B-47 Stratojet

B-47 Stratojet
Name	B-47 Stratojet
Caption	A Boeing B-47E Stratojet in flight.
Type	Strategic bomber
Manufacturer	Boeing
Designer	George S. Schairer
First flight	17 December 1947
Introduced	June 1951
Retired	1969 (USAF), 1977 (USAF drone)
Status	Retired
Primary user	United States Air Force
Number built	2,032
Developed from	Boeing XB-47
Developed into	Boeing B-52 Stratofortress

B-47 Stratojet was a long-range, six-engined, jet-powered strategic bomber designed to fly at high subsonic speeds and at high altitudes to avoid enemy interceptor aircraft. Developed by Boeing in the late 1940s, it became the backbone of the Strategic Air Command's (SAC) nuclear deterrent force throughout the 1950s. Its revolutionary swept-wing design, derived from captured German World War II research, set the standard for a generation of large jet aircraft, including the Boeing B-52 Stratofortress.

Development and design

The genesis of the B-47 can be traced to a 1943 United States Army Air Forces requirement for a jet-powered reconnaissance bomber. Boeing's design team, led by George S. Schairer, incorporated pioneering German aerodynamic data on swept wings obtained after the war, which was crucial for high-speed flight. The prototype, the Boeing XB-47, first flew in 1947, featuring a radical design with six General Electric J47 turbojet engines mounted in pods under a thin, 35-degree swept wing and a tandem bicycle-type landing gear. This configuration, along with a lightweight yet strong structure, was optimized for the high-altitude bombing mission. The aircraft's defensive armament was limited to a remotely controlled tail turret, as its primary defense was its speed and altitude.

Operational history

Entering service with the Strategic Air Command in 1951, the B-47 became the first-line strategic nuclear bomber for the United States, forming the core of America's nuclear deterrent during the Cold War. Wings such as the 2d Bomb Wing at Hunter Air Force Base were among the first equipped. The bomber was a central component of SAC's alert posture, with crews and aircraft maintained on ground alert, ready to launch within minutes. It never saw combat in its primary role, but RB-47 reconnaissance variants conducted perilous intelligence-gathering missions along the borders of the Soviet Union, with several shot down, including incidents over the Barents Sea and the Sea of Japan. The type's high operational tempo revealed issues with fatigue, leading to a significant modification program. By the early 1960s, it was gradually replaced by the Boeing B-52 Stratofortress and Convair B-58 Hustler, with the last frontline units retiring the aircraft by 1966, though some served as reconnaissance platforms and drones into the 1970s.

Variants

The primary production model was the B-47E, which featured more powerful J47-GE-25 engines, an MD-4 fire control system for its tail guns, and provisions for external fuel tanks and ordnance. The RB-47B, RB-47E, and RB-47H were dedicated photographic and electronic reconnaissance variants operated by units like the 55th Strategic Reconnaissance Wing. The EB-47E was modified for electronic countermeasures roles. The B-47B was the first major production version, while the specialized WB-47B was used for weather reconnaissance. Trainer versions included the TB-47B, and the final variant was the QB-47, a target drone used for testing air defense systems and missiles like the BOMARC.

Operators

The sole primary operator was the United States Air Force, specifically its Strategic Air Command (SAC). Numerous SAC wings operated the type across bases in the United States, United Kingdom, Morocco (at Sidi Slimane Air Base), and Spain. The U.S. Navy also used a small number of aircraft, designated JB-47E, for test purposes. No B-47s were exported to foreign air forces under the Military Assistance Program, though Royal Air Force crews occasionally flew them in exchange programs.

Specifications (B-47E)

* **Crew:** 3 (pilot, co-pilot/navigator, tail gunner) * **Length:** 109 ft 10 in (33.5 m) * **Wingspan:** 116 ft 0 in (35.4 m) * **Height:** 28 ft 0 in (8.5 m) * **Empty weight:** 79,074 lb (35,867 kg) * **Max takeoff weight:** 230,000 lb (104,326 kg) * **Powerplant:** 6 × General Electric J47-GE-25 turbojet engines, 7,200 lbf (32 kN) thrust each * **Maximum speed:** 607 mph (977 km/h) at 16,300 ft (5,000 m) * **Range:** 3,935 mi (6,330 km) with external tanks * **Service ceiling:** 40,500 ft (12,300 m) * **Armament:** 2 × 20 mm M24A1 cannons in a remote-controlled tail turret; up to 20,000 lb (9,072 kg) of ordnance, including nuclear weapons like the Mark 15 nuclear bomb, in an internal bomb bay.

Aircraft on display

Due to the large number built, many B-47s survive in museums. Notable examples include a B-47E at the National Museum of the United States Air Force at Wright-Patterson Air Force Base in Ohio, an RB-47H at the Strategic Air Command & Aerospace Museum in Ashland, Nebraska, and a B-47B at the March Field Air Museum in Riverside, California. Others are displayed at the Museum of Aviation (Warner Robins) in Georgia, the Pima Air & Space Museum in Arizona, and the Castle Air Museum in Atwater, California.

Category:United States bomber aircraft 1940–1949 Category:Swept-wing aircraft Category:Six-engined jet aircraft