The next production version was the B-50B (Model 345-2). It was externally identical to the B-50A, with all the differences being internal. The aircraft had an increase in the gross weight from 168,480 pounds to 170,400 pounds and was equipped with a strengthened wing containing a new type of lightweight fuel cell.
The B-50B introduced a new wrinkle into the production block number system. Instead of starting the block numbers over at -1 for the new series, the B-50B block numbers simply continued on from where the B-50A blocks had ended. Consequently, the first B-50B was B-50B-40 and continued on to -60. Subsequent B-50s continued this practice.
The first B-50B (47-118) took off on its maiden flight on January 14, 1949. The first example (47-118) was retained at the factory for test work under the designation EB-50B, and was at one time fitted with a track-tread undercarriage in place of the conventional wheels. This was designed to reduce the overall pressure exerted on the ground by spreading the aircraft weight over a larger ground contact area. However, the caterpillar type tracked landing gear proved to be inefficient and difficult to maintain and was never used on any production aircraft. The EB-50B was later converted back to a conventional landing gear system and used for other test projects.
All of the other B-50Bs were sent to Wichita for conversion to the reconnaissance role under the designation RB-50B. The RB-50B featured four camera stations (supporting a total of 9 cameras), weather reconnaissance instruments, and extra crew members housed inside a capsule that was installed in the aircraft's rear bomb bay. The RB-50B was capable of being refuelled by the British-developed hose refuelling system, and could carry a 700-gallon auxiliary fuel tank under each wing.
In 1951, the RB-50Bs were again modified. There were three different configurations produced, which were later redesignated RB-50E, RB-50F, and RG-50G respectively.
There were 14 RB-50E conversions carried out. The RB-50E was earmarked for photographic reconnaissance and observation missions. The crew was normally ten. According to the type of mission being flown, the left-side gunner could serve as a weather observer or as an inflight refuelling operator. The defensive armament consisted of 13 0.50-inch machine guns, housed in five electrically-operated turrets.
The RB-50F resembled the RB-50E but carried the SHORAN radar navigation system designed to conduct mapping, charting, and geodetic surveys. However, the SHORAN system interfered with the RB-50F's defensive armament, so the SHORAN radar and its associated equipment were housed in removable kits. The first RB-50F aircraft entered service with SAC in January of 1951. A total of 14 RB-50F conversions were carried out.
Electronic reconnaissance was the primary mission of the RB-50G. It entered SAC service between June and October 1951. A total of 15 RB-50B-->RB-50G conversions were made. The RB-50G differed significantly from the RB-50E and F, so much so in fact that it was assigned a different manufacturer's number of Model 345-30-025. The RB-50G featured six electronic countermeasures stations, which required a number of internal structural changes. Some external modification had to be made to accommodate the radomes and antennae of the aircraft's new radar equipment. During the reconfiguration process, the 16-crew RB-50G was fitted with the improved nose of the B-50D, which had a large molded plastic cone and an optically-flat bomb-aiming window in the lower portion instead of the seven-piece B-29 unit that was used throughout the B-50B series. In contrast to the RB-50F, the RG-50G could use its defensive armament while operating its new electronic equipment.
Leaks from the new light-weight fuel cells were an unexpected problem.
Very early in the production run of the B-50B, these leaky cells had
to be replaced by a new type of fuel cell. Pending the availability
of new cells, deliveries of new B-50Ds were actually stopped. The new
aircraft experienced fuel tank overflows, leaks in fuel check valves,
failures of the engine turbosuperchargers, warped turbos and warped
turbo bucket wheels. The B/RB-50Bs shared the B-50A's trailing wing
cracking problem. The permanent solution to this problem was to use
heavier metal in the fabrication of future wing flaps, but was not
quick to be implemented.
Serials of Boeing B-50B Superfortress:
47-118/127 Boeing B-50B-40-BO Superfortress
c/n 15802/15811
118 retained by the factory for test work under
designation EB-50B.
All later modified to RB-50B configuration.
119,120,122/127 modified as RB-50E for special
photographic missions.
121 modified as RB-50F with navigational radar.
47-128/137 Boeing B-50B-45-BO Superfortress
c/n 15812/15821
All later modified to RB-50B configuration.
128/132, 135 modified as RB-50E for special
photographic missions.
134, 137 modified as RB-50F with navigational
radar.
133, 136 modified as RB-50G with additional
radar and B-50D type nose.
47-138/147 Boeing B-50B-50-BO Superfortress
c/n 15822/15831
All later modified to RB-50B configuration.
138/142, 144, 146 modified as RB-50F with
navigational radar.
143, 145, 147 modified as RB-50G with additional
radar and B-50D type nose.
47-148/157 Boeing B-50B-55-BO Superfortress
c/n 15832/15841
All later modified to RB-50B configuration.
148/154, 156,157 modified as RB-50G with
additional radar and B-50D type nose.
47-158/162 Boeing B-50B-60-BO Superfortress
c/n 15842/15846
All later modified to RB-50B configuration.
158/160, 162 modified as RB-50F with
navigational radar.
161 modified as RB-50G with additional
radar and B-50D type nose.
Sources:
-
American Combat Planes, Third Enlarged Edition, Ray Wagner, Doubleday,
1982.
-
Post World War II Bombers, Marcelle Size Knaack, Office of Air Force
History, 1988.
-
Boeing Aircraft Since 1916, Peter M. Bowers, Naval Institute Press,
1989.
-
United States Military Aircraft Since 1909, Gordon Swanborough and
Peter M. Bowers, Smithsonian, 1989.
- USAF museum website, http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2620
