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|First flight||25 June 1947|
|Primary user||United States Air Force|
|Unit cost||US $1,144,296|
|Developed from||B-29 Superfortress|
|Variants||Boeing C-97 Stratofreighter|
The Boeing B-50 Superfortress was a post-World War II revision of the wartime United States B-29 Superfortress with larger Pratt & Whitney R-4360 radial engines, a taller vertical stabilizer, and other improvements.
Design and development
The B-50 program began life as the XB-44 Superfortress. One B-29A-5-BN (s/n 42-93845) was modified by Pratt & Whitney in 1944 to accept the larger engines; the resulting engine testbed first flew in May 1945. If the engine modification had been included in the B-29 program, the resulting model was to have been known as the B-29D. However, due to other structural changes that would also be necessary to address the increased power, weight and fuel consumption, it was decided to change its military designation to a new model. Since the B-44 program was only for the engine modification, that designation was not considered, and in December 1945 the program was named B-50 Superfortress.
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 redesignation was an outright military ruse to win appropriations for the procurement of an airplane that by its 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."
Revisions to the B-50 (from its predecessor B-29) would result in a top speed just short of 400 mph (644 km/h), faster than many World War II propeller-powered fighters. Changes included:
- Larger 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 propeller, greater fuel load, and revised landing gear loading)
- Revised routing for engine gases (cooling, intake, exhaust and intercooler ducts; also oil lines)
- Upgraded fire-control equipment (to control remote turrets)
- Landing gear strengthening (takeoff weight increased from 133,500 lb/60,555 kg to 173,000 lb/78,471 kg)
- Increased fuel capacity (this was largely addressed by adding underwing fuel tanks).
- Revisions to flight control systems (the B-29 was already difficult to fly; with its increased weight the B-50 would have been much harder to hand-fly).
Redesigned with a larger upper fuselage, the B-50 design would form the basis for the Boeing 377 series of airliners and C-97/KC-97 military transports, with 816 of the KC-97 built. The B-29 and B-50s would be phased out with introduction of the jet powered 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.
Boeing built 371 of the various B-50 models and variants between 1947 and 1953, the tanker versions serving until 1965.
Although constructed in relatively small numbers, the B-50 was the last member of the B-29 family and was one of the last piston-engined bombers built. The B-50 was retired from its main role as atomic bomber in 1955. A number were converted into KB-50 tankers and lasted long enough to be deployed to Southeast Asia in support of tactical operations.
B-50s were grounded and removed completely from inventory when wreckage of a KB-50 that broke up in flight in 1965 revealed corrosion problems in the fleet.
No flying examples exist today, although several can be found in various air museums.
- XB-44: One B-29A was handed over to Pratt & Whitney to be fitted with the new Wasp Major 28-cylinder engines. Initially designated B-29D, this was eventually changed to B-50A in December 1945. (x1, converted)
- B-50A--First production version of the B-50. It had new wings that were stronger and lighter than the units on the B-29. It also had taller vertical tail than the B-29. (x60)
- B-50B--Increase in gross weight over the A model, from 168,480 lb (76,420 kg) to 170,400 lb (77,290 kg). Also included a new type of lightweight fuel cell. (x45)
- B-50D--Definitive production version of the B-50. The 7-piece nose cone window was replaced by a single plastic cone and a flat bomb-aimer's window. Many included the new boom-type refueling system. (x222)
- DB-50D--Drone director conversion of a B-50D, to be used with the GAM-63 RASCAL missile. (x1, converted)
- EB-50B--Single conversion of a B-50B to be fitted with a track-tread undercarriage. (x1, converted)
- KB-50--Air to air refueling tanker conversions of the bomber. (x134, converted)
- KB-50J--Tanker B-50s with improved performance, via two extra General Electric J47 turbojets under the outer wings. (x112, converted)
- KB-50K--Tanker conversions of the TB-50H trainer aircraft. (x24, converted)
- RB-50B--All but one of the B-50Bs were converted into the recon role. These were fitted with nine cameras in four stations, weather instruments, and a bomb bay capsule holding the extra crew members. (x44, converted)
- RB-50E--Special photographic conversions of the RB-50B, modified at Wichita. (x14, converted)
- RB-50F--Conversions of the RB-50B, fitted with SHORAN navigation radar for special missions. (x14, converted)
- RB-50G--Conversions of the RB-50B, fitted with electronics countermeasures stations along with the SHORAN radar. (x15, converted)
- TB-50A--Trainer conversion of the B-50A. (x11, converted)
- TB-50D--Trainer conversion of the B-50D. (x11, converted)
- TB-50H--Newly built trainer planes. (x24)
- WB-50 --Weather reconnaissance conversion of the B-50.
- WB-50D--Weather reconnaissance conversions of outdated B-50Ds, fitted with meteorological equipment. (x36, converted). Some of these flew highly classified missions for atmospheric sampling between 1953 and 1955 to detect Soviet detonation of atomic weapons.
- YB-50C--Version to be fitted with the Variable Discharge Turbine version of the R-4360 engine. None were built.
- B-54A--Proposed version of the YB-50C.
- RB-54A--Proposed reconnaissance version of the YB-50C.
Only five B-50 type aircraft survive today, from the 371 produced.
- B-50A AF Serial No. 46-0010. This aircraft, "Lucky Lady II", is disassembled and stored outside at The Air Museum Planes Of Fame in Chino, CA.
- WB-50D AF Serial No. 49-0310. This aircraft has been moved indoors after many years outside at the US Air Force Museum in Dayton, OH.
- WB-50D AF Serial No. 49-0351. This aircraft is displayed outdoors at Castle Air Museum in Atwater, CA.
- KB-50J AF Serial No. 49-0372. This aircraft is displayed outdoors at Pima Air & Space Museum in Tuscon, AZ.
- KB-50J AF Serial No. 49-0389. This aircraft is displayed outdoors at McDill AFB in Tampa, FL.
- Crew: 8: Pilot, co-pilot, flight engineer, radio/electronic countermeasures operator, two side gunners, top gunner and tail gunner
- Length: 99 ft 0 in (30.2 m)
- Wingspan: 141 ft 3 in (43.1 m)
- Height: 32 ft 8 in (10.0 m)
- Wing area: 1736 ft² (161.3 m²)
- Empty weight: 80,610 lb (36,560 kg)
- Loaded weight: 121,850 lb (55,270 kg)
- Max takeoff weight: 173,000 lb (78,470 kg)
- Powerplant: 4× Pratt & Whitney R-4360 radial engines, 3,500 hp (2,600 kW) each
- Maximum speed: 395 mph (343 kn, 636 km/h)
- Cruise speed: 244 mph (212 kn, 393 km/h)
- Combat radius: 2,100 NM (2,400 mi, 3,860 km)
- Ferry range: 5,000 NM (5,760 mi, 9,270 km)
- Service ceiling: 36,650 ft (11,170 m)
- Rate of climb: 2,225 ft/min (11.3 m/s)
- Wing loading: 70.19 lb/ft² (343 kg/m²)
- Power/mass: 0.115 hp/lb (193 W/kg)
- 20,000 lb (9,100 kg) internally
- 8,000 lb (3,600 kg) on external hardpoints
- 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.
|Wikimedia Commons has media related to: B-50 Superfortress|
- B-50 Design and Specifications, Global Security.org
- Boeing B-50 Superfortress Joe Baugher's Encyclopedia of American Aircraft
- B-29 & B-50 production batches and serial numbers