Aviation of World War II

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B-25G/H "Mitchell"

Strafer

North American

B-25G Mitchell

The B-25G (NA-96) was the first version of the Mitchell to introduce the 75-mm cannon. It was intended for anti-shipping strikes in the South Pacific.

In the B-25G, a standard 75-mm Army M4 cannon was mounted to fire forward through the nose. This gun was a revision of the famous French 75 of World War I. The basic concept had been found to be feasible with experiments on a converted Douglas B-18A Bolo. However, since the effects of the heavy muzzle blast on the nose structure of the Mitchell were unknown, a complete forward fuselage section was built and trucked to a secret area in California where firing tests could be conducted out of the way of prying eyes. Guided by these tests, the structure was progressively strengthened until full resistance to prolonged firing of 75-mm rounds could be demonstrated.

Although the B-25G had not been as successful in combat as had been hoped, North American nevertheless received an order for 1000 cannon-carrying attack strafers under the designation B-25H.

The B-25H (NA-98) differed from the G primarily in having a much more powerful armament suite. A lighter-weight 75-mm T13E1 cannon was fitted in the nose tunnel. The nose was fitted with four fixed 0.50-inch machine guns instead of two. These guns were installed in a line across the nose and carried 400 rounds each. A pair of 0.50-inch machine guns were installed in individual blisters on the right hand side of the fuselage, each gun carrying 400 rounds. Two flexible machine guns were provided at the waist stations, installed on flexible mounts behind large cylindrically-shaped "bay windows" and firing through sockets cut into their lower rear corners. These windows were slightly staggered, with the starboard side being positioned slightly further forward of the port side so that the two gunners would not get in each other's way. Two 0.50-inch machine guns were installed in an armored Bell M-7 turret in the extreme tail. In order to accommodate a seated gunner, the aft fuselage was deepened slightly and the tail was raised seven inches further above the fuselage reference line than it was on previous Mitchell versions. A transparent cupola was provided for the tail gunner, who sat behind a wall of armor plate that protected him from gunfire from the rear. In addition, the upper turret was moved forward on the fuselage to a position above the navigator's station in order to maintain proper balance against the additional weight added to the rear by the waist guns and tail turret. This new turret was more heavily braced and had a higher dome than did previous Mitchell dorsal turrets.

One of the more controversial changes introduced by the B-25H was the deletion of the co-pilot position. The elimination of the co-pilot's seat, armor plate, and controls resulted in a saving of over 300 pounds of weight. At the position of the co-pilot, a jump seat for the navigator was provided since his position had now been preempted by the forward-moved dorsal turret. General James Doolittle had always questioned the need for a co-pilot in the B-25 and B-26. However, General George Kenney, commander of the Fifth Air Force in the Pacific, vehemently objected and claimed that he needed the second pilot for long, over-water missions under hazardous conditions. However, General Arnold overruled these objections, and the B-25H was delivered without a co-pilot's position.

Mitchell
B-25G B-25H
Crew 5 5
Dimensions
Wing span, m(ft) 20.60 (67.6) 20.60 (67.6)
Wing area, m²(sq ft) 56.67 (610) 56.67 (610)
Length, m(ft) 16.49 (54.1) 16.49 (54.1)
Height, m(ft) 4.80 (15.7) 4.80 (15.7)
Weight:
Empty weight, kg(Ib) 9,060 (19,974) 9,060 (19,974)
Loaded weight, kg(Ib) 15870 (35,000) 15,190 (33,500)
Powerplant
Wright «Cyclone»
14-cyl. radials
2 × R-2600-13 R-2600-13
power, hp 2 × 1700 2 × 1700
Performance
Speed, km/h (mph) Maximum 454 (282) 441 (274)
at altitude, m(ft) 4,572 (15,000) 4,572 (15,000)
Cruising range, km/h (mis/h) 399 (248) 370 (230)
Service ceiling, m (ft) 7410 (24.310) 7560 (24.800)
Service range, km (mis) 2511 (1,560) 2173 (1,350)
Armament
Cannon 75-mm 30in 1 1
Machine guns 12.7-mm .50 6 14
Bombs, kg 1360 (3,000 Ib) 1450 (3,200 Ib)

                                                                                                                                                                                                              
Photo Description
Drawing B-25H-1-NA 'Mitchell' Drawing B-25H-1-NA 'Mitchell'
B-25H 'Mitchell' B-25G, 823 BS, 38 BG 'Mitchell' B-25G, 823 BS, 38 BG.

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Bibliography

  • "Encyclopedia of military engineering" /Aerospace Publising/
  • "American warplanes of World War II" /under cor. David Donald/