Lame boxes in the sky: Why there is still no Concorde successor
Commercial airliners fly at speeds of around 800 km/h. There was once the Concorde, which was three times as fast. Why there is no successor 15 years after their last flight.
A Concorde, the first and only supersonic commercial airliner. In 2003 it took off for the last time. (Image: Chris Bacon/AP (Shannon, 7. August 2001))
The sky is wide and free, you think. That could be accelerated quite a bit. Still, the planes fly at a relatively modest speed of 800 kilometers per hour. Why not faster? One remembers the Concorde, the first supersonic airplane of the British and French, which flew with legendary 2400 km/h – in well three hours from London to New York. But for 15 years, none of these supersonic aircraft has taken to the skies again.
"The catalyst for the end of Concorde was the disaster involving an Air France plane in Paris on 25. July 2000," says Jurg Wildi, president of the Swiss Association of Aeronautical Sciences and lecturer at ETH Zurich. Metal parts lying on the runway had damaged Concorde’s fuel tank during takeoff. The plane subsequently crashed shortly after takeoff near Paris, killing 113 people.
Jurg Wildi, President of the Swiss Association for Flight Sciences.
But that alone was not the reason for the end of the once celebrated Concorde, as Wildi explains. The decisive factors were the cost, the environmental impact and the noise caused by this extremely fast aircraft. The Concorde, whose last flight was on 24. The Concorde, which could be admired on October 2003, was a prestige and technology project of England and France. "It was operating in a niche market," says Wildi. There were only a few such aircraft, and the extremely high development costs for the supersonic aircraft had to be passed on to them. A flight with the Concorde was only therefore already an expensive pleasure. In addition, maintenance costs were also very high, because the heavily loaded engines in particular needed a lot of care. "Also the comfort for the passengers was not great. It was tight in the seats because Concorde was a very slim aircraft, for aerodynamic reasons," says Wildi.
Immensely high fuel consumption
The Concorde’s fuel consumption was also immense. "The plane had engines like a fighter plane."And then when the plane accelerated to top speed, it resulted in a pressure surge with a very loud sonic boom. "The aircraft could therefore only accelerate fully over the sea, away from populated areas," explains Jurg Wildi.
But Concorde flew with technology developed more than thirty years ago. With today’s knowledge, the operation of a supersonic airliner should be possible again. In fact, the enterprising British billionaire Richard Branson is planning to build a successor to Concorde. The commercial aircraft "Boom" is to fly at a speed of 2700 kilometers per hour. Wildi mentions a similar project called "Aerion". Business jets are to travel at 1.5 times supersonic speed in this project supported by Airbus.
Enormous thrust and energy
In such niches of private and business aviation, Wildi can imagine supersonic traffic sooner or later. But not in normal air traffic. "Commercial aircraft fly at a speed of 85 percent the speed of sound," says Wildi. "Mach 0.85". If this speed is exceeded, the aircraft’s drag increases dramatically due to the changed flow conditions around the aircraft. To overcome this compression drag and fly faster than Mach 0.85, an airplane would need an enormous amount of thrust and energy. The Concorde did it like a military aircraft with brute force.
Today’s airlines, which have to optimize everywhere for cost reasons, will therefore hardly be able to afford such a reduction in efficiency through higher speeds. In addition, while travel time is reduced – Branson’s plane would get you to New York in three hours – passengers lose most of their travel time getting to the airport and waiting around. "Calculated from door to door, the pure flight time amounts to the half. For short distances, a supersonic flight will never be worthwhile anyway," says Wildi.
Also, the problem of sonic boom would have to be solved so that these planes could accelerate fully over populated areas. But research is being done on that, says the aviation expert.
Aircraft need two-thirds less fuel
As well as making aircraft more efficient and quieter. With some success. The Zurich-based flight scientist states:
And also the noise caused by an airplane could be reduced by 75 percent. This is mainly due to improvements in engines and aerodynamics. Lighter and aerodynamically improved through the use of carbon and aluminum, the planes offer less drag, so less thrust is needed, making the planes quieter. The engines are decisive for noise during takeoff, aerodynamics during landing. The improvements apply to all aircraft manufacturers in the market dominated by Boeing and Airbus.
According to Wildi, commercial aircraft traveling at 2.5 to 3 times the speed of sound would be technically feasible in theory. Because the effort increases with the speed, but not realistically. The trend is to halve fuel consumption in the next 30 years, as well as noise emissions. Research is also being conducted into hybrid-electric engines and biofuels. Such plant-based fuels are already being blended into kerosene today.
High supersonic speeds are being exploited in military aviation. Fighter jets are traveling at more than twice the speed of sound; further development is focused on combat systems and networking the aircraft. Speed is the name of the game in spy aviation. The U.S. SR-71 reconnaissance aircraft can fly at three times the speed of sound, and a new spy plane is even expected to accelerate to Mach 5. Jurg Wildi doubts whether this is worth the effort. "Such aircraft are in competition with satellites." And these already have the earth in detail in their sights.