The Boeing B-47 Stratojet was designed and developed by the Boeing Aircraft back in the late 1940s under the designation Mole 450. The Boeing B-47 Stratojet is a long range turbojet powered and six-engine aircraft that was used by the USAF as their strategic bomber on the subsonic speeds at the high altitudes for avoiding any of the enemy interceptor aircraft. The main mission role for developing the Boeing B-47 Stratojet was to sue it as the Nuclear Bomber which could strike the enemy targets located within the Soviet Union.
The Boeing B-47 Stratojet’s development came after the retirement from the USAF to build a reconnaissance bomber aircraft that could harness the jet propulsion technology. Another great innovation in the design was the swept wing placement that had been taken from German designs. The Boeing B-47 Stratojet with its jet engines was the first of the best combat built jet aircraft after World War II and it also led the world into the development of the jet airliners.
USAF ordered for 2 prototypes which faced their competition with the CONVAIR XB-46, Martin XB-48 and the North American XB-45 and won the contract for delivery of 10 Boeing B-47 Stratojet aircraft.
With the Boeing B-47 Stratojet entering the USAF, the UAF was the one air force in the world that helped the massive bomber power in the world by late 1950s. Due to the tensions from the Cold War, nearly 2000 of these bombers were built to keep up with demands of USAF.
The Boeing B-47 Stratojet served with the USAF until mid 1960s before being replaced by the Boeing B-52 Superfortress. During its life, the aircraft served the following mission roles.
- Photographic reconnaissance
- Electronic intelligence
- Weather reconnaissance
The last aircraft retired back in 1969 from military service while during the testbeds, Boeing B-47 Stratojets were used until 1977.
Origin and First Flight:-
Due to the rising tensions of the Cold War of USA and Soviet Union, the USAF was in need of a Reconnaissance Bomber platform an issued their requirement for a bomber with jet engines. Many companies came forward like Lockheed martin, North American, CONVAIR and Boeing. Out of all the proposed design by these companies, the design of the Boeing’s Model 450 which was alter designated as SB-47 was approved by USAF. These 2 prototype models were given the designations SN 46-066 and SN 46-065. Both of them were powered by 6 of the Allison series turbojet engines. The aircraft would be operated by 3 crewmembers each; 2 pilots and one bombardier. The very first flight by an XB-47 was achieved back in 1947.
Following that USAF ordered for 10 more of these bombers and deliveries were made in the December 1950. 4 of these 10 Boeing B-47 Stratojet aircraft had the autopilot feature as well as the nav-attack and the radar system. Ejection seats were built in for all 3 crew members.
The rear of any bomber aircraft is its most vulnerable position to be attacked by an interceptor aircraft and this was why, the rear of the Boeing B-47 Stratojet was fitted with 2 12.7 mm machine guns that were remote controlled in the tail section. These guns were later replaced with cannons. Due to the Soviet building the SAM (Surface to air missile) systems, the Boeing B-47 Stratojet was forced to be a low-level bomber and was thus upgraded for such rigorous flights.
The internal ordnance carrying capacity was added in the B-47EW variant of the aircraft which allowed for it to carry a total of 25000 lbs of munitions. This was used mainly for carrying either 2 of the Mk 14 nuclear bombs or 28 of the conventional drop bombs weighing 500lbs each.
First USAF Deliveries:-
Following the successful first flight, USAF ordered for 10 of these bombers and the deliveries were made in the December of that very same year. Following the evaluation phases 87 more were ordered and then 399 more until the figure reached a full 2000 mark.
Reconnaissance variant of Boeing B-47 Stratojet:-
USAF asked for one specially made reconnaissance variant of the Boeing B-47 Stratojet which was designated as RB-47 that was fitted with extensive ECM (Electronic Countermeasures) equipments. The Boeing B-47 Stratojet went on to be serving the SAC (Strategic Air Command). 24 of the base Boeing B-47 Stratojet models were upgraded to become RB-47 that had cameras in the internal bombing bay. Still, these RB47s were used for daytime missions.
A single Boeing B-47 Stratojet was equipped with 6 of the General Electric J47-GE-25 turbojet engines; each of which generated a thrust of 7200 lbs. for JATO launches, the aircraft was also fitted with a single rocket system which would generate a thrust of 36000 lbs.
This much propulsion allowed for the Boeing B-47 Stratojet to fly at top speed of almost 600 mph for a ferry range of about 3870 miles at a maximum altitude of about 41000 feet. The aircraft rose to air with climbing rate of 4350 feet per minute.
Total number of Being B-47 produced and other operators:-
The mass production of the Boeing B-47 Stratojet started back in 1950 with the delivery of the first 10 units. Later the USAF approved the Boeing B-47 Stratojet for its nuclear bomber and reconnaissance roles. During its 10 years of production, nearly 2039 of these bombers were created in all their variant form. This high number of Boeing B-47 Stratojet aircraft manufactured was due to the increased tensions cased from Cold War threats.
The primary operator of this aircraft was only the US Air Force with some units also exported to the Canadian Air Force.
Replacement and Retirement:-
By the mid 1960s, the Boeing B-47 Stratojet had run its course of action in the USAF as better aircraft like the Boeing B-52 Superfortress and Convair B-58 Hustler made their way. Despite these aircraft, the aircraft went on to serve the USAF and the entire US military as the strategic deterrence and defense platform well until 1969; when it was formally retired.
Still, the aircraft was used for the testbeds by military and other US government services until 1977.