B-47 Stratojet (bomber)
B-47 medium bombers, made by Boeing, and other companies under Boeing license, officially were the B-47 Stratojet but the "official" nickname was hardly ever used. Between 1947 and 1957, Boeing, Douglas and Lockheed built 2,039 Stratojets. At its peak use in 1958, the USAF operated 28 B-47 bomb wings and four RB-47 reconnaissance wings, totaling 1,357 B-47s and 175 RB-47s. The USAF phased out its last B-47 bombers in 1965, and the USAF retired its last Stratojet, a WB-47E, in 1969. Designed to meet a 1944 requirement, the first XB-47 prototype flew in December 1947, performing far beyond its competitors. In May 1951 the B-47 began replacing the propeller-driven B-29s and B-50s in SAC's medium bomber units. While it could carry about the same bomb tonnage as the B-29 and B-50 aircraft it replaced, the B-47's top speed was more than 200 mph faster. Since the B-47 did not have the range or maximum bombload of SAC's heavy bombers (the B-36 and later the B-52), Stratojet units regularly deployed to forward air bases around the world on temporary duty.
It was a graceful-looking aircraft, with swept wings and six underwing jet engines. Nevertheless, it had a relatively short service life as a bomber, from 1951 to 1965. While the B-52 heavy bomber effectively replaced it, there was a period in which the B-58 Hustler as a supersonic medium bomber replacement, and some B-58s did enter service.
Nuclear strike role
B-47s had shorter range (3,500-nm) than the earlier B-36 hybrid propeller/jet and contemporary B-52 all-jet heavy bombers, and B-50 medium bombers . Its advantage over the B-36 included hile it could carry about the same bomb tonnage as the aircraft it replaced, the B-47's top speed was more than 200 mph faster than the propeller- and hybrid-aircraft.
Able to carry 20,000 in its bomb bays, at first, with large nuclear weapons, the B-47 would carry 1 or 2 high-yield bombs. As a relatively inexpensive aircraft, however, the number of B-47s that were built compensated for the payload. 
Its shorter range required that it operate from forward bases closer to its Soviet targets, in locations including in the Alaska, Guam, Spain, Morocco, and the United Kingdom. At first, these deployments lasted three months, but beginning in 1957, they were shortened to three weeks. Eventually, international politics made forward deployment less attractive, and the B-52 and missiles led to the retirement of the B-47 in the strike role.
While the B-47 could be refueled in midair, its 3-man crew and other features gave it shorter endurance than the B-52. Still, missions up to 36 hours were flown. For many years, a number of B-52 aircraft on nuclear deterrence missions stayed constantly airborne, and, during the Cuban Missile Crisis, a maximum number of B-52s went to airborne alert. B-47s, however, dispersed to civilian airports rather than stay on airborne alert.
In addition to its role as a nuclear strike bomber, the Stratojet's speed and payload made it a useful strategic reconnaissance aircraft, in the RB-47 imagery intelligence or ERB-47 electronic intelligence variants. Between 1952 and 1956, photographic reconnaissance B-47s conducted several overflights of the Soviet Union, providing detailed pictures of Soviet military and industrial facilities. Stratojets gathered intelligence about Soviet air defense systems and the Soviet intercontinental ballistic missile program. WB-47 Weather reconnaissance versions of the B-47 not only collected weather data, but also took air samples of Soviet nuclear detonations.
These essential RB-47 missions over and along the border of the Soviet Union were hazardous, and Soviet fighters damaged one reconnaissance Stratojet and shot down two, with the loss of seven USAF personnel killed and two temporarily imprisoned.