The Roswell Report: Fact vs. Fiction in the New Mexico Desert

the balloon and permits gas to be introduced into the top of the cell first. As the balloon is laid out and shotbags are positioned, this tube must be kept clear. At the point where the bubble is pinched off the folds of the balloon are carefully divided; the inflation tube is made as free as possible with only one layer of polyethylene above and one below it. The tube is then pulled up above and between the arms of the releasing device or the heavy shot bags, and the remainder of the fabric is pinned down so that no shifting will permit premature release.

Depending upon the load to be lifted and the rate of rise desired, a pre-computed amount of helium is fed into the balloon (see Section IV, A). This amount is determined by noting the equilibrium pressure and temperature of the gas in each cylinder. A manifold is used to feed the gas from the tanks to the inflation tube in the balloon. Shown in Figures 26 and 27 this manifold system consists of an adjustable number of flexible pigtails leading into a main line of heavy copper tubing. This main line and the fittings are capable of withstanding the full tank pressure of about 2500 feet psi. Two pressure gages are included in the main line and it is thus possible to make last-minute checks of the amount of gas (pressure) in each tank. (Due to variable gage-calibrations, it has been found necessary to establish the lift-pressure ratio of each gage before using it.) In the main line of the manifold, two valves control the gas flow. The inflation tube is often initially twisted when the balloon is first laid out. A small amount of gas at very low pressure should be valved into the tube to strengthen it. In addition to the fine valve control required for this preliminary gas feed, it is also necessary for a manifold valve to permit high gas flow from the tanks even when the pressure is greatly reduced. For this, the coarse globe valve is used.

Once the tube has been checked, inflation should proceed as rapidly as possible. The balloon is outdoors and so subject to buffeting by the wind. The limiting factor of speed of inflation is the vibration of the fabric near the open end of the inflation tube.

As a result of the extreme cooling of the rapidly expanding gas, the manifold and the tank valve generally become coated with frost. Too rapid cooling may actually cause the valve to freeze shut.