Boeing C-135 Stratolifter

Boeing C-135 Stratolifter is a military transport aircraft derived from the prototype Boeing 367-80 jetliner. Developed in the mid-1950s for the United States Air Force, it served as a dedicated cargo and personnel carrier, forming the basis for a prolific family of special-mission variants. While its production run was limited compared to the tanker-focused Boeing KC-135 Stratotanker, the C-135 provided critical strategic airlift during the Cold War and demonstrated the versatility of the basic airframe.

Development and design

The C-135's origins are directly tied to the Boeing 367-80, a company-funded demonstrator that first flew in 1954. In response to a United States Air Force requirement for a jet-powered tanker-transport, Boeing developed the Boeing KC-135 Stratotanker. A parallel cargo variant, initially designated KC-135A-LO, was soon ordered, featuring a strengthened floor, a large side cargo door, and the removal of refueling equipment. This model was redesignated the C-135A Stratolifter. Powered by four Pratt & Whitney J57 turbojets, the early C-135A shared the high-wing, narrow-body design of the Boeing 707 but was structurally distinct. The subsequent C-135B model introduced more powerful and efficient Pratt & Whitney TF33 turbofan engines, significantly improving performance and range. The design emphasized rapid loading and global reach, supporting the Military Air Transport Service's evolving logistics doctrine.

Operational history

Entering service with the United States Air Force in 1957, the C-135 Stratolifter fleet was primarily operated by the Military Air Transport Service and its successor, the Military Airlift Command. It provided vital strategic airlift for high-priority cargo, personnel, and Medevac missions across global USAF bases and theaters of operation. During the Vietnam War, C-135s were heavily utilized for logistical support between the Continental United States and Southeast Asia. The aircraft also played key roles in special operations, including supporting early NASA space programs by transporting components. Although eventually supplanted in the pure transport role by larger aircraft like the Lockheed C-141 Starlifter and Lockheed C-5 Galaxy, many airframes were converted for other duties. The last C-135s in the standard transport configuration were retired from active USAF service in 1992.

Variants

The primary transport variants were the C-135A and re-engined C-135B. However, the airframe proved exceptionally adaptable, spawning numerous special-mission derivatives operated under the "C-135" series designation. These include the Boeing WC-135 Constant Phoenix for atmospheric sampling, the Boeing NC-135 for testbed roles, and the Boeing OC-135B Open Skies observation aircraft. The most prolific and significant variant is the Boeing RC-135 family, used for electronic intelligence and reconnaissance by units like the 55th Wing. Other modifications produced the Boeing EC-135 for airborne command post duties and the Boeing VC-135 for VIP transport. Many of these specialized aircraft remain in service long after the original transports were retired.

Operators

The primary and essentially sole operator of the C-135 Stratolifter in its dedicated transport form was the United States Air Force. Specific units included the Military Airlift Command and various Air Mobility Command squadrons. The numerous special mission variants derived from the C-135, such as the Boeing RC-135 and Boeing WC-135, continue to be operated by the United States Air Force, with frontline units like the 55th Wing at Offutt Air Force Base. No C-135 Stratolifters were exported for use as transports, though the similar Boeing KC-135 Stratotanker was used by several allied nations including France and Turkey.

Specifications (C-135B)

* **Crew:** 3 (pilot, co-pilot, navigator) + loadmasters * **Capacity:** 126 passengers or 44,000 lb (20,000 kg) of cargo * **Length:** 134 ft 6 in (41.0 m) * **Wingspan:** 130 ft 10 in (39.9 m) * **Height:** 38 ft 4 in (11.7 m) * **Empty weight:** 98,466 lb (44,663 kg) * **Max takeoff weight:** 275,000 lb (124,740 kg) * **Powerplant:** 4 × Pratt & Whitney TF33-PW-102 turbofan engines, 18,000 lbf (80 kN) thrust each * **Maximum speed:** 580 mph (930 km/h, 500 kn) * **Range:** 4,500 mi (7,200 km, 3,900 nmi) with maximum payload * **Service ceiling:** 50,000 ft (15,000 m)

Category:United States military transport aircraft 1950–1959 Category:Boeing aircraft Category:Four-engined jet aircraft