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Jumat, 11 September 2009

MARAUDERS


B-26 Marauder
A US Army Air Forces B-26B with D-Day invasion stripes
Role Medium bomber
National origin United States
Manufacturer Glenn L. Martin Company
First flight 25 November 1940
Introduced 1941
Status Retired
Primary users United States Army Air Forces
United States Army Air Corps
Royal Air Force
South African Air Force
Produced 1941–1945
Number built 5,288[1]
Unit cost $102,659.33/B-26A[2]

The Martin B-26 Marauder was a World War II twin-engine medium bomber built by the Glenn L. Martin Company.

The first US medium bomber used in the Pacific Theater in early 1942, it was also used in the Mediterranean Theater and in Western Europe. The plane distinguished itself as "the chief bombardment weapon on the Western Front" according to an United States Army Air Forces dispatch from 1946,[citation needed] and later variants maintained the lowest loss record of any combat aircraft during World War II. Its late-war loss record stands in sharp contrast to its unofficial nickname "The Widowmaker" — earned due to early models' high rate of accidents during takeoff.

A total of 5,288 were produced between February 1941 and March 1945; 522 of these were flown by the Royal Air Force and the South African Air Force.

Contents

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[edit] Design and development

In March 1939, the United States Army Air Corps issued Circular Proposal 39-640, a specification for a twin-engined medium bomber. Six months later, Glenn L. Martin Company was awarded a contract for 201 planes. This design, Martin Model 179, was accepted for production before a prototype even flew. The B-26 went from paper concept to working plane in approximately two years. The lead designer was Peyton M. Magruder.

Closeup view of Martin B-26C in flight.

Once the first aircraft came off the production line in November 1940, Martin conducted tests, the results of which were promising. The first B-26, with Martin test pilot William K. "Ken" Ebel at the controls, flew on 25 November 1940 and was effectively the prototype. Deliveries to the U.S. Army Air Corps began in February 1941 with the second plane, 40-1362. In March 1941, the Army Air Corps started Accelerated Service Testing of the B-26 at Patterson Field, Ohio.

The Martin electric turret was retrofitted to some of the first B-26s. Martin began testing a taller vertical stabilizer and revised tail gunner's position in 1941.

[edit] Accidents

 This section may contain original research or unverified claims. Please improve the article by adding references. See the talk page for details. (October 2008)

While the B-26 was a fast plane with better performance than the contemporary B-25 Mitchell, its relatively small wing area and resulting high wing loading (the highest of any aircraft used at that time) required an unprecedented landing speed (120-135 mph/193-217 km/h indicated airspeed depending on load). At least two of the earliest B-26s suffered hard landings and damage to the main landing gear, engine mounts, propellers and fuselage. The type was grounded briefly in April 1941 to investigate the landing difficulties. Two causes were found: insufficient landing speed (producing a stall) and improper weight distribution. The latter was due to the lack of a dorsal turret; the Martin power turret was not ready yet.

Some of the very earliest B-26s suffered collapses of the nose landing gear. It is said that they were caused by improper weight distribution but that is probably not the only reason. They occurred during low-speed taxiing, takeoffs and landings. Occasionally the strut unlocked.

The Pratt & Whitney R-2800 engines were reliable but the Curtiss electric pitch change mechanism in the propellers required impeccable maintenance. Human error and some failures of the mechanism occasionally placed the propeller blades in flat pitch and resulted in an overspeeding propeller, sometimes known as a "runaway prop". Due to its sound and the possibility that the propeller blades could disintegrate, this situation was particularly frightening for aircrews. More challenging was a loss of power in one engine during takeoff. These and other malfunctions, as well as human error, claimed a number of planes and the commanding officer of the 22nd Bombardment Group, Col. Mark Lewis.

The Martin B-26 suffered only two fatal accidents during its first year of flights, November 1940-November 1941: a crash shortly after takeoff near Martin's Middle River plant (cause unknown but engine malfunction strongly suggested) and the loss of a 38th Bombardment Group plane when its vertical stabilizer and rudder separated from the plane at altitude (cause unknown, but accident report discussed the possibility that a canopy hatch broke off and struck the vertical stabilizer).

The B-26 was not an airplane for novices. Unfortunately, due to the need to quickly train many pilots for the war, a number of relatively inexperienced pilots got into the cockpit and the accident rate increased accordingly. This occurred at the same time as more experienced B-26 pilots of the 22nd, 38th and 42nd Bombardment Groups were proving the merits of the airplane.

For a time in 1942, pilots in training believed that the B-26 could not be flown on one engine. This was disproved by a number of experienced pilots, including Jimmy Doolittle.

In 1942, Senator Harry Truman was a leading member of the Senate Special Committee to Investigate the National Defense Program (the so-called Truman Committee), which was investigating defense contracting abuses. When Truman and other committee members arrived at the Avon Park Army Air Field in Florida, they were greeted by the still-burning wreckage of two crashed B-26s. Truman criticized both Glenn L. Martin and the B-26. Indeed, the regularity of crashes by pilots training at nearby MacDill Field—up to fifteen in one 30-day period—led to the only mildly exaggerated catchphrase, "One a day in Tampa Bay."

The B-26 received the nickname "Widowmaker". Other colorful nicknames included "Martin Murderer", "Flying Coffin", "B-Dash-Crash", "Flying Prostitute" (so-named because it had "no visible means of support," referring to its small wings) and "Baltimore Whore" (a reference to the city where Martin was based).[3]

The B-26 is said[who?] to have had the lowest combat loss rate of any U.S. aircraft used during the war. Nevertheless, it remained a challenging plane to fly and continued to be unpopular with some pilots throughout its military career.

[edit] Operational history

B-26 flying over its target during World War II.

The B-26 Marauder was used mostly in Europe but also saw action in the Mediterranean and the Pacific. In early combat the aircraft took heavy losses but was still one of the most successful medium-range bombers used by the U.S. Army Air Forces.[4]

In September 1940, the Army Air Corps ordered 1,131 B-26s. The airplane began flying combat missions in the Southwest Pacific in the spring of 1942, but most of the B-26s subsequently assigned to operational theaters were sent to England and the Mediterranean area.

Bombing from medium altitudes of 10,000-15,000 ft (3,048-4,572 m), the Marauder had the lowest loss rate of any Allied bomber - less than ½%. By the end of World War II, it had flown more than 110,000 sorties and had dropped 150,000 tons (136,078 tonnes) of bombs, and had been used in combat by British, Free French and South African forces in addition to U.S. units. In 1945, when B-26 production was halted, 5,266 had been built.[5]

The B-26 was phased out of US Army Air Forces service before the end of the war. Its last mission was flown in May 1945. According to an article in the April edition of AOPA Pilot on Kermit Weeks' "Fantasy of Flight", the Marauder had a tendency to "hunt" in yaw. This instability is similar to "Dutch roll". This would make for a very uncomfortable ride, especially for the tail gunner.

[edit] Variants

The development of the B-26 in illustrated form.
U.S. Army Air Forces B-26B bomber in flight.
  • B-26 - The first produced model of the B-26, ordered based upon design alone.[6] The armament on this model consisted of two .30 inches (7.62 mm) and two .50 inches (12.7 mm) machine guns. (The last model was armed with nearly three times that number.) Approximate pcost then: $80,226.80/plane.
  • B-26A - Incorporated changes made on the production line to the B-26, including upgrading the two .30 inches (7.62 mm) machine guns in the nose and tail to .50 inches (12.7 mm).[2] A total of 52 B-26As were sent to the United Kingdom, which were used as the Marauder Mk I. Approximate cost then: $102,659.33/aircraft (×139)
  • B-26B - Model with further improvements on the B-26A.[7] Nineteen were sent to the United Kingdom, which were used as the Marauder Mk.IA. Production blocks of the 1883 planes built:
    • AT-23A or TB-26B - 208 B-26Bs converted into target tugs and gunnery trainers designated JM-1 by the Navy.
    • B-26B—Single tail gun replaced with twin gun; belly-mounted "tunnel-gun" added. (×81)
    • B-26B-1 - Improved B-26B. (×225)
    • B-26B-2 - Pratt & Whitney R-2800-41 radials. (×96)
    • B-26B-3 - Larger carburetor intakes; upgrade to R-2800-43 radials. (×28)
    • B-26B-4 - Improved B-26B-3. (×211)
    • B-26B-10 through B-26B-55 - Beginning with block 10, the wingspan was increased from 65 feet (20 m) to 71 feet (22 m), to improve handling problems during landing caused by a high wing load; flaps were added outboard of the engine nacelles for this purpose also. The vertical stabiliser height was increased from 19 feet 10 inches (6.0 m) to 21 feet 6 inches (6.6 m). The armament was increased from six to 12 .50 inches (12.7 mm) machine guns; this was done in the forward section so that the B-26 could perform strafing missions. The tail gun was upgraded from manual to power operated. Armor was added to protect the pilot and copilot. (×1242)
    • CB-26B - 12 B-26Bs were converted into transport aircraft (all were delivered to the US Marine Corps for use in the Philippines).
  • B-26C - Designation assigned to those B-26Bs built in Omaha, Nebraska instead of Baltimore, Maryland.[8] Although nominally the B-26B-10 was the first variant to receive the longer wing, it was actually installed on B-26Cs before the B-26B-10, both being in production simultaneously. 123 B-26Cs were used by the RAF as the Marauder Mk II. Approximate cost then: $138,551.27/plane (×1210)
    • TB-26C—Originally designated AT-23B. Trainer modification of B-26C. (×>300)
  • XB-26D - Modified B-26 used to test hot air de-icing equipment, in which heat exchangers transferred heat from engine exhaust to air circulated to the leading and trailing edges of the wing and empennage surfaces.[9] This system, while promising, was not incorporated into any production aircraft made during World War II. (×1, converted)
  • B-26E - Modified B-26B constructed to test the effectiveness of moving the dorsal gun turret from the aft fuselage to just behind the cockpit.[10] The offensive and defensive abilities of the B-26E was tested against in combat simulations against normal aircraft. Although test showed that gains were made with the new arrangement, the gain was insignificant. After a cost analysis, it was concluded that the effort needed to convert production lines to the B-26E arrangement was not worth the effort. (×1, converted)
  • B-26F - Angle of incidence of wings increased by 3.5º; fixed .50 inches (12.7 mm) machine gun in nose removed; tail turret and associated armour improved.[11] The first B-26F was produced in February 1944. One hundred of these were B-26F-1-MAs. Starting with 42-96231, a revised oil cooler was added, along with wing bottom panels redesigned for easier removal. A total of 200 of the 300 planes were B-26F-2s and F-6s, all of which were used by the RAF as the Marauder Mk III. The Marauder III carried the RAF serials HD402 through HD601 (ex-USAAF serials 42-96329 through 96528). The F-2 had the Bell M-6 power turret replaced by an M-6A with a flexible canvas cover over the guns. The T-1 bombsight was installed instead of the M-series sight. British bomb fusing and radio equipment were provided. (×300)
  • B-26G - B-26F with standardised interior equipment.[12] A total of 150 bombers were used by the RAF as the Marauder Mk III. (×893)
    • TB-26G - B-26G converted for crew training. Most, possibly all, were delivered to the United States Navy as the JM-2. (×57)
  • XB-26H - Test aircraft for tandem landing gear, and nicknamed the "Middle River Stump Jumper" from its "bicycle" gear configuration, to see if it could be used on the Martin XB-48.[13] (×1, converted)
  • JM-1P - A small number of JM-1s were converted into photo-reconnaissance aircraft.

[edit] Operators

Main article: List of units using the B-26 Marauder during World War II
WASPs on flightline at Laredo Army Air Field, Texas, 22 January 1944.
France
South Africa
United Kingdom
United States

[edit] Survivors

  • B-26B, part of the Fantasy of Flight collection in Polk City, Florida.
  • B-26G (s/n 43-34581) is on display at the National Museum of the United States Air Force in Dayton, Ohio. This aircraft was flown in combat by the Free French during the final months of World War II. It was obtained from the French airline Air France training school near Paris in June 1965. It is painted as a 9th Air Force B-26B assigned to the 387th Bomb Group in 1945.[14]
  • B-26G-25-MA (s/n 44-68219) is on display at the Musée de l'Air et de l'Espace in Le Bourget, France. It was also recovered from the Air France training school.[15]
  • B-26 on display in Marietta, Georgia. Provenance unknown.
  • B-26B-25-MA (s/n 41-31773) "Flak Bait." The nose section is on display at the National Air and Space Museum, Washington DC. The remainder (mid and tail fuselage sections, wings, engines, and empennage) are stored at NASM's Paul E. Garber facility in Suitland MD. This aircraft survived 207 operational missions over Europe, more than any other American aircraft during World War II and will, one day, be restored and displayed at NASM's Steven F. Udvar-Hazy Center at Dulles International Airport VA.

[edit] Specifications (B-26G)

Martin B-26G Marauder at the National Museum of the United States Air Force.

Data from Quest for Performance[16] and Jane's Fighting Aircraft of World War II[17]

General characteristics

  • Crew: 7: (2 pilots, bombardier, navigator/radio operator, 3 gunners)
  • Length: 58 ft 3 in (17.8 m)
  • Wingspan: 71 ft 0 in (21.65 m)
  • Height: 21 ft 6 in (6.55 m)
  • Wing area: 658 ft2 (61.1 m2)
  • Empty weight: 24,000 lb (11,000 kg)
  • Loaded weight: 37,000 lb (17,000 kg)
  • Powerplant: 2× Pratt & Whitney R-2800-43 radial engines, 1,900 hp (1,400 kW) each

Performance

Armament

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