Science: New Weapons

Some U.S. victories can be won on the drawing boards of industry. Last week two new fighting machines moved closer to battle:

Eager Beaver. The Army has long wanted a heavy truck that can splash ashore from landing barges and ford deep streams. Last week it had just the thing, and in quantity. Reo Motors Inc. delivered the last of 5,000 six-wheeled, 2½-ton trucks designed to start, stop and run under water as easily as above it. Called the Eager Beaver, the vehicle is a big brother of the submersible jeep (TIME, May 15). Its engine breathes and exhausts through vertical snorkel tubes like a latest-type submarine. Its wiring system is completely covered with a silicone-rubber compound that repels water. Tight oil seals keep water out of all engine openings.

Equipped to carry a five-ton load through a 7-ft.-deep stream, the Eager Beaver does even better. In a grueling Army test, with the driver wearing a portable lung, it went to a depth of eleven feet, cruised without a sputter on the bottom of a clear stream with fish swimming around it (see picture).

Flying Arrowhead. The Navy allowed Douglas Aircraft Co. to release a picture of its XF4D, an experimental jet interceptor of daring, tailless design. Intended for launching by catapult from a carrier deck, it has been test-flown successfully, but nothing has been made public about its performance.

The XF4D illustrates an aerodynamic axiom: “The more power you have, the less wing you need.” Presumably it is very fast; it may be supersonic. The short, steeply swept-back wing is shaped to minimize the Shockwave effects that are generally felt near the speed of sound. The thickness of the foreshortened wing and weblike “planform” in the center is intended to direct the air in a “three-dimensional flow”—below, above and around it.