C-97 Stratofreighter

C-97 Stratofreighter
Name	C-97 Stratofreighter
Caption	A United States Air Force C-97G in flight.
Type	Strategic airlift / Military transport aircraft
National origin	United States
Manufacturer	Boeing
First flight	9 November 1944
Introduction	1947
Retired	1978 (Israeli Air Force)
Primary user	United States Air Force
Number built	888 (all variants, including KC-97 Stratotanker)
Developed from	Boeing B-29 Superfortress
Developed into	Boeing 377 Stratocruiser

C-97 Stratofreighter. The Boeing C-97 Stratofreighter was a long-range heavy-lift military transport aircraft developed from the Boeing B-29 Superfortress bomber. It entered service with the United States Air Force in 1947 and was notable for its distinctive double-deck "double-bubble" fuselage, which provided immense cargo capacity. The design also formed the basis for the commercial Boeing 377 Stratocruiser and the crucial KC-97 Stratotanker.

Development and design

The C-97 was conceived during World War II to meet a United States Army Air Forces requirement for a large-capacity cargo carrier. Engineers at Boeing adapted the wings, tail, and engines from the proven Boeing B-29 Superfortress, mating them to a completely new, voluminous fuselage. This innovative structure, created by joining two B-29 fuselage sections side-by-side and adding a connecting lobe, was known as the "double-bubble" design. Power was provided by four Pratt & Whitney R-4360 Wasp Major radial engines, the same powerplants used on the later Boeing B-50 Superfortress. The first flight of the XC-97 prototype occurred on 9 November 1944 at Boeing Field in Seattle.

Operational history

The C-97 entered operational service with the Military Air Transport Service (MATS) at the onset of the Cold War. It became a workhorse for global strategic airlift, playing vital roles during the Berlin Airlift and the Korean War, transporting everything from troops and vehicles to essential supplies. The aircraft's long range was demonstrated in numerous record-setting flights, including non-stop journeys from Hawaii to Virginia and across the Atlantic Ocean. While later supplanted in the pure transport role by jet aircraft like the Lockheed C-141 Starlifter, the tanker variant, the KC-97 Stratotanker, served for many years with the Strategic Air Command, providing crucial aerial refueling for bombers like the B-47 Stratojet and B-52 Stratofortress.

Variants

The primary transport variants included the initial **YC-97**, the **C-97A** with a reinforced floor and a rear cargo door, and the **C-97C** equipped for medical evacuation. The definitive transport model was the **C-97G**, which incorporated improved R-4360-59 engines and could be configured for various roles. The most numerous and significant variant was the **KC-97 Stratotanker**, developed for Strategic Air Command. Other specialized versions included the **EC-97** for electronic intelligence gathering and a single **VC-97** used as a presidential transport, nicknamed "Columbine III" for Dwight D. Eisenhower.

Operators

The primary military operator was the United States Air Force, including units of the Military Air Transport Service, Strategic Air Command, and the Air National Guard. The Israeli Air Force became a significant foreign operator, using ex-USAF C-97Gs and KC-97s for heavy transport and aerial refueling missions into the 1970s. A single aircraft was also operated briefly by the Spanish Air Force. Several aircraft were later converted for civilian use as firefighting airtankers or heavy cargo carriers.

Specifications (C-97G)

* **Crew:** 5 (pilot, co-pilot, flight engineer, navigator, radio operator) * **Capacity:** 134 troops or 69 litters or 35,000 lb (15,900 kg) cargo * **Length:** 110 ft 4 in (33.63 m) * **Wingspan:** 141 ft 3 in (43.05 m) * **Height:** 38 ft 3 in (11.66 m) * **Powerplant:** 4 × Pratt & Whitney R-4360 Wasp Major radial engines, 3,500 hp (2,600 kW) each * **Maximum speed:** 375 mph (603 km/h, 326 kn) * **Range:** 4,300 mi (6,900 km, 3,700 nmi) * **Service ceiling:** 35,000 ft (11,000 m)

Aircraft on display

Several C-97 airframes are preserved in museums. Examples include a C-97G at the National Museum of the United States Air Force at Wright-Patterson Air Force Base in Ohio, a KC-97L at the Strategic Air Command & Aerospace Museum in Ashland, Nebraska, and an Israeli Air Force C-97 on display at the Israeli Air Force Museum at Hatzerim Airbase. A firefighting variant is part of the collection at the Evergreen Aviation & Space Museum in McMinnville, Oregon.

Category:United States military transport aircraft 1940–1949 Category:Boeing aircraft Category:Four-engined tractor aircraft