Military Factory logo

Boeing B-47 Stratojet

United States (1951)
Picture of Boeing B-47 Stratojet Strategic Medium / Heavy Bomber Aircraft
Picture of Boeing B-47 Stratojet Strategic Medium / Heavy Bomber Aircraft Picture of Boeing B-47 Stratojet Strategic Medium / Heavy Bomber Aircraft
+ Images
This entry's gallery contains additional pictures. Click to View.

The Boeing B-47 scored many firsts in the realm of high-altitude jet-powered bomber aircraft - including a tricycle-style undercarriage configuration.


Detailing the development and operational history of the Boeing B-47 Stratojet Strategic Medium / Heavy Bomber Aircraft.  Entry last updated on 5/17/2018. Authored by Dan Alex. Content ©www.MilitaryFactory.com

The swept-wing B-47 Stratojet produced by Boeing was a milestone in American bomber design in several ways. The system pioneered the now-traditional bomber layout found on many of today's bomber aircraft and offered up performance capabilities unheard of before then. As a post-war/Cold War aircraft design, the system was the epitome of what the American military sought in terms of high-level penetration systems capable of nuclear strikes deep within enemy territory.

The XB-47 was proposed as early as 1945 - the final year of World War 2 - and beat out a notable flying wing design proposed by the Northrop aviation firm. Two XB-47 prototypes were constructed as SN 46-065 and 46-066. Each was initially powered by 6 x Allison J35-GE-7 turbojet engines slung under each swept-back wing with both prototypes eventually receiving General Electric J47-GE-3 turbojets. The engines were split into pairings and single mounts as individual nacelles. The aircraft was crewed by three personnel made up of two pilots and a bombardier. From there, the first XB-47 achieved first flight in 1947.

With its immense size, the B-47 made use of no fewer than eighteen rocket-propelled boosters to help it achieve flight, resulting in a dazzling display of power and smoke upon take-off. To decrease runway landing distances, the Stratojet deployed a drag chute to significantly slow the airframe down upon landing - a practice utilized even today in modern aircraft types. An impressive inherent range meant that the B-47 was ideally suited to forward and rearward operating bases across Europe and the United States. In an age before accurate surface-to-air missile systems became the norm, the B-47 was really only threatened by the latest in the delta wing interceptors of the Soviet Union. As such, since the rear portion of any bomber was susceptible to attack from interceptors, the B-47 mounted two remote-controlled 12.7mm machine guns (later upgraded to 20mm cannons) in her tail. As far as her external design goes, the B-47 was conventional with a forward held cockpit (including glazed nosecone), a cylindrical fuselage and a conventional empennage mounting a single vertical tail fin and applicable horizontal planes. At rest, the aircraft took on a noticeable "nose up" position that required the use of a rolling ladder platform for the crew to gain entry. The undercarriage consisted of a pair of double-tired landing gear legs along the fuselage centerline with a pair of smaller single-tired legs under the inner pair of engine nacelles. With the advent of improved Soviet surface-to-air missile systems (SAM), the B-47 was forced to take more of a low-level bombing role and thus the structure was optimized for the rigors of such flight. Internal ordnance was finalized in the B-47E model which could carry 25,000lb of munitions in the form of 2 x Mk 15 nuclear drop bombs or up to 28 x 500lb conventional drop bombs.

The B-47A was the initial production model serving as evaluation airframes numbering ten examples. The first unit was delivered in December of 1950 and followed closely to the original XB-47 prototypes fitted with J47-GE-11 series turbojet engines of 5,200lbf. At least four were fitted with autopilot and their nav-attack systemsas well as radar. Ejection seats were afforded the two pilots and the bombardier - the former's seats ejecting upwards with the latter's seat ejecting downwards. B-47A models were in service up until 1952 and were followed into service by the improved B-47B models.

B-47Bs served as the first true operational forms of the Stratojet to which the USAF put on order some 87 examples. First flight was on April 26th, 1951 and the dire need by the USAF to field the B-47 ensured a total of 399 B-47Bs were delivered. The first production batch was fitted with J47-GE-11 engines with follow up deliveries being given J47-GE-23 series turbojets of 5,800lbf. Since the B-47 series, up to this point, held an inherently short operational range, an in-flight refueling boom was added to the right side of the nose section to help increase range as well as jettisonable external fuel tanks between the outboard and inner pairing of engines. The addition of this assembly deleted the bombardier's glazed nose cone. The resulting changes produced a heavier end-product than the XB-47 and B-47A before it and several weight-saving measures were enacted - including the removal of the ejection seats.

A specialized reconnaissance version of the B-47 existed - aptly designated as the RB-47 - with extensive onboard Electronic CounterMeasures (ECM) equipment installed. The similarities between the B-47 and the RB-47 were consistent which allowed all RB-47s to be retrofitted to carry bombs if need be. Despite the inherently limited internal carrying capacity of the base aircraft - either for munitions or electronics equipment - the B-47 made up for it in quantity with over 2,000 produced in one form or another - many eventually seeing operation with the Strategic Air Command (SAC). The RB-47B consisted of 24 B-47B airframes modified for the reconnaissance role - these fitting eight internal cameras in the forward bomb bay. Of note was that these airframes were only capable of daylight operations.


Picture of the Boeing B-47 Stratojet Strategic Medium / Heavy Bomber Aircraft
Picture of the Boeing B-47 Stratojet Strategic Medium / Heavy Bomber Aircraft


TB-47B were trainer conversion models of the B-47B production model. At least 66 of B-models were converted as such and saw the loss of their defensive tail armament as well as the inclusion of a fourth position seat for the instructor.

The Stratojet existed in several short-live forms that included the YDB-47B missile launcher platform, the WB-47B weather reconnaissance platform, the KB-47B refueler and the CL-52 from Canadair to be used as a test airframe for the Orenda Iroquois engine to power their (ultimately) cancelled Avro CF-105 Arrow interceptor. Similarly, a B-47E was loaned to the United States Navy for the testing of the GE TF34-2 turbofan engine to be used in the Lockheed S-3 Viking anti-submarine aircraft and designated as the NB-47E. Several specialized ECM conversion models existed and were noted for their "E" designators as in the EB-47E, EB-47E(TT) and ETB-47E. The JB-47E was used to test early fly-by-wire systems while QB-47E were radio-controlled target drones.

Boeing further proposed a four engine variant of the B-47 to be powered by 4 x Allison J35-A-23 turbojet engines of 10,090 thrust each. Engine issues eventually delayed and ultimately cancelled this Stratojet version in December of 1952. The XB-47D was an experimental platform fielding Wright turboprops for the USAF but was never furthered after performance did not improve over that of the original's turbojets.

The markers of B-47C and B-47D were assigned to specialized B-47 variants that were never selected for serial production by the USAF.

The definitive B-47 became the B-47E model. First flight was recorded on January 30th, 1953 fielding J47-GE-25 turbojet engines of 5,970lbf. These were then upgraded to the J47-GE-25A series engines sporting water-methanol injection systems to provide extra thrust during take-off. The original 18 JATO packs were further increased to 33 and could be jettisoned after use. Ejection seats were brought back into the fold. The defensive tail armament was upgraded to a pairing of 20mm cannons. The second B-47E production block differed little when compared to the first while the third block added an Electronic CounterMeasures (ECM) suite and chaff dispenser, the former noted as an under-fuselage bulge. The fourth production block featured a reinforced airframe and landing gear as well as an increased internal fuel capacity and, therefore, longer range. The internal bomb load was increased to an extend as well (25,000lbs) but made smaller to accommodate the smaller technology of newer nuclear ordnance. The B-47E was produced in 1,341 examples with production handled by Boeing, Lockheed and Douglas facilities.

As the B-47B before it, the B-47E was also modified for the reconnaissance role to become theRB-47E to which some 240 examples were built. These were noted for their elongated nose assemblies which housed up to eleven cameras. Night reconnaissance was now possible with the newer RB-47Es. The B-47E was also modified for the weather reconnaissance role as the WB-47E to which 34 were produced.

The RB-47H was an ELINT (ELectronic INTelligence) platform and were joined by a further variant known as the ERB-47H. These were noted for their blistered noses and pressurized bomb bays (serving as a crew cabin) and differentiated by the latter's antenna fairing under the nose. RB-47K were utilized in weather reconnaissance roles up until 1963. The EB-47L was used as an airborne communications relay platform (in the advent of all-out nuclear war) beginning in 1963.

By 1965, the B-47 program had all but run its course, now replaced by the Convair B-58 Hustler and the Boeing B-52 Stratofortress series of bombers (both aircraft detailed elsewhere on this site). Despite this somewhat average span for operational service, the B-47 became a major contributor to the United States Air Force in terms of strategic defense and deterrence. Serving as a capable high- or low-level bomber and reconnaissance platform ensured the system a good historical reputation and paved the way for future American bomber designs capitalizing on the successes pioneered in the groundbreaking B-47.




General Assessment (BETA)
Firepower  
Bar chart graphic
Performance  
Bar chart graphic
Survivability  
Bar chart graphic
Versatility  
Bar chart graphic
Impact  
Bar chart graphic


Rating: 80 (of 100)
The rating is an internal assessment derived from forty factors pertaining to this entry.
Relative Maximum Speed Rating
Hi: 750mph
Lo: 375mph
    This entry's maximum listed speed (600mph).

    Graph average of 562.5 miles-per-hour.
City-to-City Ranges
NYC
 
  LON
LON
 
  PAR
PAR
 
  BER
BER
 
  MOS
MOS
 
  TOK
TOK
 
  SYD
SYD
 
  LAX
LAX
 
  NYC
Graph showcases the Boeing B-47E-IV Stratojet's operational range (on internal fuel) when compared to distances between major cities.
Aviation Era
Pie graph section
Pie graph section
Pie graph section
Pie graph section
Pie graph section
Useful in showcasing the era cross-over of particular aircraft/aerospace designs.
Unit Production Comparison
Comm. Market HI*: 44,000 units
Military Market HI**: 36,183 units
2039
2039


  * Commercial Market High belongs to Cessna 172.

  ** Military Market High belongs to Ilyushin Il-2.


Altitude Visualization
Small airplane graphic
  Compare this entry against other aircraft using our Comparison Tool  
National Flag Graphic
Origin: United States
Year: 1951
Type: Strategic Medium / Heavy Bomber Aircraft
Manufacturer(s): Boeing Company - USA
Production: 2,039
Status: Retired, Out-of-Service
Global Operators:
Canada; United States
Historical Commitments / Honors:

Military lapel ribbon for Operation Allied Force
Military lapel ribbon for the Arab-Israeli War
Military lapel ribbon for the Battle of Britain
Military lapel ribbon for the Battle of Midway
Military lapel ribbon for the Berlin Airlift
Military lapel ribbon for the Chaco War
Military lapel ribbon for the Cold War
Military lapel ribbon for the Cuban Missile Crisis
Military lapel ribbon for the Falklands War
Military lapel ribbon for the French-Indochina War
Military lapel ribbon for the Golden Age of Flight
Military lapel ribbon for the 1991 Gulf War
Military lapel ribbon for the Indo-Pak Wars
Military lapel ribbon for the Iran-Iraq War
Military lapel ribbon for the Korean War
Military lapel ribbon for the 1982 Lebanon War
Military lapel ribbon for the Malayan Emergency
Military lapel ribbon for the attack on Pearl Harbor
Military lapel ribbon for the Six Day War
Military lapel ribbon for the Soviet-Afghan War
Military lapel ribbon for the Spanish Civil War
Military lapel ribbon for the Suez Crisis
Military lapel ribbon for the Vietnam War
Military lapel ribbon for Warsaw Pact of the Cold War-era
Military lapel ribbon for the WASP (WW2)
Military lapel ribbon for the World War 1
Military lapel ribbon for the World War 2
Military lapel ribbon for the Yom Kippur
* Ribbons not necessarily indicative of actual historical campaign ribbons. Ribbons are clickable to their respective campaigns/operations.
Measurements and Weights icon
Structural - Crew, Dimensions, and Weights:
Unless otherwise noted the presented statistics below pertain to the Boeing B-47E-IV Stratojet model. Common measurements, and their respective conversions, are shown when possible.

Operational
CREW


Personnel
3


Dimension
LENGTH


Feet
108.01 ft


Meters
32.92 m


Dimension
WIDTH


Feet
116.14 ft


Meters
35.4 m


Dimension
HEIGHT


Feet
28.02 ft


Meters
8.54 m


Weight
EMPTY


Pounds
79,073 lb


Kilograms
35,867 kg


Weight
LOADED


Pounds
229,999 lb


Kilograms
104,326 kg

Engine icon
Installed Power - Standard Day Performance:
6 x General Electric J47-GE-25 turbojet engines generating 7,200 lb of thrust each; 1 x 36,000lb rocket system for JATO launch.

Performance
SPEED


Miles-per-Hour
600 mph


Kilometers-per-Hour
965 kph


Knots
521 kts


Performance
RANGE


Miles
3,870 mi


Kilometers
6,228 km


Nautical Miles
3,363 nm


Performance
CEILING


Feet
40,499 ft


Meters
12,344 m


Miles
7.67 mi


Performance
CLIMB RATE


Feet-per-Minute
4,350 ft/min


Meters-per-Minute
1,326 m/min

Supported Weapon Systems:

Graphical image of an aircraft medium machine gun
Graphical image of an aircraft heavy machine gun
Graphical image of an aircrat automatic cannon
Graphical image of an air launched nuclear weapon
Graphical image of an aircraft conventional drop bomb munition
Armament - Hardpoints (0):

STANDARD (B-47B):
2 x 12.5mm heavy machine guns in rear remote-controlled powered turret.

STANDARD (B-47E):
2 x 20mm cannons in rear remote-controlled powered turret.

OPTIONAL:
Up to 25,000lbs of internal ordnance to include both nuclear and conventional drop bombs.
Variants: Series Model Variants
• Model 424 - Initial Model Designation
• Model 432 - Secondary Model Designation accepted and allowed for further development contracts.
• Model 448 - Swept Flying Wing surfaces from captured German research.
• Model 450 - Six engines moved from fuselage positions to underwing nacelles.
• XB-47 - Prototype Model Designation fitted with 6 x Allison J35-2 turbojet engines of which two ordered/produced.
• B-47 - Production Series Designation
• B-47A - Developmental Models of which 10 were produced.
• B-47B - First Operational Service Variant of which 399 were produced.
• B-47E - Fitted with uprated engines, inflight refueling capabilities, ejection seats and updated operational systems; 1,591 produced of this type.
• B-47B-II - Same as the B-47B models except for overall re-strengthening of the structure.
• B-47E-II - Same as the B-47E models except for overall re-strengthening of the structure.
• RB-47B - Reconnaissance Variant