B-47 Stratojet
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The Boeing Model 450 B-47 Stratojet was a long-range, six-engined, jet-powered medium bomber
built to fly at high subsonic speeds and at high altitudes. It was primarily designed to drop nuclear bombs on the Soviet Union
. With its engines carried in pods under the swept wing, the B-47 was a major innovation in post-World War II
combat jet design, and helped lead to modern jet airliner
s.
The B-47 entered service with the United States Air Force
's Strategic Air Command
(SAC) in 1951. It never saw combat as a bomber, but was a mainstay of SAC's bomber strength during the 1950s and early 1960s, and remained in use as a bomber until 1965. It was also adapted to a number of other missions, including photo reconnaissance, electronic intelligence and weather reconnaissance, remaining in service as a reconnaissance platform until 1969 and as a testbed until 1977.
reconnaissance bomber, drawn up by the U.S. Army Air Forces (USAAF) to prompt manufacturers to start research into jet bombers. Boeing was among several companies that responded to this request; its initial design, the Model 424, was basically a scaled-down version of the piston-engined Boeing B-29 Superfortress equipped with four jet engines. The next year, this concept evolved into a formal request-for-proposal to design a new bomber with a maximum speed of 550 mph (800 km/h), a cruise speed of 450 mph (725 km/h), a range of 3,500 mi (5,600 km) and a service ceiling of 45,000 ft (13,700 m).
North American Aviation
, the Convair Corp.
, Boeing
and the Glenn Martin Company submitted proposals for the new long-range jet bomber in December 1944. Wind tunnel testing had shown that the drag from the engine installation of the Model 424 was too high, so Boeing engineers then tried a revised design, the Model 432, with the four engines buried in the forward fuselage. The USAAF awarded study contracts to all four companies, requiring that North American and Martin concentrate on four-engined designs (to become North American B-45 and Martin XB-48
), while Boeing and Convair were to build six-engined aircraft (the B-47 and B-46
). The powerplant was to be General Electric's
new TG-180 turbojet engine.
inspected German aeronautics laboratories
from the beginning of May through the end of July 1945, in search of German developments that might help the United States. One of the Boeing engineers on the mission, George S. Schairer
, studied German reports on the effects of wing sweepback
on the performance of aircraft as they approached the speed of sound, and realizing the possible implications for the new bomber, sent word back to Boeing to stop work on the straight-winged design and switch to swept wings.
Analysis work by Boeing engineer
Vic Ganzer suggested an optimum sweepback angle of about 35 degrees. Boeing's aeronautical engineers modified their Model 432 design to include swept wings and tail
, resulting in the "Model 448", which was presented to the USAAF in September 1945. The Model 448 retained its 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 disliked the installation of engines within the fuselage, considering it a fire hazard.
The engines were moved out to streamlined pods pylon mounted 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. The Army Air Force liked this new configuration, and so Boeing's team of engineers continued to refine it, with the outer engines being moved further inboard, to about 3/4 of the wingspan
. The thin wings provided no room into which wheels could be retracted, so a "bicycle landing gear" was chosen, with 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
(i.e. lifting the nose during take-off) impossible, the landing gear was designed so that the aircraft rested on the ground at the proper angle for take-off.
The first XB-47 was rolled out on 12 September 1947, a few days before the USAAF became a separate service, the U.S. Air Force on 18 September 1947. The XB-47 prototype flew its first flight on 17 December 1947 (the anniversary of the Wright Brothers
' first four flights on December 17, 1903), with the test pilots Robert Robbins and Scott Osler at the controls of the airplane. It flew from Boeing Field
in Seattle to the Moses Lake Airfield
in central Washington state, in a flight that lasted just 27 minutes, with no major problems. Robbins had to pull up the flaps with the emergency hydraulic system, and the "engine fire" warning lights
kept lighting up. Robbins reported that the flight characteristics of the aircraft were good.
.
turbojets with 5,200 lbf (23 kN) thrust each. The J47 or "TG-190" was a redesigned version of the TG-180/J35. The first XB-47 prototype was later retrofitted with these engines.
Flight testing of the prototypes was particularly careful and methodical, since the design was so new in many ways. The prototypes initially suffered from "Dutch roll
", an instability that caused the aircraft to weave in widening "S" turns. This problem was remedied by the addition of a "yaw damper
" control system that applied rudder automatically to damp out the weaving motion. The prototypes also had a tendency to pitch up. This problem was solved by adding small vanes called "vortex generator
s" onto the wings that caused turbulence to prevent airflow separation.
Boeing test pilot Rob Robbins had originally been skeptical about the XB-47, saying that before the initial flight he had "prayed to God to please help me" through the flight. The aircraft was so unusual that he simply didn't know if it would fly. Robbins soon realized that he had an extraordinary aircraft.
In early 1948, the United States Air Force
(having become a separate service in 1947) sent up a chase plane
from Muroc (now Edwards
) Air Force Base in California to help calibrate the bomber's airspeed system. Robbins reported later:
Yeager would test-fly the XB-47 later in its development cycle and would years later note that the aircraft was so aerodynamically clean that he had difficulty putting it down on the runway.
. The North American design won that round of the competition, and as an interim measure the USAF had 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 Bill Allen
inviting USAF General K.B. Wolfe, in charge of bomber production, for a ride on the XB-47. A formal contract for 10 aircraft was signed on 3 September 1948.
The XB-47, which looked unlike any contemporary bomber, was described by some observers as a "sleek, beautiful outcome that was highly advanced". The 35-degree swept wings were shoulder-mounted, with the twin inboard turbojet engines mounted in neat pods, and the outboard engines tacked under the wings short of the wingtips. With the exception of a change from the shoulder-mounted wing configuration to being under the fuselage, most future airliners would use a similar configuration, with the engines mounted in underwing pylons.
The wing airfoil was identified by Boeing as the BAC 145, but this was actually the NACA 64A(.225)12 mod airfoil. The wing's flexibility was a concern, as it could flex as much as 5 ft (1.5 m) up or down, and major effort was expended to ensure that flight control could be maintained as the wing moved up and down. As it turned out, most of the worries proved unfounded. The aircraft's maximum speed was limited to 425 knots (832.9 km/h) to avoid control reversal
, where aileron inputs by the pilot would cause the wings to twist and produce a roll in the opposite direction to that desired by the pilot. The wings were fitted with a set of Fowler flaps that extended well behind the wing, to enhance lift at slow speeds.
The XB-47 was designed to carry a crew of three in a pressurized forward compartment: a pilot and copilot, in tandem, in a long fighter-style bubble canopy, and a navigator in a compartment in the nose. The copilot doubled as tail gunner, and the navigator as bombardier. The bubble canopy could pitch up and slide backward, but as the cockpit was high off the ground, crew entrance was through a door and ladder on the underside of the nose.
(17.7 kN) of thrust. Early jet engines did not develop good thrust at low speeds, so to help a heavily loaded bomber take off, the XB-47 prototype had provisions for fitting 18 solid-fuel rocket-assisted takeoff
(RATO) rockets with 1,000 lbf (4.4 kN) thrust each. Fittings for nine such units were built into each side of the rear fuselage, arranged in three rows of three bottles.
The performance of the Model 450 design was projected to be so good that the bomber would be as fast as fighters then on the drawing board, and so the only defensive armament was to be a tail turret with two .50 in (12.7 mm) Browning machine guns, which would in principle be directed by an automatic fire-control system. The two XB-47s were not fitted with the tail turret as they were engineering and flight test aircraft; indeed, the prototypes had no combat equipment at all.
Fuel capacity was enormous, at 17,000 gal (64,400 l), more than triple the 5,000 gal (19,000 l) on the B-29 Superfortress. That meant that maintaining fuel trim to ensure a stable center of gravity in flight would be a very critical copilot duty. The total bombload capacity was to be 10,000 lb (4.5 metric tons). Production aircraft were to be equipped with state-of-the-art electronics for navigation, bombing, countermeasures, and turret fire control
.
) provided drag so that the aircraft could be flown at approach speeds with the engines throttled at ready-to-spool-up medium power. Training typically included an hour of dragging this chute around the landing pattern for multiple practice landings.
The aircraft was so aerodynamically slick that rapid descent ("penetration") from high cruise altitude to the landing pattern required dragging the deployed rear landing gear.
Unusually high wing loading (weight/wing area) required a high landing speed of 180 knots (352.8 km/h). To shorten the landing roll, Air Force test pilot Major
Guy Townsend
promoted the addition of a 32 ft (9.75 m) German-designed "ribbon" drag chute. (Jet engine thrust reversers were still a "far-future" concept.). As a consequence, the B-47 was the first mass-produced aircraft to be equipped with an anti-skid braking system.
The total number of B-47s built was 2,032.
The USAF Strategic Air Command
operated B-47 Stratojets (B-47s, EB-47s, RB-47s and YRB-47s) from 1951 through 1965.
When B-47s began to be delivered to the Air Force, most crews were excited about getting their hands on the hot new bomber, an aircraft whose performance was closer to that of jet fighters of the period than SAC's extant B-36 Peacemaker
bomber. The B-47 was so fast that in the early days the aircraft set records with ease. The aircraft handled well in flight, with a fighter-like light touch to the controls. The large bubble canopy
for the pilot and co-pilot enhanced the fighter-like feel of the aircraft with improved vision, but the design would also cause variations in internal temperatures for the three-man crew.
It took the Air Force until 1953 to turn the B-47 into an operational aircraft. The aircraft was sluggish on takeoff and too fast on landings, a very unpleasant combination. If the pilot landed at the wrong angle, the aircraft would "porpoise", bouncing fore-and-aft. If the pilot didn't lift off for another go-around, instability would quickly cause the bomber to skid onto one wing and cartwheel. Because the wings and surfaces were flexible and bent in flight, low altitude speed restrictions were necessary to ensure effective flight control.
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, with only three officer crew members to keep the B-47 flying right. The B-52 Stratofortress
, in contrast, generally had six crewmen, 5 officers and 1 enlisted, with far more internal cabin space.
technology at the time, and the need to place some equipment outside the pressurized crew compartment. Much work was done to improve avionics reliability, but they remained problematic throughout the B-47's operational life.
Several models of the B-47 starting in 1950 included a fuel tank inerting system
, in which dry ice
was sublimated into carbon dioxide
vapor while the fuel pumps operated or while the in-flight refueling system was in use. The carbon dioxide was then pumped into the fuel tanks and the rest of the fuel system, ensuring that the amount of oxygen in the fuel system was low, and thereby reducing the probability of an explosion. Ten carbon dioxide tanks and heaters were involved. The system was implemented largely to reduce risks from static electricity
discharges occurring during in-flight refueling.
Initial mission profiles included the loft bombing
(Low Altitude Bombing System) of nuclear weapons. As the training for this imposes repeated high stress on the aircraft, the airframe lifetime would have been severely limited by metal fatigue
, and this maneuver was eliminated.
, Morocco
, Spain
, Alaska
, Greenland and Guam
. B-47 bombers were often set up on "one-third" alert, with a third of the 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 USSR
at short notice.
Crews were also trained to perform "minimum interval takeoffs (MITO)", with one bomber following the other into the air at intervals of as little as 15 seconds, to launch all bombers as fast as possible. MITO could be hazardous, as the bombers left turbulence and, with first generation turbojet engines with water injection
systems, dense black smoke that blinded pilots in the following aircraft.
The B-47 would be 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 after that.
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. Bomber crews were trained in "pop-up" attacks, coming in at low level at 425 knots (832.9 km/h) and then climbing abruptly near the target before releasing a nuclear weapon, and the similar "toss bombing
" procedure, in which the aircraft released the weapon while climbing, and then rolled away to depart the area before bomb detonation. Strategic operations of the 2,000 B-47s required 800 Boeing KC-97 Stratotankers.
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 out of Homestead AFB, Florida was engaged in a simulated combat exercise with a North American F-86 Sabre, the bomber simulating an attacking aircraft and the fighter a defender. As was the practice at the time, the B-47 was carrying a single 7600 lb (3,447.3 kg) Mark 15 nuclear bomb
without its core. During this exercise, the F-86 collided with the B-47. The F-86 pilot ejected and the fighter crashed, while the B-47 suffered substantial damage, including loss of power on one of its outboard jet engines. The bomber pilot had to "safe" soft drop the Mark 15 weapon off the coast of Savannah, Georgia
near Tybee Island after three unsuccessful landing attempts at Hunter Air Force Base. The bomb was jettisoned and the aircraft landed safely. An extensive nine-month search was mounted for the unarmed bomb, but proved futile.
Final phaseout of B-47 bomber wings began in 1963, and the last bombers were out of service by 1965. The very last USAF operational aircraft was grounded in 1969. The U.S. Navy
kept specialized B-47 test aircraft in occasional use up to 1976. The final recorded flight of a B-47 was on 17 June 1986, when a B-47E was flown from the Naval Air Weapons Station China Lake
, California, to Castle Air Force Base
, California, for static display at the Castle Air Museum.
variants. The first overflight of Soviet territory with an RB-47 took place on 15 October 1952, when an RB-47B flying out of Alaska overflew Soviet airfields in Eastern Siberia. RB-47s operated from almost every airfield that gave them access to the USSR, and they often probed Soviet airspace, and on occasion, their pilots were caught in situations from which mostly speed and evasion in retreat saved them. At least five of these aircraft were fired on, and three of these were shot down. The RB-47s fired back with their tail turrets, although it is uncertain if they scored any kills, Nonetheless, these were the only shots fired in anger by any B-47.
On 8 May 1954, after a top secret reconnaissance mission in the Kola Peninsula
, a 4th Air Division 91 Strategic Reconnaissance Wing RB-47E reconnaissance aircraft, with Hal Austin at the controls, flew west from the Soviet Union. The RB-47E was flying at high altitude, out of reach of MiG-15
s, but unknown to USAF intelligence some MiG-17
s had been stationed in the area that were able to intercept the intruder. The RB-47E was chased by three Soviet MiG-17 fighters attempting to destroy the aircraft with their guns over Soviet and Finnish airspace. Although sustaining damage, the RB-47E managed to escape over Sweden back to its home base at RAF Fairford
, Gloucestershire. Its top speed and combat radius
superiority to the Soviet fighter jets were the deciding factors. The mission marked the first time a jet aircraft equipped with modern photography equipment was used for American military reconnaissance. The incident was kept secret by all parties.
Other interceptions resulted in losses. A RB-47 flying out of Alaska was scouting out the Kamchatka Peninsula
on 17 April 1955, when it was bounced by Soviet MiG-15s in international airspace. The RB-47 and its crew disappeared. Between 21 March and 10 May 1956, 16 RB-47Es and 5 RB-47Hs operating from Thule performed overflights the length of Siberia 156 times under Project HOMERUN
. The Soviets filed an angry complaint with the US government, which attributed the overflights to "navigational difficulties". MiGs bounced RB-47s on three separate occasions in the fall of 1958: over the Black Sea on 31 October, over the Baltic on 7 November, and over the Sea of Japan
on 17 November.
On 1 July 1960, a PVO Strany MiG-19
shot down an RB-47H (AF Serial No. 53-4281) reconnaissance aircraft in the international airspace over the Barents Sea
with four of the crew being killed and two captured by the Soviets, but released in 1961. The co-pilot reported that the MiG-19 jammed ("whited-out") his MD-4 FCS scope, rendering the RB-47H defenseless. The last known confrontation between MiGs and RB-47s took place on 27 April 1965, when an ERB-47H was jumped by North Korean MiG-17s over the Sea of Japan. The MiGs scored hits on the aircraft, but the ERB-47H managed to make it back to Yokota Air Base in Japan with two engines out.
While a few of these aircraft performed special duties during the Vietnam War
, such as relaying ELINT data from drones, they were eventually replaced by much more efficient and capable Boeing RC-135 platforms. The last RB-47H was retired on 29 December 1967.
The final 15 RB-47Es, built beginning in December 1955, were fitted with additional equipment, including the AN/APD "side looking airborne radar (SLAR)" system, and gear to sample the air for fallout
from nuclear tests
. These last examples were given the new designation of RB-47K. The RB-47Ks were generally used for weather reconnaissance missions, carrying a load of eight "dropsonde
" weather sensors that were released at various checkpoints along the aircraft's flight path. Data radioed back from the dropsondes was logged using equipment operated by the navigator. The RB-47Ks stayed in service until 1963.
XB-47
B-47A
The first 10 aircraft were designated "B-47A", and were strictly evaluation aircraft. The first was delivered in December 1950. The configuration of the B-47As was close to that of the initial XB-47 prototypes. They were fitted with J47-GE-11 turbojets, offering the same 5,200 lbf (23 kN) thrust as the earlier J47-GE-3, and they also featured the built-in RATO bottles.
B-47B
YB-47C / RB-47C / B-47Z / B-56
XB-47D
B-47E
RB-47H/ERB-47H
YB-47J
RB-47K
EB-47L
Canada
and crash landed on a stretch of road that ran parallel to the runway. Two cars were crushed by the crash landing, killing two occupants, Robert W. Glass and Dr. Robert Bundy, and injuring a third, Dorothy Phillips. Mr. Glass and Dr. Bundy both worked for the Minnesota Honeywell Corporation at the time, a firm which had just completed flight tests on an inertia guidance sub-system for the X-20 Dyna-Soar
project at the base. Mrs. Phillips was the wife of Master Sergeant
James Phillips, a crew chief at the base. Mrs. Phillips was treated for moderate injuries and released later that day. Both vehicles were destroyed by fire. The QB-47 that crashed was used for Bomarc Missile Program
tests, which normally operated from Eglin AFB Auxiliary Field Number Three (Duke Field
), approximately 15 miles (24.1 km) north of the main base.
On 5 February 1958, a B-47 carrying a nuclear weapon had a midair collision with an F-86 fighter.
starring James Stewart
. The film features good aerial footage of both the B-47 and the B-36. The majority of B-47 scenes were filmed at MacDill AFB, Florida utilizing aircraft from the 306th Bombardment Wing.
The movie On the Threshold of Space
(1956) has footage of a B-47E being used as a test ship in the development of a downward-firing ejection seat, with Eglin Air Force Base
identified as Sovran Air Force Base.
The 1957 film Bombers B-52 shows B-47s at Castle Air Force Base
, including the proud legend 'Home of the B-47' and a fly-over in formation, before moving to focus on the new B-52 Stratofortress
.
The 1 July 1960 shoot down of an RB-47H (AF Ser. No. 53-4281) by a MiG-19
over the Barents Sea
was retold by the two surviving crewmembers: Captain John R. McKone (navigator) and Capt Freeman B. Olmstead (co-pilot), in the biographical book, The Little Toy Dog by William L. White. The title refers to a small plastic toy "Snoopy
" that Capt McKone carried with him, and kept during their seven months in Lubyanka
prison in the Soviet Union
.
A one-hour episode of the TV series Kraft Suspense Theatre
, "Streetcar, Do You Read Me?" (1965), starring Martin Milner, features extensive real footage, interior and exterior scenes, of the B-47E. The fictional story depicts a mission of the 307th Bomb Wing of the Strategic Air Command.
Medium bomber
A medium bomber is a bomber aircraft designed to operate with medium bombloads over medium distances; the name serves to distinguish them from the larger heavy bombers and smaller light bombers...
built to fly at high subsonic speeds and at high altitudes. It was primarily designed to drop nuclear bombs on the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
. With its engines carried in pods under the swept wing, the B-47 was a major innovation in post-World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
combat jet design, and helped lead to modern jet airliner
Jet airliner
A jet airliner is an airliner that is powered by jet engines. This term is sometimes contracted to jetliner or jet.In contrast to today's relatively fuel-efficient, turbofan-powered air travel, first generation jet airliner travel was noisy and fuel inefficient...
s.
The B-47 entered service with the United States Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
's Strategic Air Command
Strategic Air Command
The Strategic Air Command was both a Major Command of the United States Air Force and a "specified command" of the United States Department of Defense. SAC was the operational establishment in charge of America's land-based strategic bomber aircraft and land-based intercontinental ballistic...
(SAC) in 1951. It never saw combat as a bomber, but was a mainstay of SAC's bomber strength during the 1950s and early 1960s, and remained in use as a bomber until 1965. It was also adapted to a number of other missions, including photo reconnaissance, electronic intelligence and weather reconnaissance, remaining in service as a reconnaissance platform until 1969 and as a testbed until 1977.
Origins
The B-47 arose from an informal 1943 requirement for a jet-poweredJet engine
A jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
reconnaissance bomber, drawn up by the U.S. Army Air Forces (USAAF) to prompt manufacturers to start research into jet bombers. Boeing was among several companies that responded to this request; its initial design, the Model 424, was basically a scaled-down version of the piston-engined Boeing B-29 Superfortress equipped with four jet engines. The next year, this concept evolved into a formal request-for-proposal to design a new bomber with a maximum speed of 550 mph (800 km/h), a cruise speed of 450 mph (725 km/h), a range of 3,500 mi (5,600 km) and a service ceiling of 45,000 ft (13,700 m).
North American Aviation
North American Aviation
North American Aviation was a major US aerospace manufacturer, responsible for a number of historic aircraft, including the T-6 Texan trainer, the P-51 Mustang fighter, the B-25 Mitchell bomber, the F-86 Sabre jet fighter, the X-15 rocket plane, and the XB-70, as well as Apollo Command and Service...
, the Convair Corp.
Convair
Convair was an American aircraft manufacturing company which later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Vultee Aircraft and Consolidated Aircraft, and went on to produce a number of pioneering aircraft, such as the Convair B-36 bomber, and the F-102...
, Boeing
Boeing
The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois since 2001...
and the Glenn Martin Company submitted proposals for the new long-range jet bomber in December 1944. Wind tunnel testing had shown that the drag from the engine installation of the Model 424 was too high, so Boeing engineers then tried a revised design, the Model 432, with the four engines buried in the forward fuselage. The USAAF awarded study contracts to all four companies, requiring that North American and Martin concentrate on four-engined designs (to become North American B-45 and Martin XB-48
Martin XB-48
|-See also:-References:NotesBibliography* Jones, Lloyd S. U.S. Bombers, B-1 1928 to B-1 1980s. Fallbrook, CA: Aero Publishers, 1962, second edition 1974. ISBN 0-8168-9126-5....
), while Boeing and Convair were to build six-engined aircraft (the B-47 and B-46
Convair XB-46
|-See also:-External Links:*...
). The powerplant was to be General Electric's
GE-Aviation
GE Aviation, a subsidiary of General Electric, is headquartered in Evendale, Ohio . GE Aviation is the top supplier of aircraft engines in the world, and offers engines for the majority of commercial aircraft. GE Aviation is part of the General Electric conglomerate, which is one of the world's...
new TG-180 turbojet engine.
Swept wings
In mid-1945, with the defeat of Germany imminent, the von Kármán mission of the Army Air ForcesUSAF Scientific Advisory Board
The United States Air Force Scientific Advisory Board is a military unit that provides forecasts of long-range science and technology.-Chronology:...
inspected German aeronautics laboratories
Aeronautics
Aeronautics is the science involved with the study, design, and manufacturing of airflight-capable machines, or the techniques of operating aircraft and rocketry within the atmosphere...
from the beginning of May through the end of July 1945, in search of German developments that might help the United States. One of the Boeing engineers on the mission, George S. Schairer
George S. Schairer
George S. Schairer was an aerodynamicst at Consolidated Aircraft and Boeing whose design innovations became standard on virtually all types of military and passenger jet planes.-Early life:...
, studied German reports on the effects of wing sweepback
Swept wing
A swept wing is a wing planform favored for high subsonic jet speeds first investigated by Germany during the Second World War. Since the introduction of the MiG-15 and North American F-86 which demonstrated a decisive superiority over the slower first generation of straight-wing jet fighters...
on the performance of aircraft as they approached the speed of sound, and realizing the possible implications for the new bomber, sent word back to Boeing to stop work on the straight-winged design and switch to swept wings.
Analysis work by Boeing engineer
Engineer
An engineer is a professional practitioner of engineering, concerned with applying scientific knowledge, mathematics and ingenuity to develop solutions for technical problems. Engineers design materials, structures, machines and systems while considering the limitations imposed by practicality,...
Vic Ganzer suggested an optimum sweepback angle of about 35 degrees. Boeing's aeronautical engineers modified their Model 432 design to include swept wings and tail
Empennage
The empennage , also known as the tail or tail assembly, of most aircraft gives stability to the aircraft, in a similar way to the feathers on an arrow...
, resulting in the "Model 448", which was presented to the USAAF in September 1945. The Model 448 retained its 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 disliked the installation of engines within the fuselage, considering it a fire hazard.
The engines were moved out to streamlined pods pylon mounted 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. The Army Air Force liked this new configuration, and so Boeing's team of engineers continued to refine it, with the outer engines being moved further inboard, to about 3/4 of the wingspan
Wingspan
The wingspan of an airplane or a bird, is the distance from one wingtip to the other wingtip. For example, the Boeing 777 has a wingspan of about ; and a Wandering Albatross caught in 1965 had a wingspan of , the official record for a living bird.The term wingspan, more technically extent, is...
. The thin wings provided no room into which wheels could be retracted, so a "bicycle landing gear" was chosen, with 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
Rotation (aviation)
In aviation, rotation refers to the action of applying back pressure to a control device, such as a yoke, side-stick or centre stick, to lift the nose wheel off the ground during the takeoff roll...
(i.e. lifting the nose during take-off) impossible, the landing gear was designed so that the aircraft rested on the ground at the proper angle for take-off.
USAAF selects Boeing
The USAAF was very pleased with the refined Model 450 design, and in April 1946, the service ordered two prototypes, to be designated "XB-47". Assembly began in June 1947. People involved with the project were very excited, since they believed (correctly as it turned out) they were working on a breakthrough in aircraft design.The first XB-47 was rolled out on 12 September 1947, a few days before the USAAF became a separate service, the U.S. Air Force on 18 September 1947. The XB-47 prototype flew its first flight on 17 December 1947 (the anniversary of the Wright Brothers
Wright brothers
The Wright brothers, Orville and Wilbur , were two Americans credited with inventing and building the world's first successful airplane and making the first controlled, powered and sustained heavier-than-air human flight, on December 17, 1903...
' first four flights on December 17, 1903), with the test pilots Robert Robbins and Scott Osler at the controls of the airplane. It flew from Boeing Field
Boeing Field
Boeing Field, officially King County International Airport , is a two-runway airport owned and run by King County, Washington, USA. In promotional literature, the airport is frequently referred to as KCIA, but this is not the airport identifier. The airport has some passenger service, but is mostly...
in Seattle to the Moses Lake Airfield
Grant County International Airport
Grant County International Airport is a public use airport located five nautical miles northwest of the central business district of Moses Lake, in Grant County, Washington, United States. It is owned by the Port of Moses Lake....
in central Washington state, in a flight that lasted just 27 minutes, with no major problems. Robbins had to pull up the flaps with the emergency hydraulic system, and the "engine fire" warning lights
Aircraft warning lights
Aircraft warning lights are high-intensity lighting devices that are attached to tall structures and are used as collision avoidance measures. Such devices make structures more visible to passing aircraft and are usually used at night, although they may be used during the day as well...
kept lighting up. Robbins reported that the flight characteristics of the aircraft were good.
Canopy malfunction
During early tests of the XB-47 prototype, the canopy came off at high speed, killing pilot Scott Osler. The copilot safely landed the aircraft. This resulted in a canopy redesign, and the hiring of pilot Tex JohnstonAlvin M. Johnston
Alvin M. "Tex" Johnston was a American jet-age test pilot for Bell Aircraft and the Boeing Company.-Early years:...
.
Second X-model
The second XB-47 prototype first took the air on 21 July 1948, and was equipped with much more powerful General Electric J47-GE-3General Electric J47
|-Specifications :-Nuclear-powered version – The X39:In the 1950s, interest in the development of nuclear-powered aircraft led GE to experiment with two nuclear-powered gas turbine designs, one based on the J47, and another new and much larger engine called the X211.The design based on the J47...
turbojets with 5,200 lbf (23 kN) thrust each. The J47 or "TG-190" was a redesigned version of the TG-180/J35. The first XB-47 prototype was later retrofitted with these engines.
Flight testing of the prototypes was particularly careful and methodical, since the design was so new in many ways. The prototypes initially suffered from "Dutch roll
Dutch roll
Dutch roll is a type of aircraft motion, consisting of an out-of-phase combination of "tail-wagging" and rocking from side to side. This yaw-roll coupling is one of the basic flight dynamic modes...
", an instability that caused the aircraft to weave in widening "S" turns. This problem was remedied by the addition of a "yaw damper
Yaw damper
A yaw damper is a device used on many aircraft to damp the rolling and yawing oscillations due to Dutch roll mode. It involves yaw rate sensors and a processor that provides a signal to an actuator connected to the rudder...
" control system that applied rudder automatically to damp out the weaving motion. The prototypes also had a tendency to pitch up. This problem was solved by adding small vanes called "vortex generator
Vortex generator
A vortex generator is an aerodynamic surface, consisting of a small vane or bump that creates a vortex. Vortex generators can be found on many devices, but the term is most often used in aircraft design....
s" onto the wings that caused turbulence to prevent airflow separation.
Boeing test pilot Rob Robbins had originally been skeptical about the XB-47, saying that before the initial flight he had "prayed to God to please help me" through the flight. The aircraft was so unusual that he simply didn't know if it would fly. Robbins soon realized that he had an extraordinary aircraft.
In early 1948, the United States Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
(having become a separate service in 1947) sent up a chase plane
Chase plane
A chase plane is an aircraft that "chases" another aircraft, a spacecraft or a rocket during flight. Safety can be one function of a chase plane; others are to photo or video the target vehicle, or to collect engineering data from it...
from Muroc (now Edwards
Edwards Air Force Base
Edwards Air Force Base is a United States Air Force base located on the border of Kern County, Los Angeles County, and San Bernardino County, California, in the Antelope Valley. It is southwest of the central business district of North Edwards, California and due east of Rosamond.It is named in...
) Air Force Base in California to help calibrate the bomber's airspeed system. Robbins reported later:
Yeager would test-fly the XB-47 later in its development cycle and would years later note that the aircraft was so aerodynamically clean that he had difficulty putting it down on the runway.
X-model competitions
By mid-1948, the Air Force's bomber competition had already been through one iteration, pitting the North American XB-45 against the Convair XB-46Convair XB-46
|-See also:-External Links:*...
. The North American design won that round of the competition, and as an interim measure the USAF had decided to put the North American bomber into production on a limited basis as the B-45 Tornado
B-45 Tornado
The North American B-45 Tornado was the United States Air Force's first operational jet bomber, and the first jet aircraft to be refueled in the air. The B-45 was an important part of the United States's nuclear deterrent for several years in the early 1950s, but was rapidly succeeded by the Boeing...
. 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
Martin XB-48
|-See also:-References:NotesBibliography* Jones, Lloyd S. U.S. Bombers, B-1 1928 to B-1 1980s. Fallbrook, CA: Aero Publishers, 1962, second edition 1974. ISBN 0-8168-9126-5....
, proved superior. It is sometimes claimed that the final production decision was made as a result of Boeing president Bill Allen
William McPherson Allen
William McPherson "Bill" Allen was a U.S. aircraft businessman. Born in Lolo, Montana, he attended the University of Montana, where he became a member of the Sigma Chi Fraternity...
inviting USAF General K.B. Wolfe, in charge of bomber production, for a ride on the XB-47. A formal contract for 10 aircraft was signed on 3 September 1948.
Overview
The wing airfoil was identified by Boeing as the BAC 145, but this was actually the NACA 64A(.225)12 mod airfoil. The wing's flexibility was a concern, as it could flex as much as 5 ft (1.5 m) up or down, and major effort was expended to ensure that flight control could be maintained as the wing moved up and down. As it turned out, most of the worries proved unfounded. The aircraft's maximum speed was limited to 425 knots (832.9 km/h) to avoid control reversal
Control reversal
Control reversal is an adverse effect on the controllability of aircraft. The flight controls reverse themselves in a way that is not intuitive, so pilots may not be aware of the situation and therefore provide the wrong inputs; in order to roll to the left, for instance, they have to push the...
, where aileron inputs by the pilot would cause the wings to twist and produce a roll in the opposite direction to that desired by the pilot. The wings were fitted with a set of Fowler flaps that extended well behind the wing, to enhance lift at slow speeds.
The XB-47 was designed to carry a crew of three in a pressurized forward compartment: a pilot and copilot, in tandem, in a long fighter-style bubble canopy, and a navigator in a compartment in the nose. The copilot doubled as tail gunner, and the navigator as bombardier. The bubble canopy could pitch up and slide backward, but as the cockpit was high off the ground, crew entrance was through a door and ladder on the underside of the nose.
Engines and performance
The first prototypes were fitted with General Electric J35 turbojets, the production version of the TG-180, with 3,970 lbfPound-force
The pound force is a unit of force in some systems of measurement including English engineering units and British gravitational units.- Definitions :...
(17.7 kN) of thrust. Early jet engines did not develop good thrust at low speeds, so to help a heavily loaded bomber take off, the XB-47 prototype had provisions for fitting 18 solid-fuel rocket-assisted takeoff
JATO
JATO is an acronym for jet-fuel assisted take off. It is a system for helping overloaded aircraft into the air by providing additional thrust in the form of small rockets....
(RATO) rockets with 1,000 lbf (4.4 kN) thrust each. Fittings for nine such units were built into each side of the rear fuselage, arranged in three rows of three bottles.
The performance of the Model 450 design was projected to be so good that the bomber would be as fast as fighters then on the drawing board, and so the only defensive armament was to be a tail turret with two .50 in (12.7 mm) Browning machine guns, which would in principle be directed by an automatic fire-control system. The two XB-47s were not fitted with the tail turret as they were engineering and flight test aircraft; indeed, the prototypes had no combat equipment at all.
Fuel capacity was enormous, at 17,000 gal (64,400 l), more than triple the 5,000 gal (19,000 l) on the B-29 Superfortress. That meant that maintaining fuel trim to ensure a stable center of gravity in flight would be a very critical copilot duty. The total bombload capacity was to be 10,000 lb (4.5 metric tons). Production aircraft were to be equipped with state-of-the-art electronics for navigation, bombing, countermeasures, and turret fire control
Fire-control system
A fire-control system is a number of components working together, usually a gun data computer, a director, and radar, which is designed to assist a weapon system in hitting its target. It performs the same task as a human gunner firing a weapon, but attempts to do so faster and more...
.
Drag chutes
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 big bomber could not easily do a "touch and go" momentary landing. A small "approach chute" (drogue parachuteDrogue parachute
A drogue parachute is a parachute designed to be deployed from a rapidly moving object in order to slow the object, or to provide control and stability, or as a pilot parachute to deploy a larger parachute...
) provided drag so that the aircraft could be flown at approach speeds with the engines throttled at ready-to-spool-up medium power. Training typically included an hour of dragging this chute around the landing pattern for multiple practice landings.
The aircraft was so aerodynamically slick that rapid descent ("penetration") from high cruise altitude to the landing pattern required dragging the deployed rear landing gear.
Unusually high wing loading (weight/wing area) required a high landing speed of 180 knots (352.8 km/h). To shorten the landing roll, Air Force test pilot Major
Major
Major is a rank of commissioned officer, with corresponding ranks existing in almost every military in the world.When used unhyphenated, in conjunction with no other indicator of rank, the term refers to the rank just senior to that of an Army captain and just below the rank of lieutenant colonel. ...
Guy Townsend
Guy M. Townsend
Guy Mannering Townsend III was a retired United States Air Force Brigadier General, test pilot, and combat veteran...
promoted the addition of a 32 ft (9.75 m) German-designed "ribbon" drag chute. (Jet engine thrust reversers were still a "far-future" concept.). As a consequence, the B-47 was the first mass-produced aircraft to be equipped with an anti-skid braking system.
Production numbers
| 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 2,032.
Early years
Strategic Air Command
The Strategic Air Command was both a Major Command of the United States Air Force and a "specified command" of the United States Department of Defense. SAC was the operational establishment in charge of America's land-based strategic bomber aircraft and land-based intercontinental ballistic...
operated B-47 Stratojets (B-47s, EB-47s, RB-47s and YRB-47s) from 1951 through 1965.
When B-47s began to be delivered to the Air Force, most crews were excited about getting their hands on the hot new bomber, an aircraft whose performance was closer to that of jet fighters of the period than SAC's extant B-36 Peacemaker
Convair B-36
The Convair B-36 "Peacemaker" was a strategic bomber built by Convair and operated solely by the United States Air Force from 1949 to 1959. The B-36 was the largest mass-produced piston engine aircraft ever made. It had the longest wingspan of any combat aircraft ever built , although there have...
bomber. The B-47 was so fast that in the early days the aircraft set records with ease. The aircraft handled well in flight, with a fighter-like light touch to the controls. The large bubble canopy
Bubble canopy
A bubble canopy is a canopy made like a soap bubble, which attempts to provide 360° vision to the pilot.-History:Bubble canopies have been in use since World War II. The British had already developed the "Malcolm hood", which was a bulged canopy, but the British Miles M.20 was one of the first...
for the pilot and co-pilot enhanced the fighter-like feel of the aircraft with improved vision, but the design would also cause variations in internal temperatures for the three-man crew.
It took the Air Force until 1953 to turn the B-47 into an operational aircraft. The aircraft was sluggish on takeoff and too fast on landings, a very unpleasant combination. If the pilot landed at the wrong angle, the aircraft would "porpoise", bouncing fore-and-aft. If the pilot didn't lift off for another go-around, instability would quickly cause the bomber to skid onto one wing and cartwheel. Because the wings and surfaces were flexible and bent in flight, low altitude speed restrictions were necessary to ensure effective flight control.
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, with only three officer crew members to keep the B-47 flying right. The B-52 Stratofortress
B-52 Stratofortress
The Boeing B-52 Stratofortress is a long-range, subsonic, jet-powered strategic bomber operated by the United States Air Force since the 1950s. The B-52 was designed and built by Boeing, who have continued to provide maintainence and upgrades to the aircraft in service...
, in contrast, generally had six crewmen, 5 officers and 1 enlisted, with far more internal cabin space.
Training and problems
The B-47's reliability and serviceability were regarded as good. The only major problem was poor avionics reliability, normal in this environment given the vacuum tubeVacuum tube
In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
technology at the time, and the need to place some equipment outside the pressurized crew compartment. Much work was done to improve avionics reliability, but they remained problematic throughout the B-47's operational life.
Several models of the B-47 starting in 1950 included a fuel tank inerting system
Inerting system
An inerting system increases the safety of a fuel tank, ball mill, or other sealed or closed-in tank that contains highly flammable material. Inert in scientific terminology means ‘not readily reactive with other elements; forming no chemical compounds or something that is not chemically...
, in which dry ice
Dry ice
Dry ice, sometimes referred to as "Cardice" or as "card ice" , is the solid form of carbon dioxide. It is used primarily as a cooling agent. Its advantages include lower temperature than that of water ice and not leaving any residue...
was sublimated into carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
vapor while the fuel pumps operated or while the in-flight refueling system was in use. The carbon dioxide was then pumped into the fuel tanks and the rest of the fuel system, ensuring that the amount of oxygen in the fuel system was low, and thereby reducing the probability of an explosion. Ten carbon dioxide tanks and heaters were involved. The system was implemented largely to reduce risks from static electricity
Static electricity
Static electricity refers to the build-up of electric charge on the surface of objects. The static charges remain on an object until they either bleed off to ground or are quickly neutralized by a discharge. Static electricity can be contrasted with current electricity, which can be delivered...
discharges occurring during in-flight refueling.
Toss bombing
Toss bombing is a method of bombing where the attacking aircraft pulls upwards when releasing its bomb load, giving the bomb additional time of flight by starting its ballistic path with an upward vector.The purpose of toss bombing is to compensate for the gravity drop of the...
(Low Altitude Bombing System) of nuclear weapons. As the training for this imposes repeated high stress on the aircraft, the airframe lifetime would have been severely limited by metal fatigue
Fatigue (material)
'In materials science, fatigue is the progressive and localized structural damage that occurs when a material is subjected to cyclic loading. The nominal maximum stress values are less than the ultimate tensile stress limit, and may be below the yield stress limit of the material.Fatigue occurs...
, and this maneuver was eliminated.
Prime years
By 1956, the U.S. Air Force had 28 wings of B-47 bombers and five wings of RB-47 reconnaissance aircraft. The bombers were the first line of America's strategic nuclear deterrent, often operating from forward bases in the UKUnited Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
, Morocco
Morocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...
, Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
, Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
, Greenland and Guam
Guam
Guam is an organized, unincorporated territory of the United States located in the western Pacific Ocean. It is one of five U.S. territories with an established civilian government. Guam is listed as one of 16 Non-Self-Governing Territories by the Special Committee on Decolonization of the United...
. B-47 bombers were often set up on "one-third" alert, with a third of the 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 USSR
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
at short notice.
Crews were also trained to perform "minimum interval takeoffs (MITO)", with one bomber following the other into the air at intervals of as little as 15 seconds, to launch all bombers as fast as possible. MITO could be hazardous, as the bombers left turbulence and, with first generation turbojet engines with water injection
Water injection (engines)
In internal combustion engines, water injection, also known as anti-detonant injection, is spraying water into the cylinder or incoming fuel-air mixture to cool the combustion chambers of the engine, allowing for greater compression ratios and largely eliminating the problem of engine knocking...
systems, dense black smoke that blinded pilots in the following aircraft.
The B-47 would be 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 after that.
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. Bomber crews were trained in "pop-up" attacks, coming in at low level at 425 knots (832.9 km/h) and then climbing abruptly near the target before releasing a nuclear weapon, and the similar "toss bombing
Toss bombing
Toss bombing is a method of bombing where the attacking aircraft pulls upwards when releasing its bomb load, giving the bomb additional time of flight by starting its ballistic path with an upward vector.The purpose of toss bombing is to compensate for the gravity drop of the...
" procedure, in which the aircraft released the weapon while climbing, and then rolled away to depart the area before bomb detonation. Strategic operations of the 2,000 B-47s required 800 Boeing KC-97 Stratotankers.
Later years
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.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 out of Homestead AFB, Florida was engaged in a simulated combat exercise with a North American F-86 Sabre, the bomber simulating an attacking aircraft and the fighter a defender. As was the practice at the time, the B-47 was carrying a single 7600 lb (3,447.3 kg) Mark 15 nuclear bomb
Mark 15 nuclear bomb
The Mark 15 nuclear bomb, or Mk-15, was a 1950s American thermonuclear bomb, the first relatively lightweight thermonuclear bomb created by the United States....
without its core. During this exercise, the F-86 collided with the B-47. The F-86 pilot ejected and the fighter crashed, while the B-47 suffered substantial damage, including loss of power on one of its outboard jet engines. The bomber pilot had to "safe" soft drop the Mark 15 weapon off the coast of Savannah, Georgia
Savannah, Georgia
Savannah is the largest city and the county seat of Chatham County, in the U.S. state of Georgia. Established in 1733, the city of Savannah was the colonial capital of the Province of Georgia and later the first state capital of Georgia. Today Savannah is an industrial center and an important...
near Tybee Island after three unsuccessful landing attempts at Hunter Air Force Base. The bomb was jettisoned and the aircraft landed safely. An extensive nine-month search was mounted for the unarmed bomb, but proved futile.
Final phaseout of B-47 bomber wings began in 1963, and the last bombers were out of service by 1965. The very last USAF operational aircraft was grounded in 1969. The U.S. Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
kept specialized B-47 test aircraft in occasional use up to 1976. The final recorded flight of a B-47 was on 17 June 1986, when a B-47E was flown from the Naval Air Weapons Station China Lake
Naval Air Weapons Station China Lake
- About : is part of under Commander, Navy Installation Command and is located in the Western Mojave Desert region of California, approximately north of Los Angeles. Occupying three counties – Kern, San Bernardino and Inyo – the installation’s closest neighbors are the cities of Ridgecrest,...
, California, to Castle Air Force Base
Castle Air Force Base
Castle Air Force Base is a former United States Air Force Strategic Air Command base located northeast of Atwater, northwest of Merced and about east southeast of San Francisco, California....
, California, for static display at the Castle Air Museum.
Reconnaissance
The only B-47s to see anything that resembled combat were the aerial reconnaissanceAerial reconnaissance
Aerial reconnaissance is reconnaissance that is conducted using unmanned aerial vehicles or reconnaissance aircraft. Their roles are to collect imagery intelligence, signals intelligence and measurement and signature intelligence...
variants. The first overflight of Soviet territory with an RB-47 took place on 15 October 1952, when an RB-47B flying out of Alaska overflew Soviet airfields in Eastern Siberia. RB-47s operated from almost every airfield that gave them access to the USSR, and they often probed Soviet airspace, and on occasion, their pilots were caught in situations from which mostly speed and evasion in retreat saved them. At least five of these aircraft were fired on, and three of these were shot down. The RB-47s fired back with their tail turrets, although it is uncertain if they scored any kills, Nonetheless, these were the only shots fired in anger by any B-47.
On 8 May 1954, after a top secret reconnaissance mission in the Kola Peninsula
Kola Peninsula
The Kola Peninsula is a peninsula in the far northwest of Russia. Constituting the bulk of the territory of Murmansk Oblast, it lies almost completely to the north of the Arctic Circle and is washed by the Barents Sea in the north and the White Sea in the east and southeast...
, a 4th Air Division 91 Strategic Reconnaissance Wing RB-47E reconnaissance aircraft, with Hal Austin at the controls, flew west from the Soviet Union. The RB-47E was flying at high altitude, out of reach of MiG-15
Mikoyan-Gurevich MiG-15
The Mikoyan-Gurevich MiG-15 was a jet fighter developed for the USSR by Artem Mikoyan and Mikhail Gurevich. The MiG-15 was one of the first successful swept-wing jet fighters, and it achieved fame in the skies over Korea, where early in the war, it outclassed all straight-winged enemy fighters in...
s, but unknown to USAF intelligence some MiG-17
Mikoyan-Gurevich MiG-17
The Mikoyan-Gurevich MiG-17 is a high-subsonic fighter aircraft produced in the USSR from 1952 and operated by numerous air forces in many variants. Most MiG-17 variants cannot carry air-to-air missiles, but shot down many aircraft with its cannons...
s had been stationed in the area that were able to intercept the intruder. The RB-47E was chased by three Soviet MiG-17 fighters attempting to destroy the aircraft with their guns over Soviet and Finnish airspace. Although sustaining damage, the RB-47E managed to escape over Sweden back to its home base at RAF Fairford
RAF Fairford
RAF Fairford is a Royal Air Force station in Gloucestershire, England. It is a standby airfield, not in everyday use. Its most prominent use in recent years has been as an airfield for United States Air Force B-52s during the 2003 Iraq War, Operation Allied Force in 1999, and the first Gulf War in...
, Gloucestershire. Its top speed and combat radius
Combat radius
Combat radius refers to the distance from an airbase that a warplane can reach, patrol there for a set amount of time and return to base with minimal fuel left, thus completing a combat mission...
superiority to the Soviet fighter jets were the deciding factors. The mission marked the first time a jet aircraft equipped with modern photography equipment was used for American military reconnaissance. The incident was kept secret by all parties.
Other interceptions resulted in losses. A RB-47 flying out of Alaska was scouting out the Kamchatka Peninsula
Kamchatka Peninsula
The Kamchatka Peninsula is a peninsula in the Russian Far East, with an area of . It lies between the Pacific Ocean to the east and the Sea of Okhotsk to the west...
on 17 April 1955, when it was bounced by Soviet MiG-15s in international airspace. The RB-47 and its crew disappeared. Between 21 March and 10 May 1956, 16 RB-47Es and 5 RB-47Hs operating from Thule performed overflights the length of Siberia 156 times under Project HOMERUN
HOMERUN
HOMERUN was a secret US aerial reconnaissance operation against the USSR in 1956.Project HOMERUN was conducted between March and May 1956. During that time RB-47E and RB-47H reconnaissance aircraft flew almost daily flights over the North Pole to photograph and gather electronic intelligence over...
. The Soviets filed an angry complaint with the US government, which attributed the overflights to "navigational difficulties". MiGs bounced RB-47s on three separate occasions in the fall of 1958: over the Black Sea on 31 October, over the Baltic on 7 November, and over the Sea of Japan
Sea of Japan
The Sea of Japan is a marginal sea of the western Pacific Ocean, between the Asian mainland, the Japanese archipelago and Sakhalin. It is bordered by Japan, North Korea, Russia and South Korea. Like the Mediterranean Sea, it has almost no tides due to its nearly complete enclosure from the Pacific...
on 17 November.
On 1 July 1960, a PVO Strany MiG-19
Mikoyan-Gurevich MiG-19
The Mikoyan-Gurevich MiG-19 is a Soviet second-generation, single-seat, twin jet-engined fighter aircraft. It was the first Soviet production aircraft capable of supersonic speeds in level flight. A comparable U.S...
shot down an RB-47H (AF Serial No. 53-4281) reconnaissance aircraft in the international airspace over the Barents Sea
Barents Sea
The Barents Sea is a marginal sea of the Arctic Ocean, located north of Norway and Russia. Known in the Middle Ages as the Murman Sea, the sea takes its current name from the Dutch navigator Willem Barents...
with four of the crew being killed and two captured by the Soviets, but released in 1961. The co-pilot reported that the MiG-19 jammed ("whited-out") his MD-4 FCS scope, rendering the RB-47H defenseless. The last known confrontation between MiGs and RB-47s took place on 27 April 1965, when an ERB-47H was jumped by North Korean MiG-17s over the Sea of Japan. The MiGs scored hits on the aircraft, but the ERB-47H managed to make it back to Yokota Air Base in Japan with two engines out.
While a few of these aircraft performed special duties during the Vietnam War
Vietnam War
The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...
, such as relaying ELINT data from drones, they were eventually replaced by much more efficient and capable Boeing RC-135 platforms. The last RB-47H was retired on 29 December 1967.
The final 15 RB-47Es, built beginning in December 1955, were fitted with additional equipment, including the AN/APD "side looking airborne radar (SLAR)" system, and gear to sample the air for fallout
Nuclear fallout
Fallout is the residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and shock wave have passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes...
from nuclear tests
Nuclear testing
Nuclear weapons tests are experiments carried out to determine the effectiveness, yield and explosive capability of nuclear weapons. Throughout the twentieth century, most nations that have developed nuclear weapons have tested them...
. These last examples were given the new designation of RB-47K. The RB-47Ks were generally used for weather reconnaissance missions, carrying a load of eight "dropsonde
Dropsonde
A dropsonde is a weather reconnaissance device created by the National Center for Atmospheric Research , designed to be dropped from an aircraft at altitude to more accurately measure tropical storm conditions as the device falls to the surface...
" weather sensors that were released at various checkpoints along the aircraft's flight path. Data radioed back from the dropsondes was logged using equipment operated by the navigator. The RB-47Ks stayed in service until 1963.
Variants
- Section source: Baugher.
XB-47
- Two prototype aircraft. Two built as Model 450-1-1 and 450-2-2 respectively,(46-065 and 46-066). Powered by six Allison J-35-GE-7 turbojet engines for the first flights. The second, and subsequent, aircraft were built with the specified General Electric J-47-GE-3 engines, which were retro-fitted to the first XB-47.
B-47A
The first 10 aircraft were designated "B-47A", and were strictly evaluation aircraft. The first was delivered in December 1950. The configuration of the B-47As was close to that of the initial XB-47 prototypes. They were fitted with J47-GE-11 turbojets, offering the same 5,200 lbf (23 kN) thrust as the earlier J47-GE-3, and they also featured the built-in RATO bottles.
- Four of the B-47As were fitted with the K-2 bombing and navigation system (BNS), with an HD-21D autopilot, an analog computerAnalog computerAn analog computer is a form of computer that uses the continuously-changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved...
, APS-23 radar, and a Y-4 or Y-4A bombsight. Two were fitted with the tail turret, one of them using an Emerson A-2 fire control systemFire-control systemA fire-control system is a number of components working together, usually a gun data computer, a director, and radar, which is designed to assist a weapon system in hitting its target. It performs the same task as a human gunner firing a weapon, but attempts to do so faster and more...
(FCS), another an early version of the General Electric A-5 FCS. The eight other B-47As had no defensive armament.
- The B-47As were fitted with ejection seats. The pilot and copilot ejected upward, while the navigator had a downward ejection seat built by Stanley AviationStanley AviationStanley Aviation is an aerospace company started by Robert M Stanley, the aviation pioneer, in Buffalo, New York in 1948.The company has since acquired several other companies and has been most recently acquired by Eaton Corporation....
. Minimum safe ejection altitude was about 500 ft (150 m).
- While the XB-47s had been built by Boeing at their Seattle, Washington, plant, the B-47As and all following Boeing B-47 production were built at a government-owned factory in Wichita, KansasWichita, KansasWichita is the largest city in the U.S. state of Kansas.As of the 2010 census, the city population was 382,368. Located in south-central Kansas on the Arkansas River, Wichita is the county seat of Sedgwick County and the principal city of the Wichita metropolitan area...
, where the company had built B-29s in the past. The switch was made as the Seattle plant was burdened with KC-97 StratotankerKC-97 StratotankerThe Boeing KC-97 Stratotanker was a United States strategic tanker aircraft based on the Boeing C-97 Stratofreighter. It was succeeded by the Boeing KC-135 Stratotanker.-Design and development:...
production and other urgent tasks.
- Most of the B-47As were phased out of service by early 1952, though one did perform flight tests for NACA for a few more years. While the Air Force put the B-47As through their paces, the Cold WarCold WarThe Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...
was rising to full force, with a hot warKorean WarThe Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union...
intensifying in Korea. The USAF's Strategic Air CommandStrategic Air CommandThe Strategic Air Command was both a Major Command of the United States Air Force and a "specified command" of the United States Department of Defense. SAC was the operational establishment in charge of America's land-based strategic bomber aircraft and land-based intercontinental ballistic...
(SAC) needed an effective nuclear deterrent to keep the Soviet Union in line, and the Stratojet was an excellent tool for the task, and Boeing was already working on production bombers.
B-47B
- Following a series of preliminary contracts for production B-47s, in November 1949, even before the first flight of the B-47A, the Air Force had ordered 87 B-47Bs, the first operational variant of the type. The first B-47B flew on 26 April 1951. A total of 399 were built, including eight that were assembled by Lockheed
Lockheed CorporationThe Lockheed Corporation was an American aerospace company. Lockheed was founded in 1912 and later merged with Martin Marietta to form Lockheed Martin in 1995.-Origins:...
and ten that were assembled by DouglasDouglas Aircraft CompanyThe Douglas Aircraft Company was an American aerospace manufacturer, based in Long Beach, California. It was founded in 1921 by Donald Wills Douglas, Sr. and later merged with McDonnell Aircraft in 1967 to form McDonnell Douglas...
, using Boeing-built parts.
- The USAF was impatient to get their hands on as many B-47s as they could as quickly as possible, and signed up Lockheed and Douglas for the additional production. 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 batch of 87 B-47Bs featured the same J47-GE-11 engines as the B-47As, but all subsequent production featured substantially uprated J47-GE-23 turbojets with 5,800 lbf (26 kN) thrust. Early production aircraft were retrofitted with the improved engines. They all featured the built-in RATO system used on the XB-47 and B-47A.
- All featured full combat systems. Early production retained the K-2 BNS installed on some of the B-47As, but most production featured the K-4A BNS, which featured an AN/APS-54 warning radar and an AN/APT-5 electronic countermeasures (ECM) system.
- The K-4A used a periscopic bombsight fitted into the tip of the nose of the aircraft, with the transparent plexiglas nose cone of the XB-47 and B-47A replaced by a metal nose cone. There were four small windows on the left side of the nose and two on the right. Another visible change from the earlier models was that the B-47B had a vertical tailplane with a squared-off top, rather than a rounded top as with its predecessors.
- The bomb bay of the B-47B was shorter than that of the XB-47 and B-47A, since nuclear weapons had shrunk in the interim. However, the B-47B could carry a much larger bombload, of up to 18,000 lb (8,200 kg). All B-47Bs carried the tail turret with twin 20 mm (0.79 in) guns and the B-4 radar-guided FCS. The B-4 FCS proved troublesome, in fact so troublesome that in some B-47Bs it was replaced with an N-6 optical sight. The copilot could swivel his seat around to face backward and sight the guns directly.
- In practice, even the enormous fuel capacity of the B-47 was still not enough to give it the range the Air Force wanted, and in fact there had been substantial prejudice against the type among the senior Air Force leadership because of the limited range of the initial design. Solution of this problem was a high priority, and so an "in-flight refueling (IFR)" receptacle was fitted in the right side of the nose for "boom"-style refueling from KB-50 and KC-97 aircraft. This was the main reason for the deletion of the plexiglas nose cone for the bombardier navigator.
- The B-47B was also fitted with a pair of jettisonable external tanks, carried between the inboard and outboard engine assemblies. These external drop tanks were very large, with a capacity of 1,780 gal (6,750 l).
- The B-47B suffered a considerable gain in weight compared to the B-47A, and so as a weight-reduction measure the ejection seats were deleted, and a windbreak panel was fitted to the aircraft's main door to make escapes easier. Some sources also claim that a fatal ejection-seat accident in a B-47A contributed to this decision. Whatever the case, this was not a very popular measure with crews, as getting out of the aircraft even at altitude was troublesome. In 1956 all the surviving B-47Bs were modified to the same standard as the B-47Es, ejection seats were added.
- Between 1945 and 1956 Boeing at Wichita modified the surviving B-47Bs from line numbers 235 to 399 to the same standard as the B-47E under program High Noon, this included fitting ejections seats and enhancement of systems. The was followed by the Ebb Tide program that modified the 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 would have addition modification as drone directors DB-47Bs, and the 1 to 134 range which would have the same High Noon modification but without some of the non-combat changes. Following the modification programs the aircraft are sometimes referred to as the B-47B-II.
- YRB-47B
- :The Air Force had considered building a specialized RB-47B reconnaissance variant to complement the B-47B bomber version, but as it turned out schedule slips and the like ensured that the RB-47E was the first production reconnaissance variant. As an interim measure before the RB-47E went into service, 91 B-47B bombers were fitted with a heated pod with eight cameras that was stowed in the forward bomb bay, and these aircraft were designated YRB-47Bs. They were capable of daylight reconnaissance only and when the RB-47Es were delivered they returned to the bomber role
- TB-47B
- :A total of 66 B-47Bs which were survivors of the first batch of 87 non-combat B-47Bs were re-designated TB-47B in 1953 to alleviate logistics problems due to different engines and systems. Most of them were used as trainers and some were modified for Air Training Command by Douglas at Tulsa under the Field Goal programme, the simple modification added a fourth seat for an instructor and removed the tail turret. These aircraft were upgraded to the latest B-47E standard in 1956 under the Ebb Tide programme and were joined by 41 more early build aircraft also designated TB-47B. These aircraft provided valuable crew training through most of the 1950s
- MB47-B
- :With the introduction of the hydrogen bomb, the USAF contemplated the conversion of a few B-47Bs into MB-47B drones, which would essentially be huge cruise missileCruise missileA cruise missile is a guided missile that carries an explosive payload and is propelled, usually by a jet engine, towards a land-based or sea-based target. Cruise missiles are designed to deliver a large warhead over long distances with high accuracy...
s carrying H-bombs. The program was known as "Brass Ring". Closer examination of the scheme showed that it was impractical, and Brass Ring was cancelled on the appropriate date of 1 April 1953 - YDB-47B
- :There were various flight tests through the 1950s for using the B-47B as a launcher for the big 31 ft (9.5 m) liquid-fueled AGM-63 Rascal missile, and one B-47B was modified to become a YDB-47B Rascal launcher. However, the Rascal program was politically problematic, and never became operational, though a total of 74 B-47Bs were modified into DB-74B Rascal launchers before the program got the axe
- WB-47B
- :In 1956, a single B-47B was converted into a WB-47B weather reconnaissance aircraft and operated by the Military Air Transportation Service (MATS), making it one of the few B-47s that wasn't operated by SAC. This aircraft remained in service with the Air Weather Service of the Military Airlift CommandMilitary Airlift CommandThe Military Airlift Command is an inactive United States Air Force Major Command of the USAF which was headquartered at Scott Air Force Base, Illinois. It was constituted on 1 January 1966 and active until the end of the Cold War, when the Air Force table of organization was revised...
(MAC) until the mid-1960s - KB-47B
- :In 1953, two B-47Bs were modified for testing the probe-and-drogue refueling system. The tanker was given the designation KB-47G and was known as "Maw" by flightcrews, and was fitted with a British-built tanker kitCobham plcCobham plc is a British manufacturing company based in Wimborne Minster, Dorset, England. It is listed on the London Stock Exchange and is a constituent of the FTSE 250 Index...
. The refueling test aircraft was given the designation YB-47F and was known as "Paw", though other aircraft were also used as refueling targets. The program was cancelled in 1954 as it turned out the KB-47G simply could not carry enough fuel to make it a useful tanker. The idea of fielding B-47 tanker conversions came up again a few years later, but the economics didn't make sense, and the notion was finally put to rest for good in 1957
- Canadair CL-52
- :One of the most unusual B-47B conversions was the Canadair CL-52 which was a B-47B loaned in 1956 to the Royal Canadian Air ForceRoyal Canadian Air ForceThe history of the Royal Canadian Air Force begins in 1920, when the air force was created as the Canadian Air Force . In 1924 the CAF was renamed the Royal Canadian Air Force and granted royal sanction by King George V. The RCAF existed as an independent service until 1968...
to test the new, powerful Orenda Iroquois turbojet (rated at 19,250 lbf (85.6 kN) dry, 25,000 lbf (111 kN) afterburning) for the Avro Canada CF-105 Arrow interceptorInterceptor aircraftAn interceptor aircraft is a type of fighter aircraft designed specifically to prevent missions of enemy aircraft, particularly bombers and reconnaissance aircraft. Interceptors generally rely on high speed and powerful armament in order to complete their mission as quickly as possible and set up...
. Canadair Aircraft, the sub-contractor, attached the Iroquois engine to the right side of the rear fuselage near the tail; due to the large exterior diameter of the engine, no other location was feasible. Flying the CL-52 was reportedly a nightmare. After the Arrow project was cancelled in early 1959, the B-47B/CL-52, with about 35 hours of engine flight tests to its credit, was returned to the U.S. Some sources claimed it was bent out of shape by the tests, but in any case, it was subsequently scrapped. The CL-52 was the only B-47 to be used by any foreign service
YB-47C / RB-47C / B-47Z / B-56
- A four-engined variant of the B-47, the YB-47C, was proposed by Boeing in 1950 to be powered by four Allison J35Allison J35|-See also:-External links:*...
-A-23 turbojet engines, providing 10,090 lbf (45 kN) thrust each, in place of the six GEs J47s. The J35 turbojet engine was being developed during the late 1940s, and it was provisionally rated at 9700 pounds (with afterburnerAfterBurnerThe AfterBurner is a lighting solution for the Game Boy Advance system that was created by Triton-Labs.Originally, portablemonopoly.net was a website created to petition Nintendo to put some kind of light in their Game Boy Advance system...
) or 8500 pounds thrust without AB. Thus 4 * 8500 = 34,000 pounds using that engine, as compared to 6 * 5200 = 31,200 pounds in the production B-47. So the conversion would be lighter, simpler and more powerful. J71-A-5Allison J71|-External links:*...
- A contract was signed with Boeing in January 1950, calling for rework of one B-47B aircraft. The date for first flight was projected as April 1951.
- A combination of delays and less-than-expected performance of the J35 led to the consideration of other engines. The Allison J71Allison J71|-External links:*...
was proposed, however problems with this engine meant that this was not feasible for the by-then redesignated B-56A. The Pratt & Whitney J57, eventually rated at 17,000 pounds thrust, was also considered, but that engine was still in development, and the Boeing B-52 Stratofortress, which was being concurrently developed (first flight was April 1952), had priority for this engine.
- The B-56 was cancelled in December 1952 before conversion of the prototype was started. The donor fuselage that would have been the basis of the XB-56 protoype was then used as a ground instructional airframe.
- Beginning in 1951, two XB-47Ds were modified from B-47Bs as purely experimental platforms, with a big Wright YT49-W-1 turboprop engine spinning a huge four-paddle prop, replacing each of the inboard two-jet pods. Difficulties with engine development delayed first flight of the XB-47D until 26 August 1955. The aircraft's performance was comparable to that of a conventional B-47, and its reversible propellers shortened the landing roll, but the USAF did not follow up the idea.
B-47E
- The designations B-47C and B-47D were applied to special variants that never went into production (described later), and so the next production version of the B-47 was the definitive B-47E.
- The first B-47E flew on 30 January 1953. Four "blocks" or "phases" of the B-47E were built, each incorporating refinements on the previous block, and also sometimes featuring production changes within a block. Older blocks were generally brought up to the specifications of later blocks as they were introduced.
- Early production "B-47E-Is" also known featured J47-GE-25General Electric J47|-Specifications :-Nuclear-powered version – The X39:In the 1950s, interest in the development of nuclear-powered aircraft led GE to experiment with two nuclear-powered gas turbine designs, one based on the J47, and another new and much larger engine called the X211.The design based on the J47...
turbojets with 5,970 lbf (27 kN) thrust, but they were quickly changed to J47-GE-25A engines, which featured a significant improvement in the form of water-methanol injection. This was a scheme in which a water-methanol mix was dumped into the engines at takeoff, increasing mass flowMass flow rateMass flow rate is the mass of substance which passes through a given surface per unit time. Its unit is mass divided by time, so kilogram per second in SI units, and slug per second or pound per second in US customary units...
and so temporarily kicking the thrust up to 7,200 lbf (32 kN). Methanol was apparently added to the water as an anti-freezing agent. The engines left a trail of black smoke behind them when water-methanol injection was on.
- Jet-Assisted Take Off or JATOJATOJATO is an acronym for jet-fuel assisted take off. It is a system for helping overloaded aircraft into the air by providing additional thrust in the form of small rockets....
modifications were performed on early B-47E-Is. They had the 18 built-in JATO bottles, and were quickly exchanged for an external, jettisonable "split V" or "horse collar" rack fitted under the rear fuselage. The rack carried 33 JATO bottles, in three rows of 11 bottles. The built-in JATO system was eliminated because of worries about having the JATO bottles so close to full fuel tanks, and in any case once the rocket bottles were exhausted they were just dead weight. The racks were expendable, and were dropped over specific range areas after takeoff.
- The internal fuel capacity of initial production B-47Es was cut to 14,627 gal (55,369 l) as a weight-saving measure. This was considered acceptable because of the use of the big external tanks and the fact that the USAF had refined mid-air refueling to the point where it could be relied upon as a standard practice.
- One welcome change in the B-47E relative to the B-47B was the return of the ejection seats, the Air Force senior leadership having reconsidered the earlier decision to delete them. In addition, the twin .50 in guns (12.7 mm) in the tail turret were replaced with twin 20 mm (0.79 in) cannon to provide more firepower, backed up by an A-5 FCS in early production and an MD-4 FCS in later production.
- A final change in the B-47E was that most of the windows in the nose were deleted, with only one left on each side. However, many pictures of B-47Es show them with the full set of windows used on the B-47B. Whether the number of windows varied through B-47E production, or whether these were B-47Bs updated to B-47E specification, is unclear.
- The B-47E-II featured only minor changes from late production B-47E-Is. The B-47E-III featured an ECM suite, consisting of a radar jammer in a bulge under the fuselage plus a chaffChaff (radar countermeasure)Chaff, originally called Window by the British, and Düppel by the Second World War era German Luftwaffe , is a radar countermeasure in which aircraft or other targets spread a cloud of small, thin pieces of aluminium, metallized glass fibre or plastic, which either appears as a cluster of secondary...
dispenser, as well as improved electrical alternators.
- The B-47E-IV was a much more substantial update, featuring stronger landing gear, airframe reinforcement, greater fuel capacity, and a bombload uprated to 25,000 lb (11,300 kg), though the bomb bay was once again shortened because of the introduction of more compact nuclear weapons.
- Another improvement was the introduction of the MA-7A BNS, a major step up from its predecessors. The MA-7A included the AN/APS-64 radar, with a range as long as 240 mi (390 km). The AN/APS-64 could be used as a long range "identification friend or foeIdentification friend or foeIn telecommunications, identification, friend or foe is an identification system designed for command and control. It is a system that enables military and national interrogation systems to identify aircraft, vehicles, or forces as friendly and to determine their bearing and range from the...
(IFF) transponder" interrogator to allow a B-47E-IV to find a tanker or other B-47, or it could be used as a high-resolution ground-targeting radar. The B-47E-IV retained the optical bombsight, though this was rarely used.
- A total of 1,341 B-47Es were produced. 691 were built by Boeing, 386 were built by Lockheed, and 264 were built by Douglas. Most B-47Bs were rebuilt up to B-47E standards. They were given the designation of B-47B-II, though it appears that in practice they were simply called B-47Es.
- TEE TOWN B-47E
- :In 1955, a 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, KS, location of Forbes AFB) and so these aircraft were known as "Tee Town B-47s". They retained their normal bombing capability
- EB-47E
- :The Tee Town B-47s then led to a specialized ECM conversion of the B-47E, which was given the designation EB-47E. The initial EB-47 conversion featured a set of 16 jammers in a removable cradle stored in the bomb bay, plus radar warning receivers and chaff dispensers. These were known as "Phase IV" or "Blue Cradle" EB-47Es. The more advanced "Phase V" EB-47E featured a pressurized module that was stowed in the bomb bay, with 13 jammers under control of two Crows. While the Phase IV jammer system was "broadband", blanketing a wide range of frequencies in hopes of jamming radars operating somewhere within that range, the Phase V jammer system could be selectively tuned to specific radar frequencies by the crows, permitting much higher jammer power on the frequencies that did the most good. A radar jammer tends to announce its presence and location by the radio signals it emits, and EB-47E crews were perfectly aware that they were unlikely to return from an operational mission into the USSR. If they could cover for B-47 bombers, however, the sacrifice would be worth it. About 40 B-47Es were converted to EB-47Es. Of course they couldn't carry bombs, but they did retain the tail turret
-
- B-47E 52-0410 and 52-0412 were converted to EB-47Es in the mid-1960s for service with U.S. Navy's Fleet Electronic Warfare Support Group (FEWSGFEWSGThe Fleet Electronic Warfare Support Groups ' mission as part of the US Navy was to provide electronic warfare simulation in a controlled environment during fleet exercises to help operators deal with EW threats, VAQ-33, VAQ-34 and VAQ-35 were the primary electronic aggressor squadrons to provide...
). Considered to be on indefinite loan from USAF, these aircraft were unlike the USAF EB-47Es, with some of their ECM gear fitted into pods carried on the external fuel tank pylons. They were used for tests of naval ECM systems and as "electronic aggressors" in naval and joint exercises. These two aircraft were the last B-47s in operational service, and 52-0410 performed the very last operational flight of a B-47 on 20 December 1977 when it was flown to Pease AFB, NH and put on display at the main gate. Following the closure/realignment of Pease AFB in 1991 and its conversion to Pease International Tradeport and Pease ANGB, this aircraft was disassembled and trucked to Ellsworth AFB, SD where it donated its nose and engines to RB-47H 53-4299, which is in the National Museum of the United States Air ForceNational Museum of the United States Air ForceThe National Museum of the United States Air Force is the official museum of the United States Air Force located at Wright-Patterson Air Force Base northeast of Dayton, Ohio. The NMUSAF is the world's largest and oldest military aviation museum with more than 360 aircraft and missiles on display...
at Wright-Patterson AFB in Dayton, OH.- EB-47E(TT)
- :Three B-47Es were converted to the highly specialized EB-47E(TT) "Tell Two" configuration to be used for "telemetry intelligenceTelemetryTelemetry is a technology that allows measurements to be made at a distance, usually via radio wave transmission and reception of the information. The word is derived from Greek roots: tele = remote, and metron = measure...
", picking up radio signals from Soviet missile tests and space launches. The Tell Two was the precursor to the RC-135S Rivet Ball and Cobra Ball. The EB-47E(TT)s featured a "Crow capsule" in the bomb bay loaded with the appropriate gear and two ECM operators (known as Crows), and also featured odd and distinctive antennas just below each side of the cockpit. All three of these aircraft were operated out of TurkeyTurkeyTurkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
, and stayed in service until 1967. The antennas on the nose of the aircraft attracted a good deal of attention from base personnel, and crews made up imaginative stories about them, for example claiming they were part of a "return to fighter (RTF)" defensive system that would cause Soviet air-to-air missiles to loop back and shoot down their own launch fighters. In reality, they were specialized receiver antennas used for intercepting telemetry signals from Soviet space and missile launches - ETB-47E
- :As with the B-47B, a few B-47Es were converted to trainers, with a fourth seat for an instructor, and given the designation ETB-47E. These aircraft were used to replace TB-47Bs that had "got too long in the tooth," and served into the early 1960s
- DB-47E / YDB-47E
- :Two B-47Es were converted to YDB-47Es to support the GAM-63 RASCALGAM-63 RASCALThe GAM-63 RASCAL is a supersonic Air-to-surface missile that was developed by the Bell Aircraft Company. The RASCAL was the United States Air Force's first nuclear armed standoff missile. The RASCAL was initially designated the ASM-A-2, then re-designated the B-63 in 1951 and finally re-designated...
stand-off missile program, and two more B-47Es were converted to DB-47Es in preparation for the operational introduction of the missile before the program was axed. These two DB-47Es were later used 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, even more mysterious modified B-47E was given the designation JRB-47E. They appear to have been test platforms for ECM systems
- NB-47E
- :Finally, a B-47E was loaned to the U.S. Navy to help test the GE TF34-2 turbofan for the Lockheed S-3 VikingS-3 VikingThe Lockheed S-3 Viking is a four-seat twin-engine jet aircraft that was used by the U.S. Navy to identify, track, and destroy enemy submarines. In the late 1990s, the S-3B's mission focus shifted to surface warfare and aerial refueling. The Viking also provided electronic warfare and surface...
carrier-based antisubmarine warfare aircraft. This B-47E 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 such interesting features as self-destruct charges and arresting gear to assist in landings. They also carried pods mounted on the external tank pylons to help in scoring weapons tests. Apparently most of the 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
- B-47E 52-0410 and 52-0412 were converted to EB-47Es in the mid-1960s for service with U.S. Navy's Fleet Electronic Warfare Support Group (FEWSG
- RB-47E
- :::The B-47E was also the basis for a number of important long-range reconnaissance variants. The only B-47s to see anything that resembled combat were these reconnaissance variants. They operated from almost every airfield that gave them access to the USSR, and often probed Soviet airspace
-
- Boeing-Wichita built 240 RB-47E reconnaissance variants, similar to the B-47E but with a nose stretched by 34 in (0.86 m), giving them an arguably more elegant appearance than the bomber variants of the B-47. The long nose was used to stow up to 11 cameras, which could include:
-
-
- An O-15 radarRadarRadar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
camera for low-altitude work. - A forward oblique camera for low-altitude work.
- A K-17 trimetrogon (three-angle) camera for panoramic shotsPanoramaA panorama is any wide-angle view or representation of a physical space, whether in painting, drawing, photography, film/video, or a three-dimensional model....
. - K-36 telescopic camerasTelephoto lensIn photography and cinematography, a telephoto lens is a specific type of a long-focus lens in which the physical length of the lens is shorter than the focal length. This is achieved by incorporating a special lens group known as a telephoto group that extends the light path to create a long-focus...
.
- An O-15 radar
-
-
- The RB-47E could carry photoflash flaresFlare (pyrotechnic)A flare, also sometimes called a fusee, is a type of pyrotechnic that produces a brilliant light or intense heat without an explosion. Flares are used for signalling, illumination, or defensive countermeasures in civilian and military applications...
for night reconnaissanceReconnaissanceReconnaissance is the military term for exploring beyond the area occupied by friendly forces to gain information about enemy forces or features of the environment....
. Although the RB-47E could be refueled in flightAerial refuelingAerial refueling, also called air refueling, in-flight refueling , air-to-air refueling or tanking, is the process of transferring fuel from one aircraft to another during flight....
, its fuel capacity was increased, to a total of 18,400 gal (70,000 literLitrepic|200px|right|thumb|One litre is equivalent to this cubeEach side is 10 cm1 litre water = 1 kilogram water The litre is a metric system unit of volume equal to 1 cubic decimetre , to 1,000 cubic centimetres , and to 1/1,000 cubic metre...
s). The navigator controlled the cameras, becoming a "navigator-photographer" instead of a "navigator-bombardier".- WB-47E
- :Following the single WB-47B weather reconnaissance conversion, in the early 1960s 34 B-47Es were converted by Lockheed into WB-47Es for weather reconnaissance. These aircraft were stripped of combat gear, including the tail turret. They were fitted with cameras in the nose to take pictures of cloud formations, and carried a special meteorological instrument pod in the bomb bay. Initially assigned to the Air Weather Service of the Military Air Transport ServiceMilitary Air Transport ServiceThe Military Air Transport Service is an inactive Department of Defense Unified Command. Activated on 1 June 1948, MATS was a consolidation of the United States Navy Naval Air Transport Service and the United States Air Force Air Transport Command into a single, joint, unified command...
(MATS), they became part of the Military Airlift CommandMilitary Airlift CommandThe Military Airlift Command is an inactive United States Air Force Major Command of the USAF which was headquartered at Scott Air Force Base, Illinois. It was constituted on 1 January 1966 and active until the end of the Cold War, when the Air Force table of organization was revised...
(MAC) when that organization was established. The last WB-47E was retired on 31 October 1969, and was the last B-47 in operational USAF service
- The RB-47E could carry photoflash flares
RB-47H/ERB-47H
- A total of 32 RB-47H models were built for the electronic intelligence (ELINT) mission, as well as three more specialized "ERB-47Hs". These aircraft featured distinctive blunt, rounded nose and sported blisters and pods for intelligence-gathering antennas and gear. They were designed to probe adversary defenses and then collect data on radar and defense communications signals.
- The bomb bay was replaced by a pressurized compartmentCabin pressurizationCabin pressurization is the pumping of compressed air into an aircraft cabin to maintain a safe and comfortable environment for crew and passengers when flying at altitude.-Need for cabin pressurization:...
, which accommodated "electronic warfare officerElectronic Warfare OfficerIn the U.S. Air Force, an Electronic Warfare Officer is a trained aerial navigator in the Air Force who has received training in enemy threat systems, electronic warfare principles and overcoming enemy air defense systems...
s (EWOs)", also known as "Crows" or "Ravens" (both being black birds, it was a reference to "black ops" meaning classified operations). There were three Crows on board the RB-47H, but only two on the ERB-47H. A distinctive bulged radomeRadomeA radome is a structural, weatherproof enclosure that protects a microwave or radar antenna. The radome is constructed of material that minimally attenuates the electromagnetic signal transmitted or received by the antenna. In other words, the radome is transparent to radar or radio waves...
fairing replaced the bomb bay doors. The RB-47H / ERB-47H retained the tail turret, and were also fitted with jammers and chaff dispensers. The only easily recognizable difference in appearance between the RB-47H and ERB-47H was that the ERB-47H had a small but distinctive antenna fairing under the rounded nose.
- The first RB-47H was delivered in August 1955 to Forbes AFB, KansasKansasKansas is a US state located in the Midwestern United States. It is named after the Kansas River which flows through it, which in turn was named after the Kansa Native American tribe, which inhabited the area. The tribe's name is often said to mean "people of the wind" or "people of the south...
. The ELINT B-47s proved so valuable that they were put through a "Mod 44" or "Silver King" update program in 1961 to provide them with updated electronics systems. Silver King aircraft could be easily recognized by a large teardrop pod for ELINT antennas attached to a pylon, mounted under the belly and offset to one side of the aircraft, as well as a pylon-style antenna attached under each wing beyond the outboard engine. It is unclear if all RB-47Hs and ERB-47Hs were updated to the Silver King specification.
- The RB-47H and ERB-47H were highly capable aircraft, but the EWO compartment was not only cramped with sitting room only, but also had both poor noise insulation and climate control. This made 12-hour missions very uncomfortable and tiring, and some sources say that the Crows even had to deal with fuel leaks on occasion. Successful ejection downward (cutting through the belly radome) was impossible on-or-near the ground. Crows sat bobsled-like on the pilot compartment access floor for takeoff and landing; having to crawl encumbered with Arctic clothing with parachute to-from their compartment along an unpressurized maintenance shelf during temporary leveloff at 10000 ft (3,048 m)
- Operations of the RB-47H and ERB-47H were often classified Top Secret, with the 10 hour missions generally flown at night. When crews were asked what they were doing, they always answered that such information was classified. On inquiries on what the blunt black nose was for, they would sometimes reply that it was a bumper, used in in-flight refueling in case they nosed into the tanker. This reply was often believed.
- The final RB-47H to be retired from service, 53-4296, was later pulled out of the "boneyard" and used for tests of avionics for the General Dynamics FB-111General Dynamics F-111The General Dynamics F-111 "Aardvark" was a medium-range interdictor and tactical strike aircraft that also filled the roles of strategic bomber, reconnaissance, and electronic warfare in its various versions. Developed in the 1960s by General Dynamics, it first entered service in 1967 with the...
. This RB-47H was fitted with an F-111-style nose and flew into the early 1970s. It was not given any special designation. It is now on display at the Air Force Armament MuseumAir Force Armament MuseumThe Air Force Armament Museum, adjacent to Eglin Air Force Base, Florida, is the only facility in the U.S. dedicated to the display of Air Force armament...
at Eglin AFB, FloridaFloridaFlorida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, 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. Other B-47Es were also apparently used in the MA-2 tests, but not given a special designation.
RB-47K
- The RB-47Ks were generally used for weather reconnaissance missions, carrying a load of eight "dropsonde" weather sensors that were released at various checkpoints along the aircraft's flight path. Data radioed back from the dropsondes was logged using equipment operated by the navigator. The RB-47Ks stayed in service until 1963.
EB-47L
- Between 1961 and 1963 36 B-47Es were modifed to carry a communications relay system. These aircraft were given the new designation of EB-47L, and were used to support U.S. flying command post aircraft in case of a nuclear attack on the US. The EB-47Ls only remained in service for a few years, as improved communications technologies quickly made them redundant by 1965.
Operators
- United States Air ForceUnited States Air ForceThe United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
- United States NavyUnited States NavyThe United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
Canada
- Royal Canadian Air ForceRoyal Canadian Air ForceThe history of the Royal Canadian Air Force begins in 1920, when the air force was created as the Canadian Air Force . In 1924 the CAF was renamed the Royal Canadian Air Force and granted royal sanction by King George V. The RCAF existed as an independent service until 1968...
– 1 B-47B loaned to Canada and converted by Canadair with the designation CL-52 to test the CF-105 Avro Arrow's Orenda engines in 1956; returned to USAF's Davis-Monthan AFB and scrapped (1957)
Survivors
About 25 surviving airframes exist in museum collections worldwide.Accidents and incidents
On 20 August 1963, a QB-47 veered off course on its landing approach at Eglin Air Force BaseEglin Air Force Base
Eglin Air Force Base is a United States Air Force base located approximately 3 miles southwest of Valparaiso, Florida in Okaloosa County....
and crash landed on a stretch of road that ran parallel to the runway. Two cars were crushed by the crash landing, killing two occupants, Robert W. Glass and Dr. Robert Bundy, and injuring a third, Dorothy Phillips. Mr. Glass and Dr. Bundy both worked for the Minnesota Honeywell Corporation at the time, a firm which had just completed flight tests on an inertia guidance sub-system for the X-20 Dyna-Soar
X-20 Dyna-Soar
The X-20 Dyna-Soar was a United States Air Force program to develop a spaceplane that could be used for a variety of military missions, including reconnaissance, bombing, space rescue, satellite maintenance, and sabotage of enemy satellites...
project at the base. Mrs. Phillips was the wife of Master Sergeant
Master Sergeant
A master sergeant is the military rank for a senior non-commissioned officer in some armed forces.-Israel Defense Forces:Rav samal rishoninsignia IDF...
James Phillips, a crew chief at the base. Mrs. Phillips was treated for moderate injuries and released later that day. Both vehicles were destroyed by fire. The QB-47 that crashed was used for Bomarc Missile Program
Bomarc Missile Program
The CIM-10 Bomarc was the only surface-to-air missile ever deployed by the United States Air Force. All other U.S. land-based SAMs were and are under the control of the United States Army....
tests, which normally operated from Eglin AFB Auxiliary Field Number Three (Duke Field
Duke Field
Duke Field , also known as Eglin AFB Auxiliary Field #3, is a military airport located three miles south of the central business district of Crestview, in Okaloosa County, Florida, United States-Units:...
), approximately 15 miles (24.1 km) north of the main base.
On 5 February 1958, a B-47 carrying a nuclear weapon had a midair collision with an F-86 fighter.
Specifications (B-47E)
Popular culture
The B-47 is featured prominently in the 1955 film Strategic Air CommandStrategic Air Command (film)
Strategic Air Command is a 1955 American film starring James Stewart and June Allyson, and directed by Anthony Mann. Released by Paramount Pictures, it was the first of four films that depicted the role of the Strategic Air Command in the Cold War era....
starring James Stewart
James Stewart (actor)
James Maitland Stewart was an American film and stage actor, known for his distinctive voice and his everyman persona. Over the course of his career, he starred in many films widely considered classics and was nominated for five Academy Awards, winning one in competition and receiving one Lifetime...
. The film features good aerial footage of both the B-47 and the B-36. The majority of B-47 scenes were filmed at MacDill AFB, Florida utilizing aircraft from the 306th Bombardment Wing.
The movie On the Threshold of Space
On the Threshold of Space
On the Threshold of Space is a 1956 Drama directed by Robert D. Webb, starring Guy Madison, Virginia Leith and John Hodiak. Historical depiction on tests done to prepare US for space travel.-Plot:...
(1956) has footage of a B-47E being used as a test ship in the development of a downward-firing ejection seat, with Eglin Air Force Base
Eglin Air Force Base
Eglin Air Force Base is a United States Air Force base located approximately 3 miles southwest of Valparaiso, Florida in Okaloosa County....
identified as Sovran Air Force Base.
The 1957 film Bombers B-52 shows B-47s at Castle Air Force Base
Castle Air Force Base
Castle Air Force Base is a former United States Air Force Strategic Air Command base located northeast of Atwater, northwest of Merced and about east southeast of San Francisco, California....
, including the proud legend 'Home of the B-47' and a fly-over in formation, before moving to focus on the new B-52 Stratofortress
B-52 Stratofortress
The Boeing B-52 Stratofortress is a long-range, subsonic, jet-powered strategic bomber operated by the United States Air Force since the 1950s. The B-52 was designed and built by Boeing, who have continued to provide maintainence and upgrades to the aircraft in service...
.
The 1 July 1960 shoot down of an RB-47H (AF Ser. No. 53-4281) by a MiG-19
Mikoyan-Gurevich MiG-19
The Mikoyan-Gurevich MiG-19 is a Soviet second-generation, single-seat, twin jet-engined fighter aircraft. It was the first Soviet production aircraft capable of supersonic speeds in level flight. A comparable U.S...
over the Barents Sea
Barents Sea
The Barents Sea is a marginal sea of the Arctic Ocean, located north of Norway and Russia. Known in the Middle Ages as the Murman Sea, the sea takes its current name from the Dutch navigator Willem Barents...
was retold by the two surviving crewmembers: Captain John R. McKone (navigator) and Capt Freeman B. Olmstead (co-pilot), in the biographical book, The Little Toy Dog by William L. White. The title refers to a small plastic toy "Snoopy
Snoopy
Snoopy is an fictional character in the long-running comic strip Peanuts, by Charles M. Schulz. He is Charlie Brown's pet beagle. Snoopy began his life in the strip as a fairly conventional dog, but eventually evolved into perhaps the strip's most dynamic character—and among the most recognizable...
" that Capt McKone carried with him, and kept during their seven months in Lubyanka
Lubyanka (KGB)
The Lubyanka is the popular name for the headquarters of the KGB and affiliated prison on Lubyanka Square in Moscow. It is a large building with a facade of yellow brick, designed by Alexander V...
prison in the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
.
A one-hour episode of the TV series Kraft Suspense Theatre
Kraft Suspense Theatre
Kraft Suspense Theatre, an anthology series, was telecast from 1963 to 1965 on NBC. Sponsored by Kraft Foods, it was seen three weeks out of every four and was pre-empted for Perry Como's Kraft Music Hall specials once monthly...
, "Streetcar, Do You Read Me?" (1965), starring Martin Milner, features extensive real footage, interior and exterior scenes, of the B-47E. The fictional story depicts a mission of the 307th Bomb Wing of the Strategic Air Command.
See also
External links
- (1950) (Part I) AN 01-20ENA-1 Handbook Flight Operating Instructions USAF Series B-47A Aircraft
- (1950) (Part II) AN 01-20ENA-1 Handbook Flight Operating Instructions USAF Series B-47A Aircraft
- National Museum fact sheet Boeing B-56A
- Description of the July 1, 1960, incident at USAF Museum website
- B-47 Crashes into Wright Peak (Adirondacks)
- RB-47E USSR Overflights by the 91st SRW- PDF on The Cold War Museum website
- Listing of Air Force Aircraft Serial Numbers, including B-47 aircraft
- B-47 Stratojet Association
- B-47 Explodes over Little Rock, AR
- Episode of "Kraft Suspense Theatre" Streetcar, Do You Read Me? (1965)
- Multipart B-47 article
- "I Fly The World's Fastest Bomber" , November 1949, Popular Science early article on B-47 for general public
- The B-47: "A Revolution in Aviation" from the Museum of Flight (Seattle)