THE old prospector rubbed his beard and squinted in amazement. “It’s the heat,” he muttered. “There just ain’t any airplane like that.” Swooping over the California desert was something that looked to him like a monstrous pterodactyl. It had to be an airplane, he finally decided, because he could hear the motors. But it was the queerest the desert had ever seen. It didn’t have any tail. What the prospector had stumbled across was a secret test flight of a new plane that no one except a few Army officers and Northrop Aircraft officials knew about. It was a flying wing that some engineers expect will revolutionize aircraft design. Some predict today's conventional airplane will become as extinct as the pterodactyl that the new flying wing resembles. Already Northrop is getting into volume production on the type. Designers have been trying to perfect a practical flying wing for decades because such a craft is about one third more efficient than an ordinary airplane. The conventional tail and fuselage are hindrances to efficient flight, but the tail group has been necessary for control, and the fuselage necessary to hold the tail behind the wing. Both elements form a drag that holds the wing back from the speed it could attain by itself. A number of flying wings have been built, one as early as 1914, but all were hard to control. Even a flying wing needs control surfaces and the only places to put them are at the wing tips. This creates a short coupling that results in bad spinning characteristics. Such flying wings are perfectly stable in smooth air butare hard to hold level in rough air. But such a wing has always been an intriguing goal. Any part of a plane that doesn’t create lift is superfluous in theory. Jack Northrop, among others, was irked by this inherent inefficiency of ordinary airplanes. His first experiment in 1929 had no fuselage, but it was not a true flying wing. An ordinary tail group was supported by two outriggers. Northrop attacked the problem again three years ago, designing a true wing with the assistance of the research staff of California Institute of Technology. Models were put to months of wind-tunnel tests. Two synchronized motion-picture cameras correlated the wind tunnel data. One camera was trained on the model while the other recorded simultaneous readings of the tunnel instruments. Eventually a shape was evolved with the characteristics Northrop wanted, plus a control system that promised to make the wing as stable and maneuverable as a conventional airplane. The shape of the wing itself contributes to stability through all three axes. Both the wing and its control system have been patented. The control system consists of an arrangement of wing tip flaps. After success in the wind tunnel the next step was to build a flying mock-up, one half or one third transport size, to see if it performed as well as the models. This wing is 28 feet from tip to tip, has considerable sweepback, and on its first flights was powered with two 60-horsepower engines later replaced by two air-cooled horizontally-opposed power plants of 120 horsepower each. The engines are completely buried in the wing and drive pusher-type propellers behind the trailing edge. Landing gear is retractable. The first test flights were made more than a year ago and since then hundreds of others have been made. At first the wing tips were deflected downward at abrupt angles to provide instant response to the controls. Later the tips were rebuilt to study their characteristics at other angles. No matter what dip the tips have, they are permanent and not movable by the pilot. Success of the wing and its control system was announced by Vance Breese and other test pilots who have flown it. They found the wing flies and handles just the same as a conventional airplane. In addition to its greater aerodynamic efficiency the flying wing is lighter, cheaper, and easier to build than conventional aircraft of similar performance. Less noise enters the cabin. The greater efficiency of the wing permits carrying present loads at present speeds with much less power than is required at present, or it permits the same power to carry the same loads at much higher speeds. Used as a passenger transport of the same capacity as present standard passenger carriers, the Northrop wing would be seven or eight feet thick. Crew, passengers, cargo, and motors would be entirely contained within the wing. A transparent leading edge as well as floor panels would permit passengers to watch the scenery. As a cargo transport, loading and unloading would be facilitated by large hatches on the upper surface of the wing. Since a few propellers are more efficient than a large number of propellers, it may be that for the huge flying wings of the future, a number of engines would be coupled to each propeller, possibly by means of an electric drive such as is used to propel some ocean-going ships. In spite of the promise of the flying wing, engineers can't agree on what the airplane of the future will be like. Some doubt that the conventional tail group will beentirely eliminated. One compromise suggestion is the so-called “manta” design, virtually a flying wing but including a vestigial tail group about half the size of present tail surfaces. In the manta much of the lift of the true flying wing is retained while much of the ordinary tail and fuselage drag is eliminated. Whatever the future holds, engineers agree that airplane design is now entering another cycle of refinement similar to the period that led to the development of the present cantilever monoplane,