 # Aeroport port area equation

1503 Views 11 Replies 7 Participants Last post by  Novicaine
Whats the equation to find the port area of an aeroport? I had it written down somewhere and can't seem to find it back. Thanks.
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pi(R^2)
3.14 iirc
pi = 3.14159265
Just a funny thing I just remembered about Pi lol I work for Domino's as well Not THIS one but still funny but yes, 3.14
http://static.funnyjunk.com/pictures/47c00445_3d08_413d.jpg
And does that gives square inches?
C'mon, guys...lol

Area of a circle...lol

And yea, I usually just use 3.1415 as 'pi'

And does that gives square inches?
Yes, sir...as long as you use inches as the radius
lol, heres the forumlas to find the length needed and minimum PA required:

LV is Length of port
Dv = port diameter (cm)
Fb = tuning frequency (Hz)
Vb = net volume (litres)
Np = number of ports
k = end correction (normally 0.732)

Lv = (23562.5*Dv^2*Np/(Fb^2*Vb))-(k*Dv)

Sd = pi*(Dia/100)^2/4
Vd = Sd*Xmax/1000
MIN DIAMETER = 100*(20.3*(Vd^2/Fb)^0.25)/Np^.5
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lol, heres the forumlas to find the length needed and minimum PA required:

LV is Length of port
Dv = port diameter (cm)
Fb = tuning frequency (Hz)
Vb = net volume (litres)
Np = number of ports
k = end correction (normally 0.732)

Lv = (23562.5*Dv^2*Np/(Fb^2*Vb))-(k*Dv)

Sd = pi*(Dia/100)^2/4
Vd = Sd*Xmax/1000
MIN DIAMETER = 100*(20.3*(Vd^2/Fb)^0.25)/Np^.5

Not trying to be lazy but if I just use a website to find port length isn't that the same info? Suppose I was build a 5cubic foot box for an '04 15" L7 tuned to 30 hz is 1-6" diameter aero port big around enough?
So I have some 5.75" diameter PVC that I am planning to flare myself to make my own aeros, I found that I need 2 with a total length of 31.5" in a 4.5 cube box( I am assuming that is after displacement of the sub, bracing, and ports?), So my ports would be (5.75*3.14)31.5/1728 = port displacement in cubic feet, correct?