American bombers and transport aircrafts

[gekho]

The North American B-25 Mitchell was an American twin-engined medium bomber manufactured by North American Aviation. It was used by many Allied air forces, in every theater of World War II, as well as many other air forces after the war ended, and saw service across four decades. The B-25 was named in honor of General Billy Mitchell, a pioneer of U.S. military aviation. The B-25 is the only American military aircraft named after a specific person. By the end of its production, nearly 10,000 B-25s in numerous models had been built. These included a few limited variations, such as the United States Navy's and Marine Corps' PBJ-1 patrol bomber and the United States Army Air Forces' F-10 photo reconnaissance aircraft.

The B-25 was a descendant of the earlier XB-21 (North American-39) project of the mid-1930s. Experience gained in developing that aircraft was eventually used by North American in designing the B-25 (called the NA-40 by the company). One NA-40 was built, with several modifications later being done to test a number of potential improvements. These improvements included Wright R-2600 radial engines, which would become standard on the later B-25.

In 1939, the modified and improved NA-40B was submitted to the United States Army Air Corps for evaluation. This aircraft was originally intended to be an attack bomber for export to the United Kingdom and France, both of which had a pressing requirement for such aircraft in the early stages of World War II. However, those countries changed their minds, opting instead for the also-new Douglas DB-7 (later to be used by the US as the A-20 Havoc). Despite this loss of sales, the NA-40B re-entered the spotlight when the Army Air Corps evaluated it for use as a medium bomber. Unfortunately, the NA-40B was destroyed in a crash on 11 April 1939. Nonetheless, the type was ordered into production, along with the Army's other new medium bomber, the Martin B-26 Marauder.



An improvement of the NA-40B, dubbed the NA-62, was the basis for the first actual B-25. Due to the pressing need for medium bombers by the Army, no experimental or service-test versions were built. Any necessary modifications were made during production runs, or to existing aircraft at field modification centers around the world. A significant change in the early days of B-25 production was a re-design of the wing. In the first nine aircraft, a constant-dihedral wing was used, in which the wing had a consistent, straight, slight upward angle from the fuselage to the wing tip. This design caused stability problems, and as a result, the dihedral angle was nullified on the outboard wing sections, giving the B-25 its slightly gull wing configuration. Less noticeable changes during this period included an increase in the size of the tail fins and a decrease in their inward cant. A total of 6,608 B-25s were built at North American's Fairfax Airport plant in Kansas City, Kansas.A descendant of the B-25 was the North American XB-28, meant to be a high-altitude version of the B-25. Despite this premise, the actual aircraft bore little resemblance to the Mitchell. It had much more in common with the B-26 Marauder.

[gekho]

The B-25 first gained fame as the bomber used in the 18 April 1942 Doolittle Raid, in which 16 B-25Bs led by the legendary Lieutenant Colonel Jimmy Doolittle, attacked mainland Japan four months after the bombing of Pearl Harbor. The mission gave a much-needed lift in spirits to the Americans, and alarmed the Japanese who had believed their home islands were inviolable by enemy troops. While the amount of actual damage done was relatively minor, it forced the Japanese to divert troops for the home defense for the remainder of the war. The raiders took off from the carrier USS Hornet and successfully bombed Tokyo and four other Japanese cities without loss. However, 15 subsequently crash-landed en route to recovery fields in Eastern China. These losses were the result of the task force being spotted by Japanese fishing vessels forcing the bombers to take off 170 mi (270 km) early, fuel exhaustion, stormy nighttime conditions with zero visibility, and lack of electronic homing aids at the recovery bases. Only one landed intact; it came down in the Soviet Union, where its five-man crew was interned and the aircraft confiscated. Of the 80 aircrew, 69 survived their historic mission and eventually made it back to American lines.

Following a number of additional modifications, including the addition of Plexiglas windows for the navigator and radio operator, heavier nose armament, and deicing and anti-icing equipment, the B-25C was released to the Army. This was the second mass-produced version of the Mitchell, the first being the lightly-armed B-25B used by the Doolittle Raiders. The B-25C and B-25D differed only in location of manufacture: -Cs at Inglewood, California, -Ds at Kansas City, Kansas. A total of 3,915 B-25Cs and -Ds were built by North American during World War II.

Although the B-25 was originally designed to bomb from medium altitudes in level flight, it was used frequently in the Southwest Pacific theater (SWPA) on treetop-level strafing and parafrag (parachute-retarded fragmentation bombs) missions against Japanese airfields in New Guinea and the Philippines. These heavily-armed Mitchells, field-modified at Townsville, Australia, by Major Paul I. "Pappy" Gunn and North American tech rep Jack Fox, were also used on strafing and skip-bombing missions against Japanese shipping trying to re-supply their land-based armies. Under the leadership of Lieutenant General George C. Kenney, B-25s of the Fifth and Thirteenth Air Forces devastated Japanese targets in the SWPA from 1942 to 1945, and played a significant role in pushing the Japanese back to their home islands. B-25s were also used with devastating effect in the Central Pacific, Alaska, North Africa, Mediterranean and China-Burma-India (CBI) theaters.

Because of the urgent need for hard-hitting strafer aircraft, a version dubbed the B-25G was developed, in which the standard-length transparent nose and the bombardier were replaced by a shorter solid nose containing two fixed .50 in (12.7 mm) machine guns and a 75 mm (2.95 in) M4 cannon, one of the largest weapons fitted to an aircraft, similar to the experimental British Mosquito Mk. XVIII, and German Ju 88P heavy cannon carrying aircraft. The cannon was manually loaded and serviced by the navigator, who was able to perform these operations without leaving his crew station just behind the pilot. This was possible due to the shorter nose of the G-model and the length of the M4, which allowed the breech to extend into the navigator's compartment.

[gekho]

The B-25G's successor, the B-25H, had even more firepower. The M4 gun was replaced by the lighter T13E1, designed specifically for the aircraft. The 75 mm (2.95 in) gun fired at a muzzle velocity of 2,362 ft/s (about 720 m/s). Due to its low rate of fire (approximately four rounds could be fired in a single strafing run) and relative ineffectiveness against ground targets, as well as substantial recoil, the 75 mm (2.95 in) gun was sometimes removed from both G and H models and replaced with two additional .50 in (12.7 mm) machine guns as a field modification. The -H also mounted four fixed forward-firing .50 (12.7 mm) machine guns in the nose, four more fixed ones in forward-firing cheek blisters, two more in the top turret, one each in a pair of new waist positions, and a final pair in a new tail gunner's position. Company promotional material bragged the B-25H could "bring to bear 10 machine guns coming and four going, in addition to the 75 mm cannon, a brace of eight rockets and 3,000 lb (1,360 kg) of bombs."

The B-25H also featured a redesigned cockpit area, with the top turret moved forward to the navigator's compartment (thus requiring the addition of the waist and tail gun positions), and a heavily modified cockpit designed to be operated by a single pilot, the co-pilot's station and controls deleted, and the seat cut down and used by the navigator/cannoneer, the radio operator being moved to the aft compartment, operating the waist guns.[3] A total of 1,400 B-25Gs and B-25Hs were built.

The final version of the Mitchell, the B-25J, looked much like the earlier B, C and D, having reverted to the longer nose. The less-than-successful 75 mm (2.95 in) cannon was deleted on the J model. Instead, 800 of this version were built with a solid nose containing eight .50 (12.7 mm) machine guns, while other J-models featured the earlier "greenhouse" style nose containing the bombardier's position. Regardless of the nose style used, all J-models also included two .50 in (12.7 mm) guns in a "fuselage package" located directly under the pilot's station, and two more such guns in an identical package just under the co-pilot's compartment. The solid-nose B-25J variant carried an impressive total of 18 .50 in (12.7 mm) guns: eight in the nose, four in under-cockpit packages, two in an upper turret, two in the waist, and a pair in the tail. No other bomber of World War II carried as many guns. However, the first 555 B-25Js (the B-25J-1-NC production block) were delivered without the fuselage package guns, because it was discovered muzzle blast from these guns was causing severe stress in the fuselage; this was cured with heavier fuselage skin patches, while later production runs returned these guns, they were often removed as a field modification for the same reason. In all, 4,318 B-25Js were built.

The B-25 was a safe and forgiving aircraft to fly. With an engine out, 60° banking turns into the dead engine were possible, and control could be easily maintained down to 145 mph (230 km/h). However, the pilot had to remember to maintain engine-out directional control at low speeds after take off with rudder - if this was attempted with ailerons, the aircraft would snap out of control. The tricycle landing gear made for excellent visibility while taxiing. The only significant complaint about the B-25 was the extremely high noise level produced by its engines; as a result, many pilots eventually suffered from various degrees of hearing loss.[5] The high noise level was due to design and space restrictions in the engine cowlings which resulted in the exhaust "stacks" protruding directly from the cowling ring and partly covered by a small triangular fairing. This directed exhaust and noise directly at the pilot and crew compartments. Crew members and operators on the airshow circuit frequently comment that "the B-25 is the fastest way to turn aviation fuel directly into noise". Many B-25's now in civilian ownership have been modified with exhaust rings that direct the exhaust through the outboard bottom section of the cowling.

[Gnomey]

Good stuff!

[Matt308]

Those are great pics. Worthy of this forum. Thanks.

[vikingBerserker]

Is the 3rd pic down post 91 showing a B-25 packing 2 x 75mm???

[gekho]

More pics

[gekho]

More pics

[Wildcat]

Does anyone know what unit "The nip clipper" is from? It appears to have some Aussies in the crew.

[Wayne Little]

Great set of pics....!!

[gekho]

More pics

[gekho]

More pics

[gekho]

Two B-25 Mitchell attack a japanese destroyer in Formosa, april 1945.

[looney]

In the picture with B25 112800 it has a glass tail what was it for?

[Airframes]

On this model of the B25 (B25C/D), it was just an observer's position. On the 'Doolittle' raid, false guns, supposedly broom handles, were fitted into the perspex blister, to give the appearance of a gun position. On the later models, such as the B25J, a proper tail gun position was incorporated, with a raised perspex cupola.