Authors: Clarence L. Johnson
Because of the importance of compressibility as an aviation industry problem and the wide interest in it, I prepared a technical paper covering our own research and what we thought the solutions might be for presentation to the American Institute of Aeronautical Sciences. It was duly cleared by the War Department, and I presented it at a meeting in January 1943. Naturally there were many requests from other companies for copies, and I supplied them.
Then the paper was recalled and labeled “secret.”
The agency charged with assisting, coordinating, and instituting this nation’s aeronautical development did not want to acknowledge the work as industry-initiated. Later NACA did do some testing on its own but had contributed nothing to solving the problem of compressibility on the P-38 except allowing the use of its wind tunnel. And this only under orders from the Army Air Corps. The successor agency, National Aeronautics and Space Administration (NASA), by contrast, has
been very aggressive and eager to assist and work with industry. I am happy to report that I enjoy excellent relations with NASA.
The matter of secrecy on compressibility became a moot point, for when the war was over and we were able to investigate, we found in German industry literature a great deal of information on compressibility, its effects, and how to avoid them. The Germans had handled it primarily with the swept wing, which they had been flying since the beginning of the Battle of Poland. Later claims to invention of the swept wing in this country are without foundation. By the end of 1943, the year I presented my paper, the Germans had all the aircraft types they were going to build, and the compressibility phenomenon was the talk of P-38 pilots everywhere.
In the course of World War II, horsepower for the P-38’s engines had been increased from 1,000 to 1,750 per engine. Yet with all this great gain in power, we had been able to increase the speed only 17 miles an hour because of compressibility, the effects being felt first on the propeller long before they were encountered on the wing.
It became obvious that we would have to design better wings and tails, but that if we wanted higher performance we would have to get rid of the propeller.
A
VIATION BEFORE WORLD WAR II
had been for the pioneer, the daring record-seeker, the sportsman pilot, a few relatively wealthy travelers, government officials, and the military.
A new Lockheed transport, the company’s first large one, would carry more people farther and faster and more safely than ever before, and economically enough to broaden the acceptance of flying as an alternative to train, ship, and automobile.
The Constellation was a tremendous challenge to Lockheed. It was our first attempt to enter the large-size transport field. Describing the company state of mind at the time, Hall Hibbard has said, “Up to that time we were sort of ‘small-time guys,’ but when we got to the Constellation we had to be ‘big-time guys’… We had to be right and we had to be good.”
Our commercial Model 14, so successful as the Hudson anti-submarine patrol bomber and the related Model 18 Lodestar—really a stretched Electra—were not large enough to compete in the expected post-war commercial air travel market.
Anticipating the future well before the war, we had worked on new designs, including Model 27, a canard, with horizontal stabilizer and control surfaces in front of the main supporting surfaces—or simply, with tail in front. We built a mockup but had the sense not to pursue this into production. The canard was impossible to make safe at high angles of attack—as the Russians later discovered with their supersonic TU-144 that crashed at the Paris Air Show in 1973.
Another was the Model 44 Excalibur, a very good “DC-4” in advance of the DC-4. It held considerable promise, and Pan American Airways expressed interest. Again, we built a mockup. Fortunately, we did not build it in prototype, as it would have been too small for competitive over-ocean service.
Then, in 1939, Howard Hughes as principal stockholder and Jack Frye as president of Transcontinental & Western Air, Inc., had asked Robert Gross if a transport could be designed to carry 20 sleeping passengers and 6,000 pounds of cargo across the US nonstop and at the highest possible cruising speeds. They suggested between 250 and 300 miles an hour at an altitude around 20,000 feet.
We abandoned our earlier studies and concentrated on the new airliner for TWA. What we proposed—Robert Gross, Hall Hibbard, and I—to Hughes at a meeting in his Muirfield Road residence in the elegant old Hancock Park section of Los Angeles was a larger airplane, capable of flying across the ocean and carrying many more people. We reasoned that it was economically unsound to carry only 20 sleeping passengers when we could accommodate more than 100 people in the same space with normal seating. Our design was capable of flying transatlantic with the Wright 3350 engine already in development for the military B-29 bomber. It was the world’s largest air-cooled engine.
Few people not involved directly realize what a tremendous job it is to design, test, and build a new type of aircraft. And the larger the airplane, the more difficult are some of the problems. For example, the horizontal tail area of the Constellation was greater than that of the early Electra’s entire wing.
The Constellation was first with many design features for passenger airliners. It was the first airplane to have complete power controls—that is, hydraulically “boosted.” The basic principle of mechanically enhancing the human effort had been used in steamships, cars, and trucks, but the application to aircraft was much more complicated. Lockheed earlier had undertaken it as a long-range research project in anticipation of the greater control problems to come as aircraft performance
increased. It was decided early to incorporate the device in Constellation design.
I had some difficulty in convincing Robert Gross of the advisability of adding this complexity to the airplane, since other aircraft manufacturers were ignoring it. Why did we need it? But I caught him one day when he had just parked his new Chevrolet in the company garage.
“Bob, you didn’t really need power to steer that car, but it makes it a hell of a lot easier, doesn’t it?” I never heard another word of dissent about power steering for aircraft.
The new airliner was to be faster, at 340 miles per hour top speed, than many World War II fighters. This soon was increased to 350 mph. Unlikely though it may seem, the Constellation transport used the same wing design as the P-38 fighter—larger, of course, and with an improved version of the Lockheed-Fowler flaps.
Its pressurized cabin allowed comfortable flight at 20,000 feet, above 90 percent of weather disturbances. It was the first airliner with this capability. Our early work on the XC-35 contributed importantly here. The airplane had excellent performance on just two of its four engines. And those powerful engines gave it an easy transcontinental and transatlantic nonstop range.
There were other innovations for transports introduced initially or in later development: integrally-stiffened wing structure, reversible propellers, turbo-compound engines, wingtip fuel tanks, and a detachable streamlined cargo pack carried under the fuselage.
That “Speedpak,” the under-fuselage baggage carrier, was a very good concept and still is. It cost only 12 miles an hour in lost speed because of extra aerodynamic drag, and the passengers’ baggage always was right there on landing. I wish we had done more with that; it never really caught on. Of course, airports were nowhere near so busy as they are today.
Six different wind tunnels were used in development of the original Constellation design. Most of the tests were conducted at the University of Washington and Lockheed’s own
tunnel, but supplementary tests were undertaken at Cal Tech and in NACA’s high-speed tunnel, spinning tunnel, and 19-foot tunnel.
Engines were tested not only in ground runup but in flight, installed in a Vega Ventura. One in the ASW series of aircraft, this was produced by a Lockheed subsidiary. It gave us a flying test bench for the Constellation engine. Installation was based on several years of work by the Civil Aeronautics Board on fire prevention, warning devices, and fire-extinguishing methods. Despite these precautions, we later would have a temporary grounding of the airplane because of fire.
Development work on the Constellation led to establishment of a second major research and development facility at Lockheed—a laboratory for mechanical and structural testing of aircraft structure and systems. We had built a full-scale fuselage mockup of the airplane. Then, because of the complexity of hydraulically boosting the entire control system, we built a mockup of that alongside the cabin mockup.
With our limited space, this all was so crowded and so unprofessional looking that Messrs Gross and Hibbard took pity on us. “All right, we’ll go for a research lab,” Gross allowed. We had a start on the very extensive and sophisticated research and development facilities that exist at Lockheed today.
We built our new research lab next to the wind tunnel and made it large enough so that we could represent in full scale the entire control system of the Constellation from cockpit to tail. We could provide the equivalent of air loads on the control surfaces by the use of very heavy springs. This is how we developed what was the first power-boosted control system for any airplane.
The electrical system on the Constellation was another of those mocked up. This served a second purpose later when a TWA plane crashed on a crew training flight. The cockpit had filled with smoke from an electrical fire. We were able to reproduce conditions in the lab and also simulated the smoke conditions in actual flight—but we wore gas masks.
In the TWA tragedy, a short circuit in an electrical fitting had set fire to oil-soaked insulation and an open door then had allowed smoke to enter and blind the pilot and copilot. Our accident investigation resulted in some redesign with extra protection against the possibility of engine fire.
That “Day of Infamy,” Sunday, December 7, 1941, put a hold on all commercial aircraft production. After Pearl Harbor, the Constellation project was stopped by military authorities who wanted Lockheed to concentrate on Hudson, P-38, and other war production. The Vega company, in pool with Boeing and Douglas, was to produce the B-17 bomber and abandon its original plans to build small civilian aircraft.
The Air Force, fortunately for the Constellation program, saw a need for military transport aircraft to carry large numbers of troops. The Constellation was “drafted.” But its production was stalled 17 times by the military during the war because of the priority of other projects when the production people were needed elsewhere.
The Constellation made its first flight on January 9, 1943, in military olive drab paint, as the C-69. We had delayed the flight for two days because of very high winds—too high for a first flight with a large, new transport. The press corps—radio and newspaper reporters, press photographers, magazine writers, newsreel cameramen—would appear each morning only to be invited twice to adjourn to the air terminal Skyroom for breakfast and a wait while we hoped for the winds to subside, finally gave up and cancelled the flight. We were all happy when the third day dawned more gently.
The airplane made six successful test flights that day. Its accelerated service tests for the military at Wright Air Development Center, Ohio, set a record—170 flying hours completed in 30 days. The airplane also had the distinction of carrying in the cockpit Orville Wright on what would be his last flight.
At the end of World War II, Lockheed was in the enviable position of having a new, highly-advanced transport, thoroughly tested in military service and ready for commercial airline production. The first deliveries of an initial Model 049
actually were conversions of Air Force C-69s already in work. It took only 90 days to turn out the first commercial model, which went to TWA in November 1945.
Checking blueprints of a milestone undertaking—development of the Constellation transport—with Hall Hibbard. Test flight of the aircraft with Howard Hughes, below, was to prove a terrifying experience
.