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Date: Tue, 18 Dec 2007 17:51:03 -0500
From: Ernest Christley <echristley@nc.rr.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Supercharging
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wrjjrs@aol.com wrote:
> Ernest,
> All that the leaf blower is is the compressor scroll of a turbo 
> charger. many of the aircraft superchargers, circa WW2 used a 
> centrifugal supercharger which is exactly what you are describing.  
> Think you will find it more trouble than it's worth. Mainly due to 
> breakage of the parts at high RPMs. You will have to design your own 
> drive, and it is a drive even if simply a shaft connection. You would 
> probably find a belt driven centrifugal supercharger and using a 
> underdriven (reducing) system. You will find a supercharged 13B will 
> make 200 HP very easily.
> Bill Jepson  
Ed, how many Hp would be required to accelerate 307CFM of air from 0 to 
150MPH?  That would be the extent of the power that the fan blades would 
have to absorb, wouldn't it?  Would there be a major drag component?

The drive is already designed and built, but what parts do you think 
might break, Bill?  It's a compressor wheel bolted up to the flywheel.  
Should I expect to see problems with it shedding blades?  I've looked 
into the leaf blower components, specifically because they were designed 
to run at the RPM we're looking at.  Literally, trying not to reinvent 
the wheel.  I'm assuming that they can take the RPM, since it is an 
industrial component that workers carry on their backs.

The shroud is the bellhousing.  Not optimum, but sturdy and simple.  I 
will probably have to add some extra aluminum sheet to keep the housing 
tight, but I don't see having much problems with that part.

Like Ed said, it's just an experiment at this point.  I'm really just 
guessing that it will be worthwhile, but it's just such a simple mod 
that I've got to try.  The labor, weight and dollar investments are all 
about right.  I just have to see how much payback there is while 
avoiding throwing pieces of metal around.