TheBoeing C-137 Stratoliner is a retired VIPtransport aircraft derived from theBoeing 707jet airliner used by theUnited States Air Force.Other nations also bought both new and used 707s for military service, primarily as VIP or tanker transports. In addition, the 707 served as the basis for several specialized versions, such as theE-3 Sentry AWACS aircraft. The designationC-18 covers several later variants based on the 707-320B/C series. The C-137 should not be confused with the similarBoeing C-135 Stratolifter; although they share a common ancestor the two aircraft have different fuselages, among other structural differences.
US Air Force procurement of the Boeing 707 was very limited, amounting to three Model 707-153s designated VC-137A. When delivered in 1959 these had four 13,500 lb (6,100 kg) dry thrustPratt & Whitney J57 (JT3C6) turbojets; when subsequently re-engined with 18,000 lbf (80 kN) dry thrustTF33-P-5 (JT3D) turbofans they were redesignated VC-137B. Only one other variant served with the Air Force: this was theVC-137CAir Force One Presidential transport, the two examples of which were Model 707-320B Intercontinentals with specialized interior furnishings and advanced communications equipment. Two further C-137C aircraft lacking Presidential transport modifications were later added.[1]
To supplement its VC-137s, the USAF converted several C-135 airframes to VC-135 VIP standard, and these were used for staff transport mainly within the United States.[1]
An EC-18BAdvanced Range Instrumentation Aircraft (ARIA) takes off on its first flight at Wright-Patterson AFB, Ohio, following its conversion from a Boeing 707-320.
The C-18 is the US military designation for the conversions of the 707-320B series.
C-18A
Eight second-hand (formerAmerican Airlines) 707-323Cs bought as crew trainers for the EC-18Bs, four later converted to EC-18B, two converted to EC-18D, one to C-18B; one was not taken into service and was used for spares.
Four C-18As modified alongsideexamples of the C-135 for Advanced Range Instrumentation Aircraft (ARIA) missions in support of theApollo space program.[2] The designationE-7 was originally applied to modified Boeing 707s before being replaced by the EC-18 designation.[3]
EC-18C
Original designation for two prototype J-STAR aircraft, later redesignated E-8A.
EC-18D
Two C-18As modified as a Cruise Missile Mission Control Aircraft (CMMCA).[2]
TC-18E
Two second-hand (formerTrans World Airlines) 707-331 aircraft modified for E-3 pilot and crew training.[2]
TC-18F
Two second-hand (formerTAP Portugal) 707-382 aircraft modified for E-6 pilot training.[2]
VC-137A Stratoliner, pictured in the early 1960s, in its early red liveryVC-137C SAM 27000 (Air Force One) atVenice Marco Polo Airport, Italy in 1987
The USAF purchased a number of 707s under the C-137 series of designations:
VC-137A
Three 707-153s (58-6970, 58-6971, 58-6972) with fourPratt & Whitney JT3C-6 engines, a 22-passenger VIP interior and provision for use as an airborne command post, re-designated VC-137B.
VC-137B
The three VC-137As re-engined with fourPratt & Whitney JT3D-3 engines in 1963, operated by the 89th Military Airlift Wing, redesignated C-137B.
C-137B
The three VC-137Bs redesignated when downgraded from VIP role.
VC-137C
Two 707-353Bs (62-6000 and 72-7000) were purchased by the USAF (in 1962 and 1972 respectively) for service aspresidential transports with call signsSAM 26000 andSAM 27000; later redesignated C-137C.
C-137C
The two VC-137Cs were redesignated when downgraded from presidential use. SAM 26000 and SAM 27000 were retired in 1998 and 2001 respectively. Both are now in aviation museums. Two further C-137Cs were acquired by the USAF on 24 March 1988, one 707-396C (a seized aircraft formerly used for arms smuggling acquired in 1985) and one 707-382B bought second hand in 1987. Their assigned tail numbers were 85-6973 and 85-6974. Tail 85-6973 would later be converted into anE-8C JSTARS.[citation needed]
EC-137D
Two aircraft built as Early Warning and Control System prototypes. Later re-engined and re-designated E-3A. A further second-hand 707-355C aircraft was acquired and configured as an airborne special operations command post.
Airborne warning and control system (AWACS) aircraft that provides all-weather surveillance, command, control and communications, to theUnited States,NATO and other air defense forces. Based on the 707-320B, production ended in 1992 after 68 had been built.
A version of the 707-320, it operates as an airborne command post and communications center, relaying instructions from theNational Command Authority. Its role in relaying to thefleet ballistic missile submarines, known as "Take Charge and Move Out", gives it the suffixTACAMO. Only one version of the E-6 currently exists, the E-6B. The E-6B is an upgraded version of the E-6A that now includes a battlestaff area for theUSSTRATCOM Airborne Command Post
The E-8C Joint Surveillance Target Attack Radar System (Joint STARS) is a USAF airborne battle management and command and control (C2) platform that conducts ground surveillance to develop an understanding of the enemy situation and to support attack operations and targeting that contributes to the delay, disruption and destruction of enemy forces.
TheIsraeli Air Force operates an undisclosed[6] number (sources[7] suggest 7) of converted Boeing 707s with flying booms in120 ("Desert Giants") Squadron. Israel's fleet are former civilian aircraft adapted for military uses such as aerial refueling of fighter jets and transport. Able to carry 20 extra fuel tanks while modified for aerial refueling, the Re’ems can be adapted to carry passengers as well as cargo such as military equipment and ammunition. Following the outbreak of theCOVID-19 pandemic in 2020, the planes have also been used to carry medical equipment.
707T/T
The 707 Tanker/Transport.Italy purchased and converted four 707s, two to tankers and two to a straight freighter. No 707 tankers remain operational as of 3 April 2008.[8] Also,Omega Aerial Refueling Services operates K707 tankers for lease.[9]
KE-3A
TheRoyal Saudi Air Force purchased eight E-3 airframes configured as aerial refueling tankers.
Airborne Early Warning, Command and Control (AEWC&C) aircraft developed in conjunction with Israel Aircraft Industries (IAI) using a former Lan Chile aircraft.
Hooking up for simulated refuelling with a NATO Boeing 707-TCA from a HI ANG KC-135R during a refuelling training mission from Geilenkirchen AB in September 1996
Three ex-Sabena airliners converted to TCA (Trainer Cargo Aircraft) in 1989 to support the NATO NAEWF E-3A training and air transport/cargo based on Boeing 707-320B. The aircraft were capable of making dry hookups with the USAF Flying Boom air-to-air refuelling system for training of pilots that were new to NAEWF, but also served as cargo/passenger transport. The two oldest/highest time 707s were replaced by two former Luftwaffe 707s in 1999. NAEWF withdrew the TCAs in 2011.[11]
58-6970 Model 707-120 USAF VC-137BSAM 970 - "Queenie", a former Air Force One jet, first used by Eisenhower, is on display at theMuseum of Flight, Seattle, WA.[12]
58-6971 Model 707-153 USAF VC-137B is on display at thePima Air and Space Museum adjacent toDavis-Monthan AFB inTucson, AZ. This aircraft became known as"Freedom One" after serving in the return of the American hostages from Tehran, Iran in 1981.[13]
Media related toBoeing C-137 Stratoliner at Wikimedia Commons
