The Forgotten American Concordes

While most are aware of the Concorde, a supersonic passenger airliner that was the result of a joint venture between the French Aérospatiale and British Aircraft Corporation, many have forgotten that there were three competing designs from the United States and Russia. The Concorde operated from 1976 to 2003, but in the ’60s and ’70s…

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Before Concorde had complete development, competitors attempted to beat them to the punch. Under an Anglo-French treaty, Sud Aviation, which became Aérospatiale, and the BAC would go on to create an aircraft that had a maximum speed over twice the speed of sound at Mach 2.04, which was 1,354 mph at cruise altitude. Air France and British Airways were the only airlines to purchase and fly Concorde.

Twenty Concordes were built, along with six prototypes and development aircraft. It is one of only two supersonic transports to have ever been operated commercially, but not the only one to try. The other that made it was the Soviet-built Tupolev Tu-144. Read ahead to learn about it, and the two American attempts to compete with the only long term supersonic passenger jet service to operate anywhere in the world…

The Russian Tupolev Tu-144

The Russian Tupolev Tu-144 was actually the first SST, or supersonic transport aircraft, to enter commercial service. It had its first flight two months before Concorde on December 31, 1968. The design was a product of the Tupolev design bureau, headed by Alexei Tupolev, of the Soviet Union and manufactured by the Voronezh Aircraft Production Association in Voronezh, Russia.

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The Tu-144 first went supersonic on June 5, 1969 and less than a year later, on May 26, 1970, it became the first commercial transport to exceed Mach 2. It conducted 55 passenger service flights, at an average service altitude of 52,000 feet, or 16,000 meters, and cruised at a speed of around 1,200 mph, or Mach 1.6.

The Soviet government published the concept of the Tu-144 in an article in the January 1962 issue of the magazine Technology of Air Transport. 10 days after the design was approved by the Council of Ministers, on July 26, 1963, the air ministry started development of the Tu-144. The prototype first flew seven years later. By all accounts, it looked like the Russian Tupolev Tu-144 was going to be the world’s first and best SST, so what happened?

The Paris Air Show Crash

On June 3, 1973, the Paris Air Show hosted an officially-approved demonstration flight of the Tu-144. At the end of what was an exact repeat of the previous day’s display, the aircraft entered a very steep climb before making a violent downwards maneuver. It tried to recover but the aircraft broke apart and crashed, destroying 15 houses while killing all six people on board and eight more on the ground.

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Apparently, the flight crew had been instructed to outperform the Concorde display by any means necessary. They departed from the approved and rehearsed flight profile, which caused the stability and control augmentation system to malfunction and not be able to prevent the loads that caused the port wing to fail. There are multiple theories as to how this happened…

Some believe the Tu-144 was attempting to avoid a French Mirage plane that was photographing it in an act of industrial espionage. Others think the crash was a result of deliberate misinformation on the part of the Anglo-French design-team who allegedly passed false blueprints to the Soviets, who they thought were planning to steal the design plans of Concorde. Either way, this and another crash in 1978 delayed its development.

Concorde Announced In 1962

Back in 1962, when the British and French governments first announced the Concorde, they wanted to show the world that European aircraft manufacturers could create the most cutting-edge designs. This was something that America was known for, and it wouldn’t be long before the USA responded to such a bold claim. But first…

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The origins of the Concorde project date back to the early ’50s. The director of the Royal Aircraft Establishment, or RAE, asked Morien Morgan, who would later be known as “the Father of Concorde”, to form a committee to study the supersonic transport concept. The program initially cost around $90 million, but it would soon encounter huge overruns and delays, causing it to eventually cost over $1.6 billion.

This extreme cost became the main factor in the production run being much smaller than anticipated. In reference to the treaty between the British and French governments, which led to its construction, the name Concorde came from the French word concorde, which means agreement, harmony or union. While the Concorde was in the early stages of development, news of the project would soon makes its way around the world…

The Pan Am Plans and JFK’s Response

When President John F Kennedy heard about the Concorde program, he acted quickly to meet the challenge and protect American national pride. In June 1962, the Kennedy Administration announced it was going to work with the private sector to develop their own SST. Kennedy was fueled by the discovery that Pan Am had planned to order six Concordes…

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On June 5, 1963, at the graduation ceremony of the US Air Force Academy, JFK delivered this message in his speech, “it is my judgment that this Government should immediately commence a new program in partnership with private industry to develop at the earliest practical date the prototype of a commercially successful supersonic transport superior to that being built in any other country of the world.”…

“An open, preliminary design competition will be initiated immediately among American airframe and powerplant manufacturers with a more detailed design phase to follow.” Essentially the US government agreed to pay for 75% of the program as incentive to develop an SST that would be bigger and faster than the European competitor. This led to two designs, one from Boeing and another from Lockheed…

The Lockheed L-2000

The director of the Federal Aviation Administration, or FAA, elected to improve upon the Concorde’s design rather than compete directly with it. The Lockheed Corporation’s official entry into the government-funded SST competition was the L-2000. It was intended to carry more than twice as many as the Concorde. It would also be significantly faster at Mach 2.7 to Mach 3.0, well over 2,000 mph, with a range of 4,000 miles.

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Lockheed’s first SST attempts date back to 1958. By 1966, the design took on its final form with a re-designed wing and fuselage lengthened to 273 feet for up to 230 passengers. The new wing featured a proportionately larger forward delta, with greater refinement to the wing’s twist and curvature.

A full-scale mock-up was presented to the FAA on December 31, 1966. The Lockheed design was judged simpler to produce and less risky, but its performance during takeoff and at high speed was slightly lower than its competition. The L-2000 was also predicted to be louder. If Lockheed had built its simpler design, it might have flown by 1971, but the Boeing was chosen. Read ahead to learn about the 2707…

The Boeing 2707

The Boeing 2707 had similar qualities as Lockheed’s entry, including a cruising speed of Mach 3, but also offered room for more passengers at a capacity of 250 to 300 seats. A key design feature of the 2707 was its use of a swing wing configuration. During development the required weight and size of this mechanism continued to grow, forcing the team to start over using a conventional delta wing.

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Boeing had worked on a number of small-scale SST studies since 1952, and eight years later, its official entry was essentially identical to its swing-wing Model 733. A major change in the design came when Boeing added canards behind the nose, which added weight. As previously stated, a full-scale mock-up was presented to the FAA along with one of the Lockheed L-2000.

The Boeing design was considered more advanced, representing a greater lead over the Concorde and thus more fitting to the original design mandate. Boeing eventually changed its advanced variable-geometry wing design to a simpler delta-wing similar to Lockheed’s design, but with a tail. The development of smaller fighters had already proven that delta-shaped wings, similar to the Concorde, could go faster than Mach 2…

The French Mirage III

The Dassault Mirage III is a single-seat, single-engine, French fighter aircraft that was the first Western European combat aircraft to exceed Mach 2 in horizontal flight. Back in 1952, the French government issued its specification, calling for a lightweight, all-weather interceptor. Amongst the respondents were Dassault with their design, which would eventually become the Mirage III.

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Over the course of its development, the initial design was made larger to bear the necessary equipment and payloads, and a newly developed Snecma Atar afterburning turbojet engine was added. In October of 1960, the Mirage IIIC performed its maiden flight and by July of 1961 a total of 95 were obtained by the French Air Force. It was rapidly followed by numerous other variants.

Export customers included overseas operators in Argentina, Australia, South Africa, Pakistan and Israel, as well as a number of non-aligned nations. The Mirage III is often considered to be a second-generation fighter aircraft and experienced a lengthy service life. It also inspired many ideas behind the SSTs discussed in this article. Read ahead to learn about another fighter that had a similar impact…

The Russian Mig 21

The Mikoyan-Gurevich MiG-21 is a supersonic jet fighter and interceptor aircraft, designed by the Mikoyan-Gurevich Design Bureau in the Soviet Union. It was popularly nicknamed “balalaika” based on the aircraft’s planform-view resemblance to the Russian stringed musical instrument. Polish pilots also compared the shape of its fuselage to a pencil, calling it ołówek.

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The MiG-21 made aviation records, became the most-produced supersonic jet aircraft in aviation history, the most-produced combat aircraft since the Korean War and was previously the longest production run of a combat aircraft. It has since been exceeded by both the McDonnell Douglas F-15 Eagle and General Dynamics F-16 Fighting Falcon.

Like the Mirage III, the MiG-21 has been flown all over the world. Approximately 60 countries over four continents have flown the MiG-21, and it still serves many nations six decades after its maiden flight back on February 14, 1956. The speed of the Mirage III and MiG-21 was largely due to use of a delta-shaped wing, which the Concorde replicated. Lockheed also modeled their SST entry after this. So how did theirs fare against Boeing’s?…

And The Winner Is…

Unlike the much more traditional variation of the delta-shaped wing on Lockheed’s L-2000, Boeing’s 2707 had a much more complicated swing-wing design, which was straight at low speeds, improving takeoff and landing. It would then swing back to become a delta wing as the speed increased. The 2707 was officially chosen as the winner on January 1, 1967, but…

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The SST was the topic of considerable concern within and outside the aviation industry. From the start, the airline industry had noted that the economics of the design were questionable, concerns that were only partially addressed during development. Outside the field, the entire SST concept was the subject of considerable negative press that will be discussed later in this article…

Boeing predicted that construction of the SST prototypes would begin in early 1967 and the first flight could be made in early 1970. Production aircraft could start being built in early 1969, with the flight testing in late 1972 and certification by mid-1974. One of the main features of 2707 was, obviously, its ability to hold more passengers and fly much faster than Concorde. This is easier said than done, and created huge implications for the plane…

Speed vs Safety and the RAE

Kit Mitchell, the principal scientific officer at the Royal Aeronautical Establishment, or RAE, during the ’60s also worked on the Concorde. He said that the main problem of the Boeing 2707 was that it was trying to do too much. There was also the fact that a lot of the technology required was still super new at the time.

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Johanna Weber and Dietrich Küchemann, also of the RAE, published a series of reports on a new wing planform, known in the UK as the “slender delta” concept. These contributed to an understanding of the physical nature of separated flow and that delta wings can produce strong vortices on their upper surfaces at high angles of attack.

This research further explained that the vortex will lower the air pressure and cause lift to be greatly increased. This effect had been noticed earlier but its qualities had not been fully appreciated. Weber suggested that this was no mere curiosity, and the effect could be deliberately used to improve low speed performance. Küchemann’s and Weber’s papers changed the entire nature of supersonic design almost overnight…

Similar Technology In Military Jets

While military jets, like the Lockheed SR-71 Blackbird supersonic reconnaissance aircraft seen below, had been designed to fly at these speeds, they could only do so for a few minutes at a time. This made the concept of SST in a passenger context not only incredibly difficult to pull off, but also very dangerous…

Wikipedia

The Boeing 2707 also faced insurmountable weight problems due to the swing-wing mechanism, which was a titanium pivot section fabricated with a weight of 4,600 pounds and measuring eleven feet long and 2.5 feet thick. The flexed fuselage, which was to be the longest ever built, threatened to make it difficult to control. By 1968, Boeing abandoned the variable geometry wing.

They decided on the tailed delta fixed wing. The new design would be smaller, with a seating capacity of 234 passengers. By the next year, in September of 1969, work began on a full-sized mock-up and two prototypes. The project was two years behind schedule. A promotional film was released claiming that airlines would soon pay back the federal investment in the project, and it was projected that SSTs would dominate the skies. But…

SST and the Space Race

Back in the ’60s, the technology required to pull off these kinds of large scale advancements was almost as much of a challenge as sending a man to the moon. This comparison makes sense considering the two cold war rivals of the space race were the Soviet Union, or USSR, and the United States, both being involved in the events discussed here.

Wikipedia

Concorde was able to work around many of these issues because, even though it flew at Mach 2, it didn’t need exotic materials and brand new untested designs. Unfortunately for the competitors, especially the winners of the competition, Boeing, they would have to go further than Concorde’s previously established standards. Concorde was the first airliner to have an analogue fly-by-wire flight-control system which was unique because it was the first commercial aircraft to employ hybrid circuits.

There were a variety of concerns with this type of aircraft, including the powerplant and engines, which called into question the intake, noise and drag. Extensive development testing with design changes and changes to intake and engine control laws would address most of the issues. In general, Concorde picked up where a previously design aircraft left off…

British V Bombers

Concorde was basically the next step up from the V-Bombers that had already been developed by the British. They were the Royal Air Force aircraft during the 1950s and 1960s that comprised the United Kingdom’s strategic nuclear strike force known officially as the V force or Bomber Command Main Force. There were three types, and the force reached its peak in June of 1964 with 50 Valiants, 70 Vulcans and 39 Victors in service.

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In relation to these and the other military aircraft discussed earlier, the biggest challenge the Concorde faced was speed. Mach 2 is 1350 mph, and Boeing claimed theirs would be 650 mph faster, which is unreal considering Concorde had a hard enough time at their level.

Due to air compression, many of the fuselage parts on the Concorde were heated to over 100°C, or 212°F, with the nose tip alone reaching 127°C, or 260°F due to aerodynamic heating. Every surface, such as windows and panels, was warm to the touch by the end of the flight. This happened as a direct result of flying Mach 2. The idea that Boeing was shooting to push this barriers helps to explain what ended up happening…

Problems Facing The Concorde

The body of the Concorde was approximately one foot longer at supersonic speeds than it was when it was on the ground. If it wasn’t carefully maintained, this expansion and contraction of the body threatened to lead to metal fatigue, which is a weakening of metal due to stress, resulting in an accumulation of small cracks.

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Due to its high speeds, large forces were applied to the aircraft during banks and turns, and caused twisting and distortion of the aircraft’s structure. In addition there were concerns over maintaining precise control at supersonic speeds. Both of these issues were resolved by active ratio changes between the inboard and outboard elevons, varying at differing speeds including supersonic.

When any aircraft passes the critical mach of that particular airframe, the centre of pressure shifts rearwards. This causes a pitch down moment on the aircraft if the centre of gravity remains where it was. The engineers designed the wings in a specific manner to reduce this shift, and the distribution of fuel along the aircraft was shifted during acceleration and deceleration to move the centre of gravity, effectively acting as an auxiliary trim control.

Range, Radiation and Cabin Pressurization

These issues meant that the Concorde had a relatively short airframe life of 45,000 hours compared to 100,000 hours for more traditional aircraft. This would have an impact on the overall running costs for the airlines. And everything from the window seals to the electrical wiring had to be designed for the increased heat. Because the Boeing 2707 was going to travel so much faster, they were unable to use aluminum…

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Boeing would instead have to make their plane from titanium, which was much more expensive. On top of this, the swing wing design, which worked well on smaller two seater fighters, needed to be so big and strong when scaled up it made the plane too heavy to be viable.

The designers had to drop the swing wing design and go back to the delta wing, which was also used by Lockheed and, of course, the Concorde. Concorde’s high cruising altitude also meant passengers received almost twice the flux of extraterrestrial ionising radiation, which required a radiometer in the flight deck. If radiation got too high, the plane would descend. Additionally, a sudden reduction in cabin pressure is hazardous to all passengers and crew. But…

Banned Over Land and the Sonic Boom

Concorde continued to solve these problems as they arose. But others would threaten the potential of SSTs. By the time the Concorde was in flight testing and the Boeing was still in the design phase people had become all too aware of a sonic boom created by these planes and it was going to be too much of a problem. As a result, supersonic flight over land was banned in most countries…

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This meant that the only viable routes were over the Atlantic from the east coast of the United States to the west coast of Europe. With these limited routes, the amount of seats that could be sold was greatly reduced and the prospect of supersonic flight was dealt a huge blow. But while commercial jets took eight hours to fly from New York to Paris, the average supersonic flight time on the transatlantic routes was just under 3.5 hours. This was an advantage.

With no other civil traffic operating at the Concorde’s cruising altitude of about 56,000 feet, Concorde had exclusive use of dedicated oceanic airways, or “tracks”, separate from the North Atlantic Tracks, the routes used by other aircraft to cross the Atlantic…

Supersonic Speeds and the Use of Fuel

While every issue, even the most difficult ones, was overcome by the design team behind the Concorde, there was little anyone could do about the cost of fuel. This would ultimately lead to the downfall of the Concorde, and subsequently, the Boeing 2707. Unfortunately for these projects, traveling at supersonic speeds requires an incredible amount of fuel…

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With the inefficiency of jet engines at low speeds Concorde burned two tons of fuel just by taxiing to the runway, let alone what it would require to take off, fly and land. The Boeing design would require even more. At the time, the idea was that if the planes could fly twice as fast and arrive at their destination in half the time, they would be able to complete twice as many journeys and charge a premium.

For a while, this made it so that fuel efficiency wasn’t as big of a problem as they initially worried it might be. When the supersonic designs were created in the 1960s fuel was cheap, but by the 1970s, when these aircraft were coming into service, something would happened that neither project could overcome…

The Bigger They Are…

Beyond the environmental concerns, which included previously discussed issues as well as the possible depletion of the ozone layer due to the high altitude flights, something else would take down the Boeing 2707. The recession of 1971 caused fuel prices to rise to a level Boeing couldn’t overcome. In March of 1971, despite the project’s strong support by the administration of President Richard Nixon, the U.S. Senate rejected further funding.

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A counterattack was organized under the banner of the “National Committee for an American SST” and nearly $1 million worth of contributions was received. In spite of this newfound support, the House of Representatives also voted to end SST funding. Many urged that this would eliminate tens of thousands of jobs, but the project was over.

The two Boeing prototypes were never finished and with the loss of the government contracts and the recession of the civilian aviation market, Boeing ended up cutting over 60,000 jobs. The Boeing 2707 became known as the plane almost ate Seattle. As a result of the mass layoffs, and with so many people moving away from the city in search of new work, this billboard was erected near Sea-Tac airport in 1971.

The Boeing 747 and Beyond

Ironically, the plane that saved Boeing from going bankrupt was the 747 jumbo jet, which was originally thought of as just a stopgap measure while supersonic planes took over air travel. The 747 first flew commercially in 1970 and held the passenger capacity record for 37 years. This is amazing considering…

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Boeing expected supersonic airliners to render the 747 and other subsonic airliners obsolete, but the demand for subsonic cargo aircraft only grew. The 747 was also expected to become obsolete after 400 were sold, but it exceeded critics’ expectations and by 2018, 1,546 aircraft had been built.

Despite the 2707 project’s failure, Boeing learned a lot from the 2707 and much of its design and components made it into other experimental aircraft built by the aerospace company. The supercritical wing, which was a design tweak that came from the 2707 project, is now routinely used on modern airlines to limit shock waves and reduce drag. Lockheed’s L-2000 design will even live on thanks to a collaboration with NASA to fly an experimental demonstrator to research the future of supersonic aircraft. This means a US built supersonic aircraft might eventually take flight…