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Excellent point, Jerry. You are correct,
completely left out the accordion pleat folding. So let me go back and add
a big fudge factor to the equation in the spread sheet.
Ed
----- Original Message -----
Sent: Monday, April 18, 2005 8:47
PM
Subject: [FlyRotary] Re: Area calcuation
for Cone air filters was [FlyRotary] Re: Air filters
Ed, the surface area of the filter is much greater than its
circumference x height due to the folding of the element. I just checked mine
and each inch equals 4 inches if stretched out. Thus the surface area on my
5.5 in. round x 5 inch high filter would be over 300 sq. in.
Jerry
On Monday, April 18, 2005, at 07:00 PM, Ed Anderson
wrote:
Bill,
I
did some research on the K&N site - they have a formula for determining
filter area needed - the trouble is there is no correlation (I could find)
between the area you calculate and the surface area of their filters.
So I just did a rough calculation of their filters surface area based on
small end - large end and length. On their double cone types I assume
the inner cone is only 10% the area of their outer cone (which is
probably very conservative). I used the 160 CID 4 stroke equivalent
displacement area for the 13B and the below formula. Which gave me at
7000 rpm a minimum of 53 sq inches
required.
Then
I did the calculation using the attached spreadsheet to compare their
different size filters for area - since they don't give it. Attached
is the spreadsheet for using the below formula and the calculations for a
truncated cone surface area.
Use
the formula below to compute the minimum size filter required for your
particular application. The usable portion of the filter is called the
EFFECTIVE FILTERING AREA which is determined by multiplying the diameter of
the filter times Pi (3.1416) times the height of the air filter in inches,
then subtracting .75-inch. We subtract .75-inch to compensate for the rubber
seals on each end of the element and the filter material near them since
very little air flows through this area.
<image.tiff>
<image.tiff>
Ed A
-----
Original Message -----
From:
William
To: Rotary motors in
aircraft
Sent: Monday, April 18, 2005 5:54
PM
Subject: [FlyRotary] Re: Air filters
If one looks at the
K&N cone filters, how big a one is
required?
Bill Schertz (really tight under my
cowl)
KIS Cruiser #
4045
<affform1.gif><affform2.gif><Filter
Size Cone.xls> Homepage: http://www.flyrotary.com/
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