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.

B-29D
Wasp Major powered bomber, with stronger structure and taller tail.
Redesignated B-50A in December 1945.

B-50A
First production version of the B-50.
Four R-4360-35 Wasp Major engines, 168,500 pounds (76,400 kg) max take-off weight.
A total of 79 were built.

TB-50A – Conversion of 11 B-50As as crew trainers for units operating the B-36.

B-50B
Improved version, with increased maximum take-off weight 170,400 pounds (77,300 kg) and new, lightweight fuel tanks.
45 built.

EB-50B – Single B-50B modified as test-bed for bicycle undercarriage, later used to test "caterpillar track" landing gear.

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 700-US-gallon (2,650 L) drop tanks under outer wings.
44 converted from B-50B.
YB-50C
Prototype for B-54 bomber, to have Variable Discharge Turbine (i.e. turbo-compound) version of the R-4360 engine, longer fuselage and bigger, stronger wings.
One prototype started but canceled before completion.

B-50D
Definitive bomber version of the B-50.
Higher max takeoff weight (173,000 pounds (78,000 kg)).
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.

DB-50D – Single B-50D converted as drone director conversion of a B-50D, for trials with the GAM-63 RASCAL missile.

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.
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.

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.

RB-50E
14 RB-50Bs converted at Wichita for specialist photographic reconnaissance.

RB-50F
Conversion of 14 RB-50Bs as survey aircraft, fitted with SHORAN navigation radar.

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.

TB-50H
Unarmed crew trainer for B-47 squadrons.
24 completed, the last B-50s built.
All later converted to KB-50K tankers.

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.
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.
B-29D
Wasp Major powered bomber, with stronger structure and taller tail. Redesignated B-50A in December 1945.
B-50A
First production version of the B-50. Four R-4360-35 Wasp Major engines, 168,500 pounds (76,400 kg) max take-off weight. A total of 79 were built.
TB-50A – Conversion of 11 B-50As as crew trainers for units operating the B-36.
B-50B
Improved version, with increased maximum take-off weight 170,400 pounds (77,300 kg) and new, lightweight fuel tanks. 45 built.
EB-50B – Single B-50B modified as test-bed for bicycle undercarriage, later used to test "caterpillar track" landing gear.
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 700-US-gallon (2,650 L) drop tanks under outer wings. 44 converted from B-50B.
YB-50C
Prototype for B-54 bomber, to have Variable Discharge Turbine (i.e. turbo-compound) version of the R-4360 engine, longer fuselage and bigger, stronger wings. One prototype started but canceled before completion.
B-50D
Definitive bomber version of the B-50. Higher max takeoff weight (173,000 pounds (78,000 kg)). 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.
DB-50D – Single B-50D converted as drone director conversion of a B-50D, for trials with the GAM-63 RASCAL missile.
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. 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.
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.
RB-50E
14 RB-50Bs converted at Wichita for specialist photographic reconnaissance.
RB-50F
Conversion of 14 RB-50Bs as survey aircraft, fitted with SHORAN navigation radar.
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.
TB-50H
Unarmed crew trainer for B-47 squadrons. 24 completed, the last B-50s built. All later converted to KB-50K tankers.
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.
Boeing B-50 Superfortress