View source for Boeing B-47 Stratojet

{{Short description|Cold War-era American jet bomber}}
{{Redirect|B-47||B47 (disambiguation)}}
{{Use dmy dates|date=July 2020}}
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{{Infobox aircraft
| name = B-47 Stratojet
| image = File:NNSA-NSO-990.jpg
| caption = Boeing B-47 Stratojet in flight
| type = [[Strategic bomber]]/[[Reconnaissance aircraft|reconnaissance]]
| national_origin = United States
| manufacturer = [[Boeing]]
| designer = 
| first_flight = 17 December 1947
| introduction = June 1951
| retired = 1969 (B-47E)<br /> 1977 (EB-47E)
| primary_user = [[United States Air Force]]
| more_users = 
| number_built = 2,042<ref>{{cite web |url=https://www.airplanes-online.com/b47-stratojet.htm |title=B-47 Stratojet No. 1 total production |url-status=dead |access-date=12 July 2021 |archive-date=12 July 2021 |archive-url=https://web.archive.org/web/20210712085758/https://www.airplanes-online.com/b47-stratojet.htm }}</ref>
| status = Retired
| variants = 
| developed_into = [[Boeing XB-56]]
}}

The '''Boeing B-47 Stratojet''' (Boeing company designation '''Model 450''') is a retired American long-[[Range (aeronautics)|range]], six-engined, [[turbojet]]-powered [[strategic bomber]] designed to fly at high [[subsonic flight|subsonic]] speed and at high altitude to avoid enemy [[interceptor aircraft]]. The primary mission of the B-47 was as a [[Nuclear weapon|nuclear bomber]] capable of striking targets within the [[Soviet Union]].

Development of the B-47 can be traced back to a requirement expressed by the [[United States Army Air Forces]] (USAAF) in 1943 for a reconnaissance bomber that harnessed newly-developed [[jet propulsion]]. Another key innovation adopted during the development process was the [[swept wing]], drawing upon captured German research. With its engines carried in [[nacelle]]s underneath the wing, the B-47 represented a major innovation in post–[[World War II]] combat jet design, and contributed to the development of modern [[jet airliner]]s. 

In April 1946, the USAAF ordered two prototypes, designated XB-47. On 17 December 1947, the first prototype performed its [[maiden flight]]. Facing off competition such as the [[North American B-45 Tornado|North American XB-45]], [[Convair XB-46]] and [[Martin XB-48]], a formal contract for 10 B-47A bombers was signed on 3 September 1948. This would be soon followed by much larger contracts.

During 1951, the B-47 entered operational service with the [[United States Air Force]]'s [[Strategic Air Command]] (SAC), becoming a mainstay of its bomber strength by the late 1950s. Over 2,000 were manufactured to meet the Air Force's demands, driven by the tensions of the [[Cold War]]. The B-47 was in service as a strategic bomber until 1965, at which point it had largely been supplanted by more capable aircraft, such as Boeing's own [[Boeing B-52 Stratofortress|B-52 Stratofortress]]. The B-47 was also adapted to perform a number of other roles and functions, including [[Imagery intelligence|photographic reconnaissance]], [[electronic intelligence]], and weather reconnaissance. While never seeing combat as a bomber, reconnaissance '''RB-47s''' would occasionally come under fire near or within Soviet air space. The type remained in service as a [[reconnaissance aircraft]] until 1969. A few served as flying testbeds up until 1977.

==Development==

===Origins===
The B-47 arose from an informal 1943 requirement for a [[Jet engine|jet-powered]] reconnaissance bomber, drawn up by the [[United States Army Air Forces]] (USAAF) to prompt manufacturers to start research into jet bombers. Boeing was among several companies to respond to the request; one of its designs, the Model 424, was basically a scaled-down version of the [[piston-engine]]d [[Boeing B-29 Superfortress|B-29 Superfortress]] equipped with four jet engines.<ref name = "Peacock AE p31">Peacock 1989, p. 31.</ref><ref name = "gungil 389">Gunston and Gilchrist 1993, pp. 38–39.</ref> In 1944, this initial concept evolved into a formal request-for-proposal to design a new bomber with a maximum speed of {{convert|550|mph|kn km/h|abbr=on}}, a cruise speed of {{convert|450|mph|kn km/h|abbr=on}}, a range of {{convert|3500|mi|nmi km|abbr=on}}, and a service ceiling of {{convert|45000|ft|sigfig=3|abbr=on}}.<ref name="Knaack p101">Knaack 1988, p. 101.</ref><ref name = "gungil 39">Gunston and Gilchrist 1993, p. 39.</ref>

In December 1944, [[North American Aviation]], [[Convair]], [[Boeing]] and the [[Glenn L. Martin Company]] submitted proposals for the new long-range jet bomber. Wind tunnel testing had shown that the drag from the engine installation of the Model 424 was too high, so Boeing's entry was a revised design, the Model 432, with the four engines buried in the forward fuselage.<ref name="Peacock AE p33">Peacock 1989, p. 33.</ref><ref name = "gungil 39"/> The USAAF awarded study contracts to all four companies, requiring that North American and Convair concentrate on four-engined designs (to become [[North American B-45 Tornado|B-45]] and [[Convair XB-46|XB-46]]), while Boeing and Martin were to build six-engined aircraft (the B-47 and [[Martin XB-48|XB-48]]). The powerplant was to be [[GE-Aviation|General Electric's]] new [[General Electric J35|TG-180]] turbojet engine.<ref name="Peacock AE p33"/>

===Swept wings===
In May 1945, the [[United States Air Force Scientific Advisory Board|von Kármán mission of the Army Air Forces]] inspected the secret German aeronautics laboratory near [[Braunschweig]]. Von Kármán's team included the chief of the technical staff at Boeing, [[George S. Schairer]]. He had heard about the controversial swept-wing theory of [[Robert Thomas Jones (engineer)|R. T. Jones]] at Langley, but seeing German models of swept-wing aircraft and extensive supersonic wind-tunnel data, the concept was decisively confirmed. He wired his home office: "Stop the bomber design" and changed the wing design.<ref>Von Karman,'' Aerodynamics: Selected Topics in the Light of their Historical Developments'', 1954.</ref><ref name = "gungil 3940">Gunston and Gilchrist 1993, pp. 39–40.</ref> Analysis by Boeing engineer Vic Ganzer suggested an optimum sweepback angle of about 35 degrees.<ref>Cook 1991, p. 152.</ref> Boeing's aeronautical engineers modified the Model 432 with swept wings and [[empennage|tail]] to produce the "Model 448", which was presented to the USAAF in September 1945. It retained the four TG-180 jet engines in its forward fuselage, with two more TG-180s in the rear fuselage. The flush-mounted air intakes for the rear engines were inadequate while the USAAF considered the engine installation within the fuselage to be a fire hazard.<ref name="Peacock AE p33"/><ref name="Knaack p102">Knaack 1988, p. 102.</ref><ref name = "gungil 40">Gunston and Gilchrist 1993, p. 40.</ref>

The engines were moved to streamlined pylon-mounted pods under the wings, leading to the next iteration, the ''Model 450'', which featured two TG-180s in a twin pod mounted on a pylon about a third of the way outboard on each wing, plus another engine at each wingtip.<ref name = "gungil 40"/> The Army Air Force liked this new configuration, so Boeing's engineers refined it, moving the outer engines further inboard to about {{frac|3|4}} of the [[wingspan]]. The thin wings provided no space for tricycle main gear to retract so it would have needed a considerable bulge in the fuselage aft of the bomb bay for lateral stability. The only way to get a bomb-bay long enough for an A-bomb was to use a "bicycle landing gear",<ref>Cook 1991, p. 164.</ref> the two main gear assemblies arranged in a tandem configuration and outrigger struts fitted to the inboard engine pods. As the landing gear arrangement made [[Rotation (aviation)|rotation]] impossible, it was designed so that the aircraft rested on the ground at the proper angle for takeoff.<ref name="Peacock AE p33"/><ref name="Bowers Boeing p383">Bowers 1989, p. 383.</ref><ref name = "gungil 42">Gunston and Gilchrist 1993, p. 42.</ref>

Pleased with the refined Model 450 design, in April 1946, the USAAF ordered two prototypes, to be designated "XB-47".<ref name="Knaack p102-3">Knaack 1988, pp. 102–103.</ref> Assembly began in June 1947. The first XB-47 was rolled out on 12 September 1947,<ref name="Bowers Boeing p383"/> a few days before the USAAF became a separate service, the [[United States Air Force]] (USAF), on 18 September 1947. According to aviation authors Bill Gunston and Peter Gilchrist, Boeing subjected the first prototype to "one of the most comprehensive ground-test programmes ever undertaken".<ref name = "gungil 43"/>

===Flight test phase===
The XB-47 prototype flew its first flight on 17 December 1947 (the anniversary of the [[Wright Brothers]]' first four flights on 17 December 1903), with test pilots Robert Robbins and Scott Osler at the controls. It lasted 27 minutes, flying from [[Boeing Field]] in [[Seattle]] to [[Grant County International Airport|Moses Lake Airfield]] in central [[Washington (state)|Washington state]].<ref name="Yenne p158">Yenne 2002, p. 158.</ref><ref name="Peacock AE p34">Peacock 1989, p. 34.</ref> While not experiencing major problems, the emergency hot wire system was needed to raise the flaps and the engine fire warning indicators falsely illuminated. Robbins stated that it had good flight characteristics.<ref name="Natola 1724">Natola 2002, pp. 17–24.</ref>

Robbins had been skeptical about the XB-47, saying that before his first flight he had prayed, "Oh God, please help me through the next two hours." Robbins soon realized that he had an extraordinary aircraft.<ref name="Natola 1724"/> [[Chuck Yeager]] also flew the XB-47, noting it was so aerodynamically clean that he had difficulty landing on the [[Edwards Air Force Base|Edwards lakebed]].<ref name="Yeager 177178">Yeager 1985, pp. 177–178.</ref> In February 1949, Russ Schleeh and Joe Howell "broke all coast-to-coast speed records" flying from [[Larson Air Force Base|Moses Lake AFB]] to [[Andrews Air Force Base|Andrews AFB]], averaging {{convert|607.8|mph|kn km/h}}.<ref name="Natola 3436">Natola 2002, pp. 34–36.</ref> During an early test flight, the canopy came off at high speed, killing pilot Scott Osler; the aircraft was safely landed by the copilot.<ref name="Flight Journal">Boyne, Walter J. "Flying the B-47: An inside look at the USAF's first jet bomber".''Flight Journal'', April 2002. Retrieved 31 March 2010.</ref> The accident resulted in a canopy redesign and the hiring of pilot [[Alvin M. Johnston|Tex Johnston]] as chief test pilot.<ref>Johnston 2000, p. 135.</ref>

The second XB-47 (46-066) prototype first flew on 21 July 1948 and, following its delivery to the USAF in December of that year, served as a flying test bed until 1954. Its final destination was [[Chanute Air Force Base|Chanute AFB]] where it was used as a maintenance and familiarization aircraft.<ref>{{Cite web |url=http://b-47.com |title=The B-47 Stratojet Association |website=The B-47 Stratojet Association |language=en-US |access-date=8 December 2016}}</ref> The second prototype was equipped with more powerful General Electric [[General Electric J47|J47-GE-3]] turbojets with {{convert|5200|lbf|kN|abbr=on|lk=in}} of static thrust each.<ref name="Yenne p165">Yenne 2002, p. 165.</ref><ref name=tjpwpwr>{{cite news |url=https://news.google.com/newspapers?id=XsxeAAAAIBAJ&sjid=szIMAAAAIBAJ&pg=6446%2C3174477 |work=Lewiston Morning Tribune |location=Idaho |agency=Associated Press |title=Boeing turbo-jet packed with power |date=October 9, 1949 |page=1}}</ref> The J47 or "TG-190" was a redesigned version of the TG-180/J35; the first prototype was later retrofitted with these engines.{{Citation needed|date=August 2019}}

Flight testing of the prototypes was careful and methodical since the design was new in so many ways. They initially suffered from "[[Dutch roll]]", an instability that caused it to weave in widening "S" turns, remedied by the addition of a "[[yaw damper]]" control system to automatically deflect the [[rudder]] to damp out the weaving motion. Wind tunnel tests had shown it would pitch up at maximum speed due to wing stall on the outboard section of the wing. This was confirmed during flight tests so small vanes called "[[vortex generator]]s" were added to prevent [[Flow separation|airflow separation]].<ref>The Road to the 707 The Inside Story of Designing the 707, William H. Cook 1991, {{ISBN|0 9629605 0 0}}, p.194-198</ref>

Both XB-47 prototypes were test flown at Edwards AFB; the first XB-47 (46-065) was disassembled and scrapped in 1954, making the second prototype (46-066) the sole surviving XB-47. Upon retirement, XB-47 (46-066) was restored and placed on display at the [[Octave Chanute Aerospace Museum]] in [[Rantoul, Illinois]], remaining there until the museum announced its closure due to financial difficulties in April 2015.<ref>{{Cite web |url=http://www.paxtonrecord.net/news/politics-and-government/2015-04-23/chanute-air-museum-closing-rantoul.html |title=Chanute Air Museum closing in Rantoul {{!}} Paxton Record |website=paxtonrecord.net |access-date=8 December 2016 |archive-date=31 October 2016 |archive-url=https://web.archive.org/web/20161031172922/http://www.paxtonrecord.net/news/politics-and-government/2015-04-23/chanute-air-museum-closing-rantoul.html |url-status=dead }}</ref> In late 2015, the Flight Test Historical Foundation<ref>{{Cite web |url=http://afftcmuseum.org/foundation/ |title=Flight Test Historical Foundation |access-date=8 December 2016 |archive-url=https://web.archive.org/web/20160911190328/http://afftcmuseum.org/foundation/ |archive-date=11 September 2016 |url-status=dead }}</ref> began fundraising to purchase XB-47 (46-066) for relocation to the [[Air Force Flight Test Museum|Flight Test Museum]] at Edwards AFB. The purchase was completed in August 2016 and on 21 September 2016 the aircraft arrived at Edwards AFB for reassembly, restoration and eventual display at the Flight Test Museum.<ref>{{Cite news |url=https://www.edwards.af.mil/News/Article-Display/Article/951797/experimental-bomber-returns-home-after-six-decades/ |title=Experimental bomber returns home after six decades |newspaper=Edwards Air Force Base |access-date=8 December 2016}}</ref>

===X-model competitions===
By mid-1948, the USAF's bomber competition had already been through one iteration, pitting the North American XB-45 against the Convair XB-46. The North American design won that round of the competition. As an interim measure, the USAF decided to put the North American bomber into production on a limited basis as the B-45 Tornado. The expectation was that B-45 production would be terminated if either of the remaining two designs in the competition, the Boeing XB-47 and the Martin XB-48, proved superior. It is sometimes claimed that the final production decision was made as a result of Boeing president [[William McPherson Allen|Bill Allen]] inviting USAF General K.B. Wolfe, in charge of bomber production, for a ride in the XB-47.<ref name="Yenne p160">Yenne 2002, p. 160.</ref> A formal contract for 10 aircraft was signed on 3 September 1948.<ref name="Knaack p107">Knaack 1988, p. 107.</ref><ref name = "gungil 4344">Gunston and Gilchrist 1993, pp. 43–44.</ref>

===Production===
[[File:B-47As, Boeing Airplane Co. Plant II, North Apron, Wichita, KS, 1951.jpg|thumb|Seven B-47A at Boeing's [[Wichita, Kansas|Wichita]] plant, January 1951]]
{| class=wikitable style="text-align:center"
|-
! Variant
| XB-47
| B-47A
| B-47B
| B-47E
| RB-47E
| RB-47H
| ERB-47H
| RB-47K
|-
! Built
| 2
| 10
| 399
| 1341
| 240
| 32
| 3
| 15
|}

The total number of B-47s built was 2,042.<ref>{{cite web |url=https://www.grissomairmuseum.com/exhibits/gallery/bombers/plane-4 |title=B-47 Stratojet total production number 2 |url-status=dead |access-date=12 July 2021 |archive-date=6 January 2022 |archive-url=https://web.archive.org/web/20220106120751/https://www.grissomairmuseum.com/exhibits/gallery/bombers/plane-4 }}</ref>

==Design==

===Overview===
[[File:XB47 on runway.jpg|thumb|The first Boeing XB-47 built (''46-0065'') on 1 December 1947]]

The XB-47, which looked nothing like contemporary bombers, was described by Boyne<ref>{{cite magazine|url=https://www.airandspaceforces.com/app/uploads/2007/08/0807_August2007.pdf#page=100|title=Airpower Classics|volume=90|issue=8|last=Boyne|first=Walter J.|author-link=Walter J. Boyne|magazine=[[Air & Space Forces Magazine]]|page=104|archive-url=https://web.archive.org/web/20240822195138/https://www.airandspaceforces.com/app/uploads/2007/08/0807_August2007.pdf|archive-date=22 August 2024|url-status=live|access-date=24 February 2008|date=August 2007}}</ref> as a "sleek, beautiful outcome that was highly advanced". The 35-degree [[swept wing]]s were shoulder-mounted, the inboard turbojet engines mounted in twin pods, at about a third of the span, and the outboard engines singly near the wing tip. This arrangement reduced the bending moment at the wing roots, saving structural weight. The engines' mass acted as counter-[[Flutter (aircraft)|flutter]] weights.<ref name = "popular 141">Fraser November 1949, p. 141.</ref>

The wing airfoil was identified by Boeing as the BAC 145, also known as the [[NACA airfoil|NACA 64A(.225)12 mod airfoil]].<ref>Lednicer, David. [http://www.ae.illinois.edu/m-selig/ads/aircraft.html "The incomplete guide to aerofoil usage."] {{Webarchive|url=https://web.archive.org/web/20100420012244/http://www.ae.illinois.edu/m-selig/ads/aircraft.html |date=20 April 2010}} ''ae.illinois.edu.'' Retrieved: 7 June 2011.</ref> Wing flexibility was a concern, flexing as much as {{convert|17.5|ft|abbr=on}} at the tip;<ref name = "gungil 4041">Gunston and Gilchrist 1993, pp. 40–41.</ref><ref name = "popular 141"/> major effort was expended to ensure that flight control could be maintained as the wing moved up and down; these worries proved to be mostly unfounded. Its maximum speed was limited to {{convert|425|kn|km/h|lk=on|abbr=on}} [[Indicated airspeed|IAS]] to avoid [[control reversal]], where aileron deflections would cause the wings to twist and produce a roll in the opposite direction to that desired by the pilot.<ref>Cook 1991, {{page needed|date=August 2019}}.</ref> The wings were fitted with a set of [[Fowler flap]]s that extended well behind the wing to enhance lift at slow speeds.<ref name="Natola 19213">Natola 2002, pp. 19, 47, 54, 207, 213.</ref> The [[flight control surface]]s were powered, augmenting the pilot's inputs and reducing the exertion required to overcome the forces involved.<ref name = "popular 139140">Fraser November 1949, pp. 139–140.</ref>

The XB-47 was designed to carry a crew of three in a [[cabin pressurization|pressurized]] forward compartment: a pilot and copilot, in [[tandem]], in a long fighter-style [[bubble canopy]], and a [[navigator]]/[[Bombardier (aircrew)|bombardier]] in a compartment in the nose. The [[First officer (aeronautics)|copilot]] doubled as [[tail gunner]] (using a remotely controlled, [[radar]]-directed tail gun), and the navigator as bombardier.<ref name = "gungil 43">Gunston and Gilchrist 1993, p. 43.</ref> The bubble canopy, which provided a high level of visibility to the pilots, pitched up and slid backward; as the cockpit was high off the ground, the crew entered via a door and ladder on the underside of the nose.<ref name = "popular 140141">Fraser November 1949, pp. 140–141.</ref> The extreme front of the nose was initially [[Glazing (window)|glazed]] for visual navigation and bomb sighting, but this requirement was soon deleted together with the glazing. Most production versions had a metal nose with no windows. A K-series [[bombsight]] provided integrated [[radar navigation]] and visual navigation, the optical portion extending through the nose in a small dome. For greater comfort, both [[heater]]s and [[refrigeration]] systems were present in the cockpit to manage the cockpit environment. There was little vibration compared to prior bombers powered by [[reciprocating engine]]s.<ref name="popular 139140"/>

===Engines and performance===
[[File:Boeing B-47B rocket-assisted take off on April 15, 1954 061024-F-1234S-011.jpg|thumb|B-47B using [[JATO]] bottles to reduce takeoff distance]]
During the late 1940s, the bomber was hailed as the fastest of its class in the world.<ref name = "popular 139">Fraser November 1949, p. 139.</ref> The first prototypes were fitted with General Electric J35 turbojets, the production version of the TG-180, with {{convert|3970|lbf|kN|abbr=on}} of thrust. Early jet engines did not develop good thrust at low speeds, so to assist take off when heavily loaded, the B-47 had provisions for fitting solid-fuel [[JATO|rocket-assisted takeoff]] (RATO) rockets, each generating roughly {{convert|1000|lbf|kN|abbr=on}} of static thrust.<ref name = "popular 142">Fraser November 1949, p. 142.</ref> Early aircraft had mounts for nine RATO units built into each side of the rear fuselage, arranged in three rows of three bottles. Most of the space within the upper fuselage was taken up by [[self-sealing fuel tank]]s, the wing having been deemed unsuitable for storing fuel.<ref name = "gungil 4143">Gunston and Gilchrist 1993, pp. 41–43.</ref>

The performance of the Model 450 was projected to be so good that the bomber would be as fast as fighters then on the drawing board;<ref name = "gungil 38">Gunston and Gilchrist 1993, p. 38.</ref> thus the only defensive armament was to be a tail turret with two [[.50 BMG|.50&nbsp;in (12.7&nbsp;mm)]] [[M2 Browning|AN/M2 Browning]] machine guns, which would in principle be directed by an automatic [[fire-control system]].<ref name = "gungil 4243">Gunston and Gilchrist 1993, pp. 42–43.</ref> The two XB-47s were neither fitted with combat equipment nor tail turrets as they were engineering and flight test aircraft only. The total bombload capacity was to be {{convert|25000|lb|t|abbr=on}}. Production aircraft were to be equipped with modern electronics for navigation, bombing, countermeasures and turret fire control. Navigation was more difficult than on earlier aircraft due to the higher speed involved.<ref name = "popular 140">Fraser November 1949, p. 140.</ref>

One problem with the aircraft was that at higher altitudes, where the pure turbojet engines could produce good fuel economy, the wing was very compromised. At the top of the B-47's envelope, about {{convert|35000|ft|m}}, it was in "[[Coffin corner (aviation)|coffin corner]]".<ref name="Natola 184">Natola 2002, p. 184.</ref> That means that at this level, which produced the most range at most weights due to fuel consumption, there was an envelope of {{convert|5|kn|km/h|abbr=on}} between maximum mach and stall speed. For the B-47 to cross the Atlantic Ocean, it had to be flown this high. Due to its rudimentary autopilot, the pilot had to leave it turned off and spend up to eight hours diligently monitoring the airspeed and adjusting the throttles to avoid going into a stall. For perspective, a modern Boeing 757 has over {{convert|50|kn|km/h|abbr=on}} of difference at even a very heavy weight at {{convert|41000|ft|m}}. Fuel capacity was enormous, at {{convert|17000|usgal|L|abbr=on|lk=in}}, more than triple the {{convert|5000|usgal|L|abbr=on}} on the B-29 Superfortress, and meant that maintaining fuel trim to ensure a stable [[center of gravity of an aircraft|center of gravity]] was a critical copilot duty.{{Citation needed|date=August 2019}}

=== Drogue chutes===
The aircraft was so aerodynamically clean that rapid descent ("penetration") from high [[cruise (aeronautics)|cruise]] altitude to the landing pattern required dragging the deployed rear landing gear. The relatively high [[wing loading]] (weight/wing area) required a high landing speed of {{convert|180|kn|km/h|abbr=on}}. To shorten the landing roll, USAF test pilot Major [[Guy M. Townsend|Guy Townsend]] promoted the addition of a {{convert|32|ft|abbr=on}} German-invented "ribbon" drag chute ([[thrust reverser]]s had not then been developed).<ref name = "popular 142"/> For the same reason, the B-47 was the first mass-produced aircraft to be equipped with an [[Anti-lock braking system|anti-skid]] braking system.{{Citation needed|date=August 2019}}

A related problem was that the aircraft's engines would have to be throttled down on landing approach. Since it could take as long as 20 seconds to throttle them back up to full power, the bomber could not easily do a "[[Touch-and-go landing|touch and go]]" momentary landing. A 16-foot "approach chute" ([[drogue parachute]]) provided [[aerodynamic drag]] so that the aircraft could be flown at approach speeds with the engines throttled at ready-to-spool-up medium power. On the ground, the pilots used the 32-foot "brake chute". The brake chute could be deployed to stop the aircraft from "porpoising", or bouncing, after a hard landing on the front nose gear.<ref name="Natola 58219">Natola 2002, pp. 58–59, 151–153, 206, 211, 219.</ref> Training typically included an hour of dragging the approach chute around the landing pattern for multiple practice landings.

==Operational history==

===Early years===
[[File:B-47E.jpg|thumb|B-47Es on a SAC base flight line]]
[[File:B-47A Stratojet.ogg|thumb|Video of a B-47 Stratojet]]
The [[USAF]] [[Strategic Air Command]] operated multiple B-47 models (B-47s, EB-47s, RB-47s and YRB-47s) from 1951 through 1965. Upon entry to service, its performance was closer to that of contemporary fighters than SAC's extant [[Convair B-36|B-36 Peacemaker]] bomber, setting multiple records with ease. It handled well in flight, the controls having a fighter-like light touch. The large bubble canopy enhanced the flying crew's vision and gave a fighter-like feel, but also caused internal temperature variations for the crew. The three-man crew consisted of the commander, copilot and a navigator/bombardier or a crew chief.<ref name="Natola 44156">Natola 2002, pp. 44–45, 136, 156.</ref>

In 1953 the B-47 became operational. It was sluggish on takeoff and too fast on landings, an unpleasant combination. If landed at the wrong angle, the B-47 would "porpoise", bouncing fore-and-aft. If the pilot did not lift off for another go-around, instability would quickly cause it to skid onto one wing and cartwheel. Because the wings and surfaces flexed in flight, low-altitude speed restrictions were necessary to ensure effective flight control.{{Citation needed|date=August 2019}} The B-47 was regarded as a maintenance "hog".<ref name="Natola 44156"/> General reliability was good, the only major issuing relating to the [[avionics]], typical of the [[vacuum tube]] technology used and the placement of equipment outside the pressurized crew compartment. Much work was done to improve avionics reliability, but avionics remained troublesome throughout the B-47's operational life.{{Citation needed|date=August 2019}}

Starting in 1950, several models of the B-47 included a fuel tank [[inerting system]], in which [[dry ice]] was [[Sublimation (phase transition)|sublimed]] into [[carbon dioxide]] vapor while the fuel pumps operated or while the in-flight refueling system was in use. The carbon dioxide was pumped into both the fuel tanks and the fuel system to ensure low oxygen levels throughout. It was implemented largely to reduce the probability of an explosion from [[static electricity]] discharges.{{Citation needed|date=August 2019}}

[[File:Strategic Air Command B-47 Stratojets - 020903-o-9999r-001.jpg|thumb|SAC B-47s, the world's first swept-wing bomber]]

Initial mission profiles included the [[toss bombing|loft bombing]] of nuclear weapons. As the training for this imposes repeated high stress on the aircraft, the airframe lifetime would have been severely limited by [[Fatigue (material)|metal fatigue]], and this maneuver was eliminated. Improved training led to a good safety record, and few crews felt the aircraft was unsafe or too demanding, but apparently there were some aircrews who had little affection for the B-47. Crew workload was high, having only three crew members to operate it.<ref name = "popular 141142">Fraser November 1949, pp. 141–142.</ref> Boeing's [[Boeing B-52 Stratofortress|B-52 Stratofortress]], in contrast, generally had six crewmen, five officers and one enlisted, with more internal cabin space.{{Citation needed|date=August 2019}}

===Prime years===
An XB-47 was flown in the 1951 [[Operation Greenhouse]] [[nuclear weapons test]]. This was followed by a B-47B being flown in the 1952 test, [[Operation Ivy]] and the 1954 test, [[Operation Castle]]. A B-47E was then flown in the 1956 test, [[Operation Redwing]].<ref name="Natola 98109">Natola 2002, pp. 98–109.</ref> [[Operation Reflex]] missions proved the long-endurance (eighteen hours) and long range capability of the B-47 and aircrews. These were "simulated strike missions against the then Soviet enemy".<ref name="Natola 110199">Natola 2002, pp. 110, 163, 194, 199.</ref>

Three B-47s flew cross country from [[March Air Force Base]] to the [[Philadelphia International Airport]] as participants in the 1955 Labor Day [[National Air Races|race]]. In the 1956 event, three B-47s participated in the G.E. Trophy race for Jet Bombers, flying from [[Kindley Field]], Bermuda, to [[Oklahoma City]]. One of these set a course speed record of {{convert|601.187|mph|kn km/h}}.<ref name="Natola 126131">Natola 2002, pp. 126–131.</ref><ref>{{cite web|url=https://www.flightglobal.com/FlightPDFArchive/1956/1956%20-%201056.PDF|title=news clipping|website=Flightglobal|access-date=9 February 2019}}</ref><ref>{{cite web|url=https://news.google.com/newspapers?nid=1955&dat=19550905&id=cg0rAAAAIBAJ&sjid=bpoFAAAAIBAJ&pg=3043,1769329&hl=en|title=Reading Eagle – Google News Archive Search|access-date=9 February 2019}}</ref>

By 1956, the USAF had 28 wings of B-47 bombers and five wings of RB-47 reconnaissance aircraft. The B-47 was the first line of America's strategic nuclear deterrent, often operating from forward bases in the UK, [[Morocco]], Spain, [[Alaska]], Greenland and [[Guam]]. B-47s were often set up on "one-third" alert, with a third of operational aircraft available sitting on hardstands or an alert ramp adjacent to the runway, loaded with fuel and nuclear weapons, crews on standby, ready to attack the [[Soviet Union|USSR]] at short notice. Crews were trained to perform "[[Minimum Interval Take Off]]s (MITO)",<ref name="Natola 36193">Natola 2002, pp. 36, 44–45, 162, 193.</ref> one bomber following another into the air at intervals of as little as 15 seconds to launch as fast as possible. MITO could be hazardous, as the bombers left wingtip vortices and general [[turbulence]] behind them; the first generation turbojet engines, fitted with [[Water injection (engines)|water-injection]] systems, also created dense black smoke.<ref name="Natola 180">Natola 2002, p. 180.</ref>

The B-47 was the backbone of SAC into 1959, when the B-52 began to assume nuclear alert duties and the number of B-47 bomber wings started to be reduced. B-47 production ceased in 1957, though modifications and rebuilds continued. Operational practice for B-47 bomber operations during this time went from high-altitude bombing to low-altitude strike, which was judged more likely to penetrate Soviet defenses. Crews were trained in "pop-up" attacks, coming in at low level at {{convert|425|kn|km/h}} and then climbing abruptly near the target before releasing a nuclear weapon.<ref name="Natola 131212">Natola 2002, pp. 131–134, 212.</ref>

===Later years===
[[File:B-47s retired at MASDC 1960s.jpg|thumb|Retired B-47s at [[Davis-Monthan Air Force Base]] in the 1960s]]
[[File:US Navy EB-47Es at Point Mugu in 1971.jpeg|thumb|U.S. Navy EB-47Es at [[Naval Air Station Point Mugu]], in 1971]]
Stress and fatigue incurred in low-altitude operations led to a number of wing failures and crashes, and an extensive refit program was begun in 1958 to strengthen the wing mountings. The program was known as "Milk Bottle", named after the big connecting pins that were replaced in the wing roots.{{Citation needed|date=August 2019}}

One of the more notable mishaps involving a B-47 occurred on 5 February 1958 near Savannah, Georgia, in the so-called [[1958 Tybee Island B-47 crash]]. A B-47 based at [[Homestead AFB]], Florida, was engaged in a simulated combat exercise against an [[North American F-86 Sabre|F-86]] fighter. As was the practice at the time, the B-47 was carrying a single {{convert|7600|lb|abbr=on}} [[Mark 15 nuclear bomb]], without its core.<ref>Rosenberg, J.R.[https://www.washingtonpost.com/wp-dyn/articles/A63419-2004Sep30.html "Radiation levels prompt search."] ''The Washington Post'', 1 October 2004. Retrieved 13 November 2015.</ref> During this exercise, the two aircraft collided. The F-86 crashed after the pilot ejected, while the B-47 suffered substantial damage, including loss of power in one outboard engine. After three unsuccessful landing attempts at [[Hunter Air Force Base]], the bomber pilot had to "safe" soft drop the Mark 15 weapon off the coast of [[Savannah, Georgia]] near [[Tybee Island]], after which the B-47 landed safely. Despite an extensive nine-month search, the unarmed bomb was never found.<ref>Dungan, Fred. [http://www.fdungan.com/savannah.htm "Loose Nukes Threaten Coast: B-47 'Broken Arrow' 1958 Savannah, GA."] ''fdungan.com''. Retrieved 11 April 2010.</ref><ref>{{cite book |last1=Winchester |first1=Jim |title=Broken Arrow: How the U.S. Navy Lost a Nuclear Bomb |date=19 June 2019 |publisher=Casemate Publishers |isbn=978-1-61200-692-5 |page=233 |url=https://books.google.com/books?id=KL3ZDwAAQBAJ |language=en}}</ref><ref>Scott, Jeff. [http://www.aerospaceweb.org/question/weapons/q0268.shtml "Ask Us – Broken Arrow Nuclear Weapon Accidents."] ''Aerospaceweb.org''. Retrieved 11 April 2010.</ref>

In 1963, the [[Kennedy administration]] offered 24 B-47E bombers as an interim [[English Electric Canberra|Canberra Mk 20]] replacement for the [[Royal Australian Air Force]] (RAAF), pending delivery of the much delayed [[General Dynamics F-111C|F-111C aircraft]]. Three B-47E aircraft flew to Australia for demonstration purposes, but RAAF declined the B-47E as technically outdated and too resource-intensive.<ref>{{cite book |last1= Lax |first1= Mark |title= From Controversy to Cutting Edge: A History of the F-111 in Australian Service |url= http://airpower.airforce.gov.au/Publications/Details/431/From-Controversy-to-Cutting-Edge.aspx |publisher= Air Power Development Centre, Department of Defence |location= Canberra, Australia |pages= 29–30, 38–40 |isbn= 978-1-92080-054-3 |date= 2010}}</ref>

During 1963, final phaseout of B-47 bomber wings began; the last were out of SAC service by 1966. The last USAF operational aircraft, WB-47Es assigned to the [[Air Weather Service]], were withdrawn from use in September 1969. Shortly before, a B-47E, USAF Serial Number 53-2280, was used as a testbed for a newly developed [[fly-by-wire]] system.<ref>Golowanow, Łukasz. [http://www.konflikty.pl/technika-wojskowa/w-powietrzu/b-47-i-poczatki-fly-by-wire/ "B-47 i początki fly-by-wire."] ''konflikty.pl''. Retrieved 16 January 2016.</ref> The [[United States Navy|U.S. Navy]] kept specialized EB-47E test aircraft from USAF inventory in occasional use to support the ''Fleet Electronic Warfare Systems Group (FEWSG)'' until December 1977, being replaced by government owned/contractor operated (GOCO) [[Boeing NC-135|NKC-135 modified Stratotankers]] also loaned from the USAF.<ref>[http://www.bing.com/images/search?q=us+navy+nkc-135&view=detailv2&&id=19125BB9A671E3B994F646223E48CFE5A4D3909F&selectedIndex=1&ccid=zLSir%2b2g&simid=607992680576451779&thid=JN.%2bGEUPS8phe%2fb6ectIKqB8g&ajaxhist=0 "US Navy us navy NKC-135."] ''US Electronic Warfare Aircraft''. Retrieved 13 November 2015.</ref>

[[File:B47 DF-ST-88-01015.jpg|thumb|Last B-47 flight: in 1986, the restored ''52-0166'' was ferried from [[Naval Air Weapons Station China Lake]] to [[Castle AFB]] for display]]
The final recorded flight of a B-47 was on 17 June 1986, when a B-47E was restored to flightworthy condition for a one-time ferry flight. This aircraft was flown from [[Naval Air Weapons Station China Lake]], California, to [[Castle Air Force Base]], California, for static display at the Castle Air Museum, where it presently resides.<ref name="Natola 217219">Natola 2002, pp. 217–219.</ref>

===Reconnaissance===
{{main|United States aerial reconnaissance of the Soviet Union}}
The only B-47s to see anything close to combat were the [[aerial reconnaissance]] variants. The first overflight of Soviet territory with a B-47B, fitted with special radar and cameras in the bomb bay, occurred on 15 October 1952, overflying Soviet airfields in Northeastern Siberia.<ref name="Natola 9097">Natola 2002, pp. 90–97.</ref> RB-47s operated from almost every airfield that gave them access to the USSR and routinely probed Soviet airspace. Occasionally, they would avoid confrontations with speed and evasion. At least five aircraft were fired upon and three were shot down. The RB-47s returned fire with their tail turrets, although it is uncertain if they scored any kills; these were the only shots fired in anger by any B-47.{{Citation needed|date=August 2019}}

On 8 May 1954, after a top secret reconnaissance mission near the [[Kola Peninsula]], a [[4th Air Division]] / [[91st Missile Wing|91st Strategic Reconnaissance Wing]] RB-47E, flown by then-Capt (later Col) Harold "Hal" Austin, overflew the Soviet Union at high altitude, out of reach of [[Mikoyan-Gurevich MiG-15|MiG-15s]]. Unknown to USAF intelligence, [[Mikoyan-Gurevich MiG-17|{{nowrap|MiG-17s}}]] capable of intercepting it had been stationed nearby. The RB-47E was chased by several MiG-17s, firing upon it with their guns over Soviet and Finnish airspace. While taking damage, the RB-47E escaped over Sweden to its home base at [[RAF Fairford]], Gloucestershire. Its top speed and [[combat radius]] superiority to the fighter jets were decisive factors. The mission marked the first time a jet aircraft equipped with modern [[aerial photography]] equipment, K-17 and K-38 cameras, was used for USAF reconnaissance over the Soviet Union. The incident was kept secret by all parties.<ref name="Natola 8589">Natola 2002, pp. 85–89.</ref>

Other interceptions resulted in losses. An RB-47 flying from Alaska was scouting the [[Kamchatka Peninsula]] on 17 April 1955, when it was intercepted by Soviet MiG-15s in international airspace before disappearing. Between 21 March and 10 May 1956, 16 RB-47Es and five RB-47Hs operating from Thule performed overflights the length of Siberia 156 times under Project [[HOMERUN]]. The Soviets filed a complaint with the US government, which attributed the overflights to "navigational difficulties". MiGs intercepted RB-47s on three separate occasions in late 1958: over the Black Sea on 31 October, over the Baltic on 7 November, and over the [[Sea of Japan]] on 17 November.{{Citation needed|date=August 2019}}

On 1 July 1960, a [[PVO Strany]] [[Mikoyan-Gurevich MiG-19|MiG-19]] [[1960 RB-47 shootdown incident|shot down an RB-47H]] (AF Serial No. 53-4281) in international airspace over the [[Barents Sea]],<ref name="Powers 152159">Powers 2004, pp. 152, 159.</ref> killing four of the crew while two were captured by the Soviets and released in 1961. The co-pilot reported that the MiG-19 jammed his MD-4 FCS (that aimed the tail guns), rendering it defenseless.<ref>[https://www.youtube.com/watch?v=g0yi6V9POjk "On the Brink: Doomsday."] YouTube. Retrieved 18 August 2019.</ref><ref>[https://web.archive.org/web/20071029173940/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=1881 "RB-47H Shot Down."] ''nationalmuseum.af.mil''. Retrieved 16 August 2019.</ref> The last known confrontation between MiGs and RB-47s occurred on 28 April 1965, when an ERB-47H was intercepted by two North Korean MiG-17s over the Sea of Japan. While hit by the MiGs, it returned to [[Yokota Air Base]] in Japan with three engines out.<ref name="Natola 208211">Natola 2002, pp. 208–211.</ref> A few operated during the [[Vietnam War]] on missions such as relaying [[Signals intelligence|ELINT]] data, but were replaced by more efficient and capable Boeing [[Boeing RC-135|RC-135s]]. The last RB-47H was retired on 29 December 1967.<ref name = "gungil 44"/>

The final 15 RB-47s, built from December 1955, were fitted with additional equipment, including the AN/APD "[[side looking airborne radar]]" (SLAR) system, and gear to sample the air for [[Nuclear fallout|fallout]] from [[Nuclear testing|nuclear tests]]. These were given the designation RB-47K and generally used for weather reconnaissance missions, carrying a load of eight "[[dropsonde]]" weather sensors that were released at various checkpoints along the flight path. Data radioed back from the dropsondes was logged by the navigator. The RB-47Ks were in service until 1963.<ref name = "gungil 45">Gunston and Gilchrist 1993, p. 45.</ref> The type was succeeded by dedicated reconnaissance aircraft such as the [[Lockheed U-2]].<ref>[http://www.coldwar.org/text_files/ussr_overflights_91srw.pdf "RB-47E USSR Overflights by the 91st SRW."] {{Webarchive|url=https://web.archive.org/web/20080227141158/http://www.coldwar.org/text_files/ussr_overflights_91srw.pdf |date=27 February 2008 }} ''The Cold War Museum''. Retrieved 16 August 2019.</ref>

==Variants==
:''Section source: Baugher.''<ref>Baugher, Joe. [http://www.joebaugher.com/usaf_bombers/b47.html "B-47 Index of Variants."] ''Baugher's Encyclopedia: USAAC/USAAF/USAF Bomber Aircraft-Third Series''. Retrieved 11 April 2010.</ref>
; XB-47
:Two prototype aircraft, Model 450-1-1 and 450-2-2 respectively,(46-065 and 46-066); powered by six Allison J-35-GE-7 turbojet engines on early flights. The second XB-47 was powered by General Electric J-47-GE-3 engines, the first was retrofitted as such.<ref name = "Lloyd">Lloyd 2005. {{page needed|date=August 2019}}.</ref>

;B-47A
[[File:B-47A.jpg|thumb|A B-47A in flight, 11 August 1950]]

:The first 10 aircraft were designated B-47A and were evaluation aircraft, the first delivered in December 1950. While the XB-47s had been built at Boeing's Seattle plant, all B-47s were built at a government-owned factory in [[Wichita, Kansas]] that had previously built B-29s.<ref name=plread>{{cite news |url=https://news.google.com/newspapers?id=6VopAAAAIBAJ&sjid=c-UDAAAAIBAJ&pg=6259%2C3673401 |work=Spokesman-Review |location=Spokane, Washington |agency=Associated Press |title=Plant readied to build B-47s |date=10 November 1948 |page=2}}</ref> Their configuration was akin to the XB-47. All were powered by J47-GE-11 turbojets, offering the same {{convert|5200|lbf|kN|abbr=on}} thrust as the earlier J47-GE-3, and had built-in rocket-assisted-take-off ([[JATO|RATO]]) bottles.<ref name = "Lloyd"/> Four were fitted with the K-2 bombing and navigation system (BNS), HD-21D autopilot, an [[analog computer]], APS-23 radar, and a Y-4 or Y-4A bombsight. Two were fitted with the tail turret mounting two [[Hispano-Suiza HS.404|20mm cannons]]; one of them used an Emerson A-2 [[fire-control system|fire control system]] (FCS), another a General Electric A-5 FCS. The eight other B-47As lacked defensive armament.

:The B-47As were fitted with [[ejection seat]]s. The pilot and copilot ejected upward, while the navigator had a downward ejection seat built by [[Stanley Aviation]].<ref>[http://www.ejectionsite.com/stanley/ "The Ejection Site."] '' ejectionsite.com''. Retrieved 11 April 2010.</ref> Minimum safe ejection altitude was about 500&nbsp;ft (150&nbsp;m). In the 1950s, there were no suitable "dummies" to test ejection seats, thus live people were used. Several volunteers were injured testing the downward ejection seat. The first person to successfully use it was USAF Colonel Arthur M. Henderson who ejected over [[Choctawhatchee Bay]], near [[Eglin Air Force Base]], Florida, on 7 October 1953.<ref>[https://books.google.com/books?id=fNwDAAAAMBAJ&pg=PA88 "I Made The First Jump."] ''Popular Mechanics'', March 1955, pp. 88–93.</ref> Most B-47As were retired by 1952, though one performed flight tests for NACA for a few more years.{{Citation needed|date=August 2019}}

;B-47B
[[File:B47B with chute.jpg|thumb|B-47B (''51-2212'') of the [[306th Flying Training Group|306th Bomb Wing (Medium)]] at [[MacDill AFB]], Florida landing with [[Drogue parachute|drogue chute]]]]
:In November 1949, prior to the B-47A's first flight, the USAF ordered 87 B-47Bs, the first operational model. The first flew on 26 April 1951. A total of 399 were built, including eight assembled by [[Lockheed Corporation|Lockheed]] and 10 assembled by [[Douglas Aircraft Company|Douglas]] using Boeing-built parts. To quickly receive B-47s in quantity, the USAF contracted both Lockheed and Douglas for additional production;<ref name = "gungil 44">Gunston and Gilchrist 1993, p. 44.</ref> Lockheed-built aircraft were designated by a "-LM (Lockheed Marietta)" suffix and Douglas-built aircraft given a "-DT (Douglas Tulsa)" suffix. Boeing production was designated by a "-BW (Boeing Wichita)" suffix, except for the Seattle-built XB-47s and B-47As, which had a "-BO" suffix.

:The initial 87 B-47Bs used the same J47-GE-11 engines as the B-47A, subsequent deliveries had uprated J47-GE-23 units with {{convert|5800|lbf|kN|abbr=on}} thrust; early aircraft were later retrofitted. It had a built-in RATO system, as used on the B-47A, along with full combat systems. Early aircraft retained the K-2 BNS installed on some B-47As, but most featured the K-4A BNS, incorporating an AN/APS-54 warning radar and an AN/APT-5 electronic countermeasures (ECM) system. The K-4A used a nose-mounted periscopic bombsight. Ejection seats were deleted as a weight reduction measure; a windbreak panel on the main door made for a difficult escape.

:The bomb bay was shorter than the B-47A's as nuclear weapons had shrunk in the interim; the B-47B could carry a larger bombload of up to {{convert|18000|lb|abbr=on}}. All B-47Bs had a tail turret with twin 20&nbsp;mm (0.79&nbsp;in) guns and the B-4 radar-guided FCS. Due to issues, this FCS was often replaced with an N-6 optical sight; the copilot could swivel his seat to face backward and sight the guns directly. A nose-mounted [[in-flight refueling]] (IFR) receptacle enabled flying boom refueling from [[Boeing KB-50|KB-50]] and KC-97 tankers, requiring the plexiglas nose cone's replacement by a metal nose cone with four small windows, two on either side of the nose. The B-47B was also fitted with a pair of jettisonable external tanks, carried between the inboard and outboard engine assemblies, with a capacity of {{convert|1780|usgal|L|abbr=on}}. Another visible change was the vertical tailplane's squared-off top instead of a rounded top.

:Between 1955 and 1956, Boeing modified surviving B-47Bs from line numbers 235 to 399 to the B-47E standard under program ''High Noon''; this included fitting ejection seats. It was followed by the ''Ebb Tide'' program covering early line numbers from 1 to 234; this included 66 aircraft from the 135 to 234 batch to the same standard as the ''High Noon'' aircraft. Another 30 in the same range had additional modification as drone directors DB-47Bs, and the 1 to 134 range which had the same ''High Noon'' modification, but lacked some non-combat changes. Following these programs, they were sometimes referred to as B-47B-II.

;;YRB-47B
:The USAF considered building a specialized RB-47B reconnaissance variant, but schedule slips ensured that the RB-47E was the first such variant. As an interim measure, 91 B-47B bombers were fitted with a heated pod stowed in the forward bomb bay that housed eight cameras. These were designated YRB-47Bs and were capable of daylight reconnaissance only. Once the RB-47E arrived, they returned to the bomber role.<ref name = "gungil 45"/>

;;TB-47B
:A total of 66 of the 87 non-combat B-47Bs were re-designated TB-47B in 1953 to alleviate logistics problems due to different engines and systems. Most were used as trainers; some were modified for Air Training Command by Douglas at Tulsa under the ''Field Goal'' program, adding a fourth seat for an instructor and removing the tail turret.<ref name = "gungil 45"/> They were upgraded to B-47E standard in 1956 under the ''Ebb Tide'' program, joined by 41 more early build aircraft, also designated TB-47B. Used for training through the 1950s.

;;MB-47B
:With the introduction of the [[hydrogen bomb]], the USAF studied converting a few B-47Bs into MB-47B drones, essentially huge [[cruise missile]]s, under the [[Project Brass Ring|Brass Ring]] program; this was more formally known as MX-1457. Due to impracticality, it was canceled on 1 April 1953.<ref>{{cite web|url=http://www.designation-systems.net/dusrm/app4/other.html|title=Missile Scrapbook: MX-1457 Brass Ring|last=Parsch|first=Andreas|year=2007|work=Directory of U.S. Military Rockets and Missiles – Appendix 4: Undesignated Vehicles|publisher=Designation-Systems|access-date=18 May 2014}}</ref>

;;YDB-47B / DB-47B
:There were flight tests through the 1950s for using the B-47B as a launcher for the 31&nbsp;ft (9.5&nbsp;m) [[GAM-63 RASCAL]] missile, and one B-47B was modified into a YDB-47B Rascal launcher.<ref name = "gungil 45"/> The Rascal never became operational; a total of 74 B-47Bs were modified into DB-47Bs before cancellation.

;;WB-47B
:In 1956, a B-47B was converted into a WB-47B weather reconnaissance model and operated by the [[Military Air Transportation Service]] (MATS), one of a few B-47s not operated by SAC. It was used by the [[Air Weather Service]] until the mid-1960s.

;;KB-47B
:In 1953, two B-47Bs were modified to test the [[Aerial refueling|probe-and-drogue]] refueling system. The tanker, fitted with [[Cobham plc|British-built tanker kit]], was given the designation KB-47G and was known as "Maw" by flightcrews. The receiver aircraft was designated YB-47F and was known as "Paw", though other aircraft (including the [[Boeing B-52 Stratofortress|YB-52]] prototype) were also used as refueling targets. The program was cancelled in 1954 as the KB-47G could not carry a practical fuel load. The idea of fielding B-47 tanker conversions was re-examined, but unfavorable economics meant that it was again discarded in 1957. In parallel to the KB-47, Boeing tested its aerial refueling system aboard its [[Dash 80]], later evolving into the [[Boeing KC-135 Stratotanker|KC-135 Stratotanker]], which had greater fuel capacity.

;;Canadair CL-52
:An unusual conversion was the [[Canadair]] CL-52: a B-47B (USAF S/N 51-2059 RCAF S/N 059X) loaned in 1956 to the [[Royal Canadian Air Force]] to test the new, powerful [[Orenda Iroquois]] turbojet (rated at {{convert|19250|lbf|kN|abbr=on}} dry, {{convert|25000|lbf|kN|abbr=on}} afterburning) for the [[Avro Arrow|Avro Canada CF-105 Arrow]] [[interceptor aircraft|interceptor]]. Canadair attached the Iroquois engine to the right side of the rear fuselage; due to the large exterior diameter of the engine, no other location was feasible.<ref>Block, Burwell, ed. [http://www.b-47.com/history/ch27/b-47ch27.html "The CL-52/B-47B."] {{webarchive|url=https://web.archive.org/web/20110930110612/http://www.b-47.com/history/ch27/b-47ch27.html |date=30 September 2011}} ''The B-47 Stratojet Association''. Retrieved 4 June 2011.</ref> Flying the CL-52 was reportedly a nightmare. After the Arrow was canceled in early 1959, the B-47B/CL-52, which saw 35 hours of engine flight tests, was returned. Some sources{{who|date=August 2019}} claimed it was bent out of shape; it was scrapped. The CL-52 was the only B-47 to be used by any foreign service.

;YB-47C / RB-47C / B-47Z / B-56
[[File:Boeing B-56A Stratojet 3-view line drawing.png|thumb|B-56]]
:A four-engined variant of the B-47, the [[Boeing XB-56|YB-47C]] was proposed by Boeing in 1950 to be powered by four [[Allison J35]]-A-23 turbojet engines, providing {{convert|10090|lbf|kN|abbr=on}} thrust each, in place of the six GE J47s. The J35 was being developed at the time, and was provisionally rated at {{convert|9700|lbf|kN|abbr=on}} (with [[afterburner]]) or {{convert|8500|lbf|kN|abbr=on}} thrust without AB. Thus 4 * 8500 = {{convert|34,000|lbf|kN|abbr=on}} using that engine, as compared to 6 * {{convert|5200|lbf|kN|abbr=on}} = {{convert|31,200|lbf|kN|abbr=on}} in the production B-47, making it lighter, simpler and more powerful.<ref name="Jones">Jones 1969, {{page needed|date=August 2019}}.</ref> [[Allison J71|J71-A-5]] A contract was signed in January 1950 for the rework of one B-47B. The first flight was projected for April 1951.<ref>[http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2676 "Fact sheet Boeing B-56A."] {{webarchive |url=https://web.archive.org/web/20121014125044/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2676 |date=14 October 2012 }} ''National Museum of the United States Air Force''. Retrieved 11 April 2010.</ref>

:Due to the J35's less-than-expected performance and delays, other engines were considered, such as the proposed [[Allison J71]],<ref name="Jones"/> however engine problems meant that it was not feasible for the by-then redesignated B-56A. The [[Pratt & Whitney J57]], eventually rated at {{convert|17,000|lbf|kN|abbr=on}} thrust, was also considered, but was still in development. The Boeing B-52 Stratofortress, which was being concurrently developed, had priority for this engine.<ref name = "Lloyd"/> Thus, the B-56 was cancelled in December 1952 before the prototype's conversion had started.<ref name = "Lloyd"/> The donor fuselage intended for the XB-56 was reused as a ground instructional airframe.{{Citation needed|date=August 2019}}
[[File:Boeing XB-47D propjet.jpg|thumb|XB-47D]]

;XB-47D
:Starting in 1951, two XB-47Ds were modified from B-47Bs as experimental platforms, replacing each inboard two-jet pod with a [[Wright T49|Wright YT49-W-1]] turboprop engine spinning a huge four-bladed prop.<ref name="Natola 3842">Natola 2002, pp. 38–42.</ref><ref>[https://www.flightglobal.com/pdfarchive/view/1955/1955%20-%200099.html "Stratopropjet"] ''Flight'', 28 January 1955, p. 99.</ref> Engine development issues delayed the XB-47D's first flight until 26 August 1955. Performance was comparable to a conventional B-47, and its reversible propellers shortened the landing roll, but the idea was not pursued.{{Citation needed|date=August 2019}}

;B-47E
[[File:B47E in flight.jpg|thumb|A B-47E in flight]]
:The designations B-47C and B-47D applied to variants that were never produced, thus the next production model was the definitive B-47E, first flying on 30 January 1953. Four "blocks" or "phases" were built, each incorporating refinements on the previous block; changes sometimes occurred mid-block. The B-47 incorporated the radar-controlled rear tail turret. A total of 1,341 B-47Es were produced; 691 built by Boeing, 386 built by Lockheed, and 264 built by Douglas. Most B-47Bs were rebuilt to B-47E standards and given the designation of B-47B-II, though they were often called B-47Es.

:Early B-47E-Is had [[General Electric J47|J47-GE-25]] turbojets with {{convert|5970|lbf|kN|abbr=on}} thrust, these were changed to J47-GE-25A engines with water-[[methanol]] injection, which increased [[mass flow rate|mass flow]] to temporarily raise thrust to {{convert|7200|lbf|kN|abbr=on}} and produce much black smoke when engaged. Jet-Assisted Take Off ([[JATO]]) was installed on early B-47E-Is, integrating 18 JATO bottles, but was removed due to its proximity to fuel tanks. A later JATO system used an external jettisonable "split V" or "horse collar" rack fitted under the rear fuselage, carrying 33 JATO bottles in three rows of 11 bottles;<ref name="Natola 31195">Natola 2002, pp. 31, 36–37, 191, 195.</ref> the expendable racks were dropped over specific range areas after takeoff. Early B-47Es had a lower internal fuel capacity of {{convert|14627|usgal|L|abbr=on}} to save weight, which was considered acceptable due to large external tanks and mid-air refueling becoming common practice. A welcome change was the return of ejection seats. The twin .50&nbsp;in guns (12.7&nbsp;mm) in the tail turret were replaced with twin 20&nbsp;mm (0.79&nbsp;in) cannon for more firepower, backed up by an A-5 FCS in early production and an MD-4 FCS in later production.<ref>[https://books.google.com/books?id=sdwDAAAAMBAJ&pg=PA116 "Electronic Tail Guns Killing the Fog and Dark."] ''Popular Mechanics'', November 1954, p. 116.</ref>

:The B-47E-II had only minor changes from later-built B-47E-Is. The B-47E-III featured an ECM suite, consisting of a radar jammer in a bulge under the fuselage plus a [[Chaff (radar countermeasure)|chaff]] dispenser, as well as improved electrical alternators. The B-47E-IV was a major update, featuring stronger landing gear, airframe reinforcement, greater fuel capacity, and an uprated bombload of {{convert|25000|lb|sigfig=3|abbr=on}} while the bomb bay was again shortened as nuclear weapons became more compact. Another addition was the MA-7A BNS, which included the AN/APS-64 radar, having a range of up to {{convert|240|mi|km|abbr=on}} and could be used as a long range "[[identification friend or foe]] (IFF) transponder" interrogator to locate other B-47s or tankers, or as a high-resolution ground-targeting radar. The B-47E-IV retained the rarely-used optical bombsight. Most nose windows were deleted; only one remained on each side.

;;TEE TOWN B-47E
:In 1955, 100 B-47E-Is were modified to carry two removable external pods, one mounted on either side of the bomb bay, with each pod containing four AN/ALT-6B jammers. The pods were known as "Tee Town pods" (for Topeka, Kansas, location of [[Forbes AFB]]) and so these aircraft were known as "Tee Town B-47s". All retained their bombing capability.

;;EB-47E
:The Tee Town B-47Es led to a specialized ECM conversion, the EB-47E. "Phase IV" or "Blue Cradle" aircraft used a removable cradle housing 16 jammers in the bomb bay, plus radar warning receivers and chaff dispensers. The advanced "Phase V" EB-47E had a pressurized module holding 13 jammers stowed in the bomb bay controlled by two [[Electronic Warfare Officer]]s (EWOs), also known as "Crows" or "Ravens".<ref name="Natola 146214">Natola 2002, pp. 146, 164–165, 182, 192, 208–211, 214.</ref> While the Phase IV jammer was "broadband", covering a wide frequency range to jam radars operating within that range, the Phase V jammer could be selectively tuned to specific radar frequencies, enabling higher jammer power on the most effective frequencies. About 40 B-47Es were converted to EB-47Es; they could not carry bombs but retained tail turrets.

:B-47E ''52-0410'' and ''52-0412'' were converted to EB-47Es in the mid-1960s for the [[U.S. Navy]]'s [[Fleet Electronic Warfare Support Group]] ([[FEWSG]]). Considered to be on indefinite loan, they differed from USAF EB-47Es in that some podded ECM gear was mounted on the external fuel tank pylons. Used as "electronic aggressors" to test ECM systems, they were the last B-47s in service, ''52-0410'' performed its last flight on 20 December 1977.

;;EB-47E(TT)
:Three B-47Es were converted to the specialized EB-47E(TT) "Tell Two" configuration to be used for "[[telemetry]] intelligence", picking up radio signals from Soviet missile tests and space launches,<ref name = "gungil 45"/> being a precursor to the RC-135S Rivet Ball and Cobra Ball. It featured two ECM operators, a "Crow capsule" in the bomb bay loaded with gear, and distinctive antennas below each side of the cockpit. All three aircraft were operated out of [[Turkey]] until 1967. Crews often made up stories about their purpose, such as a "return to fighter" defensive system that made air-to-air missiles loop back and attack their own launch fighters.

;;ETB-47E
:As with the B-47B, a few B-47Es were converted to trainers, with a fourth seat for an instructor, and designated ETB-47E. They replaced older TB-47Bs, serving into the early 1960s.

;;DB-47E / YDB-47E
:Two B-47Es were converted to YDB-47Es to support the [[GAM-63 RASCAL]] stand-off missile program; two more B-47Es were converted to DB-47Es in preparation for the missile's introduction before it was axed and were reused as drone controller aircraft.

;;JB-47E
:Several B-47Es were assigned to other specialized test duties and given the blanket designation of JB-47E. One was used in the late 1960s to test "fly by wire" control system concepts.

;;JTB-47E
:Two B-47Es were also used for secret flight experiments in the early 1960s and given the designation JTB-47E, and a third modified B-47E was given the designation JRB-47E. They appear to have been test platforms for ECM systems.

;;NB-47E
:A B-47E was loaned to the US Navy to test the GE [[General Electric TF34|TF34-2]] turbofan for the [[Lockheed S-3 Viking]]. It was given the designation NB-47E and performed test flights from 1969 through 1975.

;;QB-47E
:A total of 14 RB-47Es were converted to QB-47E target drones in 1959 and 1960. These aircraft were radio-controlled and included self-destruct charges, arresting gear to assist landings, and carried pods on the external tank pylons to help in scoring weapons tests. Apparently most missiles fired on them were directed for a near-miss, but the QB-47Es were nonetheless eventually whittled down to two survivors that were retired in the early 1970s.<ref name = "gungil 45"/>

;;RB-47E
:[[File:Reconnaissance from Thule Air Base.jpg|thumb|A typical reconnaissance route from [[Thule AB]] (Greenland) to Soviet Union flown by RB-47H crews]]
:The B-47E was the basis for several reconnaissance models, the only B-47s to see anything resembling combat. They operated from most airfields that gave access to the USSR and often probed Soviet airspace. Boeing built 240 RB-47Es, similar to the B-47E but with a nose stretched by {{convert|34|in|m|abbr=on}}, giving an arguably more elegant appearance. The long nose accommodated up to 11 cameras, possibly including an O-15 [[radar]] camera for low-altitude work, a forward oblique camera for low-altitude work, a K-17 trimetrogon (three-angle) camera for [[Panorama|panoramic shots]] and K-36 [[Telephoto lens|telescopic cameras]]. Cameras were controlled by the "navigator-photographer". Photoflash [[flares]] were carried for night photography. While it could be refueled in flight, fuel capacity was increased to a total of {{convert|18400|usgal|L|abbr=on}}.

;;WB-47E
[[File:WB 47E 55 BW Stratojet HAFB.jpg|thumb|WB-47E, [[Hill Aerospace Museum]]]]
:Following the single WB-47B conversion, in the early 1960s, 34 B-47Es were converted by Lockheed into WB-47Es for weather reconnaissance to replace 44 [[Boeing B-50 Superfortress|WB-50D Superfortresses]] that had suffered several fatal crashes between 1956 and 1960. Stripped of combat gear, they were fitted with nose cameras to photograph cloud formations and a meteorological instrument pod in the bomb bay. Initially assigned to the Air Weather Service of the [[Military Air Transport Service]] (MATS), they became part of the [[Military Airlift Command]] (MAC) upon its establishment. The WB-47Es, the last B-47s in USAF service, were retired in October 1969.

:The [[53d Weather Reconnaissance Squadron]], of the [[9th Weather Reconnaissance Wing]], operated WB-47Es from [[Hunter Air Force Base]] and [[Ramey Air Force Base]]. These assets were transferred to the [[57th Weather Reconnaissance Squadron]] for [[Operation Arc Light]], operating from [[Clark Air Base]].<ref name="Natola 177179">Natola 2002, pp. 177–179.</ref>

;RB-47H/ERB-47H
[[File:National Museum of the United States Air Force marker for the RB-47H.jpg|thumb|[[National Museum of the United States Air Force]] (NMUSAF) marker for the RB-47H showing crew stations]]
:A total of 32 RB-47H models were built for electronic intelligence ([[ELINT]]) missions, as well as three more specialized "ERB-47Hs". Featuring a distinctive blunt, rounded nose and sported blisters and pods for intelligence-gathering antennas and gear, they were designed to probe defenses and collect data on radar and communications signals. The bomb bay was replaced by a [[Cabin pressurization|pressurized compartment]], which accommodated "Crows", or Electronic Warfare Officers (EWOs).<ref name = "gungil 45"/> There were three Crows on board the RB-47H and two on the ERB-47H. A distinctive bulged [[radome]] fairing replaced the bomb bay doors. They retained the tail turret and were fitted with jammers and chaff dispensers. A recognizable difference between the RB-47H and ERB-47H was the latter's distinctive antenna fairing under the rounded nose.

:The first RB-47H was delivered in August 1955 to [[Forbes AFB]], [[Kansas]]. They received a "Mod 44" or "Silver King" program in 1961 to update electronics systems and was recognizable by a large teardrop pod for ELINT antennas upon a pylon under the belly and offset to one side, as well as a pylon-style antenna under each wing beyond the outboard engine. The EWO compartment was cramped with sitting room only and had both poor noise insulation and climate control, making 12-hour missions uncomfortable and tiring. Successful ejection downward through the belly radome was impossible near the ground. Crews sat bobsled-like on the pilot compartment's floor for takeoff and landing. They then crawled encumbered with [[Arctic]] clothing and parachute to and from their compartment along an unpressurized maintenance shelf during a temporary level-off at {{convert|10000|ft|m|abbr=on}}.

[[File:RB-47H with F-111 nose.png|thumb|300px]]

:Operations were generally flown at night and classified Top Secret.<ref name="Natola 179181">Natola 2002, pp. 179–181.</ref> The final RB-47H to be retired from service, ''53-4296'', was reactivated and fitted with an F-111-style nose to test avionics for the [[General Dynamics F-111|General Dynamics FB-111]] in the early 1970s. It was not given any [[special designation]]. It is now on display at the [[Air Force Armament Museum]] at Eglin Air Force Base, fitted with a bomber nose.

;YB-47J
:A single B-47E was modified to test the MA-2 BNS for the B-52, and given the designation YB-47J.<ref name = "gungil 45"/>

;RB-47K
:The RB-47K was a photo and weather reconnaissance variant based on the RB-47E generally used for weather reconnaissance missions, carrying eight [[dropsonde]] weather sensors that were released at various checkpoints along its flight path. Data radioed from the dropsondes was logged by the navigator. Fifteen RB-47Ks were built, the variant was in service until 1963.<ref name = "gungil 45"/>

;EB-47L
:Between 1961 and 1963, 36 B-47Es were modified to carry a communications relay system and were designated EB-47L. Used to support US flying command post aircraft in case of a nuclear attack on the US, the EB-47Ls were only briefly in service as improved communications technologies made them redundant by 1965.

==Operators==
{{See also|List of B-47 units of the United States Air Force}}
;{{USA}}
* [[United States Air Force]]
* [[United States Navy]]
;{{flag|Canada|1921}}
* [[Royal Canadian Air Force]] – One B-47B loaned to Canada and converted by Canadair with the designation CL-52 to test the [[Avro CF-105 Arrow]]'s Orenda engines in 1956; returned to the U.S. Air Force and scrapped (1957)<ref>Norris, Glenn. [https://archive.today/20120720144111/http://www.aviationweek.com/aw/blogs/commercial_aviation/ThingsWithWings/index.jsp?plckController=Blog&plckScript=blogScript&plckElementId=blogDest&plckBlogPage=BlogViewPost&plckPostId=Blog:7a78f54e-b3dd-4fa6-ae6e-dff2ffd7bdbbPost:400aeb2d-68f5-48fb-90b6-fb586bf153aa "A picture of the modified B-47 (designated CL-52 in the Royal Canadian Air Force) in flight."] ''Aviation Week & Space Technology''. Retrieved 4 June 2011.</ref>

==Accidents and incidents==
[[File:National Museum of the United States Air Force display of McKone and Olmstead artifacts.jpg|thumb|NMUSAF display of McKone and Olmstead artifacts]]
{{See also|List of military nuclear accidents}}

Over its operating life, 203 B-47s were lost in crashes, with 464 deaths. This represents approximately 10% of the total number produced.<ref name=AirForceMagazine>{{cite web | url=http://www.airforcemag.com/MagazineArchive/Pages/2013/February%202013/0213b47.aspx |last=Boyne |first=Walter J |title=The B-47's Deadly Dominance |date=February 2013 |access-date=5 January 2019}}</ref>

On 8 February 1954, a B-47 of the 22nd Bomber Wing, March AFB, California, crashed in Stoke Wood, a mile and a half short of the runway at RAF Upper Heyford, England, while on a training run. All three crew were killed.<ref>{{cite web | url=https://www.thisisoxfordshire.co.uk/news/19870527.raf-upper-heyford-heritage-centre-calls-return-missing-war-memorial-plaque/ | title=Fresh appeal for historic war memorial to be returned after it was stolen from RAF base | date=25 January 2022 }}</ref>

On 28 February 1955, a crippled B-47 crashed into a trailer park in [[Lake Charles, Louisiana]], killing the three crewmen and two people on the ground.<ref>[http://libguides.mcneese.edu/LCSesqui "Timeline of Significant Events in Lake Charles"] ''[[McNeese State University]]'', 2016. Retrieved 7 December 2016.</ref><ref>"Crash Kills Five" ''Lake Charles American Press'', 1 March 1955, Page 1. Retrieved 7 December 2016.</ref>

On 10 March 1956, four B-47s left [[MacDill Air Force Base]] in Florida for a non-stop flight to [[Ben Guerir Air Base]] in Morocco. After descending through clouds to begin their second round of [[aerial refueling]] over the [[Mediterranean Sea]] at 14,000 feet, one of the four aircraft, [[1956 B-47 disappearance|serial number 52-0534]], failed to make contact with the tanker; neither the aircraft, its two nuclear weapon [[Pit (nuclear weapon)|cores]], nor its personnel were ever found.<ref>{{cite web |url=http://www.check-six.com/lib/Famous_Missing/Broken_Arrow_B47.htm |title=Broken Arrow B-47 |website=check-six.com |date=1 July 2015}}</ref>

On 28 March 1956, a B-47 exploded near [[Wichita, Kansas]], with an instructor and two student pilots on board.<ref>{{cite news |url=https://www.newspapers.com/clip/12056711/wichita_b47_crash_kills_three_crewmen/ |title=Wichita B47 Crash Kills Three Crewmen |agency=[[Associated Press]] |newspaper=[[The Salina Journal]] |location=Salina, Kansas |date=28 March 1956 |access-date=1 July 2017 |via=newspapers.com}}</ref> It crashed four miles northeast of the city, killing its crew of three. The office of information services at [[McConnell Air Force Base]] said the explosion occurred after takeoff, probably at about 2,000 feet altitude. Wreckage was strewn along the countryside for several miles as the wings sheared off and the fuselage tumbled to earth.<ref>UP story excerpted from the ''Wichita Eagle'', evening edition, 28 March 1956.</ref>

On 27 July 1956, a B-47 of the 307th Bombardment Wing crashed at [[RAF Lakenheath]] killing its crew and causing a near radioactive incident when it hit a storage igloo containing three [[Mark 6 nuclear bomb|MK-6 nuclear weapons]]. Although the bombs involved lacked their [[Pit (nuclear weapon)|fissile cores]], each carried about {{convert|8,000|lb}} of high explosives for their trigger mechanism. The crash and ensuing fire did not ignite the high explosives and no detonation occurred.<ref>[https://web.archive.org/web/20000519154728/http://www.gwu.edu/~nsarchiv/nsa/NC/nh4_1.gif "Cable to Commander-in-Chief Strategic Air Command General Curtis LeMay."] ''[[U.S. Department of Defense]]'', 27 July 1956. Retrieved 21 September 2013.</ref>

In November 1956, B-47E serial number 51-2421 of the [[96th Bombardment Wing]], flying from [[Altus AFB]], crashed on a farm near [[Hobart, Oklahoma]], following engine problems.<ref>[http://www.ejection-history.org.uk/Aircraft_by_Type/B-47.htm "All Losses & Ejections."] {{Webarchive|url=https://web.archive.org/web/20171203054840/http://www.ejection-history.org.uk/Aircraft_by_Type/B-47.htm |date=3 December 2017 }} ''Boeing B-47 Stratojet'', 25 November 2014. Retrieved 13 November 2015.</ref> Four crewmen were killed in the incident.<ref>Taylor, Ethel. [http://rebelcherokee.labdiva.com/airplanecrash.html "Hobart, OK Air Force B-47 Stratojet crash, Nov 1956; Four killed in crash of Stratojet."] ''rebelcherokee.labdiva.com''. Retrieved 13 November 2015.</ref>

On 9 October 1957, B-47 serial number 51-2177A, of the [[447th Missile Squadron|447th Bomb Squadron]], [[321st Air Expeditionary Wing|321st Bomb Wing]] at [[Pinecastle Air Force Base]] suffered wing failure and crashed northwest of [[Orlando, Florida]], and west of [[Winter Park, Florida]], while conducting a practice demonstration for the annual Strategic Air Command Bombing Navigation and Reconnaissance Competition at Pinecastle AFB. The wing commander, Colonel Michael Norman Wright McCoy, was killed in the crash; Pinecastle AFB was later renamed [[McCoy Air Force Base|McCoy AFB]] in his honor.

On 4 December 1957, a [[MacDill Air Force Base]] B-47 exploded in mid-air over [[Choctawhatchee Bay]], [[Okaloosa County, Florida]]. Parts were scattered over a wide underwater area that varied in depth from 20 to 30 feet. Assistance from US Navy divers from the Mine Detection Laboratory, [[Panama City, Florida]], the Underwater Demolition Team No. 21 from Little Creek, Va., the 3201st Boat Squadron, APGC, recovered most of the plane. The three crew were killed.<ref>"Divers Recover Bomber From Choctawhatchee Bay," Playground News Fort Walton Beach, Florida, Thursday 19 December 1957, p. 3.</ref><ref>{{Cite web|url=https://aviation-safety.net/wikibase/225906|title=Accident Boeing B-47E Stratojet 52-241, 04 Dec 1957|first=Harro|last=Ranter|website=aviation-safety.net}}</ref>

On 5 February 1958, a B-47 was involved in a mid-air collision with an [[F-86]] fighter over Georgia, known as [[1958 Tybee Island mid-air collision]].<ref name="Natola 7780">Natola 2002, pp. 77–80.</ref>

On 26 February 1958, RB-47E serial number 52-0720 crashed six miles south of Lancaster, OH on approach to Lockbourne AFB, OH, hitting the ground at an angle of 50 degrees. It was determined that the aircraft attained an unusual attitude and/or high speed through disorientation, from which there was no recovery. In actuality, a wheel door had broken away and prevented the control surfaces being fully active.{{citation needed|date=December 2018}}

On 13 March 1958, two B-47s crashed on the same date in separate incidents when the lower wing skin failed at the same structural location.<ref>{{cite web|title=DT Handbook-Handbook of Damage Tolerance|url=http://www.afgrow.net/applications/DTDHandbook/sections/page1_1.aspx|website=AFGROW.net|publisher=LexTech, Inc|access-date=23 January 2017}}</ref> One exploded over southeast Tulsa, Oklahoma, killing one crewman and raining debris over at least 8 square miles, witnessed by thousands of people on the ground. Two of the three men on a training mission from McConnell Air Force Base in Wichita, Kansas, parachuted to safety. The third was trapped in the nose of the plane and died.<ref>Curtis, Gene. [http://www.tulsaworld.com/news/usworld/way-back-when-today-in-history/article_bd95f189-6615-5b85-ba31-484e4bc931d3.html "1958 – B-47 explodes over southeast Tulsa."] ''Tulsa World'', 13 March 2014. Retrieved 13 November 2015.</ref>

On 10 April 1958, a B-47 from [[Lockbourne Air Force Base]], Ohio, exploded mid-flight behind the [[Boeing KC-97 Stratofreighter|KC-97G]] tanker that was to refuel it. The KC-97 was unharmed, but the wreckage fell within a half-mile of a highway and none of the crew survived.<ref>H. Bruce Franklin. [https://militaryhistorynow.com/2018/09/16/broken-bombers-how-the-u-s-military-covered-up-fatal-flaws-in-the-b-47-stratojet-with-disastrous-results/ "Broken Bombers – How the U.S. Military Covered Up Fatal Flaws in the B-47 Stratojet with Disastrous Results"]</ref>

On 15 April 1958, a B-47 from [[Walker Air Force Base]] in [[New Mexico]], [[United States military aircraft serials|serial number]] 52–0562, crashed on takeoff at [[Pease Air Force Base]] in [[New Hampshire]]; all four crewmen were killed.<ref>{{cite web |url=http://www.newenglandaviationhistory.com/pease-air-force-base-april-15-1958/ |title=Pease Air Force Base – April 15, 1958 |website=newenglandaviationhistory.com |first=Jim |last=Ignasher |date=6 May 2016 |access-date=30 June 2017}}</ref><ref>{{cite news |url=https://www.newspapers.com/clip/12044354/4_die_in_jet_bomber_crash_second/ |title=4 Die In Jet Bomber Crash; Second Smashup Of Day |newspaper=Fort Lauderdale News |location=Fort Lauderdale, Florida |agency=[[Associated Press]] |date=16 April 1958 |via=newspapers.com}}</ref>

On 22 November 1958, a B-47B crashed while taking off from [[Loring Air Force Base]] in Maine, killing all four crew members on board. The plane belonged to a unit at [[McCoy Air Force Base]] in Orlando, Florida. The plane was described as having veered sharply to the right while two-thirds of the way down the runway, eventually crashing 400 feet north of the runway.<ref>"Bomber Crashes; 4 Aboard". Limestone, Maine: The Miami News. 22 November 1958. Retrieved 17 August 2012.</ref> On 25 November 1958, a KC-135 of the 42d Air Refueling Squadron crashed on takeoff roughly in the same area as the B-47 three days before.

On 4 April 1959, B-47 serial number 52-0320 crashed in the Santa Rita mountains, south of Tucson, Arizona, while attempting to land at Davis-Monthan AFB. All three crew were killed. Investigators noted that a faulty [[altimeter]] was a contributing factor.<ref>McDoniel, Chris. [http://www.p-38.com/Site/B-47E,_52-0320,_crash_near_Tucson,_AZ_(Santa_Rita_Mountains)_on_April_4,_1959.html "B-47E, 52-0320, Crash south of Tucson Az (Santa Rita Mountains) on April 4, 1958."] {{webarchive|url=https://web.archive.org/web/20130328101417/http://www.p-38.com/Site/B-47E%2C_52-0320%2C_crash_near_Tucson%2C_AZ_%28Santa_Rita_Mountains%29_on_April_4%2C_1959.html |date=28 March 2013 }} ''Aerospace Archaeology'', 2014. Retrieved 13 November 2015.</ref>

On 24 April 1959, Captain John S. Lappo, operating from [[Lockbourne AFB]] flew a B-47 with two crewmen on board under the [[Mackinac Bridge]] in [[Michigan]]. Following a [[Courts-martial in the United States#General court-martial|general court-martial]], he was grounded for life.<ref>{{cite news |title=Grounded for good |date=11 December 1959 |work=The News-Palladium |location=Benton Harbor, Michigan |page=10 |publisher = [[Ancestry.com#Newspapers.com]]}}</ref>

On 30 December 1959, a B-47B crashed at Torrejón Air Base, Spain one minute after takeoff. All four crew members were killed.<ref>{{cite web |url=http://b-47.com/?page_id=3191 |title=B-47 Losses |website=b-47.com |publisher=The B-47 Stratojet Association|date=2 March 2014}}</ref>

On 31 March 1960, B-47E serial number 52-1414, of the 384th Bomb Wing (SAC), 545th Bombardment Squadron, Little Rock AFB, exploded inflight over Little Rock, Arkansas. Three of the four crew and two civilians on the ground were killed.<ref>Lewis, Bill, and Owens, Patrick J., Gazette Staff, "FLAMING DEBRIS HITS IN HEIGHTS AND WEST SIDE – 3 Of 4 Crewmen, 2 Civilians Dead; Lieutenant Parachutes to Safety", Arkansas Gazette, Little Rock, Arkansas, 31 March 1960, page 1.</ref><ref>[https://web.archive.org/web/20090114192317/http://www.oldstatehouse.org/pdf/91Fall.pdf "Air Force Jet Bomber Explodes Over City."] ''The Arkansas News'', Fall 1991. p. 1.</ref>

On 1 July 1960 a [[1960 RB-47 shootdown incident|RB-47 was shot down over the Barents Sea by Soviet Air Defense]]. Four crewmen died and 2 survived.

On 4 January 1961, B-47 serial number 53-4244, based at Pease Air Force Base, crashed on takeoff; all four crewmen were killed.<ref>{{cite news |url=https://www.newspapers.com/clip/12043895/4_af_men_killed_in_bomber_crash/ |title=4 AF Men Killed In Bomber Crash |newspaper=[[The Newport Daily News]] |location=Newport, Rhode Island |agency=[[Associated Press]] |date=5 January 1961 |access-date=30 June 2017 |via=newspapers.com}}</ref>

On 24 February 1961, a B-47 crashed 10 miles southwest of [[Hurley, Wisconsin]], while on a practice bombing mission from the 40th Bomb Wing at Forbes Air Force Base, Topeka, Kansas. Its four crew were killed. An engine was found 600 yards from the point of impact, indicating it detached prior to the crash.<ref>"4 Air Force officers killed as jet bomber crashes in Iron Co." ''Iron County Miner'' 3 March 1961.</ref>

On 2 May 1961, a B-47 crashed eight miles southwest of Hurley, Wisconsin, only a few miles from the scene of a prior B-47 crash on 24 February 1961. Two of four crew survived. Evidence showed that it was steeply diving when the crash occurred.<ref>"Second bomber crashes near Hurley within ten weeks." ''Iron County Miner'', 5 May 1961.</ref>

In January 1962, a B-47 based at Plattsburgh Air Force Base on a training mission crashed into the side of [[Wright Peak]] in the [[Adirondack High Peaks|High Peaks in the Adirondacks]] of New York. All four crew were killed. It had veered about 30 miles east due to inclement weather. Wreckage can still be found at the summit, including a landing gear strut and a partial engine.<ref>Knight, Chris. [http://www.northcountrypublicradio.org/news/story/19141/twisted-remains-mark-site-of-1962-mountaintop-plane-crash "Twisted remains mark site of 1962 mountaintop plane crash."] ''North Country Public Radio''. Retrieved 13 November 2015.</ref><ref>[http://www.adirondack-park.net/history/b47.wright.html "B-47 Crashes into Wright Peak (Adirondacks)."] ''adirondack-park.net''. Retrieved 16 August 2019.</ref>

On 23 July 1962, a B-47 based at Dyess Air Force Base near Abilene, Texas, departed on a training mission through Montana. After crossing into [[Paradise Valley (Montana)|Paradise Valley]], it crashed into Emigrant Peak and exploded while turning toward the northwest. All four crew were killed.<ref>Wright, Michael. [http://www.bozemandailychronicle.com/news/in-memory-of-a-plane-crash/article_b821f15f-ecee-5d19-baac-0f1ead5c9edc.html "In memory of a plane crash."] {{Webarchive|url=https://web.archive.org/web/20160719113158/http://www.bozemandailychronicle.com/news/in-memory-of-a-plane-crash/article_b821f15f-ecee-5d19-baac-0f1ead5c9edc.html |date=19 July 2016 }} ''Bozeman Daily Chronicle''. Retrieved 20 July 2016.</ref>

On 3 August 1962, B-47 serial number 52-0526, based at Pease Air Force Base, crashed on takeoff; all three crew were killed.<ref>{{cite news |url=https://www.newspapers.com/clip/12043751/pease_afb_plane_crash_kills_three/ |title=Pease AFB Plane Crash Kills Three |newspaper=[[The Telegraph (Nashua)|Nashua Telegraph]] |location=Nashua, New Hampshire |agency=[[Associated Press]] |date=4 August 1962 |access-date=30 June 2017 |via=newspapers.com}}</ref>

On 22 August 1962, B-47 serial number 52-0553, based at Davis–Monthan Air Force Base near Tucson, Arizona, crashed on a training mission shortly before midnight in the [[Idaho]] mountains south of [[Smiths Ferry, Idaho|Smiths Ferry]]; controlled flight into terrain started a [[Wildfire|forest fire]], and all three crew were killed.<ref name=ciasob>{{cite news |url=https://news.google.com/newspapers?id=KdlYAAAAIBAJ&sjid=R_cDAAAAIBAJ&pg=2011%2C5413086 |work=Spokane Daily Chronicle |location=Washington|agency=Associated Press |title=Crash in Idaho sets off blaze |date=23 August 1962 |page=1}}</ref><ref name=idpktd>{{cite news |url=https://news.google.com/newspapers?id=rsNPAAAAIBAJ&sjid=vlIDAAAAIBAJ&pg=7072,1342100 |work=St. Petersburg Times |location=Florida |agency=Associated Press |title=Jet crashes against Idaho peak, 3 dead |date=23 August 1962 |page=4A}}</ref><ref name=noofboi>{{cite news |url=https://news.google.com/newspapers?id=tftVAAAAIBAJ&sjid=2-IDAAAAIBAJ&pg=2501%2C4012147 |work=Eugene Register-Guard |location=Oregon|agency=UPI |title=B47 jet crashes north of Boise |date=23 August 1962 |page=1A}}</ref>

On 20 February 1963, a B-47 of the 98th Bomb Wing based at [[Lincoln Air National Guard Base|Lincoln AFB]], [[Nebraska]], crashed in [[Bashaw Township, Brown County, Minnesota|Bashaw Township]], approximately three miles north of the town of [[Comfrey, Minnesota]]. All four crew were killed. It had just completed a low-altitude simulated bombing run near [[Heron Lake, Minnesota|Heron Lake]] when the sixth engine failed, causing it to crash in a field, resulting in a 25-foot deep by 50-foot wide crater.<ref>Buntjer, Julie. [http://www.dglobe.com/event/article/id/65767/ "Fifty years later: Jet crash memorial to be dedicated in Comfrey".]{{dead link|date=November 2016 |bot=InternetArchiveBot |fix-attempted=yes }} ''Daily Globe'' (Worthington, Minnesota), 12 July 2013.</ref><ref>Busch, Fritz. [http://www.nujournal.com/page/content.detail/id/532177/Comfrey-vet-recalls--63-B-47-crash.html "Comfrey vet recalls '63 B-47 crash".] {{webarchive |url=https://web.archive.org/web/20140203143454/http://www.nujournal.com/page/content.detail/id/532177/Comfrey-vet-recalls--63-B-47-crash.html |date=3 February 2014 }} ''The Journal'' (New Ulm, Minnesota), 11 November 2012</ref><ref>Schmierbach, Edie. [http://mankatofreepress.com/local/x766090856/Memorial-to-mark-site-of-1963-plane-crash "Memorial to mark site of 1963 plane crash".] ''The Free Press'' (Mankato, Minnesota), 17 February 2013.</ref>

On 3 May 1963, B-47E serial number 52-0051, based at [[Mountain Home Air Force Base|Mountain Home AFB]], Idaho, crashed in [[Yellowstone National Park]] in [[Wyoming]] following a collision with a [[Boeing KC-135 Stratotanker|KC-135]] during midair refueling. The co-pilot ejected safely, but the other three crewmen were killed; the tanker landed safely with no casualties.<ref name=bghntd>{{cite news |url=https://news.google.com/newspapers?id=H4E1AAAAIBAJ&sjid=fPcDAAAAIBAJ&pg=3319%2C1111506 |work=Spokane Daily Chronicle |location=Washington |agency=Associated Press |title=Downed B47 being hunted in mountains |date=4 May 1963 |page=1}}</ref><ref name=copokg>{{cite news |url=https://news.google.com/newspapers?id=IIE1AAAAIBAJ&sjid=fPcDAAAAIBAJ&pg=4802%2C1289895 |work=Spokane Daily Chronicle |location=Washington |agency=Associated Press |title=Crash victim being hunted, co-pilot OK |date=6 May 1963 |page=2}}</ref><ref name=thbdy>{{cite news |url=https://news.google.com/newspapers?id=WsteAAAAIBAJ&sjid=mDIMAAAAIBAJ&pg=2384%2C1066637 |work=Lewiston Morning Tribune |location=Idaho |agency=Associated Press |title=Third body taken from wrecked B47 |date=7 May 1963 |page=8}}</ref>

On 19 August 1963, two B-47E aircraft, serial numbers 53-2365 and 53-6206, both based at [[Schilling Air Force Base|Schilling AFB]] near [[Salina, Kansas]], collided over western [[Iowa]] and crashed several miles apart near [[Irwin, Iowa|Irwin]]. All six crewman ejected, but three were killed.<ref name=jbbcol>{{cite news |url=https://news.google.com/newspapers?id=2OdXAAAAIBAJ&sjid=_ugDAAAAIBAJ&pg=2332%2C1371252 |work=Spokesman-Review |location=Spokane, Washington |agency=Associated Press |title=Jet bombers collide; two crewman die |date=20 August 1963 |page=1}}</ref>

On 20 August 1963, a QB-47 veered off course on its landing approach at Eglin AFB and crash landed on a road parallel to the runway. It was used for [[Bomarc Missile Program]] tests, normally operated from Eglin AFB Auxiliary Field Number Three ([[Duke Field]]), approximately {{convert|15|mi|km}} north of the main base. Two cars were crushed, killing two occupants and injuring a third.<ref>"Fiery crash of drone plane kills two, injures one – Four firemen overcome in wake of blaze." ''Playground Daily News'' ([[Fort Walton Beach, Florida]]), Volume 16, Number 271, 20 August 1963, p. 1.</ref>

On 6 February 1964, B-47E serial number 52-0366, based at Mountain Home AFB, Idaho, crashed in fog on takeoff; all four crewmen were killed.<ref name=sdc4od>{{cite news |url=https://news.google.com/newspapers?id=SFpYAAAAIBAJ&sjid=bPcDAAAAIBAJ&pg=2789%2C1092989 |work=Spokane Daily Chronicle |location=Washington |agency=Associated Press |title=4 officers die in B47 crash |date=6 February 1964 |page=1}}</ref><ref name=mhsrcr>{{cite news |url=https://news.google.com/newspapers?id=OeBXAAAAIBAJ&sjid=FOkDAAAAIBAJ&pg=4012%2C1851137 |work=Spokesman-Review |location=Spokane, Washington |agency=Associated Press |title=Four air officers die as B47 crashes, burns |date=7 February 1964 |page=1}}</ref>

On 27 March 1964, B-47E serial number 52-0321, based at [[Little Rock Air Force Base|Little Rock AFB]], Arkansas, crashed shortly after takeoff, killing all four crewmen and two boys on the ground.<ref name=ppgapjcfk>{{cite news |url=https://news.google.com/newspapers?id=bWQwAAAAIBAJ&sjid=k2wDAAAAIBAJ&pg=1904%2C4196349 |work=Pittsburgh Post-Gazette |agency=Associated Press |title=Jet crashes, five killed |date=28 March 1964 |page=1}}</ref><ref name=lpulrk>{{cite news |url=https://news.google.com/newspapers?id=OWEqAAAAIBAJ&sjid=AU8EAAAAIBAJ&pg=2576%2C3671467 |work=Pittsburgh Press |agency=UPI |title=B-47 plunge kills crew, boy at play |date=28 March 1964 |page=3}}</ref>

On 27 July 1964, B-47E serial number 53-2366, based at Lincoln AFB, Nebraska, crashed shortly after takeoff; all four crewmen were killed.<ref name=ppnebr>{{cite news |url=https://news.google.com/newspapers?id=aV4bAAAAIBAJ&sjid=Ek8EAAAAIBAJ&pg=2763%2C3484084 |work=Pittsburgh Press |agency=UPI |title=Nebraska crash kills 4 in B-47 |date=27 July 1964 |page=1}}</ref><ref name=nebsdclj>{{cite news |url=https://news.google.com/newspapers?id=_M4zAAAAIBAJ&sjid=mfcDAAAAIBAJ&pg=4219%2C5796333 |work=Spokane Daily Chronicle |location=Washington |agency=Associated Press |title=B47 crash kills four in Nebraska |date=27 July 1964 |page=1}}</ref>

On 8 December 1964, B-47E serial number 52-0339, based at Pease AFB, crashed in [[Newington, New Hampshire]], shortly after takeoff; all four crewmen were killed.<ref>{{cite web |url=http://www.newenglandaviationhistory.com/pease-afb-dec-8-1964/ |title=Pease AFB – Dec. 8, 1964 |website=newenglandaviationhistory.com |first=Jim |last=Ignasher |date=15 March 2015 |access-date=30 June 2017}}</ref><ref>{{cite news |url=https://www.newspapers.com/clip/12044174/b47_crash_fatal_to_4/ |title=B-47 Crash Fatal To 4 |newspaper=[[The Newport Daily News]] |location=Newport, Rhode Island |agency=[[Associated Press]] |date=8 December 1964 |access-date=30 June 2017 |via=newspapers.com}}</ref>

On 26 February 1965, B-47E serial number 52-0171, based at Pease AFB, collided during mid-air refueling with a KC-135 over the Atlantic Ocean, {{convert|700|mi}} east of Maine. Both aircraft, with four crew members each, crashed into the water with no survivors. The bomber was one of three returning to Pease after a training mission in Spain.<ref name=jcooc>{{cite news |url=https://news.google.com/newspapers?id=KcgtAAAAIBAJ&sjid=iJwFAAAAIBAJ&pg=5283%2C4630711 |work=Reading Eagle |location=Pennsylvania |agency=UPI |title=Jets collide over ocean |date=26 February 1965 |page=4}}</ref><ref name=offcprc>{{cite news |url=https://news.google.com/newspapers?id=6PcgAAAAIBAJ&sjid=u3MFAAAAIBAJ&pg=6300%2C3609152 |work=The Day |location=New London, Connecticut |agency=Associated Press |title=Search for crashed jets continues off Cape Race |date=27 February 1965 |page=1}}</ref>

==Surviving aircraft==
[[File:Boeing B-47 at Mighty 8th Air Force Museum, Pooler, GA, US.jpg|thumb|B-47 on display at the [[National Museum of the Mighty Eighth Air Force]] ]]
{{Main|List of surviving Boeing B-47 Stratojets}}
Twenty-three surviving airframes exist in museum collections; all are located in the United States.

==Specifications (B-47E)==
[[File:B-47A 3-View line art.svg|thumb|Boeing B-47E Stratojet 3-view drawing]]
{{Aircraft specs
|ref= ''Quest for Performance.''<ref>Loftin, L.K. Jr. [http://www.hq.nasa.gov/pao/History/SP-468/cover.htm "Quest for Performance: The Evolution of Modern Aircraft."] {{Webarchive|url=https://web.archive.org/web/20060613210139/http://www.hq.nasa.gov/pao/History/SP-468/cover.htm |date=13 June 2006 }} ''NASA'' SP-468. Retrieved 22 April 2006.</ref>
|prime units?=imp
<!--
        General characteristics
-->
|crew=3
|length ft=107
|length in=1
|length note=
|span ft=116
|span in=0
|span note=
|height ft=28
|height in=0
|height note=
|wing area sqft=1428
|wing area note=
|aspect ratio=9.42
|airfoil=[[NACA airfoil|NACA 64A(.225)12 mod]] (BAC145)<ref name="Selig">{{cite web |last1=Lednicer |first1=David |title=The Incomplete Guide to Airfoil Usage |url=https://m-selig.ae.illinois.edu/ads/aircraft.html |website=m-selig.ae.illinois.edu |access-date=16 April 2019}}</ref>
|empty weight lb=80,000
|empty weight note=
|gross weight lb=133030
|gross weight note=
|max takeoff weight lb=221000<ref name="USAF Flight Handbook">"Technical Order 1B-47E-1 Flight Handbook B-47B & B-47E Aircraft"</ref> 
|max takeoff weight note=
|fuel capacity=
|more general=
* '''[[Zero-lift drag coefficient]]:''' 0.0148 (estimated)
* '''[[zero-lift drag coefficient]] area:''' 21.13{{nbsp}}ft{{sup|2}} (1.96{{nbsp}}m{{sup|2}})
<!--
        Powerplant
-->
|eng1 number=6
|eng1 name=[[General Electric J47-GE-25]]
|eng1 type=[[turbojet]] engines
|eng1 lbf=7200
|eng1 note=

|eng2 number=18 or 33
|eng2 name=[[JATO]] bottles,
|eng2 type=auxiliary jet assisted takeoff engines
<!--
        Performance
-->
|max speed mph=607
|max speed note=
|max speed mach=<!-- supersonic aircraft -->
|cruise speed mph=557
|cruise speed note=
|stall speed mph=
|stall speed note=
|never exceed speed mph=
|never exceed speed note=
|minimum control speed mph=
|minimum control speed note=
|range miles=
|range note=
|combat range miles=2013
|combat range note=with {{cvt|20000|lb}} bombload
|ferry range miles=4647
|ferry range note=with underwing tanks
|endurance=<!-- if range unknown -->
|ceiling ft=40500
|ceiling note=<ref>{{cite web |url=https://www.boeing.com/history/products/b-47-stratojet.page |title=Boeing: Historical Snapshot: B-47 Stratojet |publisher=Boeing |access-date=9 February 2019}}</ref>
|g limits=<!-- aerobatic -->
|roll rate=<!-- aerobatic -->
|climb rate ftmin=4660
|climb rate note=
|time to altitude=
|wing loading lb/sqft=93.16
|wing loading note=
|fuel consumption lb/mi=
|thrust/weight=0.22

|more performance=
<!--
        Armament
-->
|guns= 2 × [[20 mm caliber|20{{nbsp}}mm (0.787{{nbsp}}in)]] [[Hispano-Suiza HS.404#United States|M24A1 autocannon]] in a remote controlled tail turret with
|bombs={{cvt|25000|lb|0}} of ordnance, including:
** 2 × [[Mark 15 nuclear bomb|Mk15]] [[nuclear bomb]]s (3.8 megaton yield each), ''or''
** 4 × [[B28 nuclear bomb]]s (1.1–1.45 megaton yield each), ''or''
** 1 × [[B41 nuclear bomb]] (25 megaton yield), ''or''
** 1 × [[B53 nuclear bomb]] (9 megaton yield), ''or''
** 28 × 500{{nbsp}}lb (227{{nbsp}}kg) conventional bombs
|avionics=
''Data from'' Designations Of U.S. Military Electronic And Communications Equipment<ref name="designation-systems">{{cite web |title=Designations Of U.S. Military Electronic And Communications Equipment |url=http://www.designation-systems.net/usmilav/electronics.html#_JETDS_AN_Listings |website=designation-systems.net |access-date=2 September 2019}}</ref>
:* [[List of radars#AN/APD Series|AN/APD-4]]: D/E/F-Bamd Radar Direction Finding System; manufactured by ITT
:* [[List of radars#AN/APG Series|AN/APG-32]]: X-Band Tail Turret Autotrack Radar; manufactured by General Electric
:* [[List of radars#AN/APG Series|AN/APG-39]]: Gun-laying radar
:* [[List of radars#AN/APN Series|AN/APN-11]]: X-Band Beacon; used with AN/APS-3/4/6/10/15/19/23/31/33, AN/APQ-13
:* [[List of radars#AN/APN Series|AN/APN-12]]: Rendezvous Radar (or 160–230 MHz "Rebecca" Interrogator)
:* [[List of military electronics of the United States#AN/APN-42|AN/APN-42]]: Radar Altimeter; WB-47E
:* [[List of radars#AN/APN Series|AN/APN-66]]: Doppler Navigation Radar
:* [[List of radars#AN/APN Series|AN/APN-69]]: X-Band Rendezvous Beacon
:* [[List of radars#AN/APN Series|AN/APN-75]]: Rendezvous Radar
:* [[List of radars#AN/APN Series|AN/APN-76]]: Rendezvous Radar; manufactured by Olympic
:* [[List of military electronics of the United States#AN/APN-102|AN/APN-102]]: Doppler Set; manufactured by GPI; RB-47, WB-47E
:* [[List of radars#AN/APQ Series|AN/APQ-56]]: Side-Looking, Real-Aperture Radar; manufactured by Westinghouse; RB-47
:* [[List of radars#AN/APQ Series|AN/APQ-T11]]: Bombing/Navigation Radar Trainer
:* [[List of radars#AN/APQ Series|AN/APQ-T12]]: Bombing/Navigation Radar Trainer
:* [[List of radars#AN/APR Series|AN/APR-17]]: D- through I-Band Early Warning Intercept Receiver (based on AN/APR-9); manufactured by Loral; RB-47H
:* [[List of radars#AN/APS Series|AN/APS-23]]: Search Radar; manufactured by Western Electric; part of AN/ASB-3; B-47E
:* [[List of radars#AN/APS Series|AN/APS-64]]: Search Radar; WB-47E
:* [[List of radars#AN/APS Series|AN/APS-84]]: Tracking Radar; QB-47
:* [[List of radars#AN/APS Series|AN/APS-54]]: Tail-Warning Radar System; manufactured by ITT; B-47B/E
:* [[List of radars#AN/APS Series|AN/APS-84]]: Tracking Radar; QB-47
:* [[AN/APT-5]]: "Carpet IV" 350–1200 MHz L-Band Semibarrage Jamming Radar Transmitter; manufactured by General Motors (Delco Div.), Aireon; B-47A/B, RB-47K
:* [[AN/APT-8]]: 750–1200 MHz Jamming Radar Transmitter; RB-47K
:* [[AN/APT-16]]: 2300–4105 MHz D/E/F-Band Radar Jammer; manufactured by Raytheon; RB-47K
:* [[List of military electronics of the United States#AN/APX-6|AN/APX-6]]: L-Band IFF Transponder Set; manufactured by Hazeltine; used with AN/TPX-22
:* [[List of military electronics of the United States#AN/ARA-25|AN/ARA-25]]: UHF Direction Finding Group
:* [[AN/ARA-26]]: Emergency Keyer Group
:* [[List of military electronics of the United States#AN/ARC-21|AN/ARC-21]]: HF Long Range Liaison Radio Set
:* [[List of military electronics of the United States#AN/ARC-27|AN/ARC-27]]: UHF/VHF Command Radio Set (developed from AN/ARC-19); manufactured by Collins
:* [[List of military electronics of the United States#AN/ARC-65|AN/ARC-65]]: SSB/HF Liaison Radio (AN/ARC-21 modified for SSB (Single Side Band) operation)
:* [[List of military electronics of the United States#AN/ARC-89|AN/ARC-89]]: Radio Relay System; manufactured by E-Systems, ITT; part of PACCS (Post Attack Command & Control System); used with AN/ACC-1, AN/ACC-2, AN/ACC-3; EB-47L
:* [[List of military electronics of the United States#AN/ARN-6|AN/ARN-6]]: Radio Compass; manufactured by Bendix
:* [[List of military electronics of the United States#AN/ARN-12|AN/ARN-12]]: Marker Beacon Receiver
:* [[List of military electronics of the United States#AN/ARN-14|AN/ARN-14]]: Omni-Directional Receiver
:* [[AN/ARN-18]]: Glide Path Receiver
:* [[AN/ARN-65]]: TACAN Receiver
:* [[AN/ARN-70]]: LORAN Receiver
:* [[AN/ARR-36]]: HF Auxiliary Receiver; used with AN/ARC-21
:* [[AN/ART-40]]: UHF Radio Transmitter; used with AN/ARR-67; part of AN/USQ-25
:* [[AN/ARW-64]]: UHF Command Receiver; used with AN/ARW-65; QB-47
:* [[AN/ASH-13]]: Weather Data Recorder; WB-47
:* [[AN/ASN-6]]: Navigational Computer System; used with AN/APN-81, AN/APN-82; WB-47
:* [[AN/ASN-21]]: Navigation (Longitude/Latitude) Computer; WB-47E
:* [[AN/ASQ-18]]: Electronic Reconnaissance System; RB-47
:* [[AN/ASQ-32]]: Radar Navigation System; RB-47
:* [[AN/ATC-1]]: Airborne Switchboard; EB-47L
}}

==Notable appearances in media==
<!-- All content about the aircraft in fictional and gaming use has been moved to [[Aircraft in fiction]], please see [[WP:AIRPOP]] -->
{{Main|Aircraft in fiction#B-47 Stratojet}}

==See also==
{{Portal|Aviation}}
{{aircontent
|related=
* [[Boeing B-52 Stratofortress]]
* [[Boeing 367-80]]
* [[Boeing XB-55]]
* [[Boeing XB-56]]
|similar aircraft=
* [[Avro Vulcan]]
* [[Convair XB-46]]
* [[Handley Page Victor]]
* [[Ilyushin Il-28]]
* [[Junkers EF 132]]
* [[Martin XB-48]]
* [[North American B-45 Tornado]]
* [[Tupolev Tu-16]]
* [[Vickers Valiant]]
|lists=
* [[List of bomber aircraft]]
* [[List of military aircraft of the United States]]
|see also=
* [[Bold Orion]]
}}

==References==

===Citations===
{{Reflist|30em}}

===Bibliography===
{{vectorsite}}
{{Refbegin}}
* {{cite magazine|url=https://www.airandspaceforces.com/article/1297stratojet/|title=The Long Reach of the Stratojet|last=Boyne|first=Walter J.|author-link=Walter J. Boyne|date=December 1997|magazine=[[Air & Space Forces Magazine]]|volume=80|issue=12|archive-url=https://web.archive.org/web/20251007230011/https://www.airandspaceforces.com/article/1297stratojet/|archive-date=7 October 2025|url-status=live|access-date=9 March 2003}}
* Bowers, Peter M. "The Boeing B-47" ''Aircraft in Profile, Volume 4''. Windsor, Berkshire, UK: Profile Publications Ltd., 2nd revised and enlarged edition, 1970. {{ISBN|0-85383-013-4}}.
* [[Peter M. Bowers|Bowers, Peter M.]] ''Boeing Aircraft since 1916''. London: Putnam, 1989. {{ISBN|0-85177-804-6}}.
* Cook, William H. ''The Road to the 707: The Inside Story of Designing the 707.'' Bellevue, Washington: TYC Publishing, 1991. {{ISBN|0-962960500}}.
* Dennison, Robert C. "Stratojet!" ''Air Combat'', July /August 1997. (Dennison is a retired USAF officer and B-47 pilot who works with the B-47 Stratojet Association.)
* Fraser, Jim. [https://books.google.com/books?id=hyQDAAAAMBAJ&pg=RA1-PA139 "I Fly The World's Fastest Bomber."] ''Popular Science'', November 1949. Vol. 155, No. 5. pp.&nbsp;139–142. {{ISSN|0161-7370}}.
* Grant, R.G. and John R. Dailey. ''Flight: 100 Years of Aviation''. Harlow, Essex, UK: DK Adult, 2007. {{ISBN|978-0-7566-1902-2}}.
* Gunston, Bill. ''Bombers of the West''. London: Ian Allan Ltd., 1973, pp.&nbsp;126–153. {{ISBN|0-7110-0456-0}}.
* Gunston, Bill and Peter Gilchrist. ''Jet Bombers: From the Messerschmitt Me 262 to the Stealth B-2''. Osprey, 1993. {{ISBN|1-85532-258-7}}.
* Johnston, A.M. ''Tex Johnston: Jet-Age Test Pilot''. Washington D.C.: Smithsonian Institution Press, 2000. {{ISBN|1-56098-931-9}}.
* Jones, Lloyd S. ''U.S. Bombers, B-1 1928 to B-1 1980s''. Fallbrook, California: Aero Publishers, 1962, second edition 1974. {{ISBN|0-8168-9126-5}}.
* Jones, Lloyd S. ''U.S. Bombers: 1928-1980s''. Fallbrook, California: Aero Publishers, Inc., 1981. {{ISBN|978-0-8168-9126-9}}.
* Knaack, Marcelle Size. [https://web.archive.org/web/20071025174047/http://www.airforcehistory.hq.af.mil/Publications/fulltext/encyclopedia_postww2_bombers.pdf ''Post-World War II Bombers, 1945–1973''(PDF).] Washington, D.C.: Office of Air Force History, 1988. {{ISBN|0-16-002260-6}}.
* Lloyd, Alwyn T. ''Boeing's B-47 Stratoje''. North Branch Minnesota: Specialty Press, 2005. {{ISBN|978-1-58007-071-3}}.
* Loftin, Laurence K. Jr. [http://www.hq.nasa.gov/pao/History/SP-468/ch12-2.htm ''Quest for Performance: The Evolution of Modern Aircraft.''] {{Webarchive|url=https://web.archive.org/web/20120130112807/http://www.hq.nasa.gov/pao/History/SP-468/ch12-2.htm |date=30 January 2012 }} NASA Scientific and Technical Information Branch, 2004.
* Natola, Mark. "Boeing B-47 Stratojet." ''Schiffer Publishing Ltd'', 2002. {{ISBN|0-76431-670-2}}.
* Peacock, Lindsay. "Stratojet...Progenitor of a Dynasty". ''[[Air Enthusiast]]'', Thirty-eight, January–April 1989, pp.&nbsp;31–44, 63. Bromley, UK: FineScroll. ISSN 0143-5450.
* Powers, Francis. ''Operation Overflight: A Memoir of the U-2 Incident''. Potomac Books Inc., 2004. {{ISBN|9-7815-7488-422-7}}.
* Tegler, Jan. ''B-47 Stratojet: Boeing's Brilliant Bomber''. New York: McGraw-Hill, 2000. {{ISBN|0-07-135567-7}}.
* Yeager, Chuck. "Yeager." ''Bantam Book'', 1985. {{ISBN|0-5530-5093-1}}.
* Yenne, Bill. "Variant Briefing: Boeing B-47 Stratojet". ''International Air Power Review'', Volume Six, Autumn/Fall 2002, pp.&nbsp;156–171. Norwalk, Connecticut: AIRtime Publishing. {{ISBN|1-880588-46-3}}. ISSN 1473-9917.
{{Refend}}

==External links==
{{Commons}}
* {{YouTube| Y2iU_VdHD3M | "Flying the B-47 (1950)" }}
* {{YouTube| ilu3NSvl3Ow | "Meet Your Boeing B-47 (1954)" }}
* [https://web.archive.org/web/20150304185807/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2605 National Museum fact sheet Boeing B-56E]
* [https://web.archive.org/web/20110527204838/http://www.joebaugher.com/usaf_serials/usafserials.html Listing of Air Force Aircraft Serial Numbers, including B-47 aircraft]
* [https://web.archive.org/web/20121206030916/http://www.millionmonkeytheater.com/B-47.html Forgotten Jets – Boeing B-47 Stratojet series] – status of all 2,032 produced
* [http://www.b-47.com/ B-47 Stratojet Association]
* [https://digitalcollections.museumofflight.org/nodes/view/2811 Pilot's handbook of flight operating instructions for XB-47 airplane] 

{{Boeing model numbers}}
{{Boeing combat aircraft}}
{{USAF bomber aircraft}}
{{US reconnaissance aircraft}}
{{USAF system codes}}
{{Canadair}}
{{Authority control}}

[[Category:Boeing aircraft|B-47 Stratojet]]
[[Category:1940s United States bomber aircraft|Boeing B-47]]
[[Category:1950s United States bomber aircraft|Boeing B-56]]
[[Category:Six-engined jet aircraft]]
[[Category:Articles containing video clips]]
[[Category:High-wing aircraft]]
[[Category:Aircraft first flown in 1947]]
[[Category:Strategic bombers]]
[[Category:Aircraft with retractable bicycle landing gear]]