Supersonic Transport - History

History

Throughout the 1950s an SST looked possible from a technical standpoint, but it was not clear if it could be made economically viable. There was a good argument for supersonic speeds on medium and long-range flights at least, where the increased speed and potential good economy once supersonic would offset the tremendous amount of fuel needed to overcome the wave drag. The main advantage appeared to be practical; these designs would be flying at least three times as fast as existing subsonic transports, and would be able to replace three planes in service, and thereby lower costs in terms of manpower and maintenance.

Serious work on SST designs started in the mid-1950s, when the first generation of supersonic fighter aircraft were entering service. In Europe, government-subsidized SST programs quickly settled on the delta wing in most studies, including the Sud Aviation Super-Caravelle and Bristol 223, although Armstrong-Whitworth proposed a more radical design, the Mach 1.2 M-Wing. Avro Canada proposed several designs to TWA that included Mach 1.6 double-ogee wing and Mach 1.2 delta-wing with separate tail and four under-wing engine configurations. Avro's team moved to the UK where its design formed the basis of Hawker Siddeley's designs. By the early 1960s, the designs had progressed to the point where the go-ahead for production was given, but costs were so high that Bristol and Sud eventually merged their efforts in 1962 to produce Concorde.

In the early 1960s various executives of aerospace companies were telling the public and Congress that there were no technical reasons an SST could not be produced. In April 1960, Burt C. Monesmith, a vice president with Lockheed stated to various magazines that an SST constructed of steel weighing 250,000 pounds could be developed for $160 million dollars and in production lots of 200 or more sold for around $9 million. But it was the European development of the Concorde that set off panic in the US industry, where it was thought that Concorde would soon replace all other long range designs, especially after Pan Am took out Concorde purchase options. Congress was soon funding an SST design effort, selecting the existing Lockheed L-2000 and Boeing 2707 designs, to produce an even more advanced, larger, faster and longer ranged design. The Boeing design was eventually selected for continued work. The Soviet Union set out to produce its own design, the Tu-144, which was nicknamed the "Concordski."

In the 1960s environmental concerns came to the fore for the first time. The SST was seen as particularly offensive due to its sonic boom and the potential for its engine exhaust to damage the ozone layer. Both problems impacted the thinking of lawmakers, and eventually Congress dropped funding for the US SST program in 1971, and all overland commercial supersonic flight was banned.

However more recent analysis in 1995 by David W. Fahey, an atmospheric scientist at the National Oceanic and Atmospheric Administration, found that the drop in Ozone would be from 1 to 2% if a fleet of 500 Supersonic aircraft were operated. Which Mr. Fahey expressed would not be a showstopper for an advanced SST development.

Nevertheless in the mid 1970s Concorde was now ready for service. The US political outcry was so high that New York banned the plane. This destroyed the aircraft's economic prospects — it had been built with the London-New York route in mind. The plane was allowed into Washington, D.C., and the service was so popular that New Yorkers were soon complaining because they did not have it. It was not long before Concorde was flying into JFK.

Along with shifting political considerations, the flying public continued to show interest in high-speed ocean crossings. This started additional design studies in the US, under the name "AST" (Advanced Supersonic Transport). Lockheed's SCV was a new design for this category, while Boeing continued studies with the 2707 as a baseline.

By this time the economics of past SST concepts no longer made sense. When first designed, the SSTs were envisioned to compete with long-range aircraft seating 80 to 100 passengers such as the Boeing 707, but with newer aircraft such as the Boeing 747 carrying four times that, the speed and fuel advantages of the SST concept were washed away by sheer size.

Another problem was that the wide range of speeds over which an SST operates makes it difficult to improve engines. While subsonic engines had made great strides in increased efficiency through the 1960s with the introduction of the turbofan engine with ever-increasing bypass ratios, the fan concept is difficult to use at supersonic speeds where the "proper" bypass is about 0.45, as opposed to 2.0 or higher for subsonic designs. For both of these reasons the SST designs were doomed by higher operational costs, and the AST programs vanished by the early 1980s.

Concorde only sold to British Airways and Air France, with subsidized purchases that were to return 80% of the profits to the government. In practice for almost all of the length of the arrangement, there was no profit to be shared. After Concorde was privatised, cost reduction measures (notably the closing of the metallurgical wing testing site which had done enough temperature cycles to validate the aircraft through to 2010) and ticket price raises led to substantial profits.

Since Concorde stopped flying it has been revealed that over the life of Concorde, the plane did prove profitable, at least to British Airways. Concorde operating costs over nearly 28 years of operation were approximately £1 billion, with revenues of £1.75 billion.

The last regular passenger flights landed at Heathrow Airport on Friday, October 24, 2003, just past 4 p.m. – Flight 002 from New York, one from Edinburgh, Scotland, and the third which had taken off from Heathrow on a loop flight over the Bay of Biscay.