DALLAS — Today in Aviation, the original 707-120, developed by Boeing Commercial Airplanes as its first jetliner, performed its maiden flight in 1957.
Boeing derived the 707-120 from the Boeing 367-80 prototype that flew in 1954. Boeing 707 service would start regularly on October 26, 1958, with Pan American World Airways, up until 1979.
The Boeing 707, a narrow-body aircraft with long-range capabilities, played a pivotal role in ushering in the jet age. It possessed a significantly higher maximum take-off weight and nearly twice the range of other contemporary aircraft.
This remarkable achievement can be attributed to the introduction of a highly successful design family that continued to evolve with the addition of ten more models, making it one of the most prolific and diverse lineups in the industry.
The Inception of the Boeing 707
The Boeing 707 originated from the Boeing company’s military background, which was well-known for producing military aircraft during and after World War II.
After World War II, the de Havilland Comet, spearheaded by the British, emerged as the first commercial jet. However, due to structural issues and subsequent accidents, the Comet was grounded, dampening enthusiasm for commercial jetliners.
Despite this setback, Boeing Company President William Allen and his management team decided to place their confidence in a future when jet aircraft dominated commercial aviation.
Originally conceived as a prototype for an in-air refueling tanker, the 707 underwent further development and evolved into the KC-135A Stratotanker. Eventually, it transformed into a four-engine passenger aircraft equipped with turbo-jet Pratt & Whitney small-diameter engines, each generating a thrust of approximately 50 kilonewtons.
In contrast, the Boeing 787, with its two turbofan high-bypass General Electric GEnx-1B engines, delivers over 300 kN of thrust during takeoff.
Design of the Boeing 707
Taking inspiration from the work of Adolph Busemann from Germany, the Boeing 707’s designers implemented a more pronounced wing sweep compared to the de Havilland team’s approach with the Comet. With a wing sweep angle of 35°, the Boeing 707 exhibited an undesirable flying characteristic known as “Dutch roll,” which manifested as an alternating motion combining yawing and rolling.
Boeing made a notable and intriguing design choice. Unlike De Havilland, who embedded the Comet’s four engines into the wing, causing drag, Boeing took a different approach that was first tested on the company’s 367-80 prototype, also known as the ‘Dash 80’, and later incorporated into the 707. They positioned the engine pods under the wing, a concept that proved to be innovative.
This unique design allowed the pylons of the 707 to direct the airflow over the wing in a direct and streamlined manner. Manufacturers in the aviation industry have since replicated this decision regarding the placement of the engines.
The Legacy of the 707
During the 1960s, the Boeing 707 enjoyed unrivaled dominance in passenger air transportation, maintaining a strong presence on international, transcontinental, and transatlantic routes. It also found widespread use in freight and military applications, a trend that continued well into the 1970s.
As a successor to the 707, Boeing introduced the three-engine Boeing 727 in 1963. Another groundbreaking innovation came in the form of the four-engine Boeing 747, launched in 1969, which revolutionized modern aviation.
In more recent years, Boeing unveiled its latest addition to the lineup, the revolutionary 787 Dreamliner, in 2011. This aircraft stands out as the first to be constructed using carbon fiber composites and is capable of flying for over 17 hours on specific routes.
On December 20, 1957, the inaugural flight of the Boeing 707-120 took place, with FAA certification being granted on September 18, 1958. Notably, the first Iven C. Kincheloe Award, recognizing test flights pivotal to the 707’s certification, was jointly awarded to test pilots Joseph John “Tym” Tymczyszyn and James R. Gannett.
The first presidential jet plane, a specially constructed Boeing 707-120, was named SAM (Special Air Missions) 970. Whenever the president was on board, this aircraft, like any other Air Force plane, was designated as “Air Force One.” Delivered in 1959 to replace Eisenhower’s Super-Constellation, this high-speed jet transport served as a flying Oval Office, featuring a redesigned interior and advanced communication technology. In the early 1960s, it underwent an upgrade to the B “Turbofan” standard.
SAM 970 played host to Presidents Eisenhower, Kennedy, Johnson, and Nixon, as well as notable VIPs like Nikita Khrushchev during his tour of the United States and Henry Kissinger during secret advance trips to China. By 1962, the newer Boeing VC-137C had succeeded the SAM 970.
Then, during the Kennedy Administration, SAM 2600 and 2700 replaced SAM 970. However, SAM 970 continued to serve in the presidential fleet until June 1996, transporting VIPs and the Vice President.
Featured Image: The prototype Boeing 707 is pictured in flight. Photo: Boeing.