transportation revolution

The 707 gave birth to a family of transports—built around its basic design—that have dominated the global airline market ever since.

By William F. Mellberg

Many aviation historians regard the Douglas DC-3 as the greatest airliner ever built. It entered service in 1936. What made the DC-3 so great was its ability to earn a profit carrying only passengers. All previous airliners were uneconomical to operate, and early airlines depended on government subsidies to stay in business.

But despite its laudable economics and comfortable interior, the 21-seat DC-3 was no match for the passenger trains and ocean liners of the 1930s and 1940s. Airsickness was still a common affliction aboard unpressurized, propeller-driven airliners—forced to fly at lower altitudes through the most turbulent air. Moreover, their piston engines were costly to maintain and produced deafening noise and bone-rattling vibration.

In 1943, the British government formed a committee under the chairmanship of Lord Brabazon to identify postwar civil aviation requirements. The Brabazon Committee recommended several advanced concepts based upon the revolutionary new gas turbine (or "turbojet") engine that Britain's Frank Whittle had pioneered.

One of the Brabazon Committee's recommendations called for a small, jet-powered, transatlantic mailplane. The de Havilland Aircraft Co. accepted the challenge of designing and building the proposed aircraft. Many different approaches were studied under the leadership of the firm's chief designer, Ron Bishop—including several radical, tailless concepts.

The first production Comet (foreground) flies in formation with the two prototypes. This aircraft later disintegrated over the Mediterranean, in 1954.

In the end, the D.H. 106 evolved from a jet mailplane into the world's first jet airliner. The appropriately named Comet was a streamlined machine with a bullet-like nose and four de Havilland jet engines buried in its swept-back wings. Built in secrecy to protect de Havilland's commercial lead, the Comet was finally unveiled to the world on July 27, 1949. Early that evening, the company's chief test pilot, John Cunningham, was at the controls for the jet transport's historic maiden flight.

The Comet was originally built for British Overseas Airways Corp., which had placed an initial order for 14 airplanes in 1946. The initial Comet 1 model was designed to carry 36 passengers over 1,500 miles at 35,000 feet and 500 mph—twice as high and twice as fast as most contemporary propliners.

BOAC inaugurated the world's first scheduled jet service, between London and Johannesburg, on May 2, 1952. It was the dawn of the Jet Age, and passengers were effusive in their praise of the Comet's quick, quiet, smooth, vibration-free flights.

Other airlines began operating the type, as well—including two French carriers, Aeromaritime and Air France. Additional orders started coming in from Canada, Japan, Venezuela, and Brazil. The slightly larger, longer-range, 44-seat Comet 2 made its first flight in February 1952. And the 78-seat, transatlantic Comet 3 was also in the works.

The Avro Canada Jetliner, parked at Chicago's Midway Airport in 1951. The largely forgotten C102 was the first jet transport to land at Midway.

The future looked bright for de Havilland, as the Comet was in service more than six years ahead of its nearest American rival. But triumph soon turned into tragedy.

Three accidents marred the first year's Comet operations. None of those accidents was blamed on the airplane itself. But on Jan. 10, 1954, a BOAC Comet plunged into the Mediterranean, in good weather, shortly after takeoff from Rome. An engine-induced fire was thought to be the probable cause, and a number of preventive modifications were made, grounding the Comet fleet for two months. Two weeks after resuming operations, another Comet crashed near Sicily under nearly identical circumstances. The aircraft had disintegrated in flight, and the Comet 1 was grounded once again—permanently.

The mysterious crashes led to a lengthy investigation. A Comet was immersed in a water tank where loading tests simulated operational conditions and the effects of repeatedly pressurizing the cabin for high-altitude flights. These tests revealed a new and deadly phenomenon—metal fatigue. Tiny stress cracks formed around the Comet's square window frames. The structure could fail catastrophically without warning, leading to an explosive decompression of the cabin. That is what happened to the two Comets that fell into the Mediterranean, claiming the lives of all on board. The painful lessons learned from the Comet disasters were incorporated into every subsequent jet transport, and fail-safe structures were designed to stop the propagation of cracks.

The single Comet 3 became the prototype for the improved Comet 4. BOAC ordered 19 Comet 4s in 1955. On Oct. 4, 1958, the airline inaugurated the first-ever transatlantic jet service between London and New York. But de Havilland had lost the competitive edge. Only 113 Comets were produced, the last one being retired from airline schedules in 1980.

Brave New Word

Few people remember the world's second jet airliner, even though its name became a generic term. The Avro Canada C102 Jetliner prototype took off on its maiden flight from Malton, near Toronto, on Aug. 10, 1949, just two weeks after the Comet. The Jetliner is now a footnote in history. It could have been much more.

According to Jim Floyd, the Jetliner's chief designer, "The first impression expressed by most people seeing it for the first time is that it looks like a modern passenger jet. In fact, it was flying over 50 years ago—more than halfway back to the Wright Brothers. And it was the first passenger jet to be built and flown in North America."

The Jetliner was designed for intercity routes, such as those carrying the bulk of air traffic in North America. The C102's pressurized cabin could seat up to 52 passengers. Its four Rolls-Royce engines were slung in pairs under each wing.

The Jet Age did away with the sight and sound (and vibration) of piston-powered, propeller-driven airliners. This is the American Airlines 707-120B.

During numerous demonstration tours, the Jetliner became the first jet transport to land in cities such as Chicago, Washington, Tampa, Miami, Denver, and Los Angeles. On April 18, 1950, the C102 made history when it flew from Toronto to New York with the first sack of airmail to be carried by a jet. The crew received an enthusiastic welcome to Manhattan, complete with a motorcade and banquet. In 1951, the Jetliner broke all records on a triangular trip from Toronto to Chicago to New York and back. It flew at 520 mph and 36,000 feet. Nearly a decade would pass before any other transport could match its performance over similar routes.

National Airlines signed a letter of intent for four C102s, American and United each expressed serious interest in it, and the U.S. Air Force wanted to acquire 20. Howard Hughes, who owned TWA, was especially keen on the Jetliner. But just when Avro seemed to be on top of the world, the bottom fell out. The Canadian government told the firm to halt all work on the C102 in 1951. Avro was ordered to allocate all of its resources to the production of military jets for the Royal Canadian Air Force.

Tragically, for Canada (and commercial aviation), the Cold War killed the Jetliner. The Jetliner prototype was scrapped in 1956, with only its nose being saved for eventual display in Ottawa's National Aviation Museum.

Dash 80=707

While the spotlight was on the Comet and the Jetliner, the Seattle-based Boeing Aircraft Co. was busy producing its long-range Stratocruiser propliner for the airlines, and its new, record-breaking B-47 Stratojet bomber for the U.S. Air Force. The sleek-looking B-47 was powered by six jet engines, suspended in pods from sharply swept-back wings. To refuel the B-47 in flight during strategic bombing missions, Boeing produced the KC-97 flying tanker—a variant of its Model 367 Stratofreighter (which was a military version of the Stratocruiser).

Boeing engineers were convinced that the future of air travel was linked to the turbine engine. They also foresaw the need for a jet successor to the KC-97. So they started looking at turbine-powered derivatives of the Model 367 Stratofreighter. One concept, the Model 367-64, would have mated swept-back wings and podded engines to a Stratocruiser-type fuselage. Under Maynard Pennell's leadership, this proposal evolved into a more advanced jet transport design—the Model 367-80, or Dash 80.

In August 1952, three months after the Comet entered service, Boeing's president, William Allen, announced that the company was proceeding with its own jet transport as a private venture. The firm invested over $16 million in the construction of a single prototype, betting its entire future on the project. The jetliner design was Boeing's Model 707, and it would be marketed as such. But the Dash 80 designation was retained for the prototype, partly as a ruse to keep the real configuration hidden from competitors.

Powered by four Pratt & Whitney JT3 engines, the 707 would be a large airplane—over twice as heavy, and carrying four times as many passengers, as the Comet 1.

The Dash 80's first flight took place on July 15, 1954, with Boeing test pilot Tex Johnston at the controls. But the grounding of the Comet that spring cast a shadow over jetliners. Airlines were reluctant to buy the 707.

The first order came from the U.S. Air Force in September 1954, when it bought an initial batch of what later totaled over 800 KC-135 Stratotankers and related military versions of the plane.

The Boeing 367-80 is seen on a test flight over the Seattle area circa 1954. Note the provision for a refueling boom on the belly, used in KC-135 trials.

Boeing proceeded to put the Dash 80 through grueling tests to prove its structural integrity and superior performance. Meanwhile, Douglas announced its own plans for a jetliner. The DC-8 would be slightly bigger than the 707, its wider fuselage allowing six-abreast seating and greater fuel capacity for longer range.

Boeing had the advantage of being able to demonstrate a flying airplane, and Tex Johnston put on a spectacular demonstration when he barrel-rolled the Dash 80 over Seattle. But Douglas found it easier to make changes with its paper airplane.

Finally, Pan American Airways placed an order in October 1955 for 20 707s and 25 DC-8s. To get this order, Boeing had to widen the cabin by four inches, giving the 707 a "double-lobe" fuselage that accommodated six-abreast seating like the DC-8. The fuselage was also lengthened. These were expensive changes, but they were necessary to win additional orders at home and abroad.

Pan Am inaugurated 707 service between New York and Paris on Oct. 28, 1958. The carrier also introduced the larger, longer-range 707-320 Intercontinental version in 1959. During the course of one year, a dozen Pan Am 707s could carry as many people across the Atlantic as Cunard Line's giant steamships, the Queen Mary and Queen Elizabeth. People could now fly overseas in less time than it took a passenger train to travel from Chicago to Cleveland. Such statistics added up to overwhelming competition—and the beginning of the end—for ocean liners and streamliners. They also generated a flood of orders for Boeing.

American Airlines started flying 707s across the United States in January 1959. Coinciding with the dawn of the Space Age, the 707 inspired nicknames such as "Astrojet" and "Star Stream." One airline brochure declared, "Your plane is floating in a clear, dimensionless world of its own. On a particularly clear day you can sometimes see the very curve of the Earth's surface at the horizon."

Today we think nothing of boarding a jetliner in Chicago and flying halfway around the world, enjoying a meal and a movie along the way. Hundreds of millions of passengers, and countless tons of freight, are carried annually by air.

The 707 brought about this transportation revolution. It also changed the aircraft industry. But the 707 gave birth to a family of transports—built around its basic design—that has dominated the global airline market ever since.

"The 707 provided airlines with both expanded capacity and reduced costs at a time when passenger traffic was poised for tremendous growth," said Jon Proctor, editor-in-chief of Airliners magazine. "Reliable turbine engines and cheap kerosene fuel, combined with increased passenger comfort, made Boeing's gamble an instant success."

More than 1,000 707s had been built when production ended in 1991. There are still a few 707s in service, not to mention several hundred KC-135s. The Dash 80 served as a company-owned research aircraft through 1970, being used to test all sorts of new systems for Boeing jetliners. ASME named it an International Historic Mechanical Engineering Landmark in 1994.

The venerable Dash 80 took to the air one last time in August, when it flew from Boeing Field in Seattle to Washington Dulles International Airport in northern Virginia. The aircraft will be on permanent display at the National Air and Space Museum's new Steven F. Udvar-Hazy Center, whose opening marks the 100th anniversary of the Wright brothers' first flight.

Next year marks the 50th anniversary of the Dash 80's first flight. One could argue that no airplane in history— other than the Wright Flyer—has had such an enduring influence on world culture.

Bill Mellberg enjoys an unusual dual career as an aerospace writer and political humorist. He is the author of Famous Airliners and Moon Missions.

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