The Martin Marauder was not built in as large numbers as the Mitchell, because it proved more expensive to produce and maintain, and had a higher accident rate. On paper, the Martin seemed the more advanced design, and even before the first flight, the original B-26 contract had been increased by orders for 139 B-26As on September 16, and 791 B-26Bs on September 28, 1940. This brought the total to 1,131 aircraft, a big risk on an untested aircraft.
Since Martin had designed its own power turret and self-sealing tanks, the B-26 could be the first to be ready for combat. While the B-25 entered service on the West Coast, the B-26 first arrived at Langley Field, Virginia, for the 22nd Bomb Group on February 18, 1941. After delays caused by numerous mechanical difficulties and the accidental loss of five aircraft, the group had 52 B-26s by September 30. The remaining aircraft waited undelivered because of the lack of power turrets and propellers. As they were made ready, the 38th and 42nd Bomb Groups began the difficult training demanded by the B-26.
The day after the Pearl Harbor attack, the 22nd Group, still the only operational B-26 unit, was ordered from Langley Field to Muroc, California, losing one plane on the way. It remained there until February 6, 1942, when its 56 B-26s were moved by ship to Hawaii, where ferry tanks were fitted on the 48 bombers their seven-man crews would fly to Australia by April.
On April 5, 1942, this group flew the warís first Air Force medium bomber mission, attacking Rabaul with six B-26s. In a series of unescorted attacks against Japanese-held bases against strong opposition by Zero fighters, the B-26ís speed and ruggedness won praise from its crews.
Two 42nd Bomb Group squadrons were moved to Alaska to join the 28th Group. The 77th Squadron lost five of the first 14 Marauders flown up in January 1942 from California, but there were 24 B-26s of the 73rd and 77th squadrons in Alaska by May. There, weather proved a greater problem than the Japanese when they attacked on June 3, 1942, and the B-26s had to hunt through fog for the enemy.
Two British battleships had been sunk on December 10, 1941, by torpedoes carried on 50 twin-engine Japanese Navy bombers. This disaster inspired improvisation of an external rack underneath the B-26 fuselage for a 1,927-pound Navy Mark 13-1 torpedo. This rack had been tested before the war, so kits could be forwarded to combat units. There was no time for the Army pilots to practice the very different attack technique required before attempts were made against enemy ships near Midway and Dutch Harbor on June 4, 1942.
While the first five B-26As were accepted on October 31, 1941, this model did not enter service until 1942 and that contract was completed in April. Thirty still had R-2800-5 Wasps, while the rest had R-2800-39s with different carburetors, beginning on December 31, 1941, and were known as B-26A-ls.
The B-26A differed mainly by provision for two 250-gallon ferry tanks in the bomb bay; a feature later added to some of the early B-26s. Armament remained three .50-caliber guns with 1,200 rounds and two .30-caliber guns with 1,200 rounds. Top speed was listed as 313 mph by the specification, but that was with a design gross weight of only 27,200 pounds. Since empty weight was 21,959 pounds, these Marauders usually weighed some 32,200 pounds with the full fuel, bomb, and crew carried into combat.
The first Marauders in action against Germany were those of the RAF, which had first been promised 500
B-26B-1s by a lend-lease contract placed on June 26, 1941, but these were rescheduled for the AAF after Pearl Harbor. However, in May 1942, General Rommelís offensive threatened British forces in Egypt, and immediate help was required. To fill a gap in Martin Baltimore deliveries, 52 B-26A-1s at AAF stations were allocated to the RAF as the Marauder I. An additional 19 B-26As were named the Marauder IA.
After accidents in the U.S. and in transit, the RAF received 14 B-26A and 43 B-26A-1 bombers. They had been prepared for British use at Omaha, and four were ferried across the North Atlantic in June 1942 for tests in Britain. The rest were intended for North Africa and had enlarged air intakes so that filters could be fitted to protect carburetor intakes during desert operations.
By August 1942, the first had been flown down to Brazil and across the South Atlantic and Africa to No. 14 Squadron in Egypt. Their first operational sortie was made on October 28, 1942, and two months later, this squadron began torpedo reconnaissance flights over the Mediterranean.
The first B-26B was accepted on April 5, 1942, and 26 re-equipped the 69th and 70th squadrons, 38th Group, which made the first B-26 overwater flight to Hawaii. The first two B-26Bs arrived in time for the Battle of Midway, when they and two 22nd Bomb Group B-26s made a gallant, but unsuccessful, torpedo attack on June 4, 1942. The Marauder was the only Army bomber to use torpedoes in combat, aside from the A-20 Havocs provided the Soviet Navy.