The Concorde supersonic airliner first flew almost 30 years ago, and entered regular service more than 20 years ago. By now, the skies should be full of sleek supersonic jets ferrying people rapidly all around the globe.
Instead, the Concorde only services a few high-profile routes–Paris to New York and the linke–while most of us putter across the Atlantic in 747s. So what happened?
Chuck Yeager broke the sound barrier in 1947, and by 1957, General Dynamics’s B-58 bomber had proved it was possible to build a large supersonic aircraft. In 1962, the British and French governments agreed to jointly develop an supersonic transport (SST), to be called the “Concorde” after the international concorde that produced it.
Duplication of effort and miscommunication between the two countries made the hugely expensive project a nightmare for the governments involved, but the resulting plane was a remarkable technological achievement because of the immense challenges that had to be overcome to build it.
An ordinary jet is preceded by its own sound waves, which disrupt the air and push it ahead of the plane, reducing drag. When an aircraft reaches the speed of sound, however, it catches up with its sound waves and slams into relatively stagnant air, creating a sound like a thunderclap, called a sonic boom. At the same instant, drag, caused by friction between the air and the aircraft, increases enormously.
This friction is great enough to heat the outer surfaces of the Concorde to 120 degrees Celsius, necessitating special air-conditioning systems, and careful consideration of how different materials expand when heated. The high-speed rush of air also tends to distort control surfaces and changes the way jet engines work.
All these problems and more were overcome to produce the beautiful, delta-winged Concorde. Two hundred four feet in length, with a wingspan of 84 feet, it can carry 125 passengers in first-class comfort at a cruising speed of 1,320 miles per hour, twice the speed of sound. It can fly across the Atlantic and back in less time than it takes a 747 to make the trip one-way, and it does so at up to 60,000 feet–the very edge of space, so high you can see the curvature of the Earth, and more than five miles higher than 747s, sometimes seen by passengers as tiny specks, rapidly left behind. The distinctive drooping nose allows the pilot to see the runway when landing; during flight, the nose stretches straight out in front to minimize drag.
But three problems couldn’t be overcome: noise, pollution and economics. The Concorde’s sonic booms can break windows and cause other damage on the ground, and it’s also extremely noisy on takeoff and landing: its original engines produced low-frequency vibrations powerful enough to crack the foundations of houses. Those engines also produce nitric oxide, which can damage the ozone layer, especially when released at high altitude. And the Concorde requires twice as much fuel to fly across the Atlantic as an ordinary jet, yet can carry only 125 passengers–one reason why a one-way ticket costs more than $7,000 Canadian.
Because of these problems, Concorde production ended in the late 1970s. The 14 planes now in service are all there will ever be, and in 20 years, when the last one is grounded, that could be the end of supersonic passenger flight…
…or maybe not. Engineers from NASA and U.S. aviation companies are now designing the High Speed Civil Transport, which could carry 300 passengers 5,700 miles at up to 1,600 mph while meeting noise and pollution standards, with ticket prices only 20 to 25 percent higher than those for ordinary jets..
The HSCT would be a slim delta-winged craft like the Concorde, but much bigger: 320 feet long (90 feet longer than a 747), with a wingspan of about 145 feet. Its powerful engines, three times as large as current military supersonic engines, would feature giant noise supressors that mix outside air with the jet exhaust, reducing its velocity (and hence the noise it produces) while maintaining thrust by adding mass. New combustors would virtually eliminate nitric oxide production, solving the pollution problem.
The most radical thing about the HSCT would probably be the lack of forward windows. Pilots would view flat-panel synthetic displays, created by compiling information gathered by the navigation system, radar, video cameras and infrared sensors.
Boeing could move ahead with a full developmental program for the HSCT as early as 2006, probably seeking global partners to help defray the estimated $13 to $15 billion cost, and the planes could enter service in 2015–just in time to take the place of the aging Concordes, and finally make that 1960s vision of skies full of sleek supersonic airliners a reality.
