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Date: Wed, 08 Oct 2008 12:41:29 -0400
From: Ernest Christley <echristley@nc.rr.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Redrive Ratio for a Dyke Delta
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Kelly Troyer wrote:
>   Ernest,
>      Wow !!.......You are going to have a torque monster..........What are you 
> thinking
> to use for a prop ??...........Sounds like you will need all the diameter and 
> pitch and/or
> blades you can get.........Have you considered the 3 blade hi pitch (45"-105") "IVO"
> like Jim Mahr has on his 2.85 to 1 Rotary Delta ??......You might need more diameter
> than he is using.........My "IVO" is 3 blade, 74 inch but currently has the 
> 30"-90" pitch
> blades for my 2.85 to 1 redrive (may not be enough pitch)...........<:)
> --
>
>   
A four blade can be easier to build and balance than a three blade, so 
that is probably what I will go with.  I haven't measured it off yet, to 
see what I can get away with, but suffice it to say that I will be 
adding every inch of prop that I can.  I have my first attempt at a two 
blade about half done.  This one will only be good for absorbing about 
60 to 70 Hp, but it will be a good test prop to keep a blip of the 
throttle from blowing up my engine.  I'll know exactly what the final 
prop will look like after I've carved a couple for practice and then 
done the final measurements and analysis.  The four blade is a strong 
candidate due to the fairly easy build, noise reduction, and low blade 
loading.