The B-25 first gained fame as the bomber used in the April 18, 1942 Doolittle Raid, in which 16 B-25Bs, led by the legendary Lieutenant Colonel Jimmy Doolittle, 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 miles (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 by Major Paul I. "Pappy" Gunn, were also used on strafing and skip-bombing missions against Japanese shipping trying to re-supply their land-based armies. Under the leadership of Lt. Gen. 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-calibre machine guns and a 75 mm 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.

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 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 gun was sometimes removed from both G and H models and replaced with two additional .50-caliber machine guns as a field modification. The -H also mounted four fixed forward-firing .50 in (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 pounds 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.  A total of 1,400 B-25Gs and B-25Hs were built in all.

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 cannon was deleted on the J model. Instead, 800 of this version were built with a solid nose containing eight .50 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 caliber 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 .50s: 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; 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 and 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.

The Mitchell was also an amazingly sturdy aircraft and could withstand tremendous punishment. One well-known B-25C of the 321st Bomb Group was nicknamed "Patches" because its crew chief painted all the aircraft's flak hole patches with high-visibility zinc chromate paint. By the end of the war, this aircraft had completed over 300 missions, was belly-landed half a dozen times and sported over 400 patched holes. The airframe was so bent, straight-and-level flight required 8° of left aileron trim and 6° of right rudder, causing the aircraft to "crab" sideways across the sky.

An interesting characteristic of the B-25 was its ability to extend range by using one-quarter wing flap settings. Since the aircraft normally cruised in a slightly nose-high attitude, about 40 U.S. gallons (150 l) of fuel was below the fuel pickup point and thus unavailable for use. The flaps-down setting gave the aircraft a more level flight attitude, which resulted in this fuel becoming available, thus slightly extending the aircraft's range.

By the time a separate United States Air Force was established in 1947, most B-25s had been consigned to long-term storage. However, a select number continued in service through the late 1940s and 1950s in a variety of training, reconnaissance and support roles. Its principal use during this period was for undergraduate training of multi-engine aircraft pilots slated for reciprocating engine or turboprop cargo, aerial refueling or reconnaissance aircraft. Still others were assigned to units of the Air National Guard in training roles in support of F-89 Scorpion and F-94 Starfire operations. The final example of a B-25 was struck from the active USAF roles in January 1959.

Today, many B-25 are kept in airworthy condition by air museums and collectors.

Navy squadrons

Pacific squadrons

VMB-413

Was the first Marine PBJ squadron formed. Commissioned at Marine Corps Air Station (MCAS) Cherry Point, North Carolina on 1 March 1943 the squadron moved to Naval Air Station (NAS) North Island, San Diego, California in December 1943 after completing training. Departing the U.S. on 3 January 1944 with their PBJs tied down on the deck of the escort aircraft carrier USS Kalinin Bay (CVE-68) for transport to MCAS Ewa, Territory of Hawaii. The air echelon then flew their aircraft to Naval Operating Base (NOB) Espiritu Santo on Espiritu Santo Island, New Hebrides Islands (15.15S, 166.51E) arriving on 27 January 1944 with 13 PBJ-1Ds. After receiving familiarization training, VMB-413 moved forward to Stirling Island, Treasury Islands, British Solomon Islands (7.13S, 155.19E), on 7 March. Located about 30 miles (48 km) off the southwest coast of Bougainville Island, this base made it easy to fly bombing and heckling missions against targets on Bougainville and the huge Japanese base at Rabaul on New Britain Island. The squadron flew its first mission against a supply dump near Rabaul on 14 March and for the next week, joined USAAF and USN aircraft in attacking the Rabaul area. After these preliminary raids, VMB-413 switched to its primary function, night heckling raids against Japanese installations on Bougainville and Rabaul. The squadron returned to NOB Espiritu Santo in May 1944 for rest and recreation and then moved forward to Munda Airfield (8.00S, 157.15E) on New Georgia Island in the British Solomon Islands and commenced bombing and strafing heckling operations against the Kahili-Choiseul area of Bougainville Island. On 18 October 1944, the squadron moved to Marine Corps Air Facility (MCAF) Emirau on Emirau Island (1.40S, 150.00E) in the St. Matthias Group of the Bismarck Archipelago. For the remainder of the war, the squadron flew missions against the bypassed Japanese forces on New Britain and New Ireland Islands. On 17 August 1945, the squadron was ordered to transfer to Titcomb Field, Malabang, Mindanao, Philippines Islands.

 

VMB-423

Was commissioned at MCAS Cherry Point on 15 September 1943. The squadron moved to MCAS Edenton, North Carolina in October 1943 and upon completion of their training, transferred to MCAS El Centro, California arriving on 3 January 1944 with their PBJ-1Ds. The ground echelon sailed for NOB Espiritu Santo in the cargo ship and aircraft ferry USS Hammondsport (AKV-2) and the escort aircraft carrier USS Prince William (CVE-31) arriving on 11 March 1944; the air echelon arrived on 10 April. After completing familiarization training, the air echelon was operating from Stirling Island by the middle of May; their first combat mission on 14 May. Meanwhile, the ground echelon had been dispatched to Naval Auxiliary Air Facility (NAAF) Green Island (4.38S, 154.15E) in the Solomon Islands, located about halfway between Buka and New Ireland, and the air echelon joined them on 21 June; by the end of June, the squadron had ten PBJ-1Ds. For the next year, the squadron carried out day and night air attacks against targets on New Britain and New Ireland Islands in the Bismarck Archipelago and suppled CAS for Australian troops on Bougainville Island. On 12 June 1945, the squadron moved to MCAF Emirau on Emirau Island where it conducted strikes against New Britain and New Ireland Islands until 10 August at which time it began a movement to Titcomb Field, Malabang, Mindanao, Philippines Islands arriving on 16 August just after the war ended.

 

VMB-433

Was commissioned at MCAS Cherry Point on 15 September 1943. The squadron trained at Cherry Point and at Marine Corps Auxiliary Air Field (MCAAF) Camp Lejeune, North Carolina (Peters Point Field) and upon completion, moved to MCAS El Centro and continued their training syllabus. On 26 May 1944, the ground echelon departed by ship for the Solomon Islands; the next day, the air echelon departed and arrived at NAAF Green Island on 14 July for temporary duty; this temporary duty consisted of flying with VMB-413 and VMB-423 to gain combat experience. In August 1944, the air and ground echelons were reunited at NOB Espiritu Santo where the squadron remained for the remainder of the war. On 16 August 1945, the squadron was ordered to Titcomb Field, Malabang, Mindanao, Philippines Islands.

 

 

VMB-443

Was commissioned at MCAS Cherry Point on 15 September 1943 and transferred to MCAAF Camp Lejeune on 20 October to continue training. In mid-January 1944, the air echelon and some of the ground echelon went to Naval Auxiliary Air Station (NAAS) Boca Chica, Key West, Florida for torpedo training and tactics and then moved to MCAS El Centro in February in preparation for overseas assignment. The ground echelon sailed from San Diego on 18 May 1944 and arrived at NOB Espiritu Santo in June; one month later, the ground echelon moved to MCAF Emirau and joined the flight echelon which arrived on 13 August. VMB-443 began flying both day and night missions against Rabaul and other bypassed Japanese installations on New Britain and New Ireland Islands until moving to Titcomb Field, Malabang, Mindanao, Philippines Islands in August 1945 after the war had ended.

 

 

VMB-611

Was commissioned at MCAS Cherry Point on 1 October 1943. After completing training, the squadron transferred to the West Coast and the air echelon sailed from San Diego for MCAS Ewa, Territory of Hawaii on 24 August 1944 with the PBJs tied down on the deck of the escort aircraft carrier USS Manila Bay (CVE-61); the ground echelon sailed for Hawaii on 23 September. While at NAS Barbers Point, Territory of Hawaii, the squadron's PBJs were equipped with underwing zero-length high velocity aircraft rocket (HVAR) launchers and Long Range Navigation (LORAN) equipment. In October, the air echelon flew from Hawaii to MCAF Emirau; both air and ground echelons had arrived by December 1944. VMB-611 flew its first mission on 17 November, a night mission against Kavieg and for the next three months, the squadron flew night heckling missions and strikes against Vanakanau and Tobera on New Britain Island. On 17 March 1945, the ground echelon transferred to Moret Field, Zamboanga (6.54N, 122.05E) on Mindanao Island in the Philippine Islands where it was joined by the air echelon on 30 March. The squadron flew day and night combat missions in the southern Philippines until the end of the war.

 

 

VMB-612

Was formed at MCAS Cherry Point on 1 October 1943. Beginning in January 1944, the squadron began experiments in low-altitude night-radar operations and alternated operations between NAAS Boca Chica and MCAAF Camp Lejeune for tactical training. In August 1944, the squadron departed the U.S. for Kagman Base on Saipan Island (15.10N, 145.45E) in the Mariana Islands arriving on the island in late October. The air echelon flew to Saipan via MCAS Ewa, Territory of Hawaii where the PBJ-1Ds were modified by the installation of an AN/APN-4 airborne Loran receiver, underwing HVAR rocket launchers synchronized to an AN/APQ-5 airborne radar bombsight, and AN/APN-1 airborne radio altimeters calibrated to give accurate reading between 500 and 1,000 feet (152 and 305 meters). Between 13 November 1944 and February 1945, the squadron flew anti-shipping strikes using rockets against Japanese ships and land targets in the Bonin and Volcano Islands area. After the invasion of Iwo Jima in February, the squadron undertook search missions to the Marcus Island area (24.18N, 153.58E) three nights a week, a mission of 1,450 miles (2,334 km). It was during this period that the squadron began to experiment with the Tiny Tim rocket. The subsonic Tiny Tim had a diameter of 11.75 inches (29.8 cm), a length of 10.25 feet (3.12 m), a firing weight of 1,284 pounds (582.4 kg), and a warhead with an explosive charge weighing 150 pounds (68.04 kg). The Marines modified a Mk 51 bomb rack to carry the rockets and installed two on the belly of the aircraft at the bomb bay. On 1 March, the squadron received three PBJ-1Js and in April 1945, the squadron moved to South Field on Iwo Jima (24.47N, 141.20E) in the Volcano Islands to continue anti-shipping missions. Now within striking range of the Japanese Home Islands, VMB-612 began bombing targets on Kyoto on 10 April. Anti-shipping missions at night, consisting of three PBJs, were unproductive and in the middle of April, daylight raids against the Home Islands commenced. While on Iwo Jima, the squadron had conducted tests and training using the Tiny Tim rocket; the first combat mission with the Tiny Tim, an anti-shipping strike, was flown by a PBJ-1J on the night of 21/22 July from Okinawa but no targets were found. The squadron's final move began on 28 July Chimu Airfield on the eastern shore of Okinawa Island (26.31N, 127.59E) in the Ryukyu Islands. Operations with the Tiny Tims began in earnest on 11 August with one sortie followed by three sorties on 14 August and six sorties during the night of the 14^th. With the Japanese surrender, hostilities ceased at 1600 hours Tokyo time on 15 August 1945. The squadron continued experimentation with the Tiny Tims for the rest of the month.

 

 

VMB-613

Was commissioned on 1 October 1943 at MCAS Cherry Point and transferred to NAS Boca Chica for torpedo training in February 1944, Returning to MCAS Cherry Point in March, VMB-613 moved to MCAF Newport, Arkansas in August for additional training. The air echelon departed MCAF Newport with their PBJ-1Ds for Dyess Field on Roi Island (9.24N, 167.28E), Kwajalein Atoll in the Marshall Islands in October 1944; both air and ground echelons arrived in December and the squadron began operations against bypassed Japanese forces in the Marshalls in January 1945. The forward echelon deployed to Stickell Field on Eniwetok Island (11.30N, 162.15E) in Eniwetok Atoll, Marshall Islands to conduct antisubmarine patrols between 11 January and 13 March 1945. In the spring of 1945, VMB-613 was chosen to test the PBJ-1H and became the only USMC squadron to operate this type of aircraft in combat. The problem was that there were few targets to use the 75 mm gun against and the aircraft was not very effective so on 19 May, four PBJ-1Hs were detached to Iwo Jima to conduct anti-shipping missions but returned to Roi on the 28^th without attacking any targets.

 

 

VMB-614

Was commissioned on 1 October 1943 at MCAS Cherry Point. The squadron trained at Cherry Point plus NAAS Boca Chica and Marine Corps Air Facility (MCAF) Newport. The squadron was initially equipped with PBJ-1C and -1D aircraft and effective in July 1944, with PBJ-1Hs equipped with AN/APG-23 airborne gun directing radar. The PBJ-1H was not a popular aircraft and they were replaced by PBJ-1Js modified with the eight gun nose for low altitude strafing missions. The air echelon departed California on 25 July 1945 followed by the ground echelon in early August; both echelons arrived at Henderson Field, NAS Midway Islands (28.13N, 177.26W) by the end of August 1945.

 

 

The eight other squadrons that did not serve in the Pacific were:

VMB-453

Was commissioned at MCAS Cherry Point on 25 June 1944; by 31 December 1944, the squadron was equipped with six PBJ-1Ds, three PBJ-1Hs and five PBJ-1Js. VMB-453 decommissioned 20 February 1945 without seeing combat.

 

VMB-463

Was commissioned at MCAS Cherry Point on 20 July 1944; by 31 December 1944, the squadron was equipped with six PBJ-1Hs and two PBJ-1Js. VMB-463 was decommissioned on 28 February 1945 without seeing combat.

 

VMB-473

Was commissioned at MCAS Cherry Point on 25 July 1944 and moved to MCAAF Kinston, North Carolina on 15 December. By the end of December, the squadron was flying one PBJ-1C, one PBJ-1D and two PBJ-1Hs. The squadron was decommissioned on 15 March 1945 without seeing combat.

 

VMB-483

Was commissioned at MCAS Cherry Point on 26 August 1944 and moved to MCAAF Kinston in December; by the end of the month, they were flying two PBJ-1Ds, one PBJ-1G, one PBJ-1H and two PBJ-1Js. The squadron was decommissioned on 15 March 1945 without seeing combat.

 

VMB-621

Was commissioned on 10 April 1944 at MCAS Cherry Point; by the end of December 1944, the squadron had one PBJ-1D, six PBJ-1Hs and one PBJ-1J. The squadron was redesignated Marine Torpedo Bomber Squadron Six Hundred Twenty One (VMTB-621) on 31 January 1945 and re-equipped with Eastern Aircraft TBM Avengers, q.v.

 

VMB-622

Was commissioned on 10 May 1944 at MCAS Cherry Point. The squadron moved to MCAF Newport on 10 September and continued operational training; by the end of December, the squadron was equipped with eight PBJ-1Hs and one PBJ-1J. In February 1945, the squadron moved to MCAS Mojave, California where it was redesignated VMTB-622 on 15 May 1945 and re-equipped with Eastern Aircraft TBM Avengers.

 

VMB-623

Was commissioned on 15 May 1944 at MCAS Cherry Point; by the end of December, the unit had two PBJ-1Ds and 12 PBJ-1Hs. The squadron began operational training with the PBJ but was redesignated VMTB-623 on 10 February 1945 and re-equipped with Eastern Aircraft TBM Avengers.

 

VMB-624

Was commissioned on 20 June 1944 at MCAS Cherry Point. The squadron began operational training with PBJs and by the end of December had ten PBJ-1Hs and one PBJ-1J. On 15 February 1945, the squadron was redesignated VMTB-624 and re-equipped with Eastern Aircraft TBM Avengers.

The seven PBJ squadrons that saw combat in the Pacific suffered the loss of 45 aircraft, 26 in combat and 19 in non-combat operations, and 173 crew, 62 officers and 111 enlisted men.