Rockets

Infant though it be, the science of rocketry is not confined solely to crack-brained dreams of launching a howling projectile on its way to the moon. Rockets, in fact, have passed one definite milestone: they have traveled at 700 m.p.h., faster than any other self-propelled mechanism. The moon idea grew out of the solid fact that, unlike airplanes, rockets do not need air either for support or propulsion since they are pushed along by self-generated recoil forces.

Last week in Manhattan Professor Alexander Klemin, director of the Daniel Guggenheim School of Aeronautics, informed members of the Electrochemical Society of the present progress and problems of rocketry. He pointed out that the burned gas molecules shoot out of a rocket's combustion chamber at 3,000 to 4,000 ft. per sec. A rocket traveling at this speed would be 100% efficient, since all the recoil force of the molecules is turned into forward thrust.

One vexatious problem is that of weight. Fuel tanks must be light but capable of withstanding high pressure. For the moment aluminum alloys serve fairly well for tanks and motor but not for the jet nozzles which often collapse in a few minutes. This is due not only to heat but also to the abrading effect of the issuing gases. "Will electrochemists supply us," asked Professor Klemin, "with another super-aluminum alloy to withstand all this?"

Most gratifying progress made so far has been in the matter of fuel. Since a rocket is like an upward moving gun firing continuously at the ground, it was natural for the first experimenters to use gunpowder. But powder burned unevenly and it was extremely dangerous. The new technique is to use liquid oxygen and a liquid fuel such as gasoline or alcohol, which do not mix until the rocket is ready to go off. Such a mixture develops energies ten times greater than TNT.

Developer of liquid fuel is Robert Hutchings Goddard, rangy, bald, 53, foremost U. S. rocketeer. Born in Worcester, Mass., where he became professor of physics at Clark University, Goddard started puttering with rockets in 1907. The Smithsonian Institution gave him $12,000 over a period of twelve years. When one of his contraptions blew up over Worcester, the terrified townsfolk forced him to desist. He moved to Camp Devens, later to the desert near Roswell, N. Mex. Since 1930 his expenses have been paid by the Guggenheims.

To cure the tendency of rockets to wabble in flight, Dr. Goddard has worked out a small gyroscope that keeps his missiles in line by switching the tail vanes when necessary. Equipped with this and launched from his 60-ft. tower, Dr. Goddard's latest model, a twelve-footer weighing 140 Ib. with fuel, has reached speeds of 700 m.p.h., heights around 7,500 ft. Its fall is protected by an automatic parachute. Dr. Goddard, who hates to stir up gaudy talk of moon flights, announces his present objective as reaching 50 miles into the stratosphere "to obtain meteorological, astronomical, magnetic and other data of altitudes greatly exceeding those which can be reached by balloon."

More ambitious are other U. S. rocketeers, notably the American Rocket Society, of which Professor Goddard is a member, but to whose goings-on he pays no attention. These enthusiasts formerly called themselves the American Interplanetary Society. Frequently, on a deserted stretch of Staten Island, N. Y., just after dawn, the members place a hopeful model in the launching rack. The Society's president, red-bearded G. Edward Pendray, pours in the liquid oxygen, runs for safety. Members follow the flight, if any, with stopwatches and theodolites.

Last fortnight Willy Ley, president of the German Rocket Society, and Frido WT. Kessler, president of Rocket Airplane Corp., failed dismally in an attempt to send a 10-ft. rocket plane with 12-ft. wings on a four-mile mail flight from Greenwood Lake, N. Y. to Hewitt, N. J. Having sold 6,000 privately-printed stamps at 50-c- and 75-c- each to philatelists to finance their stunt, Messrs. Ley & Kessler tried again last week. Scooting along the ice, the first plane crossed the New York-New Jersey line on its belly. The second crossed the line in the air, lost a wing, crashed. The obliging postmaster at Hewitt retrieved the mail, canceled the stamps. Commented Mr. Pendray: "This performance is damned embarrassing to us serious experimenters."

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