707-120B - Four 75.6kN (17,000lb) Pratt & Whitney JT3D-1 turbofans.
707-320B - Four 80kN (18,000lb) JT3D-3s or four 84.4kN (19,000lb) JT3D-7s.
707-120B - Max speed 1010km/h (545kt), max cruising speed 1000km/h (540kt), economical cruising speed 897km/h (484kt). Range with max payload 6820km (3680nm), range with max fuel 8485km (4580nm).
707-320B - Max speed 1009km/h (545kt), max cruising speed 974km/h (525kt), long range cruising speed 885km/h (478kt). Range with max passengers 6920km (3735nm), range with max fuel and 147 passengers 9265km (5000nm).
707-120B - Operating empty 55,589kg (122,533lb), max takeoff 116,575kg (257,000lb).
707-320B - Empty 66,406kg (146,400lb), max takeoff 151,315kg (333,600lb).
Flightcrew of three or four.
707-120 max seating for 179, or 110 in two classes (44 first and 66 economy).
707-320B - Max seating for 219, or 189 single class at 81cm (32in) pitch, or 147 in two classes.
Convertible or freighter versions - 13 A type containers.
Production of commercial 707s ended in 1978 after 878 had been built. Limited production of military variants continued until 1990. Approximately 130 remain in commercial service.
Medium to long range airliner and freighter
The 707's jet speed, long range, high seating capacity and operating economics revolutionised airliner travel when it was introduced into service in 1958. The 707 also laid the foundations for Boeing's dominance of the jet airliner market.
Recognising the jet engine's potential for commercial aviation, Boeing (at great financial risk) decided to develop a jet powered transport that could fulfil military tanker transport roles but be easily adapted to become an airliner. The resulting prototype, known as the 367 Dash 80, flew for the first time on July 16 1954. Impressed, the US Air Force ordered a larger version, with a wider fuselage (12 ft, vs 11 ft for the Dash 80) into production as the KC-135 tanker/transport (more than 800 were built). At first, Boeing wanted to sell the same size aircraft to the airlines, but the airlines insisted on an even larger airplane, which Douglas promised to build (this became the DC-8). Boeing finally relented, designing the 707 as a longer aircraft with a slightly wider fuselage (12 ft 4 in).
The first production 707 (a 707-120 for Pan Am) flew on December 20 1957, and entered service later the following year. Developments of the 707-120 include the similar 707-220, the shorter 138 for Qantas, and the stretched 707-320, which flew in July 1959. The 707-120 and 320 were later reengined with JT3D turbofans (in place of the original JT3 and JT4 turbojets) to become the 707-120B, and the 707-320B respectively. The 707-320C was a convertible model, the 707-420 was powered by RollsRoyce Conways, while the proposed CFM-56 powered 707-700 upgrade was flight tested in the late 1970s but never entered production.
Most civil 707s in service today have been converted to freighters, while a number are used as corporate transports.
Many air forces have bought 707s, new or converted second-hand aircraft, for general transport, aerial refuelling, and electronic warfare. The E-3 Sentry is a dedicated airborne warning and control system (AWACS) platform with a large rotodome above the fuselage. The E-6 Mercury performs the TACAMO (Take Charge and Move Out) role with the US Navy, maintaining communication with the ballistic missile submarines. The E-8 J-Stars (Joint Surveillance Target Attack Radar System) performs the battlefield control role. Other military 707s received the designations C-137, or C-18, but many others have no special military designation. Copyright Airliners.net, some information Copyright Aerospace Publications