Abstract: A rapid acting gas valve for inflated structures employs a slider-crank drive mechanism driven by a pawl and ratchet motor to produce a high closing force in the valve while opening and closing the valve in a partial revolution of the ratchet motor shaft.

Abstract: Apparatus for assaying the purity of a gas, e.g., helium, includes an acoustic signal generating transducer in a chamber containing the gas under test. In one embodiment, a microphone spaced a given distance from the transducer senses the propagated acoustic signal. A regenerative circuit creates a pulse train of acoustic signals in the chamber having a pulse repetition rate which is a function of the gas purity. In a second embodiment a continuous acoustic signal is propagated in the chamber containing two spaced microphones. The frequency of the acoustic signal is adjusted until the signals received by the microphones are either in phase or 180.degree. out of phase. A peak or null detector detects when the desired phase relationship occurs as the signal frequency is adjusted. The gas purity is then computed from the observed pulse repetition rate or the observed frequency of the in-phase or 180.degree. out-of-phase condition. Temperature compensation is provided for both embodiments.

Abstract: The elongation of a rope or cable under impact stress is measured by attaching a light emitting diode (LED) to a free-falling weight which loads the rope upon impact. The LED is turned on in response to a drive signal indicative of stress of the rope of greater than a given value. The lit LED and an adjacent scale are photographed to provide a record of the distance through which the LED moves, when on, and this indicates the amount of elongation of the rope to failure.

Abstract: A balloon or airship having a hull of flexible material is provided with a deflation opening in the hull and a rigid frame permanently fastened to the edge of the opening. A ring of flexible sheet material has its peripheral edge removably clamped to the rigid frame. A disc of flexible sheet material larger than the central opening in the ring is fastened by an adhesive to the ring all around the central opening in the ring. A deflation tape sewed to the disc near the edge of the upper half thereof has a central free end to be pulled for peeling the adhesive-held disc from the ring to rapidly deflate the balloon.

Abstract: A variable lift inflatable airfoil for tethered balloons having a horizontal fin made up of two inflatable chambers. The primary or lower chamber is normally maintained at a greater pressure than the secondary or upper chamber. Proper inflation and deflation of the secondary chamber will stabilize the pitch attitude of the balloon at some desirable low, positive angle for any wind velocity.

Abstract: Four anchored rope lines which are arranged as boundary vertices of an equilateral square pyramid, terminate at a four way shackle connected through a short line to a hook. The hook terminates lines on the nose of the balloon which are secured by an appropriate number of nose patches, two or three on each side or in the center of the balloon nose. Conventional mooring ropes are tethered to a monorail arrangement in a conventional manner. The four anchored rope lines replace the cumbersome mooring tower and eliminate the necessity of a protective nose framework on the balloon. In another embodiment the four rope lines are secured directly to the nose patches through the four way shackle and carried aloft with the balloon. At the time of mooring the lower ends of each rope line need merely to be connected to appropriate ground terminals.