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Date: Mon, 18 Apr 2005 19:47:51 -0500
Subject: Re: [FlyRotary] Area calcuation for Cone air filters was [FlyRotary] Re: Air filters
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From: Jerry Hey <jerryhey@earthlink.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
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Ed,  the surface area of the filter is much greater than its=20
circumference x height due to the folding of the element.  I just=20
checked mine and each inch equals 4 inches if stretched out.  Thus the=20=

surface area on my 5.5 in. round x 5 inch high filter would be over 300=20=

sq. in.   Jerry




On Monday, April 18, 2005, at 07:00 PM, Ed Anderson wrote:

> Bill,
> =A0
> I did some research on the K&N site - they have a formula for=20
> determining filter area needed - the trouble is there is no=20
> correlation (I could find) between the area you calculate and the=20
> surface area of their filters.=A0 So I just did a rough calculation of=20=

> their filters surface area based on small end - large end and=20
> length.=A0On their double cone types I assume the inner cone is =
only=A010%=20
> the area of their outer cone (which is probably very conservative).=A0 =
I=20
> used the 160 CID 4 stroke equivalent displacement area for the 13B and=20=

> the below formula.=A0 Which gave me at 7000 rpm a minimum of 53 sq=20
> inches required.
> =A0
> Then I did the calculation using the attached spreadsheet to compare=20=

> their different size filters for area - since they don't give it.=A0=20=

> Attached is the spreadsheet for using the below formula and the=20
> calculations for a truncated cone surface area.
> =A0
> =A0
>
> Use the formula below to compute the minimum size filter required for=20=

> your particular application. The usable portion of the filter is=20
> called the EFFECTIVE FILTERING AREA which is determined by multiplying=20=

> the diameter of the filter times Pi (3.1416) times the height of the=20=

> air filter in inches, then subtracting .75-inch. We subtract .75-inch=20=

> to compensate for the rubber seals on each end of the element and the=20=

> filter material near them since very little air flows through this=20
> area.
>
<image.tiff>
>
<image.tiff>
>
>
> Ed A
> =A0
> =A0
> =A0
> =A0
> ----- 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
>
> =A0
>
> <affform1.gif><affform2.gif><Filter Size Cone.xls> Homepage: =20
> http://www.flyrotary.com/
>>>  Archive:   http://lancaironline.net/lists/flyrotary/List.html

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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:


=
<excerpt><fontfamily><param>Arial</param><smaller>Bill,</smaller></fontfam=
ily>

=A0

<fontfamily><param>Arial</param><smaller>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.=A0 So I just did a
rough calculation of their filters surface area based on small end -
large end and length.=A0On their double cone types I assume the inner
cone is only=A010% the area of their outer cone (which is probably very
conservative).=A0 I used the 160 CID 4 stroke equivalent displacement
area for the 13B and the below formula.=A0 Which gave me at 7000 rpm a
minimum of 53 sq inches required.</smaller></fontfamily>

=A0

<fontfamily><param>Arial</param><smaller>Then I did the calculation
using the attached spreadsheet to compare their different size filters
for area - since they don't give it.=A0 Attached is the spreadsheet for
using the below formula and the calculations for a truncated cone
surface area.</smaller></fontfamily>

=A0

<fontfamily><param>Arial</param><smaller>=A0


</smaller>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.<smaller>


=
</smaller></fontfamily></excerpt><fontfamily><param>Arial</param><smaller>=
<<image.tiff></smaller></fontfamily>

<center><excerpt><fontfamily><param>Arial</param><smaller>

=
</smaller></fontfamily></excerpt></center><fontfamily><param>Arial</param>=
<smaller><<image.tiff></smaller></fontfamily>

<center><excerpt><fontfamily><param>Arial</param><smaller>

</smaller></fontfamily></excerpt></center><excerpt>

Ed A

=A0

=A0

=A0

=A0

----- Original Message -----

<bold>From:</bold>
=
<underline><color><param>0000,0000,FFFF</param>William</color></underline>=


<bold>To:</bold> <underline><color><param>0000,0000,FFFF</param>Rotary
motors in aircraft</color></underline>

<bold>Sent:</bold> Monday, April 18, 2005 5:54 PM

<bold>Subject:</bold> [FlyRotary] Re: Air filters


<fontfamily><param>Arial</param><smaller>If one looks at the K&N cone
filters, how big a one is required?</smaller></fontfamily>

Bill Schertz (really tight under my cowl)

KIS Cruiser # 4045


=A0


<<affform1.gif><<affform2.gif><<Filter Size Cone.xls> Homepage:=20
http://www.flyrotary.com/

<excerpt><excerpt> Archive: =20
http://lancaironline.net/lists/flyrotary/List.html

</excerpt></excerpt></excerpt>=

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