Subject: [FlyRotary] Re: Test prop/club needed
On
06/30/2011 02:14 AM, Andrew Martin wrote:
> Ernest, I thought the calculation for a test
club was X section = > 1/15th of length, means a
90mm square should be 1350mm or 54” in your >
language. mine is 90x1350mm calculated to absorb
190hp@2450rpm. do I > have this wrong, or do you
have a more up to date equation? only > problem I
can see with using a test club is needing
supplemental air > for the heat exchangers or
very short runs.
> I used the attached spreadsheet.
>
>
I took the calipers to my dyno-prop today. After the
glass and micro, I have a cross section of 88mm all
around. With my 3.18 gear reduction, it will only
absorb 123Hp at 7000 RPM, according to the
spreadsheet.
The second page suggests having several bars. This
one wasn't to hard to make, so I guess making a few
more will be in my future. I need to get out to
100mm before I'll have a bar that the spreadsheet
says will absorb over 180Hp.
Brian, I'll be cutting this bar down to 52" (1320mm)
tomorrow or Sunday. With a 2.85 reduction, 6500RPM
will require 137Hp to spin the bar at 2281.
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