Will helicopters fill the peacetime skies? Will they replace the family car? Here’s the low-down on the windmill wonder of the air
PAUL R. MILTON
A FEW weeks ago helicopters were reported to have been used to evacuate wounded from the Burma jungle, where there were no airfields or roads for air or motor ambulances.
Since last year the British and American Navies are said to have been experimenting with helicopters for convoy protection.
Last May, Rear Admiral Howard L. Vickery of the U. S. Maritime Commission and War Shipping Administration announced plans to put small landing decks on ordinary tankers, from which antisubmarinepatrol helicopters could fly, thus reducing the burden on escort carriers flying orthodox naval planes, and giving convoys the protection of what some experts consider a perfect antisubmarine aerial weapon, the hovering plane that needs no vast flight deck to become air-borne.
All of which would seem to indicate that the helicopter is a practical aircraft.
But it’s not perfect.
Nearly everybody today, taught by the war news to speak glibly of heavy bombers, transports, fighters, low-wing monoplanes, jet propulsion and so on, thinks he knows what a helicopter is.
Nevertheless, let’s take a sober look at it.
The helicopter is a wingless aircraft, deriving its lift from an overhead rotary wing, or rotor, revolving horizontally on a mast. It propels the craft forward, rearward and to either side as well as up and down. At the tail is a small propeller revolving at right angles to the overhead rotor. Its purpose is to counteract torque, or the tendency of the fuselage to revolve in a direction opposite to that of the rotor. One engine directly behind the cabin drives the rotor and the antitorque propeller. Since the noise of orthodox airplanes is made by the high-speed propeller, and the helicopter has no propeller, there is virtually no noise.
The autogiro, another type of rotary-wing aircraft, is often confused with the helicopter. The autogiro, however, has an ordinary engine and orthodox propeller in the nose for forward power. The forward motion sets an overhead rotor to revolving and enables the craft to hover. The rotor is not connected with the power unit.
Aviation opinion has come to favor the helicopter because it can take off vertically, which the autogiro cannot do, and because of its greater engineering simplicity in deriving all its lift from the rotor.
The war has given helicopters, as it has given electronics and jet propulsion, a powerful stimulus of effort and financing, telescoping decades into years and years into months. Had it not been for the war helicopter development might have dragged for many years.
And does this mean that, come peace, the family helicopter will promptly fill the skies? Is it the aircraft that will replace the family car in cost, convenience and comparable numbers?
Last January a conference of helicopter designers, inventors, engineers and manufacturers was held in New York City. Competitors freely compared notes on their helicopter projects, for they realized a common interest: to evaluate the helicopter itself and its possible effects on the aviation industry.
While no formal resolutions were adopted and no uniform policy agreed on, yet it became clear that most of the men present were agreed on one thing: That overenthusiasm on behalf of the helicopter,
building up in the public mind the notion that peace would see a flood of foolproof air buggies filling the skies, might hurt the industry more than it would help. It would lead the public to expect too much too soon. “Play it down’’ became the word.
Great Golden Egg
HELICOPTERMEN are doing their best to dispel a vision of the postwar years in which great numbers of families, air-enthused by the war and by the great numbers of men returning from membership in the Air Force, will expect to get helicopters and, like automobiles, take them right out of the showrooms. Since this is simply not going to be possible, the consequent public disappointment might lead to apathy toward helicopters should they later become available in quantity, at popular prices, and technically well within the skill of untrained individuals.
To avoid this disaster, and well aware of the great golden egg they are sitting on, helicoptermen refuse to be drawn into flowery descriptions of a helicopter world to come.
However, some aviation writers have applied their technical knowledge and their imaginations to how the helicopter will serve in our future society, and what it may do to our social life. This exploration conjures up the helicopter as the family car of the future, so safe and easy to operate that it will not only do all that a family car can do, but more. No airfields will be needed, no bridges or any of the enormous investment in public and private roads that the automobile has demanded. The helicopter will enable people to live far from the cities, and thus will stimulate the process of urban decentralization already so far under way in the United States and Canada.
The reasoning behind this picture of the helicopter Continued on page 20
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future is that the small fixed-wing airplane has already proven that it is not and will not be the air carrier of the general public— that is, perform the functions now largely performed by the automobile, without extraordinary added cost and inconvenience. For one reason, the helplessness of the small fixed-wing airplane without adequate and usually expensive airfields. Despite the fact that Canada and the U. S. will have many thousands of major and subsidiary airfields and strips after the war, whereas pre-war fields were numbered in hundreds, it is contended that the small fixed-wing airplane cannot take the place now marked off for the helicopter in these visions of the future.
Assessing the future value of the helicopter first of all poses two questions:
Can it replace any present mode of transportation in the way the gasoline or Diesel-powered vehicle replaced the horse-drawn?
Can it fill transportation needs that no present means can?
Even though the helicopter may not, in present expert opinion, become an air flivver, it has the advantage over small fixed-wing planes of needing only 100th as much space for take-off ahd landing. This means that helicopter landing spaces may be located closer in to centres of population instead of far outside, as present airfields must be located because of their size. Thus a helicopter journey from one city to another will probably save much of the time now consumed in getting from city to airport at one end and from airport to city at the other. Once in the air, however, today’s helicopter offers no advantage over small airplanes in speed. Much the same situation might be expected in comparing helicopter transports against airplane transports.
If the choice of means lies between automobile and helicopter for short hauls, the advantage would seem to lie now with the automobile. By far the greater part of automobile use is at low speeds for short distances; the greater speed of the helicopter would not offer sufficient saving in time.
In hauls of 100 miles or more, however, the helicopter might produce real time savings. An automobile covering 100 miles can rarely average barely one third of its top speed. A helicopter flying only at cruising speed would still cut the time in half. And while a car must follow roads that hardly ever go in a straight line, a helicopter can fly virtually like a bee.
There iaalso another question in assessing the future value of the helicopter:
How hard is it to fly?
Sikorsky, and his chief test pilot, Les Morris, who piobably have more helicopter hours in their logbooks than any other men in the country, are optimistic:
“It is reasonable to say that the average person will be able to learn to fly a helicopter proficiently as easily us that same person could learn to drive an automobile.”
They add, however, that such a person will have to be as familiar with helicopters—in advance—as he now is with automobiles.
Colonel H. F. Gregory, chief helicopter authority in the American armed forces, throws cold water on this statement.
THE helicopter in its present state is much more difficult to e ntrol than the conventional airplane. It is complicated and therefore involves more intricate control. Thus it must be flown by a specially trained pilot, and that means schooling far more extensive than merely teaching a man how to drive a car or fly a light plane. It demands a perfect sense of equilibrium —which some people never haveand perfect coordination. The element of controllability eliminates the helicopter from the ‘U-Drive-It’ category.”
Colonel Gregory has no patience with the idea that the helicopter can replace the family car for local errands. He points out that the downblast of the rotor is equivalent to a 40-mile-an-hour gale and would blow the contents of the “backyard” helicopter landing plots helter-skelter every time mother had to hop down to the grocer’s.
The helicopter, like so many other novel scientific notions, goes back to Leonardo da Vinci, who designed one. Since then numerous inventors have hammered at the idea, some with minor success, others with failure. Proved success came in 1937 when the German warplane designer, Heinrich Focke, demonstrated a successful helicopter in Germany. A woman pilot, Hanna Rasch, flew it from Bremen to Berlin, and the following year flew it inside a sports arena in Berlin. (Hanna Rasch, incidentally, was recently announced by the Nazis to have flown inside
a robot bomb on tests to report data on stability.)
Meanwhile, I. I. Sikorsky, Russian-born designer of many a famous plane, including the transoceanic Clippers, was concentrating on helicopters in America. In 1940 he produced his successful VS-300. In 1942 he watched an improved model, the XR-4 consigned to the U. S. Army, take off from a field in Stratford, Conn. It flew the 761 miles to Wright Field, a U. S. Air Forces material and experimental centre in Ohio, in something over 16 hours spread over five days for safety’s sake.
On March 22, 1944, Colonel Gregory flew a later Sikorsky model, the XR-6, nonstop from Washington, D.C., to Patterson Field, Ohio—387 air miles. The four hours and 55 minutes consumed set a record for helicopters remaining aloft.
The Sikorsky machine, successor to the first successful helicopter on this side of the Atlantic, has one overhead rotor rotating horizontally and powered by an engine behind the pilot and passenger, who sit side by side. Wide vision out of the cabin is ensured by generous use of plexiglass.
The rotor has three blades of 38-foot diameter and it is 12 feet from the bottom of the landing wheels to the top of the rotor shaft. At the end of the tapering fuselage is a small three-bladed antitorque propeller. The landing gear is a tricycle affair, though floats for water landings can be substituted.
Controls are relatively simple—a control stick rising between the pilot’s legs, a lever at the left which controls altitude, and rudder pedals under the pilot’s feet for steering. An engineering analysis of the manner in which these controls work is too technical to discuss here, but one key fact about the Sikorsky helicopter should be explained, for it answers one of the formerly insuperable engineering problems. All control of the helicopter—its direction up or down, forwar? rearward or right and left—is exercised by changing the pitch of the rotor blades. By combining these functions in the rotor, Sikorsky accomplished a simplification of enormous significance. All successful helicopters today embody this principle.
The Sikorsky two-man helicopter weighs approximately 2,400 pounds and has achieved altitudes, fully loaded, up to 5,000 feet. Manufacture of one Sikorsky model for war use is on an assembly-line basis at the United Aircraft Corporation plant at Bridgeport, Conn., and the XR-6, another late model, is being mass-produced by an automobile manufacturer in Detroit. Another helicopter being supplied to the U. S. Army comes from the Platt-Le Page Aircraft Company.
A later but also successful arrival in the helicopter field is Bell Aircraft Corporation of Buffalo, N.Y., makers of pursuit planes. The Béll machine was designed by Arthur M. Young. The rotor is twobladed, with a spread of 33 feet, and the antitorque propeller is somewhat smaller than Sikorsky’s. The two passengers sit side by side, and the machine weighs less than 1,600 pounds.
As ascent and descent, or change of direction in helicopters, are controlled by varying the pitch of the rotor blades, both rotor and cabin tend to tilt too. Avoiding the undue tilting of the cabin—in other words gaining greater stability—has long been a sticker in helicopter engineering.
Chief feature of the Bell helicopter is its solution of the stability problem, which is accomplished by an ingenious stabilizing bar directly under the rotor blades. “The two-bladed rotor is independent on the mast,” says Young, “tending to remain in a horizontal plane without tipping, and thus giving this craft stability in the air, promising increased simplification of controls when helicopters can be made for the public.”
Last May the Bell Company duplicated the sensational feat of Hanna Rasch in Berlin in 1938 and flew its helicopter inside an armory in Buffalo to demonstrate its ability to operate within confined areas.
Another important entry in the field is Andrew Jackson Higgins, builder and mass-producer of boats and cargo ships in New Orleans. Like other helicopters the Higgins rotor is freewheeler; that is, when the engine is disengaged from the rotor shaft the rotor continues to rotate, thus ensuring a reasonably safe descent for the machine even if the engine conks out. The only complete disaster that can befall a helicopter, other than a direct crash into a hard obstacle, is breakage of the rotors.
ALso much interested in helicopters Is Consolidated Vultee, for whom William B. Stout, one of the most unorthodox airplane designers in aviation, has built Continued on page 41
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several experimental windmill planes. Another machine is the PV-2 designed by Frank Piasecki for the P-V Engineering Forum — a one-man model weighing only 1,000 pounds; the threebladed rotor is only 25 feet in diameter. The 90-horsepower engine gives the PV-2 a top speed of perhaps 100 miles an hour and a cruising speed of 55.
The helicopter designed by the late Dr. George de Bothezat has the often tried but rarely successful coaxial rotors—that is, two rotors one above the other on the same shaft. These rotate in contrary directions. Also the engine is not behind the pilot but up between the rotors. The second rotor, moving contrariwise to the first, corrects torque and thus eliminates the antitorque propeller at the tail. Control in this aircraft is exercised much as in other helicopters, though with a number of technical differences which, according to the manufacturers, the Helicopter Corporation of America, make for great simplicity. De Bothezat also had definite ideas on the practicality of very small one-passenger helicopters and of transports with a capacity of 50 or more persons. The De Bothezat helicopter is being prepared for the postwar market.
In this field it is interesting to note that a man like Higgins, who has learned how to build highly complex boats on a mass basis, is giving some of his postwar attention to helicopters. A similar interest in helicopters is expressed by Henry J. Kaiser, the mass cargo-boat builder, who has a helicopter project afoot in his Fleetwings Division but is talking little about it—yet.
Other manufacturers, too, are engaged in helicopter projects but they are still largely experimental or are bound by military security.
While practical helicopters are at the most two-place, models already in design indicate that far larger machines are believed feasible. Several large bus companies in the U. S. are thinking of using 12-passenger helicopters on connecting and feeder lines, and the P-V Engineering P’orum is developing one capable of carrying a payload of one ton, or from eight to 10 passengers, plus baggage and mail.
As in fixed-wing airplanes there is no theoretical limit to the size of helicopters. The practicability of larger
sizes depends, however, on the development of compact engines deriving more and more horsepower from relatively less and less fuel. This continuous process is what accounts, in large part, for the development of larger and better airplanes.
Present helicopter opinion decries the probable use of larger helicopters to replace large airplane transports. Sikorsky believes the airplane superior for carrying large loads over long distances at high speeds Large helicopters may be expected to be most useful where large airplanes are not— in relatively short hauls.
Present plans in the helicopter field do not vision a helicopter for the general market selling for much less than $5,000. Further, even the most economical machine will burn twice as much gasoline as an automobile for a like distance.
The need for great flying skill, plus a cost that would remove the helicopter from the average pocketbook range, means then that the first main outlet of the helicopter will be in commercial fields. These include intercity bus services using large helicopters; feeder lines for main airlines; forest-fire, border, crop and pipeline patrol; short hauls for first-class mail (an autogiro has been used successfully for some years between the Philadelphia Post Office and the airport some distance away); short-haul commercial deliveries; geological survey; rescue work; etc. The commercial possibilities in some of these uses are great, and a number of large firms, including airlines, bus companies and railroads have already embarked on concrete plans.
This, then, is the present pattern of helicopter development, subject always to the hazards of prediction: At least a dozen helicopter makes will be available perhaps within a year after the manufacturers stop making war planes. Production in large quantities for the general public will not be attempted but helicoptermen will work closely with commercial users to iron the kinks out of the air’s newest gadget, and thus educate the public in helicopter use and function by practical example.
But don’t cancel your order for a postwar automobile yet. However, helicoptermen, at moments, admit they expect the helicopter to develop faster than did the automobile. Swift engineering developments, not now even in sight, may lower the cost and show that Colonel Gregory’s doubts of helicopter fiyability by the average person are far too pessimistic.