Message-ID: <40871CE5.3050702@nc.rr.com>
Date: Wed, 21 Apr 2004 21:16:21 -0400
From: Ernest Christley <echristley@nc.rr.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Performance Props
References: <list-3183496@logan.com>
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Perry Mick wrote:
> On Wed, 21 Apr 2004 21:11:20 -0400, Chad Robinson wrote
> 
>>Perry, if you could share the formulae you're using I'd be happy to 
>>make a spreadsheet calculator for this. So far I've found very 
>>complex prop calculators but nothing straightforward.
>>
>>By the way, why are you asking desired cruise speed? 400 knots! =)
>>
>>Do your calculations focus on pitch/length or do they also provide 
>>some means of calculating dimensions at various stations from the 
>>hub, so forming templates can be made?
>>
>>Regards,
>>Chad
>>
> 
> It's not simple enough to put in a spreadsheet.
> I think Al Wick uses the Bates Prop program, I don't know anything about 
> that program and I don't know why he couldn't develop numbers for Bulent.
> The programs I use are all in the book "Modern Propeller and Duct Design" by 
> Martin Hollman. They are BASIC programs that I have improved on and now run 
> as visual basic macros. They have proven to be very good at predicting 
> reality.
> Data entry is actual blade parameters along the length of the blade, so the 
> process is "trial-and-error". Enter a blade design and examine the output to 
> see what the performance is. The Bates program might be the opposite, enter 
> performance numbers and it spits out a blade design (?).
> I want to know desired cruise speed and cruise RPM as a first estimate for 
> pitch. Actual cruise speed is limited by thrust produced and the drag of the 
> airplane, so equivalent flat plate area of the airplane is also a desirable 
> thing to know.
> 
> Perry
> 


Perry, would you like to share your algorithms.  I'll turn them into C 
code ('cause I like C), and put a genetic algorithm on the front end. 
I'm assuming you have X number of stations that you enter numbers for. 
Make each station a genetic marker, start with a couple strains and let 
them mate through a few thousand generations till you get something you 
really like.


-- 
http://www.ernest.isa-geek.org/
"Ignorance is mankinds normal state,
   alleviated by information and experience."
                                   Veeduber