Critical Pressure on Projectiles in Air Guns

Abstract

The inside pressure of an air gun is tremendously increased when it's fired. We measured the critical pressure necessary to fire a projectile and found that the critical pressure in the case of rapidly increased inner pressure was higher than in the case of gradually increased pressure. We also found that the dependence variable on the inner diameter of a barrel differed in the two cases. Experimental results suggest that friction, which does not appear in the case of gradually increased pressure, increases the inner pressure exerted on projectiles.