B-25G-NA SN 42-65128
B-25G-NA SN 42-65128

B-25G-NA

History

The B-25G-NA was designed at the request of the United States Army. The 75mm cannon, known as the M-4, had been in development and testing since 1936. In 1938, the M-4 cannon was successfully installed and tested in a Douglas B-18. The cannon was demonstrated at Eglin Field in 1940. Commercial firms were solicited to assist in further development. The improved design produced a lighter cannon and increased power.

There were a lot of unknowns with the addition of a cannon to the B-25. Engineer George Wing was set to the task. The bombardier's crawl tunnel was the perfect location for the cannon. It provided ample room for recoil as well as space in the navigators compartment for storage of ammunition. The forward section of a B-25 was assembled with modifications to test the new design. In order to fit the cannon, the nose of the B-25 was shortened by 26 inches. This was considered the most the nose could be shortened from an aerodynamic standpoint. The end of the cannon barrel was still just aft of the nose contour. Fire tests were conducted with progressively increasing propellant charges. The structure was strengthened until it could withstand prolonged firing of over-charged rounds.

B-25C-1-NA SN 41-13296 was modified to the XB-25G. Test flights were made on October 22, 1942 to test the aircraft's flight characteristics. On October 23, 1942 the first test shots were fired from the aircraft. The XB-25G was fully tested by North American prior to being flown to Eglin Field for further testing by the Air Corps. After successful testing, the Air Corps ordered 400 examples to be supplied without lower turrets. In addition to those 400 aircraft, there were an additional 65 B-25C-NA bombers modified and re-designated as B-25Gs. The majority of these modifications were done at the modification center in Kansas City. It was the production of the B-25G-NA that marked the beginning of the end of B-25 production in Inglewood, California. Although another 1,000 B-25H-NA bombers would be built, the production of P-51 Mustangs was starting. As the Inglewood, California plant production of B-25s was winding down, production was ramping up in Kansas City.

Other than the experimental aircraft built, The B-25G-NA and B-25A-NA are the only models that no airframe is known to have survived the war. Unfortunately, the B-25G-NA was not a popular aircraft. The firing of the cannon could throw off the navigational compass by as much as 15 degrees. The lower turret was never a popular item and was commonly removed in the field. The Hawaiian Air Depot replaced the cannon with the 8 gun nose on an unknown number of B-25G-NA bombers. Any remaining aircraft were sold for scrap at the end of the war.

B-25G-NA Specs
  • Model: B-25G-NA
  • Total Produced: 463 (63 were modified from B-25Cs)
  • Manufacturing Plant: Inglewood, California
  • First Test Flight: October 22, 1942
  • First Flight Crew: Edward Virgin
  • Engines: Wright R-2600-13
  • Carburetors: Holley 1685HA
  • Fuel Capacity:
    • 2 forward wing cells, total 368 gallons
    • 2 rear wing cells, total 302 gallons
    • 2 wing auxiliary cells, total 304 gallons
    • 2 side waist ferry tanks, total 125 gallons
    • Droppable bomb bay tank 335 gallons
    • 1 fixed ferry tank 585 gallons
  • Armament:
    • 75mm cannon with 21 rounds
    • 2 .50 caliber fixed guns in nose with 800 rounds
    • 2 .50 caliber guns in top turret with 800 rounds
    • 2 .50 caliber guns in bottom turrett with 700 rounds
  • Armor Protection:
    • 3/8 inch behind pilots
    • Forward of instrument panel
    • Forward of cannoneer's station
    • Bulkhead aft of turrets
    • Around ammunition rack
    • Plate below windshield
    • External flak plate on left side
  • Weights:
    • Empty: 19,200 lbs.
    • Max: 35,000 lbs.
  • Speed (Max): 280 mph at 15,000 feet
  • Service Ceiling: 24,300 ft
  • Range: 1,560 miles with 3,000 lbs. bombs
  • Crew:
    • Pilot, co-pilot, navigator/cannoneer, 2 gunners
  • Production by year:
    • 1943: 400
  • First Airplane Accepted: May 8, 1943
  • Last Airplane Accepted: August 24, 1943

Photos


Model NAA Contract SN NAA # # Produced
B-25G-1-NA NA-93 42-32384/42-32388 93-12491/93-12495 5
  • NAA Contract:
    • NA-93 signed January 14, 1942
  • Major Visual Production Block Changes:
    • Modified B-25C-15-NA
    • Greenhouse nose replaced by shorter solid nose
    • Two fixed .50 caliber nose guns
    • 75mm M-4 cannon in bombardier's crawl tunnel
  • Notable Aircraft:
Model NAA Contract SN NAA # # Produced
B-25G-5-NA NA-96 42-64802/42-64901
42-64902/42-65101		 96-16681/96-16780
96-20806/96-21005		 100
200
  • NAA Contract:
    • NA-96 signed March 28, 1942
  • Major Visual Production Block Changes:
    • Greenhouse nose replaced by shorter solid nose
    • Two fixed .50 caliber nose guns
    • 75mm M-4 cannon in bombardier's crawl tunnel
    • Lower turret deleted effective on B-25G-NA SN 42-65001
  • Notable Aircraft:
Model NAA Contract SN NAA # # Produced
B-25G-10-NA NA-96 42-65102/42-65201 96-21006/96-21105 100
  • NAA Contract:
    • NA-96 signed March 28, 1942
  • Major Visual Production Block Changes:
    • None
  • Notable Aircraft:

B-25Cs Modified to B-25Gs
SN# SN# SN# SN# SN#
42-32384 42-64581 42-64675 42-64706 42-64763
42-32385 42-64582 42-64692 42-64707 42-64764
42-32386 42-64584 42-64693 42-64748 42-64765
42-32387 42-64586 42-64696 42-64753 42-64766
42-32388 42-64587 42-64697 42-64754 42-64767
42-64531 42-64649 42-64698 42-64755 42-64768
42-64558 42-64654 42-64699 42-64756 42-64769
42-64561 42-64668 42-64700 42-64757 42-64770
42-64563 42-64670 42-64701 42-64758 42-64771
42-64565 42-64671 42-64702 42-64759 42-64772
42-64569 42-64672 42-64703 42-64760 42-64773
42-64579 42-64673 42-64704 42-64761 42-64779
42-64580 42-64674 42-64705 42-64762 42-64780



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