The first step is to calculate the volume of the altimeter bay:

Volume (cubic inches) = Bay radius (inches) X Bay Radius (inches) X Bay Length (inches) x 3.14

Volume = 3.75 X 3.75 X 16 X 3.14

Volume = 14.06 X 16 X 3.14

Volume = 224.96 X 3.14

Volume = 706.37 cubic inches

The next step is to calculate a single hole size required to stabilize the pressure:

Single Port Diameter (inches) = Volume (cubic inches) / 400

Single Port Diameter = 706.37 / 400

Single Poet Diameter = 1.77”

Since a single hole over 1 ¾” is too large for this rocket, multiple holes will be used. The calculation for the hole diameter is as follows (once again from the Missile Works RRC2 Manual)

Multiport Diameter (inches) = Single Port Diameter (inches) / [# of ports / 2]

Multiport Diameter = (1.77 / 4) / 2

Multiport Diameter = (0.44) / 2

Multiport Diameter = 0.22”