Abstract: An elemental net for a multiple element aircraft arresting net system. The elemental net has a single upper horizontal strap, several vertical straps having top ends and bottom ends, and at least two lower horizontal straps. The top ends of the vertical straps are directly affixed to the upper horizontal strap at spaced intervals along the upper horizontal strap. The bottom ends of the vertical straps are alternatingly affixed to one of the lower horizontal straps so that the lower horizontal straps are free to move relative to each other to a significant degree and so that lifting of one vertical strap will tend to lift only one of the lower horizontal straps in the vicinity of the vertical strap being lifted. The present invention provides a variable window which is free to expand or contract during aircraft engagement, permitting easier penetration of the net by a greater mix of aircraft.

Abstract: An automatic sprinkler having a force transmitting mechanism for releasably maintaining a water outlet closed includes a frangible glass bulb having a very quick response characteristic to thermal input. Substantially less than one-half the force transmitted through the force transmitting mechanism is carried by the glass bulb.