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Why Did Boeing's Proposed Supersonic 2707 Airliner Fail?

Date: December 17, 2022

Story by Dr. Omar Memon, Simple Flying

In the early 1960s, Boeing began the development of a supersonic passenger aircraft, the Boeing 2707. Boeing aimed to offer an American version of the supersonic airliner that could transport between 250 and 300 passengers at speeds approaching Mach 3 and a range of 4,000 miles (6,400 km). Four General Electric GE4 turbojet engines were selected to power the supersonic jet.

The proposed design superseded the specifications of the ongoing supersonic transport (SST) projects at the time. Boeing introduced the variable-sweep wing (swing-wing) to allow in-flight alteration of the wing geometry. Since swept wings are not fuel-efficient at subsonic speeds, the swing-wing design enables pilots to select an optimum sweep angle (in-flight) depending on the aircraft's speed.


In the mid-1950s, around the same time as the development of Concorde, Boeing was working on multiple SST designs. Boeing focused on a supersonic jet with traditional fixed delta wings. However, the idea of a swing-wing to increase the overall efficiency of the aircraft started to float around 1959.

The Federal Aviation Administration (FAA) was tasked by then President John F. Kennedy to prepare long-term national aviation goals. The FAA created Project Horizon, a commission that promoted the SST. Boeing proposed their swing-wing supersonic design capable of carrying more passengers and making faster trips than competing subsonic aircraft.

While the proposed supersonic speeds would incur high fuel costs, greater utilization of the aircraft would aid in offsetting the cost of fuel. Members of the President's task force and the FAA were skeptical of the SST, mainly due to the increasing fuel cost and more significant carbon emissions due to supersonic shockwaves. The International Air Transport Association (IATA) has recognized these challenges and released various design imperatives for an SST.

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The Boeing 2707 design

Boeing proposed a widebody design that could carry 277 passengers in a two-class configuration (30 in first class and 247 in tourist class). To comply with some of the design imperatives by IATA, Boeing added canards behind the nose of the aircraft.

Moreover, the swing-wing mechanism turned out to be much more complex and heavy than anticipated. The added weight of the canards and heavy wing mechanism had a direct impact on the operational range. While the current weight could not provide the expected range, Boeing was limited in making additional changes to the design.

In 1968, Boeing had to abandon the variable-sweep wing design and use the traditional fixed delta wing instead. Moreover, the capacity had to be reduced to seat 234 passengers. The work on the full-sized mock-up and two prototypes of the Boeing 2707-300 began in September 1969.

A few months into the production, Boeing had reserved 122 orders and delivery positions with 26 airlines. Boeing anticipated the flight testing of the supersonic jet in late 1972, followed by certifications and entry into service by 1975.

Beginning of the end

The first year into the production of the Boeing jet, opposition became increasingly vocal about the adverse effects of the SST. Depletion of the ozone layer, noise at airports, and issues of global warming began to float. Protestors of the Concorde started to relate existing environmental problems with the future of Boeing's supersonic jet.

Despite the strong support from Kennedy's administration, the US Senate and the House of Representatives rejected further funding in 1971. The government also feared that the jet would not be economically viable as fuel costs increased. The overall downturn in the aviation market also contributed to the decline of interest in the SST.

With the government funding cut, Boeing let go of over 60,000 employees, and the company could not complete the two prototypes. While Boeing had to leave the SST market early, it proved to be economically incompetent with the eventual retirement of Concorde in 2003.

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