The North American B-25 Mitchell

United States of America
United States of America

side viewfront viewunder view

The North American B-25 Mitchell is one of my favourites. Why? you could ask. Well, because I have been able to see it up close and personal . Although I have only partially seen it from the inside, it still has captured my interrest. It was a compact and powerfull puppy, used for tactical bombing. The Mitchell was named after the USAAC Colonel 'Billy' Mitchell, who was courtmartialled in the 1920's because of his insistence with respect to tactical and strategical bombing.
The type originates in 1938, when North American gambled that the US Army Air Corps’ circular proposal of January for a three-seat twin-engined attack bomber would soon lead to a full requirement for a medium attack bomber, and started work as a private venture on its NA-40 design that was evolved under the design leadership of R.H.Rice.
The NA-40 was based on an all-metal structure combining a semi-monocoque fuselage and cantilever stressed-skin flying surfaces, and in configuration was a monoplane with a rectangular-section fuselage with rounded corners, a high-set tail unit with endplate vertical surfaces, shoulder-set dihedraled wing that was tapered in thickness and chord and carried on its trailing edge the standard combination of outboard ailerons and inboard flaps, and tricycle landing gear whose single nose and twin main units retracted respectively into the underside of the forward fuselage and the underside of the nacelles for the two wing-mounted engines. Initially these engines were 2 × Pratt & Whitney R-1830-56C3-G Twin Wasp radials, rated at 1,100 hp (820 kW) for take-off each. Provision was made for a disposable weapons load in a lower-fuselage weapons bay, and the gun armament comprised 7 × 0.3 inch (7,62 mm) Browning machine guns installed as four fixed forward-firing weapons in the wing leading edges outboard of the engine nacelles, one trainable forward-firing weapon in the glazed nose position, one trainable rearward-firing machine gun in the dorsal position, and one trainable rearward-firing weapon in the ventral tunnel position.
The NA-40 prototype made its maiden flight in January 1939, and in that month the USAAC announced a requirement for a new attack bomber. The requirement called for design submissions to be made by July 1939, and North American decided to revise the NA-40 into the NA-40B (otherwise NA-40-2) with a powerplant of 2 × Wright GR-2600-A71 Cyclone 14 radial, rated at 1,500 hp (1118 kW) for take-off and 1,275 hp (951 kW) at 12,000 ft (3660 m) each, and driving a three-blade Hamilton Standard metal propeller of the constant-speed type. North American delivered the NA-40B for trials in March 1939, but the aeroplane was lost in an accident only two weeks later. The type ordered to satisfy the attack bomber requirement was the Douglas Model 7 that was ordered as the A-20. Nevertheless, the NA-40B had impressed the USAAC, and when the service issued a March 1939 circular proposal for a five-seat medium bomber North American was well placed to respond with its NA-62 design evolved from the NA-40B. The various submissions were evaluated from July 1939, and the USAAC then contracted with North American for ‘off the drawing board’ production of 184 B-25 aircraft of the NA-62 type that was basically the NA-40B with a wider fuselage that allowed a doubling of the weapons load to 3,600 lb (1633 kg), the wing moved down to the mid-set position that permitted the upper line of the fuselage to be straightened, the powerplant changed to 2 × R-2600-9 radial, rated at 1,700 hp (1.267,5 kW) for take-off and 1,350 hp (1.007 kW) at 13,000 ft (3.960 m) each, and supplied with fuel from an internal capacity of 759 Imp gal (912 US gal, 3.452 liters), the crew increased from three to five, and the defensive armament altered to one 0.5 inch (12,7 mm) Browning trainable rearward-firing machine gun operated by a prone gunner in the tail position, two 0.3 inch (7,62 mm) Browning trainable lateral-firing machine guns in single-gun beam positions operated by waist gunners, and one 0.3 inch (7,62 mm) Browning trainable forward-firing machine gun in any of three nose positions operated by the bombardier.
The B-25 initial production model was used a a service trials type, and deliveries amounted to 24 NA-62 aircraft that were delivered from February 1941 after a first flight in August 1940. The type revealed a lack of directional stability, and from the 10th aircraft onward was delivered with the flat outer wing panels that gave the Mitchell its final and highly distinctive gull-wing appearance.

Version list:

Further pictures:

North American B-25 Mitchell taking-off or landing. Note the Canadian markings, and the Squadron's emblem under the cockpit window
North American B-25 Mitchell taking-off or landing. Note the Canadian markings, and the Squadron's emblem under the cockpit window

North American B-25 Mitchell during the last stages of landing.
North American B-25 Mitchell during the last stages of landing.

North American B-25 Mitchell in full flight (looks like it's an original War color photo).
North American B-25 Mitchell in full flight (looks like it's an original War color photo).

 

Technical data on the North American B-25C Mitchell
Powerplant 2 × Wright R-2600-13 radial, rated at 1700 hp (1267.33 kW) each Role during war
  • (Ground) Attack Fighter
  • Medium Bomber
  • U-boat Destroyer
  • Maritime/Coastal patrol reconnaissance Bomber
  • Anti-shipping Aircraft
Length 52 ft 11 inch Height 15 ft 9 inch
Empty weight 20000 lb Operational weight 26208 lb typical,
28460 lb max
Wing Span 67 ft 7 inch Wing Aspect ratio 7.49
Wing Area 610 sq ft Service ceiling 21200 ft
Maximum speed 284 mph at 15000 ft Cruising speed 233 mph at optimum altitude
Initial climb rate Climb to 15,000 ft in 16 min 30 sec Range 1500 miles typical
Fuel capacity internal 811 Imp gal (974 US gal), plus provision for a weapons-bay mounted tank of 487 Imp gal (585 US gal) of auxiliary fuel that could be dropped Fuel capacity external -
Machine guns
  • 2 × 0.50 inch Browning trainable in a power operated dorsal Bendix turret, 400 rounds each
  • 2 × 0.50 inch Browning trainable in a power operated retractable ventral Bendix turret, 350 rounds each
  • 1 × 0.3 inch Browning trainable forward-firing in the nose, 600 rounds
Cannons -
Bomb load Up to 3,200 lb, carried in a under fuselage weapons bay rated at 3,200 lb. General disposables load consisted of:
  • 1 × 2,000 lb bomb, or
  • 2 × 1,600 lb bombs, or
  • 3 × 1,000 lb bombs, or
  • 6 × 500 lb bombs, or
  • 8 × 250 lb bombs, or
  • 12 × 100 lb bombs
Torpedoes/rockets -
Crew 5: pilot, navigaotr/radio operator, flight engineer/gunner, gunner/camera operator, gunner Naval or ground based Ground
First flight (prototype) January 1939 Operational Service 1941 - 1960's
Manufacturer North American Aviation, Inc Number produced 9.817 total, 1.619 this version
Metric system
Length 16.13 m Height 4.8 m
Empty weight 9072 kg Operational weight 11888 kg typical,
12909 kg max
Wing Span 20.6 m Wing Aspect ratio 7.49
Wing Area 56.67 m² Service ceiling 6462 m
Maximum speed 457 km/h at 4572 m Cruising speed 375 km/h at optimum altitude
Initial climb rate Climb to 4.570 m in 16 min 30 sec Range 2414 km typical
Fuel capacity internal 3.687 liters, plus provision for a weapons-bay mounted tank of 2.214 liters of auxiliary fuel that could be dropped Fuel capacity external -
Machine guns
  • 2 × 12,7 mm Browning trainable in a power operated dorsal Bendix turret, 400 rounds each
  • 2 × 12,7 mm Browning trainable in a power operated retractable ventral Bendix turret, 350 rounds each
  • 1 × 7,62 mm Browning trainable forward-firing in the nose, 600 rounds
Cannons -
Bomb load Up to 1.452 kg, carried in a under fuselage weapons bay rated at 1.452 kg. General disposables load consisted of:
  • 1 × 907 kg bomb, or
  • 2 × 726 kg bombs, or
  • 3 × 454 kg bombs, or
  • 6 × 227 kg bombs, or
  • 8 × 113 kg bombs, or
  • 12 × 45 kg bombs
Torpedoes/rockets -

Technical data on the North American B-25H Mitchell
Powerplant 2 × Wright R-2600-13 radial, rated at 1700 hp (1267.33 kW) each Role during war
  • (Ground) Attack Fighter
  • Medium Bomber
  • U-boat Destroyer
  • Maritime/Coastal patrol reconnaissance Bomber
  • Anti-shipping Aircraft
Length 51 ft 0 inch Height 15 ft 9 inch
Empty weight 19975 lb Operational weight 36047 lb max
Wing Span 67 ft 7 inch Wing Aspect ratio 7.49
Wing Area 610 sq ft Service ceiling 23800 ft
Maximum speed 275 mph at 13000 ft Cruising speed 230 mph at optimum altitude
Initial climb rate Climb to 15,000 ft in 19 min 0 sec Range 2700 miles max
Fuel capacity internal 811 Imp gal (974 US gal), plus provision for up to 591 Imp gal (710 US gal) of auxiliairy fuel in a 487 Imp gal (585 US gal) weapons-bay mounted tank that could be dropped and a 104 Imp gal (125 US gal) waist tank Fuel capacity external -
Machine guns
  • 4 × 0.50 inch Browning fixed forward-firing, two on each side of the nose
  • 2 × 0.50 inch Browning trainable in a power operated dorsal Bendix turret, 400 rounds each
  • 2 × 0.50 inch Browning trainable rearward-firing in the tail position
  • 2 × 0.50 inch Browning trainable lateral-firing, one in each of the beam positions
Cannons
  • 1 × 2.95 inch T13E1 fixed forward-firing in the port lower side of the nose.
Bomb load Up to 5,400 lb, carried in a under fuselage weapons bay rated at 3,000 lb and on four underwing hardpoints rated at 600 lb each. General disposables load consisted of:
  • free-fall bombs
Torpedoes/rockets
  • 8 × 5 inch air-to-surface rockets in stead of external bombs
  • 1 × 2,150 lb torpedo in stead of internal load
Crew 5: pilot, navigaotr/radio operator, flight engineer/gunner, gunner/camera operator, gunner Naval or ground based Ground
First flight (prototype) January 1939 Operational Service 1941 - 1960's
Manufacturer North American Aviation, Inc Number produced 9.817 total, 1.000 this version
Metric system
Length 15.54 m Height 4.8 m
Empty weight 9061 kg Operational weight 16351 kg max
Wing Span 20.6 m Wing Aspect ratio 7.49
Wing Area 56.67 m² Service ceiling 7254 m
Maximum speed 443 km/h at 3962 m Cruising speed 370 km/h at optimum altitude
Initial climb rate Climb to 4.570 m in 19 min 0 sec Range 4345 km max
Fuel capacity internal 3.687 liters, plus provision for up to 2.687 liters of auxiliairy fuel in a 2.214 liters weapons-bay mounted tank that could be dropped and a 473 liters waist tank Fuel capacity external -
Machine guns
  • 4 × 12,7 mm Browning fixed forward-firing, two on each side of the nose
  • 2 × 12,7 mm Browning trainable in a power operated dorsal Bendix turret, 400 rounds each
  • 2 × 12,7 mm Browning trainable rearward-firing in the tail position
  • 2 × 12,7 mm Browning trainable lateral-firing, one in each of the beam positions
Cannons
  • 1 × 75 mm T13E1 fixed forward-firing in the port lower side of the nose.
Bomb load Up to 2.449 kg, carried in a under fuselage weapons bay rated at 1.361 kg and on four underwing hardpoints rated at 272 kg each. General disposables load consisted of:
  • free-fall bombs
Torpedoes/rockets
  • 8 × 127 mm air-to-surface rockets in stead of external bombs
  • 1 × 975 kg torpedo in stead of internal load

Technical data on the North American B-25J Mitchell
Powerplant 2 × Wright R-2600-92 radial, rated at 1850 hp (1379.16 kW) each Role during war
  • (Ground) Attack Fighter
  • Medium Bomber
  • U-boat Destroyer
  • Maritime/Coastal patrol reconnaissance Bomber
  • Anti-shipping Aircraft
Length 52 ft 11 inch Height 15 ft 10 inch
Empty weight 21100 lb Operational weight 33500 lb typical,
41800 lb max
Wing Span 67 ft 7 inch Wing Aspect ratio 7.49
Wing Area 610 sq ft Service ceiling 24200 ft
Maximum speed 272 mph at 13000 ft Cruising speed 230 mph at optimum altitude
Initial climb rate 1,110 ft per minute Range 1275 miles typical
Fuel capacity internal 811 Imp gal (974 US gal), plus provision for up to 591 Imp gal (710 US gal) of auxiliairy fuel in a 487 Imp gal (585 US gal) weapons-bay mounted tank that could be dropped and a 104 Imp gal (125 US gal) waist tank Fuel capacity external -
Machine guns
  • 2 × 0.50 inch Browning fixed forward-firing, on the (port?) side of the nose
  • 1 × 0.50 inch Browning trainable forward-firing in the nose
  • 8 × 0.50 inch Browning fixed forward-firing, in the nose in stead of the former two gun positions (solid nose configuration)
  • 2 × 0.50 inch Browning trainable in a power operated dorsal Bendix turret, 400 rounds each
Cannons -
Bomb load Up to 2,000 lb, carried in a under fuselage weapons bay rated at 2,000 lb. General disposables load consisted of:
  • 1 × 2,000 lb bomb
Torpedoes/rockets
  • 8 × 5 inch air-to-surface rockets
  • 1 × 2,000 lb torpedo in stead of internal load
Crew 6: pilot, navigaotr/radio operator, flight engineer/gunner, gunner/camera operator, 2 gunners Naval or ground based Ground
First flight (prototype) January 1939 Operational Service 1941 - 1960's
Manufacturer North American Aviation, Inc Number produced 9.817 total, 4.318 this version
Metric system
Length 16.13 m Height 4.83 m
Empty weight 9571 kg Operational weight 15196 kg typical,
18960 kg max
Wing Span 20.6 m Wing Aspect ratio 7.49
Wing Area 56.67 m² Service ceiling 7376 m
Maximum speed 438 km/h at 3962 m Cruising speed 370 km/h at optimum altitude
Initial climb rate 338 m per minute Range 2052 km typical
Fuel capacity internal 3.687 liters, plus provision for up to 2.687 liters of auxiliairy fuel in a 2.214 liters weapons-bay mounted tank that could be dropped and a 473 liters waist tank Fuel capacity external -
Machine guns
  • 2 × 12,7 mm Browning fixed forward-firing, on the (port?) side of the nose
  • 1 × 12,7 mm Browning trainable forward-firing in the nose
  • 8 × 12,7 mm Browning fixed forward-firing, in the nose in stead of the former two gun positions (solid nose configuration)
  • 2 × 12,7 mm Browning trainable in a power operated dorsal Bendix turret, 400 rounds each
Cannons -
Bomb load Up to 907 kg, carried in a under fuselage weapons bay rated at 907 kg. General disposables load consisted of:
  • 1 × 907 kg bomb
Torpedoes/rockets
  • 8 × 127 mm air-to-surface rockets
  • 1 × 907 kg torpedo in stead of internal load

Here is a quick overview of all different versions, without the full technical specifications:

Different versions of the North American B-25  Mitchell
North American NA-40/NA-62 prototypes In 1938 North American decided to enter a competition for a three-seat twin-engined attack bomber. This was a big step for North American, since it was familiar with single-engined trainers, not twin-engined attack aircraft or bombers. Nevertheless, the resulting design had merits, but in the end had to concede to the Douglas Model 7, also known as the Douglas A-20 Havoc/Douglas Boston.
Nevertheless, North American was now ready to enter a competition for an advanced tactical medium bomber. Based on the experience gained, an new requirements for the new aircraft several features were changed. The new prototype to emerge was designated NA-62 by North American, and differed from the preceding prototypes NA-40 and NA-40B with respect to: a wider fuselage to enable a greater war load, the wing moved down from high-set to the mid-set position to straigthen the upper line of the fuselage, changed powerplant from 2 × Wright GR-2600-A71 Cyclone 14 radials to 2 × Wright R-2600-13 radials, the crew increased from three to five, the fuel capacity increased to 759 Imp gal (912 US gal, 3.452 liters) and improved/increased guns armament (offensive and defensive). this type was ordered 'off the drawing board', and an order for 24 service trials aircraft was placed by the USAAC
Number built: 3
North American B-25 The initial version of the B-25 was identical to the NA-62 prototype. Service trials with the aircraft showed a lack in directional stability, and from the 10th aircraft onwards all Mitchells with the flat outer wing panels that give the wings a gull-shaped apearance.
Number built: 24
North American B-25A This first updated version was modified to suit operational needs in the European Theatre. Changes include protective armor for the crew, and a revised fuel system that comprised four self-sealing tanks in the wings for 578 Imp gal (694 US gal, 2627 liters) of fuel that could be supplemented by an additional 348 Imp gal (418 US gal, 1.582 liters) of fuel in a droppable tank carried in the weapons bay. Other technical details include: a length of 54 ft 1 in (16,485 m), empty weight of 17,870 lb (8.105 kg), normal take-off weight of 25,322 lb (11.486 kg), max take-off weight of 27,100 lb (12.293 kg), max level speed of 315 mph (507 km/h) at 15,000 ft (4.570 m), typical range of 1,350 miles (2.172 km) with a weapons load of 3,000 lb (1.361 kg), climb to 15,000 ft (4.570 m) in 8 minutes 24 seconds, and a service ceiling of 27,000 ft (8.230 m).
Number built: 40
North American B-25B The original contract was signed for 184 aircraft, and the B-25B fulfilled the remainder of the batch which started with the B-25. This version saw the addition of power-operated Bendix turrets, each armed with 2 × 0.50 inch (12,7 mm) Browning trainable guns. The dorsal turret had 400 rounds for each gun, the retractable ventral turret had 350 rounds for each gun. The single 0.3 in (7,62 mm) Browning trainable gun in the nose was retained, but the 0.50 inch (12,7 mm) in the tail was removed.
Other technical details include: a length of 52 ft 11 in (16,13 m), empty weight of 20,000 lb (9.072 kg), normal take-off weight of 26,208 lb (11.888 kg), max take-off weight of 28,460 lb (12.909 kg), max level speed of 300 mph (483 km/h) at 15,000 ft (4.570 m), typical range of 1,350 miles (2.173 km) with a weapons load of 3,000 lb (1.361 kg), and a service ceiling of 23,500 lb (10.660 m).
Number built: 120
North American B-25C Mitchell This version was the first to officially receive the name Mitchell. Also it was the first version to be built in large numbers. It was based on the B-25B, and changes were made only on the 'inside' of the aircraft: it had the same external features and armament, but it's electrical system was chenged from a 12-Volt to a 24-Volt system. The powerplant was changed to 2 × Wring R-2600-13 radials, rated at at 1,700 hp (1.268 kW) for take-off and 1,400 hp (1.044 kW) at 13,000 ft (3.960 m) each, and driving a three-blade Hamilton Standard metal propeller of the constant-speed type. From the 384th aircraft onward there was additional fuel tankage, and the weapons bay was revised to enable the B-25 to carry greater loads and heavier bombs.

Apart from the standard B-25C Mitchel, several blocks were built:

B-25C-1 Mitchell Starting with the 606th aircraft, 258 aircraft were delivered with provision for external racks that allowed the Mitchell to carry a 2,000 lb (907 kg) torpedo under the fuselage instead of the internally carried bombs (although the weapons bay could still carry the jettisonable auxiliary fuel tank) or 8 × 250 lb (113 kg) bombs under the wings in addition to the internally carried bombs, thereby increasing the maximum possible disposable load from 3,200 lb (1.452 kg) to 5,200 lb (2.359 kg) on short-range missions. Another change was the replacement of the bombardier’s 0.3 in (7,62 mm) Browning machine gun by a 0.5 inch (12,7 mm) Browning trainable forward-firing machine guns with 300 rounds,
B-25C-5 Mitchell 162 examples of the B-25C-5 Mitchell (NA-92 originally ordered in June 1941 by the Netherlands) that followed between October and December 1942 the pilot was provided with a 0.50 inch (12,7 mm) Browning fixed forward-firing machine gun with 300 rounds on the starboard side of the nose.
B-25C-10 Mitchell 150 examples of the B-25C-10 Mitchell (NA-94) were destined for the UK under the Lend-Lease Act, and had an improved compass and better winterisation equipment.
B-25C-15 Mitchell 150 examples of the B-25C-15 Mitchell (NA-93) were destined for China under the Lend-Lease Act appeared in January 1943, and were fitted with individual flame-damped exhausts.
B-25C-20 Mitchell 200 examples of the B-25C-20 Mitchell (NA-96), a variant basically similar to the B-25C-15 were not bought under the Lend-Lease Act, but had been ordered by the USAAC for its own use.
B-25C-25 Mitchell 100 aircraft were built according to the B-25C-25 Mitchell standard that differed from the B-25C-20 in having a 192 Imp gal (230 US gal, 871 liter) self-sealing fuel tank in the weapons bay, and provision for a 270.6 Imp gal (325 US gal, 1230 liter) auxiliary tank carried in the weapons bay.


Number built: 1.619
North American B-25D Mitchell An initial order for 1,200 B-25D (NA-87) bombers, identical in all respects to the early-production B-25C, was placed with a new bomber production plant established in Kansas City facility in June 1941. this facility was part of a bigger production plan empowered and set in motion by the US government in December 1940. The idea was to create additional production capacity in the less industrialised mid-west, where the new plants could tap in new sources of workers, and spreading the work in stead of concentrating it on the East and West coasts. Inglewood, the original North American production facility for the B-25, provided knock-down kits for the first six aircraft and then all the detail parts for the following 94 as a means of kick-starting Kansas City production, and the first of these aircraft was delivered in February 1942. From the 10st aircraft parts from the Fisher Body Division (a General Motors Corporation Division) were used, outer wing panels and fuselage side panels from this source being added to assemblies produced in Kansas City.
The first 200 B-25D aircraft were basically similar to the B-25C with the exception of provision for 104 Imp gal (125 US gal, 473 liters) of auxiliary fuel in a waist tank for a maximum range of 2,650 miles (4265 km), but from November 1942 there followed a number of blocks that deviated from this standard:
Number built: 2.290
North American B-25G Mitchell Delivered to the extent of 405 aircraft including five B-25C conversions, this NA-96 variant was a dedicated anti-ship model evolved for use in the Pacific theater with a four-man crew and a 75 mm (2.95 in) M4 gun installed in the nose, where it was complemented by 2 × 0.50 inch (12,7 mm) Browning fixed forward-firing machine guns, 400 rounds each. Also, four ‘package’ guns on the sides of the forward fuselage augmented the offensive gun armament. The last 221 aircraft omitted the ventral turret, which was deemed superfluous for the low-level anti-ship role. The type was not notably successful because of the weight of the 75 mm (2.95 in) gun installation, in the lower port side of the forward fuselage, and the slow rate at which the 20 lb (9,1 kg) shells, carried in a 21-round tray, could be loaded by hand.
The B-25G had the same powerplant, dimensions and weights as the B-25C, but differed in details such as: max level speed of 281 mph (452 km/h) at 15,000 ft (4.570 m) declining to 268 mph (431 km/h) at sea level, max range of 2,200 miles (3541 km) with auxiliary fuel, typical range of 1.525 miles (2.454 km) with a weapons load of 3,000 lb (1.361 kg), and a service ceiling of 24,300 ft (7405 m).
Number built: 400 plus 5 conversions
North American B-25H Mitchell The NA-98 was a development of the B-25G with a five-man crew, the lighter 75 mm (2.95 in) T13E1 gun, 8 × 0.50 inch (12,7 mm) Browning fixed forward-firing machine guns (four in the nose and four on the fuselage sides), 6 × 0.50 inch (12,7 mm) Browning trainable machine guns (two weapons each in the dorsal and tail positions and single weapons in the two beam positions), provision for 3,000 lb (1.361 kg) of bombs in the weapons bay, and provision for 8 × 5 inch (127 mm) air-to-surface rocket under the wings. Even the 8 rockets alone were said to be equal to the broadside salvo of a destroyer, so you can imagine the huge firepower of this version.
Number built: 1.000
North American B-25J Mitchell This final (production) version of the Mitchell was a reversion to the medium-bomber role, as opposed to the attack aircraft role it's predecessors more or less had. The NA-108 was a six-crew development of the B-25H with a glazed nose carrying one trainable and two fixed forward-firing 0.50 inch (12,7 mm) Browning machine guns. The dorsal turret was moved farther forward to a position just to the rear of the flightdeck, and the first 150 aircraft were completed with provision for a 2,000 lb (907 kg) bomb or torpedo. Many of the aircraft were later adapted with a ‘solid’ nose accommodating a fixed forward-firing battery of 8 × 0.50 inch (12,7 mm) Browning machine guns, again more suited for the Attack aircraft role..
Number built: 4.318
North American AT-24A Mitchell An number of B-25D Mitchells were converted to act as crew trainers
Number converted: unknown out of 60
North American AT-24B Mitchell An number of B-25G Mitchells were converted to act as crew trainers
Number converted: unknown out of 60
North American AT-24C Mitchell An number of B-25C Mitchells were converted to act as crew trainers
Number converted: unknown out of 60
North American AT-24D An number of B-25J Mitchells were converted to act as crew trainers
Number converted: unknown out of 60
North American CB-25J Mitchell Conversion of B-25J Mitchells, used as utility transport.
Number converted: unknown
North American RB-25D Mitchell Redesignation of the F-10 Mitchell
Redesignated aircraft
North American TB-25C Mitchell Redesignation of the AT-24C Mitchell
Redesignated aircraft
North American TB-25D Mitchell Redesignation of the AT-24A Mitchell
Redesignated aircraft
North American TB-25G Mitchell Redesignation of the AT-24B Mitchell
Redesignated aircraft
North American TB-25J Mitchell Redesignation of the AT-24D Mitchell
Redesignated aircraft
North American TB-25K Mitchell Conversion from B-25J aircraft for training purposes for the E1 radar fire-control system
Number converted: 117
North American TB-25L Mitchell Conversion from B-25J aircraft for training purposes for pilots
Number converted: 90
North American TB-25M Mitchell Conversion from B-25J aircraft for training purposes of operators in the E5 radar fire-control system
Number converted: 40
North American TB-25N Mitchell Conversion from B-25J aircraft for training purposes for pilots, slightly differeing from the TB-25L Mitchell.
Number converted: 47
North American VB-25J Mitchell Conversion from B-25J aircraft to be operated as staff transport.
Number converted: unknown
North American F-10 This designation was accorded to 10 examples of the B-25D which were converted as photo-reconnaissance aircraft with additional fuel and a three-camera installation in the chin and ventral positions for trimetrogon photography.
Number converted: 10
North American PBJ-1C This designation was accorded to 50 B-25C aircraft transferred to the US Navy for use in the patrol bomber role.
Number transferred: 50
North American PBJ-1D This designation was accorded to 152 B-25D aircraft transferred to the US Navy for use in the patrol bomber role.
Number transferred: 152
North American PBJ-1G This designation was accorded to one B-25G aircraft transferred to the US Navy for use in the patrol bomber role.
Number transferred: 1
North American PBJ-1H This designation was accorded to 248 B-25H aircraft transferred to the US Navy for use in the patrol bomber role.
Number transferred: 248
North American PBJ-1J This designation was accorded to 255 B-25J aircraft transferred to the US Navy for use in the patrol bomber role.
Number transferred: 255
North American Mitchell Mk I for the RAF This designation was accorded to 23 examples of the B-25B transferred to the UK under the terms of the Lend-Lease Act.
Number transferred: 23
North American Mitchell Mk II for the RAF This designation was accorded to 571 examples of the B-25C and B-25D transferred to the UK under the terms of the Lend-Lease Act
Number transferred: 571
North American Mitchell Mk III for the RAF This designation was accorded to 316 examples of the B-25J transferred to the UK under the terms of the Lend-Lease Act. Of these aircraft 20 were later passed back to the USAAF.
Number transferred: 316

Operational remarks:

The B-25 Mitchell proved to be an outstanding aircraft right from the start. The aircraft entered service in the early summer of 1941 with the 34th, 37th and 95th Bombardment Squadrons and 89th Reconnaissance Squadron of the 17th Bombardment Group (Medium). The type's first kill was scored when in December 1941 a B-25A of the 17th BG claimed the sinking of a Japanese submarine off the coast of California only a short time after the Japanese attack on Pearl Harbor.
The first action during which the B-25 gained real fame was during the famous and American celebrated Doolittle Raid. It was 16 B-25B's that undertook the raid in April 1942. They took off from the aircraft carrier USS Hornet and attacked Tokyo before the survivors attempted to fly on to airfields in China. Although there was not much damage done, the psychological impact was enourmous. Until then Japan had believed to be immune to attacks on the homeland, so after the attacks the Japanese had to take into consideration counter measures against exactly these kind of raids and others. More effort had to be put into defensive measures, hampering the offensive Japanese onslaught. Historics even believe the raid was the direct cause for the Battle of Midway. This Battle, fought over a strategically very important island in the middle of the Pacific was the first big defeat for the Japanese, who lost four aircraft carriers. Japan never really recovered from this blow, and it was the beginning of the end of Japan's succes story.
Many of the B-25C and B-25D aircraft were operated in the South-West Pacific Area by units of the US 5th Army Air Force, most notably the 3rd, 22nd and 345th Bombardement Groups. It turned out that while the airframe/powerplant combination of the B-25 was well suited to this theater, there was frequent demand for attacks on shipping and small targets dispersed in jungle for which the armament was not ideal. By September 1943, therefore, some 175 examples of the B-25C and B-25D had been modified by the depot at Townsville in Australia for low-level strafing, with a crew of three. The ventral turret was removed, and the bombardier position was replaced by two pairs of 0.5 inch (12,7 mm) Browning machine guns and supplemented by two additional pairs of 0.5 inch (12,7 mm) Browning machine guns on the sides of the forward fuselage for a fixed forward-firing armament of eight heavy machine guns. The weapons bay was adapted to carry 60 small fragmentation bombs and six 100 lb (45 kg) demolition bombs.
The B-25C and B-25D were also operated by the 7th and 341st Bombardment Groups of the 10th Air Force in the China-Burma-India theater, the 1st Bombardment Group of the Chinese-American Composite Wing of the US 14th Army Air Force in China, the 28th Bombardment Group of the 11th Army Air Force in the Aleutian Islands, the 41st and 42d Bombardment Groups of the 13th Army Air Force in the Central Pacific, and the 12th, 310th, 321st and 340th Bombardment Groups of the 12th Army Air Force in North Africa and Italy.
The NA-96 variant (B-25G) was a dedicated anti-ship model evolved for use in the Pacific theater with a four-man crew and a 75 mm (2.95 inch) M4 cannon installed in the nose, where it was complemented by two 0.5 inch (12,7 mm) Browning fixed forward-firing machine guns, and by the four ‘package’ guns on the sides of the forward fuselage; the last 221 aircraft omitted the ventral turret, which was deemed superfluous for the low-level anti-ship role. The type was not notably successful because of the weight of the 75 mm (2.95 inch) cannon installation, in the lower port side of the forward fuselage, and the slow rate at which the 20 lb (9,1 kg) shells, carried in a 21-round tray, could be loaded by hand. A later version of this anti-shipping type was the more succesfull B-25H, or NA-98. The NA-98 was based on the B-25G with a five-man crew, the lighter 75 mm (2.95 inch) T13E1 gun, eight 0.5 inch (12,7 mm) Browning fixed forward-firing machine guns (four in the nose and four on the fuselage sides), six 0.5 inch (12,7 mm) Browning trainable machine guns (two weapons each in the dorsal and tail positions and single weapons in the two beam positions), provision for 3,000 lb (1.361 kg) of bombs in the weapons bay, and provision for eight 5 inch (127 mm) rocket under the wings. This was the most heavily armed version of the B-25, and it could really deliver a Big Punch.
The Mitchell was used in almost all Theatres of Operation during the War, and succesfully so. During and after the War it was used by the USA, Australia, Brazil, Canada, China, France, Great Britain, the Netherlands and the USSR.

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© by Frans Bonné, 2000
Last revision: 9/23/01