Since the 1950s, the Soviet Union, the United Kingdom, France, and the United States have all begun to develop supersonic passenger aircraft. The American Boeing Company also began research on supersonic passenger aircraft in 1952, and established a permanent research committee in 1958. By 1960, Boeing had invested more than one million U.S. dollars. This supersonic passenger aircraft research team proposed several early plans, project code-named 733. Although Boeing had many initial plans, they were all based on the traditional design of a tailless and highly swept delta wing. But by the late 1950s, Boeing was bidding for the Tactical Fighter Experimental (TFX) and began to study variable sweep wings. Although Boeing ultimately lost to General Dynamics' F-111 fighter-bomber, Boeing was participating in the TFX development process. A lot of experience has been accumulated in the design of variable sweep wings. Boeing's interest in variable swept wings continued unabated, and then a new design plan for a supersonic passenger aircraft using variable swept wings was proposed. By 1960, in Boeing's internal competition, a design using variable swept wings was proposed. The supersonic passenger aircraft plan with swept wings and capable of carrying 150 passengers for transatlantic flights finally stood out and became Boeing's mainstream design.
In mid-1962, during an exploratory meeting between the British Aircraft Company and the French Southern Aircraft Company, both parties revealed their intention to jointly develop a supersonic passenger aircraft; at the same time, the Soviet Union also launched The research and development plan of the Tu-144 supersonic passenger aircraft; in November of the same year, the British and French governments formally signed an agreement to jointly develop the Concorde. The wave of supersonic passenger aircraft from Europe and the Soviet Union was undoubtedly a challenge to the United States. Although American aircraft (such as Boeing 707, Douglas DC-8, etc.) had quickly occupied a large share of the European civil aviation market, supersonic passenger aircraft were As the future development direction of air transportation, Americans are also worried that they will lose their dominant position in the future supersonic passenger aircraft market if they start lagging behind. Therefore, NASA also launched the "Supersonic Commercial Air Transport (SCAT)" program in 1962 to study supersonic passenger aircraft on its own.
On June 5, 1963, then-U.S. President Kennedy formally established the "National Supersonic Transport (NST) Program" and promised that the U.S. government would fund 75% of the development funds for supersonic passenger aircraft. . The then FAA Administrator Najeeb Halaby believed that designing a supersonic airliner similar to Concorde would lead to direct competition and be detrimental to market share, so he set a technological change Advanced and more demanding supersonic passenger aircraft design goals. Therefore, an American supersonic aircraft would have to be larger, carry more passengers, and be faster than Concorde. The technical specifications proposed at that time were to carry 250 passengers, fly at a speed of Mach 2.7-3.0 (about 3000 kilometers per hour), and need to reach an intercontinental range of 7200 kilometers (4500 miles).
Concorde chose Mach 2.02 as its maximum cruising speed, which was determined by the aircraft's body material. When an aircraft flies at supersonic speed, air pressure and friction will heat the surface of the aircraft, and the temperature can reach over 120 degrees. The faster the speed, the higher the temperature. Tests have proven that Mach 2.02 is already the high temperature limit of duralumin. . The British Bristol Aircraft Company once considered using stainless steel as the body material of a supersonic passenger aircraft to increase the top speed to Mach 3.0, and trial-produced three Bristol 188 test aircraft to study aerodynamic heating issues, but it turns out that stainless steel aircraft are heavy , the production technology requirements are high, and the cost is too high, and its economics are beyond the affordability of civil aircraft users. However, the United States has rich experience in this area and has developed the XB-70 bomber at that time. Although the XB-70 is essentially a strategic bomber, its size and structure are similar to those of a medium-sized supersonic passenger aircraft. The XB-70 is capable of cruising at supersonic speeds of Mach 3.0 (3,200 kilometers per hour) at an altitude of 23,600 meters. Most of the aircraft body is made of stainless steel.
The design requirements for supersonic aircraft were successively sent to major aircraft manufacturers in the United States, with the fuselage and engine being divided into two separate parts for bidding.
Competitors for the fuselage include Boeing, Lockheed, and North American Aviation, while engines include Curtiss-Wright, Pratt & Whitney, and General Electric. At that time, the FAA optimistically predicted that the aviation market would demand about 500 supersonic passenger aircraft by 1990. Although the supersonic passenger aircraft in the United States had not yet been finalized, it had already received orders from airlines.
Prototypes from various companies The design was submitted to the FAA on January 15, 1964. Boeing's plan is still basically the same as the "Boeing 733" variable-sweep wing supersonic airliner design decided in 1960. The official name is Boeing 733-197, but Boeing also created two new names for the new aircraft. The first is the 1966 Model, and the second is the Boeing 2707 (Model 2707). The latter is the most widely known name, while Boeing continues to use the 733 as the project code name. The appearance of the Boeing 2707 is very similar to that of the later B-1 bomber, but the four engines of the Boeing 2707 are separated and hung under the wings in independent pods, rather than in a group of two like the B-1 bomber.
As for Boeing’s opponents, North American Aviation proposed the NAC-60 (North American NAC-60) plan, which is nothing more than an enlarged XB-70 bomber, but with a redesigned nose cone and A new composite delta wing was used, and the design retained the XB-70's front canards. Lockheed's CL-823 (Lockheed CL-823) plan is like an enlarged Concorde, but the four engines are installed separately in independent pods. In order to narrow down the selection, the FAA eliminated the North American Aviation NAC-60 and Curtiss-Wright engines first after selection. Only Boeing and Lockheed were left to compete, and were allowed to choose to use the engines of the remaining two companies at will. engine. In November 1964, the FAA conducted a second selection. At this time, Boeing had further improved the design, expanded the scale based on the Boeing 733-197, and increased the passenger capacity to 250 people, called the Boeing 733-290. In order to maximize the efficiency of the engine jets, the four engines were moved to a later position and placed under the horizontal tail. When the wings are folded back, the wings and horizontal tail will join to form a complete delta wing.
At this time, the FAA began to require the two companies to provide more detailed information about the plans to facilitate the authority's final selection in 1966. Boeing then expanded the size of the aircraft again and developed it into the Boeing 733-390 (Boeing 2707-100) with a capacity of 300 passengers. By September 1966, both Boeing and Lockheed publicly displayed full-size wooden aircraft models of their plans. Finally, on December 31, 1966, the FAA announced that Boeing would use the General Electric GE4 turbojet engine for the Boeing 733- The 390 program won, while Lockheed's L-2000 and Pratt & Whitney's JTF17 turbofan engine failed.
But the situation in the late 1960s became even more unfavorable for supersonic passenger aircraft. Public protests against environmental protection and against the sonic boom caused by supersonic aircraft became increasingly fierce. Environmentalists were one of the most influential groups at the time. Their main reasons for protest were the noise of supersonic airliners taking off and landing and sonic booms, as well as the damage to the ozone layer caused by supersonic airliners flying at high altitudes. Later, another argument emerged that supersonic airliners would affect the environment. The Massachusetts Institute of Technology confirmed that the nitrogen oxides emitted by the engines can also damage the ozone layer.
Americans’ fear and outcry over sonic booms caused by supersonic aircraft was an important turning point. An American physicist who opposes supersonic airliners, William Asahel Shurcliff, wrote and published a book called "SST and Sonic Boom Handbook" Later, it was pointed out that every flight of a supersonic passenger aircraft will cause a sonic boom zone (bang-zone) that is 2,000 miles long and 50 miles wide.
In 1965, an XB-70 bomber approached Oklahoma City during a test. Even though its sonic boom zone was only 16 miles wide at its widest, it had already caused serious impact. The authorities later received 9,594 complaints from local residents about the sonic boom causing damage to their homes. Damage complaints, of which 4,629 complaints formally filed claims, but only 229 cases ultimately received a total compensation of $12,845.32.
As the opposition grows, the negative impacts of supersonic aircraft claimed by opponents are becoming more and more unbelievable, such as affecting the work of the public, causing mental problems, endangering the mentally ill, and even harming the mentally ill. Miscarriage, but in fact there is no valid evidence for these accusations made by opponents. For example, some people say that water vapor emitted by engines into the stratosphere will continue to accumulate and surround the earth, causing "global gloom." Russell Errol Train, the first administrator of the U.S. Environmental Protection Agency and honorary chairman of the World Wildlife Fund, believes that if 500 supersonic passenger planes fly at an altitude of 65,000 feet for a long time every day, how many After this year, the moisture content in the stratosphere will increase significantly by about 50% to 100%, causing surface heat to accumulate and hindering the formation of ozone.
Left-wing parties also took this opportunity to criticize the government. In addition to concerns about the environment, the left-wing parties are also dissatisfied with the government's large investment in supporting the research and development of commercial aircraft. Therefore, the Anti-SST campaign was largely led by Democratic Senator William Proxmire, who saw the movement as a protest against the government's indiscriminate spending.
Facing opposition from all sides, FAA Administrator Halaby insisted on his opinion and tried to ignore these voices. He pointed out:
“
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.
（中文翻译）The supersonic era is coming, and I I believe it will be tomorrow. In 1980, you will be flying in one (Boeing 2707) or another (supersonic airliner) and try to remember what the debate was like.
”
——Najib Halabi, 1970
In March 1971, although the U.S. supersonic passenger aircraft program was strongly supported by then President Richard Nixon, The U.S. Senate rejected further appropriations. In order to continue this plan, supporters, under the banner of "National Committee for an American Supersonic Airliner" (National Committee for an American SST), called on supporters to donate $1 each to realize this ideal. Letters from aviation enthusiasts came in like flakes from all over the country, and nearly a million dollars in donations were collected. The labor unions were worried that the end of the Vietnam War and the Apollo program would bring a new depression to the U.S. aviation industry and cause unemployment, so they also supported the continuation of the supersonic passenger aircraft program. George Meany, then president of the American Federation of Labor-Confederation of Industrial Workers, believed that the United States started late and had lost its advantage in developing the first generation of supersonic passenger aircraft, but the United States should prepare to enter the second generation as soon as possible ( supersonic airliners of the 1980s and 1990s).
Although the differences were still huge, the U.S. Congress officially held a vote on whether to terminate funding for the supersonic passenger aircraft program as scheduled on May 20, 1971. This was a highly controversial vote. *** and party leader Gerald Ford cited George Meaney's argument: If you give a vote to supersonic airliners, you are guaranteeing 13,000 jobs today and 50,000 jobs in the secondary, and over the next decade 150,000 positions per year. Sidney Yates, who leads the opposition camp, has called for a referendum.
In the end, the U.S. Congress decided to terminate funding for the supersonic aircraft program with 215 votes against appropriation and 204 votes in favor.
At the end of the Boeing 2707 supersonic passenger aircraft program, the U.S. government and Boeing had invested more than $1 billion. At that time, the Boeing 2707 had 115 orders from 25 airlines, and the Concorde had 74 orders from 16 airlines. The two prototypes that Boeing was building could not be completed. At the same time, because Boeing also lost some government contracts and the civil aviation market also cooled down, Boeing had to lay off 60,000 people to maintain operations. Therefore, the Boeing 2707 was also nicknamed "" The airplane that almost ate Seattle."