Lynn,
You are absolutely in the wrong
business! That comment is as funny as anything I have read in a
while! But the best part is the silver nugget of truth that it
contains, :>)
Bill B
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Lehanover@aol.com
Sent: Sunday, October 03, 2010
7:54 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: Simple
Dyno
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?
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.
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.