Week 7 Update: Nozzle replacement and pressure tank calculations

Over the course of this week, the nozzle of the air blow gun was replaced with a threaded 4 inch brass pipe, the tip of the pipe was cut with a pipe cutter. The following figure shows the current status of the design:

The shooting mechanism with four inch brass pipe

The height of the assembly is 19.6" and the width of the design 8.6". The length from the tip of the barrel to the tip of the air valve is 20.4".

Calculations were also made to estimate the amount of air that can be blown into the bag. Assuming the tank is approximately a cylinder with a base of radius 0.625” and length 10”, its volume is 12.3 in². Since atmospheric pressure is 14.7 psi, the air in the tank is 8.2 times more compressed than the surrounding air. The tank could therefore potentially release a volume of 8.2x12.3-12.3=87.9 in². Since the bag has a maximum diameter of 1”, the maximum length the air blow gun could extend the bag to is 87.9/(πx(0.5x1)²)=111.9 in=9.3 ft. Therefore, in theory, the air blow gun can release a sufficient amount of air to extend the 2.5 foot long bag.