Rami,
Looks like Bs and Cs.....
By the end of 1941, the USAAF 22nd Bomb Group (BG) had been equipped with the Marauder, and after the Pearl Harbor attack on 7 December 1941 the 22 BG was shipped off to Australia, arriving in February 1942. These Marauders performed the type's first combat mission, a raid on the main Japanese base in the South Pacific at Rabaul on New Britain on 5 April 1942. Some of the Marauders operating in the South Pacific were fitted with an additional machine gun in the nose.
Four Marauders were used in the torpedo-bomber role at the Battle of Midway in June 1942, attacking Japanese carriers but scoring no hits and losing two of their number. Torpedo-carrying Marauders attacked the Japanese carrier RYUJO off the Aleutians the same day, but no hits were scored. These were the first and last times the Marauder saw combat with the USAAF as a torpedo bomber.
The pilot of one of the Marauders at Midway, Lieutenant James P. Muri, did establish a legend of sorts by flying straight up the deck of the carrier AKAGI after his torpedo run, sending Japanese deck crew sprawling on their faces. Muri insisted later he didn't pull this stunt out of any sense of daring, instead seeing the carrier as being the only place he could go where he might not be shot at for a moment, but whatever the motivation the Japanese were flabbergasted. His Marauder, SUZIE-Q, made it back to Midway, but it was so thoroughly shot full of holes that it was simply stripped of what little useful hardware was left and then shoved into the Pacific by a bulldozer.
In April 1942, production had moved on to the "B-26B", the definitive Marauder variant, though it was built in a series of production blocks with successive improvements. The initial "B-26B-1" subvariant had new engine cowlings; deleted the propeller spinners; added armor protection and a new ventral gun position with a single flexible 12.7 millimeter gun; and had a revised tailgun position with twin 12.7 millimeter tail guns in a new rear fuselage that extended the aircraft's length by 70 centimeters (28 inches).
These additions increased the aircraft's weight while engine power remained the same, but later B-26B production blocks, starting with the "B-26B-2", had P&W R-2800-41 engines with 1,492 kW (2,000 HP) each. The "B-26B-3" was essentially identical to the B-26B-2, but had larger carburetor air intakes on top of the engine cowling to allow fit of sand filters for desert operations.
By this time, the Marauder's safety record had become very controversial. There were obvious difficulties with the long takeoff run, fast landing speeds, and unfamiliar tricycle landing gear configuration. Another problem was that the electrically operated propellers were prone to wiring faults, causing them to go to flat pitch and "runaway" at high RPM. The ground crews were also unused to working on an aircraft that had so many electrical systems; techs tended to run the batteries down while performing maintenance, leading to battery power failure and loss of prop pitch control on takeoff.
The result was a series of deadly accidents. Flight training was conducted out of Tampa, Florida, resulting in the motto "a Marauder a day in Tampa Bay", and the B-26 became known as "the Martin Murderer", the "Baltimore Whore" or "the Flying Prostitute", the last two partly because the wings were so short the aircraft was said to have "no visible means of support".
The real problem was that the USAAF was going into war in a great hurry with new, advanced equipment, and the service was forced to figure out how to train crews for faster aircraft as an ongoing exercise. Matters improved once the USAAF obtained twin-engine trainers, allowing cadet pilots to get twin-engine experience before moving on to the Marauder; gave ground crews battery carts; and tightened up other procedures.
Coming up with such improved procedures took time, and meanwhile there was a public outcry against the Marauder. The type had its champions who managed to protect it. Reports from crews flying combat missions with the Marauder were enthusiastic, and the prestigious Colonel Jimmy Doolittle took a B-26A on a stateside tour to show off what it could do, often putting it through its paces after feathering an engine. He did admit that it was an unforgiving aircraft.
Martin made changes in the design in hopes of improving aircraft safety. The "B-26B-4" introduced a longer nosewheel leg to give the aircraft a higher wing incidence to reduce takeoff run, and also changed the ventral gun to one flexible 12.7 millimeter gun on each beam position. The "B-26B-5" added slotted flaps to reduce landing speed. A total of 641 B-26B-1 through B-26B-5 Marauders was built, and then Martin began production of the "B-26B-10", with significant changes. The B-26B-10 featured greater wingspan in hopes of reducing the Marauder's wing loading, a new power-operated Martin-Bell tail turret with twin 12.7 millimeter guns, and four fixed forward-firing 12.7 millimeter guns for strafing, fitted in "packages" beneath the cockpit. The tailfin was increased in height and area to improve yaw stability. The engines were R-2800-43s, with mechanical improvements but no increase in horsepower over the -41 engines.
Source:
http://www.vectorsite.net/avb26.html