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Date: Sun, 03 Oct 2010 08:33:31 -0500
From: Charlie England <ceengland@bellsouth.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Simple Dyno
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  On 10/3/2010 6:54 AM, Lehanover@aol.com wrote:
> In a message dated 10/3/2010 2:04:01 A.M. Eastern Daylight Time, 
> echristley@nc.rr.com writes:
>
>>     Has there been a compilation of data from folks spinning various
>>     sizes of fence posts with known HP engines? Results corrected to
>>     sea level standard day and all of that?
>>     Where did this come from?
>>     Thank you.
>>     Lynn E. Hanover
>     I think I've been monitoring this list since forever.  I posted a
>     message concerning this technique on Monday, September 11, 2006
>     9:02 AM.
>
>     At that time, I had lost the equation information, and I'm very
>     happy to see them come around again.  More detailed equations are
>     in the alt.rec.aviation.homebuilt newsgroup, if anyone can find an
>     archive somewhere that dates back before 2006.  I'm pretty sure
>     that it included correction for standard atmosphere, but I haven't
>     been able to find it.
>
>     LE Hanover wrote:
>
> Here is a simple mechanism for reducing readings to some standard so 
> that HP readings from any source (that had also been corrected to sea 
> level standard day) can be accurately compared.
> http://www.csgnetwork.com/relhumhpcalc.html
> Way back when I had a Stuska Dynamometer I used big graphs to pull off 
> the SAE correction data. No computers back then. I talked to "Ohio" 
> George Montgomery (famous racer back then) who built a killer 33 
> Anglia drag car, about some problems I had getting past a development 
> point. He said connect the dots on your SAE graphs and you will see 
> that the published results are boxed in several areas. And so it was. 
> 95% of those dots were on a straight line. So I got a 48" steel ruler 
> and drew that line omitting the aberrations. No more problems. Thank 
> you SAE.
> I had my inlet air temperature bulb inside the air cleaner. I had a 
> weather station beside the dyno. I had a wet bulb sling psychrometer. 
> (because it came with the dyno) The kind you swing around your head. 
> Now they are digital and just spin around a little handle. But, like 
> building my first flow bench, I started getting smart real quick.
> You may not know this, bet there is a solid silver fence post in the 
> cellar at the National Bureau of Standards in a velvet lined box, In 
> its center, an SAE-2 bolt pattern. kept at a constant 68 degrees. Its 
> length measured twice per week with a CO2 laser. Cooler you know. 
> doesn't change the length. You can see it with special permission. You 
> must wear a moon suit, so the air in the vault room is not affected by 
> your visit. No pictures please. The seemingly sharp edges actually 
> have a radius. Verified by the annual electron beam sweep, and 
> collection of Gamma ray backscatter.
> It is worth the trip. The old guy who is in charge of that thing has 
> the formulas in his head. He knew Eiffel. He instructed in a Jenny. 
> Has a thousand stories, and loves to talk about planes.
> Or, you could use fuel flow to calculate HP, and your fence post will 
> not kill any bugs, or worse, and its lack of airflow will not overheat 
> your engine. Spend the fence post building time working on the plane.
> But I could be completely wrong.
> Lynn E. Hanover
Using Lynn's idea, make yourself a variable rpm dyno load by spending 
your $700, not on an AL bar, but on a manual adjust IVO prop (its 
highest & best use...  ;-)  )

Charlie