Help! how to make aeroport box

Hi guys this is jay villaraza from the philippines , i need some help due to i heard aero ports/pnr are good for spl , i used to make L ported box for spl db drag here in our country but wanted to make an aeroport box , the db nationals in our country will be dec so i need to make a new box but i dont know how to calculate W-H-D of the box and the diamter of the port and lenght of pvc pipe and how to tune how will i know its tuning frequency , hehee sorry about this ,im just used to make L ported box , download winisd but seems i cant input the small parameters but just copy it from the manual of subwoofer.
google some sites but its ust how to make an aeroport with pvc pipe with flaring

any one who can help me with this thanks alot guys

heres my subwoofer

i just use 1x12 for spl db drag

http://www.ground-zero-audio.com/english/05_nw12spl.htm