The Boeing 2707 was an American supersonic passengerairliner project during the 1960s. After winning a competition for a government-funded contract to build an American supersonic airliner, Boeing began development at its facilities in Seattle, Washington. The design emerged as a large aircraft with seating for 250 to 300 passengers and cruise speeds of approximately Mach 3. It was intended to be much larger and faster than competing supersonic transport (SST) designs such as Concorde.
The SST was the topic of considerable concern within and outside the aviation industry. From the start, the airline industry 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, centered on the issue of sonic booms and effects on the ozone layer.
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 switch to a conventional delta wing. Rising costs, environmental concerns, noise, and the lack of a clear market led to its cancellation in 1971 before two prototypes were completed.
Development
Early studies
Boeing had worked on a number of small-scale SST studies since 1952. In 1958, it established a permanent research committee, which grew to a $1 million effort by 1960. The committee proposed a variety of alternative designs, all under the name Model 733.[1] Most of the designs featured a large delta wing, but in 1959 another design was offered as an offshoot of Boeing's efforts in the swing-wingTFX program (which led to the purchase of the General Dynamics F-111 instead of the Boeing offering). In 1960, an internal competition was run on a baseline 150-seat aircraft for trans-Atlantic routes, and the swing-wing version won.[2]
Shortly after taking office, President John F. Kennedy tasked the Federal Aviation Administration with preparing a report on "national aviation goals for the period between now and 1970".[3] The study was prompted in the wake of several accidents, which led to the belief that the industry was becoming moribund. Two projects were started, Project Beacon on new navigational systems and air traffic control, and Project Horizon on advanced civil aviation developments.
Only one month later the FAA's new director, Najeeb Halaby, produced the Commission on National Aviation Goals, better known as Project Horizon. Among other suggestions, the report was used as a platform to promote the SST. Halaby argued that a failure to enter this market would be a "stunning setback".[4] The report was met with skepticism by most others. Kennedy had put Lyndon Johnson on the SST file, and he turned to Robert McNamara for guidance. McNamara was highly skeptical of the SST project and savaged Halaby's predictions; he was also afraid the project might be turned over to the DoD and was careful to press for further studies.[4]
The basic concept behind the SST was that its fast flight would allow them to fly more trips than a subsonic aircraft, leading to higher utilization. However, it did this at the cost of greatly increased fuel use. If fuel costs were to change dramatically, SSTs would not be competitive. These problems were well understood within the industry; the IATA released a set of "design imperatives" for an SST that were essentially impossible to meet—the release was a warning to promoters of the SST within the industry.[4]
Concorde
By mid-1962, it was becoming clear that tentative talks earlier that year between the British Aircraft Corporation and Sud Aviation (later Aérospatiale) on a merger of their SST projects were more serious than originally thought. In November 1962, still to the surprise of many, the Concorde project was announced.[5] In spite of marginal economics, nationalistic and political arguments had led to wide support for the project, especially from Charles de Gaulle.[6] This set off something of a wave of panic in other countries, as it was widely believed that almost all future commercial aircraft would be supersonic,[7] and it looked like the Europeans would start off with a huge lead. As if this were not enough, it soon became known that the Soviets were also working on a similar design.[8]
Three days after the Concorde announcement, Halaby wrote a letter to Kennedy suggesting that if they did not immediately start their own SST effort, the US would lose 50,000 jobs, $4 billion in income, and $3 billion in capital as local carriers turned to foreign suppliers.[9] A report from the Supersonic Transport Advisory Group (STAG) followed, noting that the European team was in the lead in basic development, and suggested competing by developing a more advanced design with better economics. At the time, more advanced generally meant higher speed. The baseline design in the report called for an aircraft with Mach 3 performance with 2,400 miles (3,900km) range in order to serve the domestic market. They felt that there was no way to build a transatlantic design with that performance in time to catch the Concorde's introduction, abandoning the trans-Atlantic market to the Europeans.[6]
In spite of vocal opponents, questions about the technical requirements, and extremely negative reports about its economic viability, the SST project gathered strong backing from industry and the FAA. Johnson sent a report to the president asking for $100 million in funding for FY 1964. This might have been delayed, but in May, Pan Am announced they had placed 6 options on the Concorde. Juan Trippe leaked the information earlier that month, stating that the airline would not ignore the SST market, and would buy from Europe if need be.[10] Pan Am's interest in Concorde angered Kennedy, who called his administration to get Pan Am to redirect its potential funding back to the US SST program.[11]
Kennedy introduced the National Supersonic Transport program on June 5, 1963, in a speech at the US Air Force Academy.[12][11]
Design competition
Requests for proposals were sent out to airframe manufacturers Boeing, Lockheed, and North American for the airframes; and Curtiss-Wright, General Electric and Pratt & Whitney for engines. The FAA estimated that there would be a market for 500 SSTs by 1990. Despite not having a selected design, orders from air carriers started flowing in immediately.[13] Preliminary designs were submitted to the FAA on January 15, 1964.[14]
The NAC-60 was North American's entry. It retains a number of features from the B-70 it was based on, notably the high-mounted canard behind the cockpit area, and details of the engine area under the rear fuselage.
Boeing's entry was essentially identical to the swing-wing Model 733 studied in 1960; it was known officially as the Model 733-197, but also referred to both as the 1966 Model and the Model 2707. The latter name became the best known in public, while Boeing continued to use 733 model numbers internally. The design resembled the future B-1 Lancer bomber, with the exception that the four engines were mounted in individual nacelles instead of paired pods used on the Lancer.[14] The blended wing root spanned almost all of cabin area, and this early version had a much more stubby look than the models that would ultimately evolve. The wing featured extensive high-lift devices on both the leading and trailing edges, minimizing the thrust required, and thus noise created, during climb out. The proposal also included optional fuselage stretches that increased capacity from the normal 150 seats to 227.
Lockheed's entry, designated CL-823, was essentially an enlarged Concorde. Like the Concorde, it featured a long and skinny fuselage, engines under the wing, and a compound delta planform. The only major design difference was the use of individual pods for the engines, rather than pairs. The CL-823 lacked any form of high-lift devices on the wings, relying on engine power and long runways for liftoff, ensuring a huge noise footprint. The CL-823 was the largest of the first-round entries, with typical seating for 218.[14]
The North American NAC-60 was essentially a scaled-up B-70 with a less tapered fuselage and new compound-delta wing. The design retained the high-mounted canard above the cockpit area, and the box-like engine area under the fuselage. The use of high-lift devices on the leading edge of the wing lowered the landing angles to the point where the "drooping nose" was not required, and a more conventional rounded design was used. Compared to the other designs, the rounded nose profile and more cylindrical cross-section gave the NAC-60 a decidedly more conventional look than the other entries. This also meant it would fly slower, at Mach 2.65.[14]
A "downselect" of the proposed models resulted in the NAC-60 and Curtiss-Wright efforts being dropped from the program, with both Boeing and Lockheed asked to offer SST models meeting the more demanding FAA requirements and able to use either of the remaining engine designs from GE or P&W. In November, another design review was held, and by this time Boeing had scaled up the original design into a 250-seat model, the Model 733-290. Due to concerns about jet blast, the four engines were moved to a position underneath an enlarged tailplane. When the wings were in their swept-back position, they merged with the tailplane to produce a delta-wing planform.
Both companies were now asked for considerably more detailed proposals, to be presented for final selection in 1966. When this occurred, Boeing's design was now the 300-seat Model 733-390. Both the Boeing and Lockheed L-2000 designs were presented in September 1966 along with full-scale mock-ups. After a lengthy review the Boeing design was announced as the winner on January 1, 1967.[15] The design would be powered by the General Electric GE4/J5 engines. Lockheed's L-2000 was judged simpler to produce and less risky, but its performance was slightly lower and its noise levels slightly higher.
Refining the design
The 733-390 would have been an advanced aircraft even if it had been only subsonic. It was one of the earliest wide-body aircraft designs, with 2-3-2 row seating arrangement at its widest section[15] in a fuselage that was considerably wider than aircraft then in service. The SST mock-up included both overhead storage for smaller items with restraining nets, as well as large drop-in bins between sections of the aircraft. In the main 247-seat tourist-class cabin, the entertainment system consisted of retractable televisions placed between every sixth row in the overhead storage. In the 30-seat first-class area, every pair of seats included smaller televisions in a console between the seats. Windows were only 6 inches (150mm) due to the high altitudes the aircraft flew at maximizing the pressure on them, but the internal pane was 12 inches (300mm) to give an illusion of size.
Boeing predicted that if the go-ahead were given, 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.[15]
Model of Boeing SST
A major change in the design came when Boeing added canards behind the nose—which added weight. Boeing also faced insurmountable weight problems due to the swing-wing mechanism, a titanium pivot section having been fabricated with a weight of 4,600 pounds (2,100kg) and measuring 11 feet (3.4m) long and 2.5 feet (76cm) thick,[16] and the design could not achieve sufficient range. Flexing of the fuselage (it would have been the longest ever built) threatened to make control difficult. In October 1968, the company was finally forced to abandon the variable geometry wing.[17][18] The Boeing team fell back on a tailed delta fixed wing. The new design was also smaller, seating 234, and known as the Model 2707-300. Work began on a full-sized mock-up and two prototypes in September 1969, now two years behind schedule.
A promotional film claimed that airlines would soon pay back the federal investment in the project, and it was projected that SSTs would dominate the skies with subsonic jumbo jets (such as Boeing's 747) being only a passing intermediate fad.
By this point, the opposition to the project was becoming increasingly vocal. Environmentalists were the most influential group, voicing concerns about possible depletion of the ozone layer due to the high altitude flights, and about noise at airports, as well as from sonic booms.[20]
The latter became the most significant rallying point, especially after the publication of the anti-SST paperback, SST and Sonic Boom Handbook edited by William Shurcliff, which claimed that a single flight would "leave a 'bang-zone' 50 miles (80km) wide by 2,000 miles (3,200km) long" along with a host of associated problems. During tests in 1964 with the XB-70 near Oklahoma City, the path had a maximum width of 16 miles (26km), but still resulted in 9,594 complaints of damage to buildings, 4,629 formal damage claims, and 229 claims for a total of $12,845.32, mostly for broken glass and cracked plaster.[21] As the opposition widened, the claimed negative effects increased, including upsetting people who do delicate work (e.g., brain surgeons), and harming persons with nervous ailments.[20]
One concern was that the water vapor released by the engines into the stratosphere would envelop the earth in a "global gloom". Presidential Adviser Russell Train warned that a fleet of 500 SSTs flying at 65,000ft (20,000m) for a period of years could raise stratospheric water content by as much as 50% to 100%. According to Train, this could lead to greater ground-level heat and hamper the formation of ozone.[20] Later, an additional threat to the ozone was found in the exhaust's nitrogen oxides, a threat that was later validated by MIT.[22] More recent analysis in 1995 by David W. Fahey, an atmospheric scientist at the National Oceanic and Atmospheric Administration, and others found that the drop in ozone would be from 1 to 2% if a fleet of 500 supersonic aircraft was operated.[23] Fahey expressed the opinion that this would not be a fatal obstacle for an advanced SST development.[24]
During the 1970s the alleged potential for serious ozone damage and the sonic boom worries were picked up by the Sierra Club, the National Wildlife Federation and the Wilderness Society.[25] Supersonic flight over land in the United States was eventually banned, and several states added additional restrictions or banned Concorde outright.
Senator William Proxmire (D-Wisconsin) criticized the SST program as frivolous federal spending.[20]
Halaby attempted to dismiss these concerns, stating "The supersonics are coming−as surely as tomorrow. You will be flying one version or another by 1980 and be trying to remember what the great debate was all about."[20]
Government funding cut
In March 1971, despite the project's strong support by the administration of President Richard Nixon, the U.S. Senate rejected further funding. A counterattack was organized under the banner of the "National Committee for an American SST", which urged supporters to send in $1 to keep the program alive.[26] Afterward, letters of support from aviation buffs, containing nearly $1million worth of contributions, poured in. Labor unions also supported the SST project, worried that the winding down of both the Vietnam War and Apollo program would lead to mass unemployment in the aerospace sector. AFL–CIO President George Meany suggested that the race to develop a first-generation SST was already lost, but the US should "enter the competition for the second generation—the SSTs of the 1980s and 1990s".
Despite this newfound support, the House of Representatives also voted to end SST funding on May20, 1971. The vote was highly contentious. Gerald Ford, then Republican Leader, shouted Meany's claims that "If you vote for the SST, you are ensuring 13,000 jobs today plus 50,000 jobs in the second tier and 150,000 jobs each year over the next ten years." Sidney Yates, leading the "no" camp, offered a then-uncommon motion to instruct conferees[27] and eventually won the vote against further funding, 215 to 204.[28]
At the time, there were 115 unfilled orders by 25 airlines, while Concorde had 74 orders from 16 customers.[29] The two prototypes were never completed. Due to the loss of several government contracts and a downturn in the civilian aviation market, Boeing reduced its number of employees by more than 60,000. The SST became known as "the airplane that almost ate Seattle." As a result of the mass layoffs and so many people moving away from the city in search of work, a billboard was erected near Seattle–Tacoma International Airport in 1971 that read, "Will the last person leaving Seattle – turn out the lights".[30]
Aftermath
The SST race has had several lasting effects on the industry as a whole. The supercritical wing was originally developed as part of the SST efforts in the U.S., but is now widely used on most jet aircraft. In Europe, the cooperation that allowed Concorde led to the formation of Airbus, Boeing's foremost competitor, with Aérospatiale becoming a main component of Airbus.[31]
When Concorde was launched, sales were predicted to be 150 aircraft, but only 14 aircraft were built for commercial service. Service entry was only secured through large government funding subsidy.[citation needed] These few aircraft went on to have a very long in-service flight life and were claimed to be ultimately commercially successful for their operators, until finally removed from service in the aftermath of the type's only crash in 2000 and the 9/11 terrorist attacks when Airbus decided to end servicing arrangements.[32]
Its Soviet counterpart, the Tupolev Tu-144, was less successful, operating for only 55 passenger flights before being permanently grounded for various reasons.[33]
With the ending of the 2707 project, the entire SST field in the U.S. was moribund for some time. By the mid-1970s, minor advances, combined, appeared to offer greatly improved performance. Through the second half of the 1970s, NASA provided funding for the Advanced Supersonic Transport (AST) project at several companies, including McDonnell Douglas, Boeing, and Lockheed. Considerable wind tunnel testing of the various models was carried out at NASA's Langley Research Center.[34]
Ultimately, supersonic passenger service was not economically competitive, and ceased with the retirement of Concorde in 2003; as of 2024[update], no commercial supersonic aircraft operate in the world, due largely to poor fuel economy and high maintenance costs.[35]
Legacy
The Museum of Flight in Seattle parks a British Airways Concorde a few blocks from the building where the original 2707 mockup was housed in Seattle.[36] While the Soviet Tu-144 had a short service life,[37] Concorde was successful enough to fly as a small luxury fleet from 1976 until 2003, with British Airways lifetime costs of £1bn producing £1.75bn in revenues in the niche transatlantic market.[38] As the most advanced supersonic transports became some of the oldest airframes in the fleet, profits eventually fell, due to rising maintenance costs.[39]
The final-configuration Boeing 2707 mockup was sold to a museum and displayed at the SST Aviation Exhibit Center in Kissimmee, Florida, from 1973 to 1981. In 1983, the building, complete with SST, was purchased by the Faith World church. For years the Osceola New Life Assembly of God held services there with the airplane still standing above. In 1990, the mock-up was sold to aircraft restorer Charles Bell, who moved it, in pieces, to Merritt Island, in order to preserve it while it waited for a new home as the church now wanted the space for expansion.[citation needed] The forward fuselage was on display at the Hiller Aviation Museum of San Carlos, California, for many years, but in early 2013, was moved back to Seattle,[40] where it is undergoing restoration at the Museum of Flight.
Seattle's NBA basketball team, formed in 1967, was named the Seattle SuperSonics (shortened to "Sonics"). The name was inspired by the newly won SST contract.[41]
Concorde is a retired Anglo-French supersonic airliner jointly developed and manufactured by Sud Aviation and the British Aircraft Corporation (BAC). Studies started in 1954, and France and the UK signed a treaty establishing the development project on 29 November 1962, as the programme cost was estimated at £70 million . Construction of the six prototypes began in February 1965, and the first flight took off from Toulouse on 2 March 1969. The market was predicted for 350 aircraft, and the manufacturers received up to 100 option orders from many major airlines. On 9 October 1975, it received its French Certificate of Airworthiness, and from the UK CAA on 5 December.
The Tupolev Tu-144 is a Soviet supersonic passenger airliner designed by Tupolev in operation from 1968 to 1999.
A sonic boom is a sound associated with shock waves created when an object travels through the air faster than the speed of sound. Sonic booms generate enormous amounts of sound energy, sounding similar to an explosion or a thunderclap to the human ear.
A supersonic transport (SST) or a supersonic airliner is a civilian supersonic aircraft designed to transport passengers at speeds greater than the speed of sound. To date, the only SSTs to see regular service have been Concorde and the Tupolev Tu-144. The last passenger flight of the Tu-144 was in June 1978 and it was last flown in 1999 by NASA. Concorde's last commercial flight was in October 2003, with a November 26, 2003 ferry flight being its last airborne operation. Following the permanent cessation of flying by Concorde, there are no remaining SSTs in commercial service. Several companies have each proposed a supersonic business jet, which may bring supersonic transport back again.
The Lockheed L-2000 was Lockheed Corporation's entry in a government-funded competition to build the United States' first supersonic airliner in the 1960s. The L-2000 lost the contract to the Boeing 2707, but that competing design was ultimately canceled for political, environmental and economic reasons.
The Bristol Type 223 was an early design for a supersonic transport. In the late 1950s and early 1960s the Bristol Aeroplane Company studied a number of models as part of a large British inter-company effort funded by the government. These models eventually culminated in the Type 223, a transatlantic transport for about 100 passengers at a speed around Mach 2. At about the same time Sud Aviation in France was developing the similar Super-Caravelle design, and in November 1962 the efforts were merged to create the Concorde project.
The Boeing Sonic Cruiser was a concept jet airliner with a delta wing–canard configuration. It was distinguished from conventional airliners by its delta wing and high-subsonic cruising speed of up to Mach 0.98. Boeing first proposed it in 2001, but airlines generally preferred lower operating costs over higher speed. Boeing ended the Sonic Cruiser project in December 2002 and shifted to the slower but more fuel-efficient 7E7 airliner.
A supersonic aircraft is an aircraft capable of supersonic flight, that is, flying faster than the speed of sound. Supersonic aircraft were developed in the second half of the twentieth century. Supersonic aircraft have been used for research and military purposes, but only two supersonic aircraft, the Tupolev Tu-144 and the Concorde, ever entered service for civil use as airliners. Fighter jets are the most common example of supersonic aircraft.
The SAI Quiet Supersonic Transport (QSST) was a project by Supersonic Aerospace International (SAI) to develop a "virtually boomless" commercial supersonic business jet. The project was announced around the year 2000 and provided update announcements until 2010. After three years without any updates, the last update was in 2013. As of 2023, there have been no more updates, and the project appears to have been abandoned.
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The Next Generation Supersonic Transport is a supersonic transport (SST) being developed by the Japanese Space Agency JAXA. By comparison to the Concorde this new design will carry three times as many passengers and fly roughly at the same speed 1,522.4 mph (2,450.1 km/h). It also has twice the range. The goal is to achieve a ticket price comparable to that of commercial business class. JAXA had expected to launch the plane by 2015. An 11.5-meter prototype was tested on October 10, 2005.
The Gulfstream X-54 is a proposed research and demonstration aircraft, under development in the United States by Gulfstream Aerospace for NASA, that is planned for use in sonic boom and supersonic transport research.
The Anti-Concorde Project, founded by environmental activist Richard Wiggs, challenged the idea of supersonic passenger transport, and curtailed Concorde's commercial prospects. When Concorde entered service in 1976, of the 74 options held at the time of the first flight, only those for the state airlines of Britain (BOAC) and France were taken up, so that only 20 were built, although flights were also flown for Braniff International and Singapore Airlines. It triggered research into the factors affecting the creation of sonic booms, which led to the Shaped Sonic Boom Demonstration which achieved their goal of reducing the intensity of sonic booms, and echoed public concern about aircraft noise that resulted in more restrictive noise limits for aircraft and airport operations, as well as changes in both operating procedures and aircraft design to further reduce noise levels.
In aviation, a strake is an aerodynamic surface generally mounted on the fuselage of an aircraft to improve the flight characteristics either by controlling the airflow or by a simple stabilising effect.
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The Zero Emission Hyper Sonic Transport or ZEHST is a planned hypersonic passenger jet airliner project by the multinational aerospace conglomerate EADS and the Japanese national space agency JAXA.
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The North American NAC-60 was the first American supersonic transport (SST) project. The development took place in the 1960s as part of a government-funded design competition to build an American SST as the joint Anglo-French Concorde and the short-serviced Soviet Tupolev Tu-144 were underway. The design, however, due to being slower and smaller than the expectations of the American SST Race, was rejected in favor of the Lockheed and Boeing designs, allowing them to get further study.
References
↑ Dave Lewis (December 1961). "D Day for the SST". Flying: 23.
↑ "NASA Dryden Fact Sheet - Tu-144LL". August 12, 2015. Archived from the original on April 2, 2016. Retrieved February 7, 2016. NASA Dryden Tu-144 "Limited range and other technical problems led to service being discontinued in 1978 after only 102 passenger flights"
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