The Boeing B-29 Superfortress is a heavy bomber with four propeller-driven engines that was primarily utilized by the United States during World War II and the Korean War.
Its nomenclature is a reference to its predecessor, the B-17 Flying Fortress.
The Superfortress was specifically designed for strategic bombing at high altitudes, but it also proved to be highly effective in low-altitude night incendiary bombing and in the deployment of naval mines to blockade Japan.
Notably, the B-29s were responsible for dropping the atomic bombs on Hiroshima and Nagasaki, making them the only aircraft to have ever utilized nuclear weapons in combat.
Variants
XB-29
The XB-29, also known as the Boeing Model 345, was the inaugural prototype or experimental model that was officially received by the United States Army Air Corps (USAAC).
This aircraft featured several enhancements to the original design proposal, such as an increased number of larger guns and self-sealing fuel tanks.
In August of 1940, two aircraft were commissioned, followed by an additional order for a third in December of the same year.
A mock-up of the aircraft was finalized in the spring of 1941, and it successfully completed its maiden flight on September 21, 1942.
YB-29
The YB-29 aircraft, an enhanced version of the XB-29, was manufactured for the purpose of service testing, with a total of 14 units produced.
The testing phase commenced during the summer of 1943, during which numerous modifications were implemented on the aircraft.
Notably, the engines were upgraded from Wright R-3350-13s to R-3350-21s, resulting in improved performance.
Additionally, the YB-29 featured four-bladed propellers as opposed to the three-bladed propellers found on the XB-29.
Furthermore, various alternative options for the remote-controlled defensive systems were evaluated on a subset of these aircraft.
B-29
The B-29 served as the initial iteration of the Superfortress aircraft.
Due to the pressing demand for a new bomber, the production design was concurrently developed alongside service testing.
Remarkably, the inaugural B-29 was finalized a mere two months following the delivery of the first YB-29.
A total of 46 B-29s of this model, constructed by the Glenn L. Martin Company at their Omaha facility, were utilized for the atomic bomb missions, having been modified to meet Silverplate specifications.
B-29A
The B-29A underwent significant improvements, including an enhanced wing design and defensive modifications.
In response to a demonstrated vulnerability to head-on fighter attacks, the forward dorsal turrets were equipped with four machine guns, doubling their previous capacity.
Unlike previous models, the B-29A wing was constructed from three sections, simplifying the manufacturing process and increasing the airframe’s strength.
Production of the B-29A continued until May 1946, with the final aircraft completed at that time.
Although the B-29A saw extensive use during the Korean War, it was quickly phased out with the introduction of the B-47 Stratojet, a jet bomber.
Washington B Mk 1
The aforementioned nomenclature pertains to a fleet of 88 B-29A aircrafts that were procured by the Royal Air Force.
B-29B
In the B-29B aircraft, similar to the previously dedicated Silverplate versions for atomic raids, all defensive armament, except for the tail turret, was removed. Initially, the armament consisted of two .50 in AN/M2 machine guns and one 20 mm M2 cannon, which was later replaced with three .50 in AN/M2s. The removal of these guns resulted in a weight reduction, leading to an increase in the top speed from 357 mph to 364 mph (575 km/h to 586 km/h). Furthermore, this version incorporated an enhanced APQ-7 “Eagle” bombing through-overcast radar, which was installed in an airfoil-shaped radome beneath the fuselage.
B-29C
The B-29C variant was developed by upgrading the B-29A model with enhanced Wright R-3350 engines.
The Army Air Force had initially placed an order for 5,000 units, however, the request was subsequently withdrawn following the conclusion of World War II, and no units were ultimately produced.
B-29D (XB-44)
The B-29D aircraft was an enhanced iteration of the original B-29 design, boasting 28-cylinder Pratt & Whitney R-4360-35 Wasp Major engines, each with a power output of 3500 hp (2600 kW).
This represented a significant increase in power, almost 60% more than the standard Duplex-Cyclone engine.
Additionally, the B-29D featured a taller vertical stabilizer and a reinforced wing.
The XB-44 was the testbed designation for the B-29D model.
Following the conclusion of World War II, the B-29D was retrofitted with the quartet of Wasp Major engines, resulting in the B-50 variant, which served in the U.S. bomber fleet throughout the 1950s.
The Boeing KB-29 was an aircraft derived from the Boeing B-29 Superfortress, specifically designed to meet the air refueling requirements of the United States Air Force (USAF).
This modification resulted in the development and production of two primary variants, namely the KB-29M and KB-29P.
EB-29
The EB-29, denoting “exempt,” served as a carrier aircraft specifically designed to accommodate and deploy experimental aircraft through its modified bomb bay.
These conversions took place in the years subsequent to the conclusion of World War II.
RB-29J
(RB-29, FB-29J, F-13, F-13A)
The initial iterations of the B-29/B-29A aircraft, which underwent modifications for the purpose of photo reconnaissance, were designated as F-13/F-13A, with the letter “F” signifying their role in photography.
These aircraft were equipped with three K-17B, two K-22, and one K-18 cameras.
Between the years 1945 and 1948, the designation was changed to FB-29J.
Subsequently, in 1948, the F-13/FB-29s were reclassified as RB-29 and RB-29A.
Furthermore, six B-29A/F-13A aircraft were subjected to modifications, which included the installation of the Wright R-3350-CA-2 fuel injected engines.
These modified aircraft were then designated as YB-29Js, and later converted into RB-29Js.
In January 1949, RB-29s were assigned to the 91st Strategic Reconnaissance Wing and subsequently relocated to Yokota AB, Japan in December 1950.
Their purpose was to provide support during the Korean War, and they were attached to the 15th Air Force, Far East Air Force.
SB-29
The SB-29 ‘Super Dumbo’ was a post-World War II adaptation of the B-29 aircraft specifically tailored for air-sea rescue operations.
A total of sixteen B-29s underwent modifications to accommodate a droppable A-3 lifeboat beneath the fuselage.
These aircraft were subsequently redesignated as SB-29 and primarily employed as rescue support for air units engaged in extended flights over bodies of water.
TB-29
The TB-29 aircraft was specifically designed as a trainer variant of the B-29, primarily utilized for the purpose of training crew members for bombing missions.
Additionally, a subset of these aircraft was employed for target towing operations, with the designation specifically assigned to B-29s that underwent modifications exclusively for this purpose.
During the 1950s, the TB-29 aircraft played a crucial role in the development of intercept tactics for the United States Air Force’s fighter aircraft.
These aircraft were primarily utilized as radar targets, serving as invaluable tools in honing the skills and strategies required for effective interception manoeuvres.
WB-29
The WB-29 aircraft were originally manufactured for production purposes but were subsequently modified to carry out weather monitoring missions.
An observation position was installed above the central fuselage section to facilitate these operations.
These aircraft were utilized for conducting routine data-gathering flights, including those originating from the UK and extending over the Atlantic.
Additionally, they were employed to venture into the core of hurricanes or typhoons in order to collect valuable information.
Furthermore, certain WB-29s were equipped with air sampling scoops to assess radiation levels subsequent to nuclear weapons tests.
Airborne Early Warning
In 1951, three B-29 aircraft underwent significant modifications to support their integration into the Airborne Early Warning program.
The foremost section of the fuselage was extensively altered to accommodate the installation of an AN/APS-20C search radar, while the interior underwent modifications to accommodate radar and Electronic Counter Measures (ECM) equipment.
MX-767 Banshee
The Air Material Command undertook a comprehensive investigation from 1946 to 1950 to explore the feasibility of converting B-29 aircraft into long-range cruise missiles.
This endeavor, officially designated as MX-767, was assigned the codename Project Banshee.
Flight tests were conducted as part of this initiative; however, no complete conversions were executed before the project was ultimately discontinued.
Navy P2B patrol bomber
On March 14, 1947, the United States Navy procured four B-29-BWs from the United States Army Air Forces.
These aircraft underwent modifications to enable them to undertake extended range patrol missions and were subsequently designated as P2B-1S.
Other Types
XB-39
A solitary YB-29 aircraft has been meticulously altered to incorporate water-cooled Allison V-3420-17 Vee type engines.
Tupolev Tu-4
In 1945, three B-29 aircraft were compelled to make an emergency landing in Soviet territory following a bombing mission on Japan due to insufficient fuel.
In pursuit of a contemporary long-range bomber, Joseph Stalin directed the Tupolev OKB to undertake the reverse-engineering of the Superfortress.
KJ-1 AEWC
The Chinese People’s Liberation Army Air Force made an attempt to utilize the Tu-4 airframe for the KJ-1 AWACS aircraft.
B-50 Superfortress
The Boeing B-29 Superfortress underwent a post-World War II revision, which included the installation of more powerful Pratt & Whitney R-4360 radial engines, a reinforced structure, an increased height of the tail fin, and various other enhancements.
B-50 Variants
B-50A The B-50A was the initial production version of the B-50.
It was equipped with four R-4360-35 Wasp Major engines and had a maximum take-off weight of 168,500 pounds (76,400 kg).
A total of 79 B-50A aircraft were manufactured.
TB-50A Eleven B-50A aircraft were converted into crew trainers for units operating the B-36.
B-50B This improved version of the B-50 had an increased maximum take-off weight of 170,400 pounds (77,300 kg) and featured new lightweight fuel tanks.
A total of 45 B-50B aircraft were built.
EB-50B A single B-50B aircraft was modified as a testbed for a bicycle undercarriage and later used to test “caterpillar track” landing gear.
RB-50B The RB-50B was a conversion of the B-50B for strategic reconnaissance purposes.
It featured a capsule in the rear fuselage that carried nine cameras in four stations, as well as weather instruments and extra crew.
Additionally, it could be fitted with two 700-US-gallon (2,650 L) drop tanks under the outer wings.
A total of 44 RB-50B aircraft were converted from the B-50B.
YB-50C The YB-50C was a prototype for the B-54 bomber.
It was intended to have a Variable Discharge Turbine version of the R-4360 engine, a longer fuselage, and bigger, stronger wings.
However, only one prototype was started before the project was cancelled.
B-50D
The B-50D is the definitive bomber version of the B-50 aircraft.
It has a higher maximum take-off weight of 173,000 pounds (78,000 kg).
It is equipped with a receptacle for in-flight refuelling using the Flying boom system, as well as provision for underwing drop tanks.
The modified nose glazing features a single plastic cone and a flat bomb-aimer’s window, replacing the previous 7-piece nose cone window.
A total of 222 B-50D aircraft were built.
DB-50D
The DB-50D is a single B-50D aircraft that has been converted into a drone director for trials with the GAM-63 RASCAL missile.
KB-50D
The KB-50D is a prototype conversion of two B-50D aircraft into three-point aerial refuelling tankers.
These tankers use drogue-type hoses for refuelling.
The KB-50D served as the basis for later production conversions, including the KB-50J and KB-50K.
TB-50D
The TB-50D is a conversion of early B-50D aircraft that did not have aerial-refuelling receptacles.
These aircraft were converted into unarmed crew trainers.
A total of eleven TB-50D aircraft were converted.
WB-50D
The WB-50D aircraft were converted from surplus B-50Ds to serve as weather reconnaissance aircraft, replacing the worn-out WB-29s.
These aircraft were equipped with specialized equipment such as doppler radar, atmospheric samplers, and additional fuel storage in the bomb bay.
From 1953 to 1955, some of these WB-50Ds were utilized for highly classified missions involving atmospheric sampling, specifically to detect Soviet atomic weapons detonation.
RB-50E
The RB-50E aircraft were converted from 14 RB-50Bs at the Wichita facility, specifically for the purpose of conducting specialist photographic reconnaissance missions.
RB-50F
Similarly, the RB-50F aircraft were converted from 14 RB-50Bs and were equipped as survey aircraft, featuring SHORAN navigation radar.
RB-50G
The RB-50G aircraft were conversions of the RB-50B model, specifically designed for electronic reconnaissance.
These aircraft were fitted with Shoran navigation systems and six electronic stations, accommodating a 16-man crew.
A total of 15 RB-50Bs were converted for this purpose.
TB-50H
The TB-50H aircraft were unarmed crew trainers intended for B-47 squadrons.
A total of 24 TB-50Hs were completed, marking the final production of B-50s.
Subsequently, all of these aircraft were converted into KB-50K tankers.
KB-50J
The KB-50J is a series of air-to-air refuelling tankers that have been enhanced with two additional General Electric J47 turbojets mounted under the outer wings.
A total of 112 aircraft, including B-50D, TB-50D, RB-50E, RB-50F, and RB-50G models, have been converted to this configuration, resulting in improved performance.
KB-50
The KB-50 is another variant of the tanker aircraft, with 136 conversions carried out by Hayes Industries.
These conversions involve relocating the auxiliary fuel tanks to the outboard position of the engines and installing a hose pod under the wingtips.
These modifications enable the aircraft to function as a three-point hose-drogue tanker.
KB-50K
The KB-50K is a tanker conversion of the TB-50H trainer aircraft, with a total of 24 conversions completed.
B-54A
The B-54A is a proposed version of the YB-50C aircraft.
Similarly, the RB-54A is a proposed reconnaissance version of the YB-50C aircraft.
Lastly, the WB-50 is a weather reconnaissance aircraft that has been converted from B-50A models.
