Boeing B-50 Superfortress

{{Short description|Piston-engined strategic bomber aircraft family, 1947}}  {{Infobox aircraft |name = B-50 Superfortress |image = Boeing B-50D-95-BO 050421-F-1234P-006 (cropped).jpg |caption = A Boeing B-50D in flight |type = Strategic bomber |national_origin= United States |manufacturer = Boeing |designer = |first_flight = 25 June 1947 |introduction = 1948 |retired = 1965 |status = |primary_user = United States Air Force |more_users = |produced = 1947–1953 |number_built = 370 |developed_from = Boeing B-29 Superfortress |variants = Boeing B-54 |developed_into = Boeing C-97 Stratofreighter }}

The '''Boeing B-50 Superfortress''' is a retired American strategic bomber. A post–World War II revision of the Boeing B-29 Superfortress, it was fitted with more powerful Pratt & Whitney R-4360 radial engines, stronger structure, a taller tail fin, and other improvements. It was the last piston-engined bomber built by Boeing for the United States Air Force, and was refined into Boeing's final such design, the prototype B-54. Although not as well known as its direct predecessor, the B-50 was in USAF service for nearly 20 years.

After their primary service with Strategic Air Command (SAC) ended, B-50s were modified to serve as KB-50 aerial tankers for Tactical Air Command (TAC) and WB-50 weather reconnaissance aircraft for the Air Weather Service. These tanker and hurricane-hunter variants were retired in March 1965 after metal fatigue and corrosion were found in the wreckage of a KB-50J, ''48-065'', that crashed on 14 October 1964.<ref>[http://cgibin.rcn.com/jeremy.k/cgi-bin/gzUsafSearch.pl?target=&content=B-50 "Serial Number Search, B-50 48-065"]. US Military Aircraft Serial Number Search. Retrieved 8 August 2010.</ref>

==Design and development== [[File:Boeing-Pratt & Whitney XB-44 061020-F-1234S-012.jpg|thumb|The sole XB-44 Superfortress was a B-29 Superfortress converted to test the possibility of using the R-4360 radial engine.]]

Development of an improved B-29 started in 1944, with the desire to replace the unreliable Wright R-3350 Duplex-Cyclone engines with the more powerful four-row, 28-cylinder Pratt & Whitney R-4360 Wasp Major radial engines, America's largest-ever displacement aircraft piston engine in large-scale production.<ref name="Knaack p163">Knaack 1988, p. 163.</ref> A B-29A-5-BN (serial number ''42-93845'') was modified by Pratt & Whitney as a testbed for the installation of the R-4360 in the B-29, with four {{convert|3000|hp|kW|lk=on|adj=on}} R-4360-33s replacing the {{convert|2200|hp|kW|adj=on}} R-3350s. The modified aircraft, designated ''XB-44 Superfortress'', first flew in May 1945.<ref name=Bowers>{{cite book|last1=Bowers|first1=Peter M.|title=Boeing aircraft since 1916|date=1989|publisher=Putnam|location=London|isbn=0851778046|pages=345–352|edition=3rd}}</ref><ref name="B-44 fact">[https://archive.today/20120805120459/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2656 "Boeing/Pratt & Whitney XB-44 factsheet"]. ''National Museum of the United States Air Force''. Retrieved: 27 June 2010.</ref>

The planned Wasp-Major powered bomber, the B-29D, was to incorporate considerable changes in addition to the engine installation tested in the XB-44. The use of a new alloy of aluminum, 75-S rather than the existing 24ST, gave a wing that was both stronger and lighter, while the undercarriage was strengthened to allow the aircraft to operate at weights of up to {{convert|40000|lb|kg|}} greater than the B-29. A larger vertical fin and rudder (which could fold to allow the aircraft to fit into existing hangars) and enlarged flaps were provided to deal with the increased engine power and weight, respectively.<ref name=Bowers/><ref name="Peacock AI p204">Peacock 1990, p. 204.</ref>{{#tag:ref|The new tail had also been tested on a B-29 testbed, s/n 42-24528, although unlike the XB-44, it was not given a separate designation.<ref name=Bowers/>|group=nb}}

Armament was similar to that of the B-29, with two bomb bays carrying {{convert|20000|lb|kg|}} of bombs, and a further {{convert|8000|lb|kg|}} externally. Defensive armament was 13 × 12.7 mm (.50 BMG) machine guns (or 12 machine guns and one {{cvt|20|mm|in|1}} cannon) in five turrets.<ref name=Bowers/><ref name="Peacock AI p204"/>

First flying in May 1945, the sole XB-44 proved {{convert|50|-|60|mph|km/h|abbr=on|-1}} faster than the standard B-29, although existing sources do not indicate how much of this increased speed was due to differing aircraft weight due to deleted armament or increased power due to the R-4360-33 engines.<ref>[https://archive.today/20120805120459/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2656 "XB-44 Superfortress Factsheet"]. . National Museum of the United States Air Force. Retrieved: 28 December 2012.</ref>

An order for 200 B-29Ds was placed in July 1945, but the ending of World War II in August 1945 prompted mass cancellations of outstanding orders for military equipment, with over 5,000 B-29s canceled in September 1945.<ref name=Bowers/> In December that year, B-29D orders were cut from 200 to 60, while at the same time the designation of the aircraft was changed to ''B-50''.<ref name="Knaack p163"/>

Officially, the aircraft's new designation was justified by the changes incorporated into the revised aircraft, but according to Peter M. Bowers, a long-time Boeing employee and aircraft designer and a well-known authority on Boeing aircraft, "the re-designation was an outright military ruse to win appropriations for the procurement of an airplane that by its B-29D designation appeared to be merely a later version of an existing model that was being canceled wholesale, with many existing examples being put into dead storage."<ref name=Bowers/>

The first production B-50A (there were no prototypes, as the aircraft's engines and new tail had already been tested) made its maiden flight on 25 June 1947. 78 more B-50As followed.<ref name=Bowers/> The last airframe of the initial order was held back for modification to the prototype YB-50C, a planned version to be powered by R-4360-43 turbo-compound engines. It was to have a longer fuselage, allowing the two small bomb bays of the B-29 and the B-50A to be replaced by a single large bomb bay, more suited to carrying large nuclear weapons. It would also have longer wings, which required additional outrigger wheels to stabilize the aircraft on the ground.<ref name="Knaack p181-2">Knaack 1988, pp. 181–182.</ref><ref name="Willis p162-3">Willis 2007, pp. 162–163.</ref>

Orders for 43 B-54s, the planned production version of the YB-50C, were placed in 1948, but Curtis LeMay, commander of Strategic Air Command (SAC), deemed it inferior to the Convair B-36 Peacemaker and having little capacity for further improvement, while requiring an expensive redevelopment of air bases owing to the type's undercarriage. The B-54 program was therefore canceled in April 1949, with work on the YB-50C being stopped before it was completed.<ref name="Knaack p181-2"/><ref name="Willis p162-3"/>

While the B-54 was canceled, production of less elaborate developments continued as a stopgap until jet bombers such as the Boeing B-47 and B-52 could enter service. Forty-five B-50Bs, fitted with lightweight fuel tanks and capable of operating at higher weights, were built, followed by 222 B-50Ds, capable of carrying underwing fuel tanks and distinguished by a one-piece plastic nose dome.<ref name="Willis p162">Willis 2007, p. 162.</ref><ref name="Peacock AI p205-6">Peacock 1990, pp. 205–206.</ref>

To give the Superfortress the range to reach the Soviet Union, B-50s were fitted to be refueled in flight. Most of the B-50As were fitted with the early "looped hose" refueling system, developed by the British company Flight Refuelling Limited, in which the receiving aircraft would use a grapple to catch a line trailed by the tanker aircraft (normally a Boeing KB-29) before hauling over the fuel line to allow transfer of fuel to begin. To replace this clumsy system, Boeing designed the "flying boom" method to refuel SAC's bombers, with most B-50Ds being fitted with receptacles for flying boom refueling.<ref name="Peacock AI p205-6"/><ref name="Willis p156-8">Willis 2007, pp. 156–158.</ref><ref name="Knaack p186-7">Knaack 1988, pp. 186–187.</ref>

Revisions to the B-50 (from its predecessor B-29) increased top speed to just under {{convert|400|mph|km/h}}. Changes included: * More powerful engines * Redesigned engine nacelles and engine mounts * Enlarged vertical tail and rudder (to maintain adequate yaw control during engine-out conditions) * Reinforced wing structure (required due to increased engine mass, larger gyroscopic forces from larger propellers, greater fuel load, and revised landing gear loading) * Revised routing for engine gases (cooling, intake, exhaust and intercooler ducts; also oil lines) * Upgraded remote turret fire-control equipment * Landing gear strengthened and takeoff weight increased from {{convert|133500|to|173000|lb|kg}} * Increased fuel capacity with underwing fuel tanks being added.<ref>[https://books.google.com/books?id=r9gDAAAAMBAJ&pg=PA91 "On Permanent Alert"]. ''Popular Mechanics'', November 1950, pp. 91–94, see bottom page 92.</ref> * Improvements to flight control systems (the B-29 was difficult to fly; with increased weights the B-50 would have been more so). * Nose wheel steering rather than a castering nose wheel as on the B-29

The C-97 military transport was, in its 1944 prototype, essentially a large upper fuselage tube attached to a B-29 lower fuselage and wings, with an inverted figure-eight cross-section. In its production version it incorporated the key elements of the B-50 platform including, after the first 10 in production, the enlarged tailfin of the B-50. The B-29 and B-50 were phased out with introduction of the jet-powered Boeing B-47 Stratojet. The B-50 was nicknamed "Andy Gump", because the redesigned engine nacelles reminded aircrew of the chinless newspaper comic character popular at the time.

==Operational history== thumb|B-50D-90-BO (''48-086'') with R-4360 engine differences visible thumb|Boeing B-50D of 43d Bombardment Wing 15th Air Force while on detachment to England in May 1953 thumb|Boeing KB-50J (''48-0088'') in flight [[File:KB-50J refueling VMA-214 FJ-4B.jpg|thumb|KB-50J refueling a North American FJ-4B Fury from VMA-214.]] [[File:Boeing WB-50D 90302 53 WRS BWD 18.05.57 edited-2.jpg|thumb|Boeing WB-50D of the 53d Weather Reconnaissance Squadron based at RAF Burtonwood, England]] [[File:WB-50D.JPG|thumb|WB-50D used for weather reconnaissance on display at the National Museum of the United States Air Force]] [[File:Bell X-1-3 being mated with the motherplane.jpg|thumb|B-50 being used in the Bell X-1 test program.]]

Boeing built 370 of the various B-50 models and variants between 1947 and 1953, the tanker and weather reconnaissance versions remaining in service until 1965.

The first B-50As were delivered in June 1948 to the Strategic Air Command's 43d Bombardment Wing, based at Davis–Monthan Air Force Base, Arizona. The 2d Bombardment Wing at Chatham Air Force Base, Georgia also received B-50As; the 93d Bombardment Wing at Castle Air Force Base, California and the 509th Bombardment Wing at Walker Air Force Base, New Mexico received B-50Ds in 1949. The fifth and last SAC wing to receive B-50Ds was the 97th Bombardment Wing at Biggs Air Force Base, Texas in December 1950.

The mission of these wings was to be able to deliver atomic bombs on enemy targets.<ref name="Ravenstein, Charles A 1977">Ravenstein, Charles A. ''Air Force Combat Wings Lineage and Honors Histories, 1947–1977''. Maxwell AFB, Alabama: Office of Air Force History, 1984. {{ISBN|0-912799-12-9}}.</ref>

B-50s from the 4925th Special Weapons Group of Kirtland Air Force Base in Albuquerque, New Mexico dropped atomic bombs in a series of tests in Frenchman Flat, Nevada from 1951 to 1953.<ref>"Nevada Test Site Guide, National Nuclear Security Administration, DOE-NV 715 Rev1, 2005"</ref>

The 301st Bombardment Wing at MacDill Air Force Base, Florida received some B-50As reassigned from Davis–Monthan in early 1951, but used them for non-operational training pending the delivery of B-47A Stratojets in June 1951. The B-50 was built as an interim strategic bomber to be replaced by the B-47 Stratojet, but delays to the Stratojet forced the B-50 to soldier on until well into the 1950s.<ref name="Ravenstein, Charles A 1977"/>

A strategic reconnaissance version of the B-50B, the RB-50 was developed in 1949 to replace the aging RB-29s used by SAC in its intelligence-gathering operations against the Soviet Union. Three different configurations were produced, which were later redesignated RB-50E, RB-50F, and RB-50G. The RB-50E was earmarked for photographic reconnaissance and observation missions; The RB-50F resembled the RB-50E but carried the SHORAN radar navigation system designed to conduct mapping, charting, and geodetic surveys, and the mission of the RB-50G was electronic reconnaissance. These aircraft were operated primarily by the 55th Strategic Reconnaissance Wing. RB-50Es were also operated by the 91st Strategic Reconnaissance Wing as a replacement for RB-29 photographic reconnaissance aircraft flown over North Korea during the Korean War.<ref>Baugher, Joe. [http://www.joebaugher.com/usaf_bombers/b50_2.html "Boeing B-50B Superfortress"]. ''USAF Bombers: Boeing B-50 Superfortress,'' 17 June 2000. Retrieved: 8 August 2010.</ref>

The vast northern borders of the Soviet Union were wide open in many places during the early Cold War years, with little defensive radar coverage and limited detection capability. RB-50 aircraft of the 55th SRW flew many sorties along the periphery and, where necessary, into the interior. Initially, there was little opposition from the Soviet forces as radar coverage was limited and, if the overflying aircraft were detected, the World War II-era Soviet fighters could not intercept the RB-50s at their high altitude.<ref name="spyflight.co.uk">[http://www.spyflight.co.uk/main.htm "Boeing F-13A / RB-29A / RB-50"]. {{Webarchive|url=https://web.archive.org/web/20180930030518/http://www.spyflight.co.uk/main.htm |date=2018-09-30 }} ''Spyflight.com''. Retrieved: 8 August 2010.</ref>

The deployment of the MiG-15 interceptor in the early 1950s made these flights exceedingly hazardous, with several being shot down by Soviet air defenses and the wreckage being examined by intelligence personnel. RB-50 missions over Soviet territory ended by 1954, replaced by the RB-47 Stratojet intelligence aircraft that could fly higher at near-supersonic speed.<ref name="spyflight.co.uk"/>{{Failed verification|date=November 2021|reason=I don't see any mentions of a shootdown here.}}

The B-47 Stratojet was manufactured in large numbers beginning in 1953 and eventually replaced the B-50Ds in SAC service; the last being retired in 1955. With its retirement from the nuclear-bomber mission, many B-50 airframes were converted to aerial refueling tankers.

The B-50, with more powerful engines than the KB-29s in use by Tactical Air Command (TAC), was much more suitable to refuel tactical jet fighter aircraft, such as the F-100 Super Sabre. As tankers, KB-50s had extensively reinforced outer wing panels, the necessary equipment to air-refuel simultaneously three fighter-type aircraft by the probe and drogue method, and removed defensive armament.

The first KB-50 flew in December 1955 and was accepted by the Air Force in January 1956. The tankers steadily entered the operational inventory of TAC supplanting TAC's KB-29s. By the end of 1957, all of the command's aerial refueling squadrons had their full complement of KB-50s. KB-50s, and later KB-50Js with two General Electric J47 jet engines were used by TAC, and also by USAFE and PACAF overseas as aerial tankers. Some were deployed to Thailand and flew refueling missions over Indochina in the early years of the Vietnam War until being retired in March 1965 due to metal fatigue and corrosion.<ref>[http://www.tactankers.com Tac Tankers.Com]</ref><ref>Baugher, Joe. [http://www.joebaugher.com/usaf_bombers/b50_12.html "Boeing KB-50 Superfortress"]. ''USAF Bombers: Boeing B-50 Superfortress,'' 17 June 2000. Retrieved: 8 August 2010.</ref>

In addition to the aerial tanker conversion, the Air Weather Service by 1955 had worn out the WB-29s used for hurricane hunting and other weather reconnaissance missions. Thirty-six former SAC B-50Ds were stripped of their armament and equipped for long-range weather reconnaissance missions. The WB-50 could fly higher, faster and longer than the WB-29. However, between 1956 and 1960 it experienced 13 major operational accidents, six of them involving the loss of the entire crew, and 66 crew-member fatalities.<ref name="Hurricane Hunters Association">{{Cite web |url=https://www.hurricanehunters.com/history/ |title=Hurricane Hunters Association |access-date=2022-05-23 |archive-date=2022-05-23 |archive-url=https://web.archive.org/web/20220523152016/https://www.hurricanehunters.com/history/ |url-status=dead }}</ref><ref name="Boeing WB-50D Superfortress">Baugher, Joe. [http://www.joebaugher.com/usaf_bombers/b50_7.html "Boeing WB-50D Superfortress"]. ''USAF Bombers: Boeing B-50 Superfortress,'' 17 June 2000. Retrieved: 8 August 2010.</ref>

After the weather reconnaissance fleet was grounded in May 1960 because of fuel leaks, plans were set in motion in 1962 to modify B-47 Stratojets being phased out of SAC to replace it in the role. The WB-50 had an important role during the Cuban Missile Crisis, when it monitored the weather around Cuba to plan photo-reconnaissance flights. The WB-50 was retired in 1965 due to metal fatigue and corrosion.<ref name="Hurricane Hunters Association"/><ref name="Boeing WB-50D Superfortress"/>

==Variants== ;XB-44 :One B-29A was handed over to Pratt & Whitney to be used as a testbed for the installation of the new Wasp Major 28-cylinder engines in the B-29.<ref name="B-44 fact"/> ;B-29D :Wasp Major powered bomber, with stronger structure and taller tail. Redesignated B-50A in December 1945.<ref name="Knaack p163"/> ;B-50A :First production version of the B-50. Four R-4360-35 Wasp Major engines, {{convert|168500|lb|kg}} max take-off weight. A total of 79 were built.<ref name="B50A fact">[https://archive.today/20121212231517/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2606 "Boeing B-50A Factsheet"]. . National Museum of the United States Air Force. Retrieved: 28 June 2010.</ref> :'''TB-50A''' – Conversion of 11 B-50As as crew trainers for units operating the B-36.<ref name="Peacock AI p205">Peacock 1990, p. 205.</ref> ;B-50B :Improved version, with increased maximum take-off weight {{convert|170400|lb|kg}} and new, lightweight fuel tanks. 45 built.<ref name="B50B fact">[https://web.archive.org/web/20120705115509/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2607 "B50B Factsheet"]. . National Museum of the United States Air Force. Retrieved: 28 June 2010.</ref> thumb|EB-50B with track-tread undercarriage :'''EB-50B''' – Single B-50B modified as test-bed for bicycle undercarriage, later used to test "caterpillar track" landing gear.<ref name="Peacock AI p205"/><ref>"Favonius." [http://www.flightglobal.com/pdfarchive/view/1949/1949%20-%201260.html "American Notebook: Some Caterpillars Fly"]. ''Flight'', 7 July 1949, p. 24.</ref> :'''RB-50B''' – Conversion of B-50B for strategic reconnaissance, with capsule in rear fuselage carrying nine cameras in four stations, weather instruments, and extra crew. Could be fitted with two {{convert|700|usgal|L|-1|adj=on|lk=in}} drop tanks under outer wings. 44 converted from B-50B.<ref name="RB-50B fact">[https://archive.today/20121212202657/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2642 "RB-50B Factsheet"]. . National Museum of the United States Air Force. Retrieved: 28 June 2010.</ref><ref name="Knaack p177">Knaack 1988, p. 177.</ref> ;YB-50C :Prototype for B-54 bomber, to have Variable Discharge Turbine version of the R-4360 engine, longer fuselage and bigger, stronger wings. One prototype started but canceled before completion.<ref name="Knaack p181-2"/><ref name="YB-50C Factsheet">[https://web.archive.org/web/20090806074352/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2671 "YB-50C Fact sheet"]. . National Museum of the United States Air Force. Retrieved: 28 June 2010.</ref> ;B-50D :Definitive bomber version of the B-50. Higher max takeoff weight ({{cvt|173000|lb|kg|disp=or}}). Fitted with receptacle for flying boom in-flight refueling and provision for underwing drop tanks. Modified nose glazing with 7-piece nose cone window was replaced by a single plastic cone and a flat bomb-aimer's window. A total of 222 were built.<ref name=Bowers/><ref name="B-50D Factsheet">[http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2608 "B-50D Factsheet"] {{webarchive |url=https://web.archive.org/web/20120616103257/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2608 |date=June 16, 2012 }}. ''National Museum of the United States Air Force.'' Retrieved: 28 June 2010.</ref> :'''DB-50D''' – Single B-50D converted as drone director conversion of a B-50D, for trials with the GAM-63 RASCAL missile.<ref name=Bowers/><ref name="DB-50D Factsheet">[https://web.archive.org/web/20120616101521/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2618 "DB-50D Factsheet"]. . National Museum of the United States Air Force. Retrieved: 30 June 2010.</ref> :'''KB-50D''' – Prototype conversion of two B-50Ds as three-point aerial refueling tanker, using drogue-type hoses. Used as the basis for later production KB-50J and KB-50K conversions.<ref name="KB-50D Factsheet">[https://web.archive.org/web/20090806062116/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2631 "KB-50D Factsheet"]. . National Museum of the United States Air Force. Retrieved: 30 June 2010.</ref><ref name="Peacock AI p206">Peacock 1990, p. 206.</ref> A further conversion from a TB-50D was also designated KB-50D. :'''TB-50D''' – Conversion of early B-50Ds lacking aerial-refueling receptacles as unarmed crew trainers. Eleven were converted.<ref name="Peacock AI p206"/><ref name="TB-50D Factsheet">[https://web.archive.org/web/20110817072748/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2648 "TB-50D Factsheet"]. . National Museum of the United States Air Force. Retrieved: 30 June 2010.</ref> :'''WB-50D''' – Conversion of surplus B-50Ds as weather reconnaissance aircraft to replace worn out WB-29s. Fitted with doppler radar, atmospheric sampler and other specialist equipment, and extra fuel in the bomb bay. Some were used to carry out highly classified missions for atmospheric sampling from 1953 to 1955 to detect Soviet detonation of atomic weapons.<ref name="WB-50 preserve">[https://web.archive.org/web/20071115211506/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=369 "Boeing WB-50D Superfortress"]. . National Museum of the United States Air Force. Retrieved: 30 June 2010.</ref><ref name="Peacock AI p207">Peacock 1990, p. 207.</ref><ref name="Knaack p195-6">Knaack 1988, pp. 195–196.</ref> ;RB-50E :14 RB-50Bs converted at Wichita for specialist photographic reconnaissance.<ref name="RB50E Factsheet">[https://archive.today/20121212020021/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2643 "Boeing RB-50E"]. . National Museum of the United States Air Force. Retrieved: 30 June 2010.</ref><ref name="Knaack p178-9">Knaack 1988, pp. 178–179.</ref> ;RB-50F :Conversion of 14 RB-50Bs as survey aircraft, fitted with SHORAN navigation radar.<ref name="RB-50F Factsheet">[https://archive.today/20121212025356/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2644 RB-50F Factsheet"]. . National Museum of the United States Air Force. Retrieved: 30 June 2010.</ref><ref name="Knaack p179">Knaack 1988, p. 179.</ref> ;RB-50G :Conversion of the RB-50B for electronic reconnaissance. Fitted with Shoran for navigation, and six electronic stations, with 16-man crew; 15 converted.<ref name="Peacock AI p207"/><ref name="Knaack p179"/> ;TB-50H :Unarmed crew trainer for B-47 squadrons. 24 completed, the last B-50s built. All later converted to KB-50K tankers.<ref name="Knaack p197-9">Knaack 1988, pp. 197–199.</ref> ;KB-50J :Conversions to air-to-air refueling tankers with improved performance from two extra General Electric J47 turbojets under the outer wings, 112 converted from B-50D, TB-50D, RB-50E, RB-50F and RB-50G aircraft. ;KB-50 :136 conversions to three-point hose-drogue tankers by Hayes Industries, with the auxiliary fuel tanks outboard of the engines and hose pod under the wing-tips. ;KB-50K :Tanker conversions of the TB-50H trainer aircraft. 24 converted. ;B-54A :Proposed version of the YB-50C. ;RB-54A :Proposed reconnaissance version of the YB-50C. ;WB-50 :Weather reconnaissance aircraft converted from B-50A aircraft.

==Surviving examples== [[File:Boeing WB-50D Superfortress ‘0-90351’ “Flight of the Phoenix” (29288235450).jpg|thumb|WB-50D ''Flight of the Phoenix'', on display at Castle Air Museum in Atwater, California.]]

From the 370 produced only five B-50 aircraft survive:

; B-50A AF Ser. No. 46-0010 ''Lucky Lady II'' – The first plane to fly around the world nonstop, between February 26 and March 2, 1949. Was refueled four times in air by KB-29 tanker planes of the 43rd Air Refuelling Squadron, over the Azores, Saudi Arabia, the Philippines and Hawaii. The circumnavigation took 94 hours and 1 minute, and covered {{convert|37743|km|mi|order=flip}} at an average speed of {{cvt|398|km/h|mph|order=flip}}. Lucky Lady II was disassembled after a serious accident, and its forward fuselage is stored outside at Planes of Fame Air Museum in Chino, California.<ref>[https://planesoffame.org/aircraft "B-50A Superfortress, s/n 46-010 'Lucky Lady II'"]. Planes of Fame Museum. Retrieved: 13 January 2020.</ref>

; WB-50D AF Ser. No. 49-0310 – National Museum of the United States Air Force at Wright-Patterson Air Force Base in Dayton, Ohio.<ref>[https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/198073/boeing-wb-50d-superfortress/ "WB-50D Superfortress, s/n 49-0310"]. National Museum of the United States Air Force. Retrieved: 14 December 2017.</ref>

AF Ser. No. 49-0351 ''Flight of the Phoenix'' – Castle Air Museum at the former Castle Air Force Base in Atwater, California. This was the last B-50 to be flown, being delivered to MASDC at Davis–Monthan Air Force Base, Arizona, on 6 October 1965. It was put on display at the Castle Air Museum in 1980.<ref>[https://www.castleairmuseum.org/collection "WB-50D Superfortress, s/n 49-0351"]. Castle Air Museum. Retrieved: 14 December 2017.</ref>

; KB-50J AF Ser No. 49-0372 – Pima Air & Space Museum adjacent to Davis-Monthan Air Force Base in Tucson, Arizona.<ref>[https://pimaair.org/museum-aircraft/boeing-kb-50j/ "KB-50J Superfortress, s/n 49-0372"]. Pima Air & Space Museum. Retrieved: 24 November 2021.</ref>

[[File:KB50 Dover.jpg|thumb|KB-50J 49-0389, on outdoor display at the Air Mobility Command Museum]]

AF Ser. No. 49-0389 – Air Mobility Command Museum in Dover, Delaware. Formerly an outdoor display at MacDill Memorial Park at MacDill Air Force Base in Tampa, Florida. In 2018, 49-0389 was dismantled and relocated to the Air Mobility Command Museum; as of 2023, the airframe was on outdoor display while undergoing restoration<ref>[https://amcmuseum.org/at-the-museum/aircraft/kb-50j-superfortress/ "KB-50J Superfortress Restoration Underway"]. Air Mobility Command Museum. Retrieved: 24 November 2021.</ref>

==Operators== ; United States : United States Air Force {{Col-begin}} {{Col-break|width=50%}} Strategic Air Command<ref name="Ravenstein, Charles A 1977"/> ; B-50 Superfortress : 2d Bombardment Wing, 1949–1953 : 43d Bombardment Wing, 1948–1954 : 93d Bombardment Wing, 1949–1954 : 97th Bombardment Wing, 1950–1955 : 306th Bombardment Wing, 1951 : 509th Bombardment Wing, 1949–1954

;RB-50 Superfortress : 55th Strategic Reconnaissance Wing, 1950–1954 : 91st Strategic Reconnaissance Wing, 1949–1950 (B-50); 1950–1951

Air Weather Service<ref>{{cite book|editor=Maurer, Maurer|title=Combat Squadrons of the Air Force, World War II|orig-year=1969|url= https://archive.org/details/CombatSquadronsOfTheAirForceWWII/page/n1/mode/2up |edition= reprint|year=1982|publisher=Office of Air Force History|location=Washington, DC|isbn=0-405-12194-6|oclc=72556|lccn=70605402}}</ref><ref>Tabaco, Joseph. [http://tabacofamily.com/jtabaco/AWRA/units.html "Air Force Weather Reconnaissance Organizational History"]. ({{webarchive |url=https://web.archive.org/web/20100713110952/http://tabacofamily.com/jtabaco/AWRA/units.html |date=July 13, 2010 }}) ''tabacofamily.com''. Retrieved: 23 August 2010.</ref> ;WB-50 Superfortress : 53d Weather Reconnaissance Squadron, 1955–1965 : 54th Weather Reconnaissance Squadron, 1955–1960; 1962–1965 : 55th Weather Reconnaissance Squadron, 1958–1960 (TB-50); 1960–1963 : 56th Weather Reconnaissance Squadron, 1956–1962 : 57th Weather Reconnaissance Squadron, 1956–1958 : 58th Weather Reconnaissance Squadron, 1956–1958 : 59th Weather Reconnaissance Squadron, 1955–1960 {{Col-break|width=50%}} Tactical Air Command<ref>[http://www.tactankers.com/tactanker_patch.htm "Tactical Tankers: KB-29/KB-50, 1953–1965"]. ''TAC Tankers.Com''. Retrieved: 23 August 2010.</ref> ;KB-50 Superfortress : 420th Air Refueling Squadron :: 47th Bombardment Wing, Tactical, 1955–1964 (USAFE) : 421st Air Refueling Squadron :: 49th Fighter-Bomber Group, 1955–1957 :: 67th Tactical Reconnaissance Wing, 1957–1960 :: 3d Tactical Bombardment Wing (Attached), November 1960 – June 1962 (PACAF) : 427th Air Refueling Squadron :: 4505th Air Refueling Wing, 1959–1963 : 429th Air Refueling Squadron :: 4505th Air Refueling Wing, 1958–1963 : 431st Air Refueling Squadron :: 4505th Air Refueling Wing, 1958–1963 :: 4440th Aircraft Delivery Group, 1963–1965 : 622d Air Refueling Squadron :: 4505th Air Refueling Wing, 1957–1963 {{col-end}}

==Specifications (B-50D)== frameless|right|3-view line drawing of the Boeing WB-50 Superfortress

{{Aircraft specs |ref=Encyclopedia of U.S. Air Force Aircraft and Missile Systems Volume II: Post–World War II Bombers, 1945–1973<ref name="Knaack p200-1">Knaack 1988, pp. 200–201.</ref> |prime units?=imp  |genhide= |crew= 8 to 10: Pilot, co-pilot, bombardier, navigator, flight engineer, radio/electronic countermeasures operator, two side gunners, top gunner and tail gunner |capacity= |length m= |length ft=99 |length in=0 |length note= |span m= |span ft=141 |span in=3 |span note= |upper span m= |upper span ft= |upper span in= |upper span note= |mid span m= |mid span ft= |mid span in= |mid span note= |lower span m= |lower span ft= |lower span in= |lower span note= |width m= |width ft= |width in= |width note= |height m= |height ft=32 |height in=8 |height note= |wing area sqm= |wing area sqft=1,720 |wing area note= |aspect ratio= |airfoil= |empty weight kg= |empty weight lb=84,714 |empty weight note= |gross weight kg= |gross weight lb=121,850 |gross weight note= |max takeoff weight kg= |max takeoff weight lb=173,000 |max takeoff weight note=(max overload weight) |fuel capacity= |more general=  |eng1 number=4 |eng1 name=Pratt & Whitney R-4360-35 |eng1 type=28 Cyl. four-row air-cooled radial piston engine |eng1 kw= |eng1 hp=3,500 |eng1 note= |power original= |thrust original= |eng2 number=2 |eng2 name=General Electric J47-GE-23 |eng2 type=Turbojet |eng2 kn= |eng2 lbf=5200 |eng2 note= (auxiliary engines in KB-50J tanker only) |eng2 kn-ab= |eng2 lbf-ab= |more power=  |perfhide= |max speed kmh= |max speed mph=394 |max speed kts= |max speed note=at 30,000 ft (9,150 m) |cruise speed kmh= |cruise speed mph=244 |cruise speed kts= |cruise speed note= |stall speed kmh= |stall speed mph= |stall speed kts= |stall speed note= |never exceed speed kmh= |never exceed speed mph= |never exceed speed kts= |never exceed speed note= |minimum control speed kmh= |minimum control speed mph= |minimum control speed kts= |minimum control speed note= |range km= |range miles= |range nmi= |range note= |combat range km= |combat range miles=2,394 |combat range nmi= |combat range note= |ferry range km= |ferry range miles=7,750 |ferry range nmi= |ferry range note= |endurance= |ceiling m= |ceiling ft=36,900 |ceiling note= |g limits= |roll rate= |glide ratio= |climb rate ms= |climb rate ftmin=2,200 |climb rate note= |time to altitude= |lift to drag= |wing loading kg/m2= |wing loading lb/sqft=70.19 |wing loading note= |disk loading kg/m2= |disk loading lb/sqft= |disk loading note= |power/mass={{convert|0.115|hp/lb|kW/kg|abbr=on}} |more performance=  |guns=<br/> ** 13 × .50 in (12.7 mm) M2 Browning machine guns in 4 × remote controlled turrets and 1 × manned tail turret |bombs=<br/> ** 20,000 lb (9,100 kg) internally ** 8,000 lb (3,600 kg) on external hardpoints Optional: in specially modified planes; one {{convert|43,600|lb|kg|abbr=on}} T-12 Cloud Maker, one M-110, {{convert|22,376|lb|kg|abbr=on}} Grand Slam copy, or two {{convert|12,660|lb|kg|abbr=on}} Tallboy copies and numerous nuclear weapons. |rockets= |missiles= |hardpoints= |hardpoint capacity= |hardpoint rockets= |hardpoint missiles= |hardpoint bombs= |hardpoint other= |other armament= |avionics= }}

==See also== {{aircontent  |related= * Boeing B-29 Superfortress * Boeing B-54 * Boeing 377 Stratocruiser * Boeing C-97 Stratofreighter * Tupolev Tu-4 |similar aircraft=  * Tupolev Tu-85 |lists=  * List of bomber aircraft * List of military aircraft of the United States * List of United States military aerial refueling aircraft |see also= * Aerial refueling }}

==References==

===Notes=== {{Reflist|group=nb}}

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

===Bibliography=== {{Refbegin}} * {{cite book|last1=Bowers|first1=Peter M.|title=Boeing Aircraft Since 1916|date=1989|publisher=Putnam|location=London|isbn=0851778046|pages=345–352|edition=3rd}} * Grant, R.G. and John R. Dailey. ''Flight: 100 Years of Aviation''. Harlow, Essex, UK: DK Adult, 2007. {{ISBN|978-0-7566-1902-2}}. * Jones, Lloyd S. ''U.S. Bombers, B-1 1928 to B-1 1980s''. Fallbrook, California: Aero Publishers, 1974, First edition 1962. {{ISBN|0-8168-9126-5}}. * Knaack, Marcelle Size. ''Encyclopedia of U.S. Air Force Aircraft and Missile Systems: Volume II: Post–World War II Bombers, 1945–1973''. Washington, DC: Office of Air Force History, 1988. {{ISBN|0-16-002260-6}}. * Knaack, Marcelle Size. ''Post-World War II Bombers''. Washington, D.C.: Office of Air Force History, 1988. {{ISBN|0-912799-59-5}}. * Peacock, Lindsay. "The Super Superfort". ''Air International'', Vol. 38, No 4, April 1990, pp. 204–208. Stamford, UK: Key Publishing. ISSN 0306-5634. * Swanborough, F.G. and Peter M. Bowers. ''United States Military Aircraft since 1909''. London: Putnam. First edition 1963. * Willis, David. "Warplane Classic: Boeing B-29 and B-50 Superfortress". ''International Air Power Review'', Volume 22, 2007, pp. 136–169. Westport, Connecticut: AIRtime Publishing. ISSN 1473-9917. {{ISBN|978-1-88058-893-2}}. {{Refend}}

== Further reading == * {{Cite book |last=Hays |first=Geoffrey |year=2013 |title=Boeing B-50 |url=http://www.ginterbooks.com/AIRFORCE/AFL215.htm |series=Air Force Legends No. 215 |location=Simi Valley, Calif. |publisher=Ginter Books |isbn=978-0-9846114-9-2 |oclc=821025195 |access-date=1 February 2015}}

==External links== {{Commons category}} * [http://www.joebaugher.com/usaf_bombers/b50.html Boeing B-50 Superfortress, Joe Baugher] {{Webarchive|url=https://web.archive.org/web/20101102030606/http://joebaugher.com/usaf_bombers/b50.html |date=2010-11-02 }} * [https://web.archive.org/web/20080723185246/http://www.warbird-central.com/american/bombers/B-29/B-29_serials.html B-29 & B-50 production batches and serial numbers] * [https://web.archive.org/web/20080620211007/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2656 National Museum XB-44 Superfortress Factsheet] * [https://web.archive.org/web/20110916231821/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=850 National Museum Fact Sheet for Pratt & Whitney R-4360]

{{Boeing military aircraft}} {{B-29 family}} {{Boeing model numbers}} {{Electronic warfare navbox}} {{USAF bomber aircraft}} {{Authority control}}

Boeing B-50 Category:Aircraft first flown in 1947 Boeing KB-50J Superfortress Category:Aircraft with retractable tricycle landing gear B-50 Superfortress B-50 Category:Four-engined piston aircraft Category:Four-engined tractor aircraft Category:Mid-wing aircraft Category:United States military tanker aircraft