Plane Model Makers Aim At 5000 m.p.h.

Gisborne Herald, Volume LXXVII, Issue 23271, 5 June 1950, Page 6

Plane Model Makers Aim At 5000 m.p.h.

(By William Flynn, a Reuter Correspondent)

MOFFETT FIELD, Cal

A human hair, even a blonde one noticed by a brunette wife on a husband’s blue serge suit, is an inconspicuous object, but to artisans who work here it is larger than the cables that suspend a bridge.

They are the men who build aircraft trame" and wing models —with tolerances held as fine as one-millionth of an inch as compared with the average two to four thousands diameter of a human hair.

The models are used in development of super-sonic aircraft designs at the Ames Aeronautical Laboratory of the national advisory committee for aeronautics. part of this huge naval station on the San Francisco Peninsula. Fabricated from metal, wood and plastics, the models range in size from a fraction cf an inch for testing in a miniature tunnel that simulates a 2500 mile-an-hour wind to huge frameworks with 70-foot wing spans that are subject to 250-mile-an-hour winds in the largest wind tunnel in the world. The model, regardless of size, must be finished to microscopic dimensions. The usual tolerance of the “rough jobs” is two one-thousandths of an inch, just half the diameter of the average human hair. For the really fine work, the artisans measure surface scratches only one-millionth ot an inch deep. The measurement is accomplished with optical devices and controlled light beams. Imperfections Magnified This high degree of tolerance is necessary because the slightest imperfection is magnified thousands of times when the model is placed in the wind tunnel to be battered by forces that simulate speeds as high as 2500 miles an hour, three times the speed of sound at sea level under standa&l atmospheric conditions. The_ "“model makers, headed by Edward W. “Red” Betts, chief of the division that employs 650 men, are the human link between the idea men and the material shapes that permit practical testing of theories.

The national advisory committee for aeronautics is chartered by the Federal Government and its activities are financed with Federal funds. It confines its activity to basic research to determine the most efficient shapes for wings and other component parts of aircraft When the information is checked as far as humanly possible, by both wind tunnel and flight experiments, the knowledge is made available to civilian aircraft designers and builders, the air force and navy. The scientists work not only on new designs but also seek to improve existing aircraft models by refinements. One of the most spectacular achievements of the laboratory was a wartime project. The Mustang F-51 fighter, the plane needed by the United States Air Force to provide escort for bombers en route to Berljn and later Tokyo, was in production when it was discovered that an inefficient engine cooling system made the plane worthless for its mission. New Air Intake Duct Made Within three weeks, working around the clock, the laboratory designed a new air intake duct in the wings that remedies the deficiency and permitted a change in design without halting production The first models were modified without difficulty. Since the end or the war the scientists have tried to explore the future for developments of a practical super-sonic plane. The wind tunnels now hold models with triangular shaped wings which, in one respect, appear to be the secret for efficient .penetration of the sonic barrier, but the slide rule scientists are calling continually on the model makers to produce a new design because the basic triangular or “Delta” wing has one glaring fault. It flies efficiently at 1000 miles an hour but drops like a stone when the speed is cut to only 250 or 300 miles an hour. As landing and take-ofi both involve this “inefficient” speed, the problem of saving the pilot and crew must be changed through refinement to the wing. The model makers are fashioning the changing designs according to the provided specificatins. They use everything from high test steel to plywood and putty. Each of the jobs is handfinished by machinists and wood workers who have the skill of artists. If they make more than one model of a design, they lose interest for more than that number is “mass production” to them. Director of Division Mr. Betts, .director of the division, is a veteran of 25 years’ service with the N.A.C.A. He began as a mechanic at the organisation's first laboratory at Langley Field. Virginia, in 1925. He came to Moffett to head the department when it was established in 1940. His staff) of artisans originally was recruited from the ranks of journeymen mechanics, but he has had no difficulty in obtaining the required man-power as the old timers died or retired. Graduates of technical trade schools are considered good material of N.A.C.A. specialised training. All the workers are Federal civil service employeees. Their wages, set after an annual review of compensation rates for similar work in private industry in the area, now average 3515 dollars for a 2080-hour work year. While the laboratory is concerned principally with the design of aircraft, its jurisdiction also includes the design of guided missile shape. The scientists are attempting to determine means of stability and control of such “shapes” at speeds as high as 5000 miles an I hour. They are unconcerned with the j “rarso” that the “shape” may carry. Their only concern is its efficiency in I flight.