you dump 350 Hp into my 4 blade you get 
1080 pounds of thrust. This thrust starts to drop as soon as you start 
moving and my brakes won't hold at full throttle so I never get maximum 
static thrust.

Regards
Brent Regan

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