04/30/2014. Remarks by Johan Visschedijk: "US Army Air Corps requirements for a new high-speed medium bomber were circulated to the US aircraft manufacturers on January 25, 1939. Emphasis was placed in the outline specification upon the need for good speed, range and ceiling performance; a crew of five, a 2,000 lb (907 kg). bomb-load and four 0.30 in (7.62 mm) guns were to be carried. By omitting reference to the characteristics at the lower end of the performance range, the USAAC tacitly admitted that high landing speeds and long take-offs would be accepted in order to obtain the required speed.
A design to meet this specification was submitted to an Army Board at Wright Field by Glenn L. Martin Co. on July 5, 1939, accompanied by a guarantee to build a certain quantity of the bombers in a given time. In the AAC evaluation of the designs submitted by various manufacturers, points were awarded in various categories up to a maximum of 1,000; the Martin 179 design scored 140 points over the next-best project. With WW II imminent in Europe, the AAC took the unprecedented step of ordering its new medium bomber into production immediately the design had been accepted; in September 1939 Martin received a contract for 1,100 and the type was numbered B-26.
The Martin 179 design had been projected – by Peyton M. Magruder – with the highest wing loading of any aircraft then designed for the AAC, in order to obtain the high speed performance. Associated with the comparatively small wing were two large nacelles for the 1,850 hp Pratt & Whitney R-2800 Double Wasp engines and a rotund but beautifully-streamlined fuselage. As specified, one 0.30 in (7.62 mm) gun was mounted for tail defense; another was hand-operated on a ball-mounting in the nose, and two 0.50 in (12.7 mm) guns equipped the Martin 250CE electrically-operated dorsal turret. The wing was shoulder mounted to leave the center fuselage free for bomb stowage.
Construction of the first B-26s at the Martin plant in Baltimore, Maryland, was directed by William K. (Ken) Ebel, then Martin's chief engineer, who also piloted the first B-26 (s/n 40-1361) on its first flight on November 25, 1940. The next B-26 followed in February 1941. As no prototypes had been ordered, the first few production aircraft were reserved for test purposes. The first 201 aircraft were of the plain B-26 type, with 1,850 hp R-2800-5 engines and a gross weight of 30,035 lb (13,624 kg); the maximum bomb load was 5,800 lb (2,631 kg), and the speed of 315 mph (507 kmh) was the best of all B-26 models.
Deliveries to the AAC began on February 22, 1941 but units were slow to become operational on the type because its high landing speed (inevitable with the chosen wing loading) made conversion training a lengthy, and at times dangerous, process. An increase in gross weight to 32,200 lb (14,606 kg) on the B-26A, which followed the B-26 in the second half of 1941, did nothing to improve the problem. The higher weight arose from the introduction of additional optional fuel tanks in the bomb bay, shackles for a 22 in (56 cm) torpedo beneath the fuselage, 0.50 in (12.7 mm) guns in the nose and tail and other additional equipment. A change was made from 12 volt to 24 volt electrical system, and most of the 139 B-26As built had R-2800-9 or -39 engines.
By the end of 1941, the 22nd Bombardment Group had equipped with B-26s, which it took from Langley Field, Virginia, to Australia on December 8, 1941, in one of the first overseas deployments of home-based US Army Air Forces units of the War (the USAAC had been renamed on June 20, 1941). The 22nd took its Marauders into action for the first time in April 1942 in attacks on New Guinea. With fuel in the bomb bays to obtain the necessary range, the bomb-load was limited to 2,000 lb (907 kg) and these raids were probably of more consequence as morale raisers than for the damage they caused. In June
B-26As were in action as torpedo bombers at the Battle of Midway and, flown by the 73rd and 77th Bombardment Squadrons from Alaska, in attacks on shipping in the Aleutians.
In May 1942, production of the B-26B began, and this became the most-produced variant, existing in a number of distinct versions. Initially, the changes from the B-26A comprised improved crew protection armor, refined internal equipment, deletion of propeller spinners, revised cowling details, a ventral "tunnel" gun and a new tail gun position with two 0.50 in (12.7 mm) guns. The gross weight increased to 36,500 lb (16,556 kg) with a 5,200 lb (2,359 kg) bomb and torpedo load. The engines were 1,850 hp R-2800-5s, but these were changed to 1,920 hp R-2800-41 or -43 in the second series of Bs (block numbers -2, -3 and -4).
In the B-26B-4, the nose-wheel strut was lengthened to improve the takeoff performance (by increasing the effective wing incidence) and two 0.50 in (12.7 mm) beam guns replaced the 0.30 in (7.62 mm) tunnel gun of the earlier Bs. A further series of modifications introduced slotted flaps on the B-26B-5. Production of these versions totaled 641.
With the B-26B-10 and subsequent models (also known to the makers as the B-26-B1), an effort was made to make the Marauder a less tricky aeroplane on the approach and landing by increasing wing span and area (65 ft to 71 ft and 602 sq.ft to 659 sq.ft or 20.73 to 21.64 and 55.93 to 61.22 sq.m respectively). In theory, this reduced the wing loading, but the permissible gross weight was also increased to 38,200 lb (17,327 kg) with the introduction of still more defensive armament. A second gun was added to the nose armament, and two "package" guns were installed on each side of the lower fuselage just behind the cockpit; a Martin-Bell power operated tail turret also became standard. The increased wing span was accompanied by a taller fin and rudder.
Martin built 1,242 of the B-26B-10 and later variants at Baltimore, and established, later in 1942, a second production source of Marauders at Omaha, Nebraska, where the same type was built as the B-26C. Omaha built 1,235 of the latter version.
All early B-26 operations were in the Pacific area, but in November 1942, the 17th, 319th and 320th Bombardment Groups of the AAF arrived in North Africa with B-26Bs and B-26Cs, which they took into operation in December. As part of the 12th AF, these Marauder-equipped groups followed the Allied ground forces from North Africa through Sicily to Italy, Sardinia, Corsica and into the South of France.
The first B-26s arrived in the UK in February 1943 and flew their first mission with the 8th AF on May 14, 1943, when 11 B-26s made a disastrous low-level attack on IJmuiden, from which none returned. More success attended strategic high level operations, started in July with an attack on Abbeville, but the B-26 did not find its optimum employment in Europe until applied to tactical air support duties. In November, all 8th Air Force B-26 groups, in common with other light and medium bombers, were transferred to the newly formed 9th AF, with which they served with conspicuous success in support of the forthcoming invasion of Europe.
Final production models of the Marauder had the wing incidence angle increased by 3.5° in a further attempt to improve the takeoff performance. This and other detail changes distinguished the B-26F, of which Martin built 300 in 1943; 200 of these went to the RAF under Lend-Lease. Minor equipment changes were responsible for a change of designation to B-26G, which was in most respects similar to the B-26F. Martin built 893 B-26Gs (of which 150 went to the RAF) and a further 57 TB-26Gs which were stripped of armament and operational equipment to serve as trainers and target tugs. The last B-26 was delivered by Martin on March 30, 1945.
The single XB-26D was a B-26 conversion in 1942 with wing de-icing by hot air ducted from the engines. Another experimental type was the single B-26E, a converted and stripped B-26B with the dorsal turret relocated forward, over the navigator's position. The last Marauder designation was the XB-26H, with an experimental installation of a four-wheel bicycle undercarriage of the type then being designed for the Martin XB-48 and the Boeing XB-47.
In 1943, a conversion program was initiated to strip B-26s of operational equipment and provide them with target towing gear. In all, 208 B-26B and 350 B-26C were converted in this way, and re-designated AT-23A and AT-23B in the advanced trainer category. These designations were later changed to
TB-26B and TB-26C respectively, and TB-26G models were produced as such, as noted above. The USN received 225 AT-23Bs as JM-1s and another 47 TB-26Gs became JM-2s.
All B-26s were finally declared obsolete and withdrawn from service by the USAF in 1948 (few survived even until that date in an airworthy condition) and the B-26 designation was transferred to the Douglas A-26 in June 1948, the same date the USAAF was renamed US Air Force."
07/21/2007. Remarks by Curtiss
Aldrich: "The original source for this photo is from an official press release dated December 23, 1940 from the Glenn L. Martin Company. The photograph was taken at Martin's private airport near Baltimore, Maryland, USA. The caption mentions the new B-26 is 'ready for final tests' and 'expected to prove itself the world's fastest bombing airplane'. Its also staed it is the 'latest weapon of the U.S. Army Air Corps'...... Note the plane has no turrets or guns yet fitted, and it's the short wing version; probably a serious hot-rod!"