The K-airships are designed for a maximum speed of 65 knots with an internal gas pressure of 1.5 inches of water. 

Since the automatic air valves, as .pointed out above, are operated by the air pressure of the ballonets, the corresponding gas pressure at which they open depends on the gas inflation of the ship. If, for instance, the ship is 85% gas inflated and the ballonets are more than half infle.ted, it can be seen, by referring to the curve in Fig. VII that the gas pressure in the envelope is about 0.32 inches of water less than the air pressure in the ballonets. The air valve of the forward ballonet will open, therefore, at air pressure of 1.5 inches of water, while the corresponding gas pressure is .32 inches of water less than the setting of th~ gas valve or 1.18 inches. 

It will still be possible, however, to maintain the recommended operating gas pressure of 1.5 inches of water by opening the forward air damper and regulating the scoop opening so as to produce air circulation through the air damper and the partially opened air valve. 

CAUTION: The matter of the proper regulation of the air scoops is of the utmost importance. If the scoops are opened too wide, excessive pressure may be built up in the envelope causing loss of gas. If the scoops are not opened enough, the gas pressure may drop to a dangerously low value resulting in buckling of the envelope. 

