HELICOPTER’S DAY

Evening Star, Issue 23374, 18 September 1939, Page 10

HELICOPTER’S DAY

WILL PRESENT PLANES GO? ADVANTAGES SEEN It requires a high degree of temerity, if not outright recklessness, to make predictions about the aeroplane of to-morrow, in view of the tremendous development of the last 10 or 15 years, writes C. B. Allen, a member of the U.S. Air Safety Board, in the New York ‘ Herald-Tribune.’ The prophets of the era through which aviation has just passed, however, vastly under-estimated what really would he accomplished by the aeroplane, and there are few men of vision in the industry to-day who do not believe that even more progress will be made in the next decade.

Some of America’s best designers even go* so far as to say that the aeroplane as we know it to-day may disappear altogether in the next few years, except possibly in long-range transportation. They see in recent developments, both in America and abroad, a definite, inevitable trend towards rotary wing aircraft. Many of them feel that the helicopter or some other machine of the same general nature is destined to replace fixedwing aircraft entirely in the field of private flying, and possibly also in air transportation. There are even those who foresee a time when gigantic helicopters carrying a hundred passengers or more will engage in regular transoceanic flights, attaining top speeds in the neighbourhood of 300 to 400 miles an hour, yet capable of hovering in mid-air when desired, and of making vertical ascents and descents in perfect safety. . Perhaps this is a visionary prediction, and one that never will bo fulfilled,_ but it is almost in the realm of certainty that the world is on the verge of great things in the development of rotary wing aircraft, one which may well revolutionise flying as we know it to-day. More than a year ago a Gbrman helicopter not only established a whole new series of world records for aircraft of this type, but startled incredulous aircraft designers all over the world by taking off and flying around inside an exhibition hall smaller than Madison Square Garden. It rose vertically from the ground, hung suspended in mid-air at the will of its tiny woman pilot, and moved forward, sidewise, up, down, and even backwards in response to her touch on the : controls. A helicopter of that type undoubtedly will make its appearance in the United States during 1939, and it is entirely possible that American-built helicopters of even more phenomenal performance will be in the air to challenge the German bidder for supremacy ■in this new field of flying. If the proponents of the helicopter are able to substantiate their claims for rotary wing aircraft, and to produce a machine that is inherently eas.y to operate and safe to fly, they will give the development of aviation an impetus such as it has never known since the Wright brothers achieved their triumph at Kitty Hawk. Development of a practical flying machine capable of rising vertically from the earth and of returning safely to the ground in the same manner will bring to mankind its age-old dream of the “ back yard ” or even “ roof-top ” aeroplane. Such a development would give flying a utility undreamed of heretofore; it would do away with the necessity of larger and ever larger airports, and it would revolutionise the American scheme of urban and suburban life to an even greater degree than did the development of the automobile.

it would decentralise the population of our great cities by enabling office workers to commute with no more inconvenience over distances five or 10 times as great as they now cover by trains or in their own automobiles. Whether the helicopter or any other form of rotary wing aircraft eventually will supplant the aeroplane in the field of long-range transportation is a moot question even among those who believe that planes are headed for the aeronautical junk heap so far as private flying is concerned.. The answer to this question involves many factors, but the principal ones are whether it will he possible to fly faster and carry a given load of passengers and cargo with rotary wing aircraft than in some form of the aeroplane as we know it to-day. Theoretically, - the helicopter 'is .superior to the aeroplane from an efficiency point of view, because it involves only a single-stage translation of power from the engines driving it to the surfaces that support it in the air. In simple words, the helicopter supports itself in flight and attains forward speed from propellers or air-foils driven directly by its engines, whereas a two-stage translation of power is involved in the aeroplane—the motor drives a propeller, which, in turn, hauls a set of wings through the air. In every translation of power there are inevitable losses of efficiency, and it is contended by helicopter enthusiasts

that the aeroplane is fundamentally less • efficient than their type of machine. Whether practical helicopters can be made in sizes large enough to handle the transoceanic air travel of the future only time and the ingenuity of rotary wing aircraft designers can tell. So far as the immediate future is concerned, there is little doubt that air travellers across the Atlantic and Pacific will ride in fixed-wing craft of the multi-motored flying boat or land plane type. There has been much talk in recent years of so-called stratosphere flying, and this term has gained considerable hold in the popular imagination. The advantages of flying “ over the weather ” have heen emphasised from many sources and with considerable justification. Not so much has been said about the disadvantages of operating aircraft in the stratosphere or substratosphere, but there are practical difficulties to be overcome. Whether the solution of these problems is worth as much in operating advantages as it will cost in terms of increased structural weights andl design complications is a matter on which the experts themselves are far from being agreed. One development which was inspired initially by the desire to operate aircraft in the stormless reaches of the stratosphere now seems destined' for adoption generally in air-line operation. This is the so-called supercharged or sealed-cabin aeroplane. Its original purpose was to maintain normal atmospheric pressure for the passengers andl crew of aeroplanes flying at abnormal heights, but its contribution to passenger comfort how indhr cates that it will be an inevitable feature of the air liner of to-morrow. This is especially true with respect to sleeper planes, passengers on which now have to be awakened by cabin attendants every time the plane comes down for a landing, even from such normal cruising levels as B,oooft to 10,000 ft. The air lines have discovered that unless they do rouse their sleeping passengers, the_ change in atmospheric pressure which occurs during such descents causes acute discomfort and occasionally serious after-effects in the aural and nasal passages. A passenger who is awake during the descent of an aeroplane from such reasonable altitude ordinarily experiences no ill effects, because he swallows frequently on the way down, thereby clearing the eustachian tubes which lead from the throat to the ears, and relieving the eardrum pressure which he otherwise would feel. A sleeping passenger, however, fails to dlo this, and may wake up when he reaches the ground, to find his ear passages painfully clogged and sometimes seriously affected. For this reason most designers now agree that the constant pressure cabin is an assured thing in the big transport planes of the future. With such cabin supercharging, it will be possible to bring planes down even from great heights without the present necessity of slow descent during the last, hundred miles or so of flight as the aeroplane approaches scheduled stops. This ability to descend quickly will, in many cases be an addted safety factor, since it will enable the aeroplanes to pass speedily through levels where serious icing conditions may exist. For these reasons alone it appears certain that pressure cabins are on the cards, whether future air travellers ride through the sub-stratosphere or never rise above accepted present-day cruising levels.