BIGGEST YET

Evening Post, Volume CXXVI, Issue 73, 23 September 1938, Page 8

BIGGEST YET

THE NEW DOUGLAS

AN ENGLISHMAN'S JMPRES-

SIONS

CONVINCING TESTS

"It suddenly dawned on me that I was walking about underneath her, peering at this and that, and muttering to myself. ... A workman brought some high steps; We climbed up into the great silver fuselage. Immediately one got a truer impression of the size of the D.C.4, which her grace tends to disguise when viewed from the ground. Resting as she does in a horizontal position on her tricycle landing gear, one cannot get in or out except by ladder. At least, to get out would involve a drop enough to snap the average ankle, and nobody could conceivably climb up." Thus Lord Cottenham set out in the "Aeroplane" his first impression of the new 42-passenger Douglas transport, which literally dwarfs all its landplane passenger predecessors and throws doubts again upon the certainty of the outcome of the "landplane or flying-boat" controversy for the economic transport of passengers over ocean stages—and economic transport essentially means many passengers at moderate fares, rather than few passengers at high fares. That battle is by no means over. Lord Cottenham not only saw the Douglas tested, but was a passenger on some of the flights, and writes with a real enthusiasm of the extraordinarily fine performance of the great machine and of the success of the tricycle landing gear, employed for the first time upon a large plane. He goes into facts and figures, but his sidelights are most telling. One hundred thousand engineering hours, he says, went to the tests of individual features of the plane before ever she left the ground. A scale model alone went through 866 wind tunnel tests, at a cost of £5000. Fuel and oil tanks were put under- vibration tests for 125 hours. The main landing gear was "drop-tested" to a- maximum of 120,0001b, and the nose-wheel to 54,0001b. Enormous stresses were j applied to wings, fuselage, and tail surfaces, till the metal skin wrinkled under the strains and returned to normal. PLANES ARE ENGINEERED. "In a way," he wrote, after his description of the tests, "one may say that aeroplanes are no longer designed, but engineered. No theory enters into design that cannot be supported by j the known results of established practice in aerodynamics and metallurgy. The day of the hit-or-miss idea, the I-can-1 improve-it-at-the-last-minute . method, j has long since gone. Donald Douglas j himself said that the D.C.4 contains no- i thing revolutionary, nothing that he! and the men like him had not had; ideas about long ago: there had obvi-| ously been great advances in the use: of metals, but the D.C.4 could have been built 16 years ago, by different and difficult methods, but she could •have been built. What she represented was really an immensely intricate: and complicated feat of engineering." The test flights were watched by a great crowd of sightseers (very different, the editor of the "Aeroplane" re- j marks, from the dead secrecy of first tests of machines in England) and the description given emphasised particu-lai-ly the moderate demands for runway. "Accelerating towards us, the angle given by 'her nose-wheel made her seem to be already flying. But as she drew level . . . the nose-wheel lifted and she ran past on her main landing gear, and was scarcely fast be* fore that, too, left the ground. Her first take-off, slightly downhill, had taken between ten and eleven seconds." j Increasing size of aeroplanes does not mean continually increasing demands for larger and larger flying fields. TRICYCLE LANDING GEAR. Huge though she is, Lord Cottenham wrote of the landing after the flight he made, the pilot turned her, as the saying goes, on a dime, and taxied back much faster than would have been comfortable with the ordinary tail wheel. A second landing was made. "This time Carl put her down just inside the boundary, gave us a word of warning, and put his brakes on hard. The result would have been a revelation to those who say that big aeroplanes cannot be landed except on vast fields. Thereupon, an amusing and instructive incident ensued. Claiming that he had seen a jack-rabbit, the pilot swung the D.C.4 round on her axis and careered off over the rough ground away from the runway. Steering this way and that, accelerating sharply, pulling up, twisting the big ship like a polo pony, he played with it as a lad coasts about on a scooter. And, as iff he thought the nose-wheel hadn't had enough to do, he taxied up to 60 m.p.h., pulled the nose-wheel up and banged it down again. Then he just took Off, all three wheels, shoved the column forward, and flew the D.C.4 into the ground again. She landed with no more than a hefty jolt and did her famous imitation of a high-speed trol-ley-car. Chuckling among ourselves, we finished for the day, but beneath all the humour, even those who expected most from her were palpably impressed." .