Martin B-10
The Martin B-10 was the first all-metal monoplane bomber to go into regular use by the United States Army Air Corps, entering service in June 1934.[1] It was also the first mass-produced bomber whose performance was superior to that of the Army's pursuit aircraft of the time.[2] The B-10 served as the airframe for the B-12, B-13, B-14, A-15 and O-45 designations.
The B-10 included several revolutionary features, and won Martin the Collier Trophy in 1932 for its design.
Design and development
The XB-10 began as the Martin Model 123, a private venture by the Glenn L. Martin Company of Baltimore, Maryland. It had a crew of four: pilot, copilot, nose gunner and fuselage gunner. As in previous bombers, the four crew compartments were open, but it had a number of design innovations as well. The most important of these were a deep belly for an internal bomb bay and retractable main landing gear. Its 600 hp (447 kW) Wright SR-1820-E Cyclone engines allowed for significant power. It first flew on 16 February 1932 and was delivered for testing to the U.S. Army on 20 March.
The B-10 began a revolution in bomber design. Its all-metal monoplane build, along with its features of closed cockpits, rotating gun turrets, retractable landing gear, internal bomb bay, and full engine cowlings, would become the standard for decades.[2] It made all existing bombers completely obsolete. In 1932, Martin received the Collier Trophy for designing the XB-10.
The XB-10 delivered to the Army was slightly different from the original aircraft. Where the Model 123 had NACA cowling rings, the XB-10 had full engine cowlings to decrease drag.[3] It also sported a fully rotating glass turret for the nose gunner, 675 hp (503 kW) Wright R-1820-19 engines, and an eight-foot increase in the wingspan. When the XB-10 flew during trials in June, it recorded a speed of 197 mph (317 km/h) at 6,000 ft (1830 m). This was an impressive performance for 1932.[2]
Following the success of the XB-10, a number of changes were made, including reduction to a three-man crew, addition of canopies for all crew positions, and an upgrade to 675 hp (503 kW) engines. The Army ordered 48 of these on 17 January 1933. The first 14 aircraft were designated YB-10 and delivered to Wright Field, starting in November 1933. The production model of the XB-10, the YB-10 was very similar to its prototype.
Operational history
In 1935 the Army ordered an additional 103 aircraft designated B-10B. These had only minor changes from the YB-10. Shipments began in 1935 July. B-10Bs served with the 2nd Bomb Group at Langley Field, the 9th Bomb Group at Mitchel Field, the 19th Bomb Group at March Field, the 6th Bomb Group in the Panama Canal Zone, and the 28th Bomb Group in the Philippines. In addition to conventional duties in the bomber role some modified Yb-10s and B-12As were operated for a time on large twin floats for coastal patrol.[4][5]
The Martin Model 139 was the export version of the Martin B-10. With an advanced performance, the Martin company fully expected that export orders for the B-10 would come flooding in.
The Army owned the rights to the Model 139 design. Only once the Army's orders had been filled in 1936, Martin received permission to export Model 139s, and delivered versions to several air forces. For example, six Model 139Ws were sold to Siam in April 1937, powered by Wright R-1820-G3 Cyclone engines; 20 Model 139Ws were sold to Turkey in September 1937, powered by R-1820-G2 engines.
Legacy
At the time of its creation, the B-10B was so advanced that General Henry H. Arnold described it as the air power wonder of its day. It was 1.5 times as fast as any biplane bomber, and faster than any contemporary fighter. The B-10 began a revolution in bomber design; it made all existing bombers completely obsolete. However, the rapid advances in bomber design in the 1930s meant that the B-10 was eclipsed by the B-17 Flying Fortress and B-18 Bolo before the United States entered World War II. The B-10's obsolescence was proved by the quick defeat of B-10B squadrons by Japanese Zeros during the invasions of the Dutch East Indies and China.[3]
An abortive effort to modernize the design, the Martin Model 146 was entered into a USAAC long-distance bomber design competition 1934-1935, fated to lose out to the Douglas B-18 and revolutionary Boeing B-17. The sole prototype was so similar in profile and performance to the Martin B-10 series that the other more modern designs easily "ran away" with the competition.
Variants
- Martin Model 123
- Private venture of Martin company, predecessor of the XB-10, served as prototype for the series.[6]
- XB-907
- US Army designation for the Model 123 in evaluation[6]
- XB-907A
- Modified XB-907 after Martin returned it to U.S. Army for further operational trials[3]
- XB-10
- Designation of the XB-907A when purchased by the United States Army Air Corps, Modified Martin Model 123 with full engine cowlings, fully rotating nose glass turret, more powerful engines, and increased wingspan.[2]
- YB-10
- Model 139, production version of the XB-10 with crew reduced to three members, canopies for all crew members and better engines (675hp R-1820-25), 14 built, some flown temporarily as float-planes.[4]
- B-10
- Two additonal aircraft ordered in 1936.[4]
- RB-10MA
- One former NEIAF Model 139WH-3A model impressed in July 1942 and flown from Australia to the United States.[4]
- YB-10A
- The YB-10A was different from a YB-10 only in its engines. It used Wright R-1820-31 turbo-supercharged radials, allowing it to attain speeds of 236 mph (380 km/h). This made it the fastest aircraft of the B-10 series. Despite this advantage, only one was built, as a test aircraft.[4]
- B-10B
- Main production version with two 775hp R-1820-33 engines, 103 built.[4]
- B-10M
- A number of B-10Bs converted as target tugs.[4]
- YB-12
- Re-engined version of the YB-10 with Pratt & Whitney R-1690-11 "Hornet" radial engines. These 775 hp (578 kW) engines gave similar performance to those on the B-10B (218 mph [351 km/h]), seven built.[4]
- B-12A
- The production version of the YB-12 with provision for a 365 U.S. gal (1,381 L) bomb bay tank, giving the B-12A a combat range of 1,240 miles (1,995 km), 25 built.[4]
- YB-13
- Re-engined version of the YB-10 powered by two 700hp Pratt & Whitney R-1860-17 radial engines. Ten were on order but cancelled before production started, not built.[4]
- XB-14
- The last of the 48 XB-10–airframes ordered by the army was a version of the YB-10 using Pratt & Whitney YR-1830-9 "Twin Wasp" radial engines, one built.[4]
- A-15
- Proposed attack variant of the YB-10 with two 750hp R-1820-25 engines, was never built. The contract fell to the A-14 Shrike.[7]
- YO-45
- One YB-10 temporarily tested in the high-speed observation role.
- Martin Model 139
- Martin export version of the B-10 bomber, six sold to Siam
- Model 139WA
- Martin demonstrator for Argentina
- Model 139WAA
- Export version for Argentine Army, 22 built
- Model 139WAN
- Export version for the Argentine Navy, 12 built.
- Model 139WC
- Export version for China, nine built.[1][8]
- Model 139WH
- Export version to Netherlands for use in the Dutch East Indies. Produced in block series H-1 (13 built), H-2 (26 built) and H-3. The 139WH-3 (also known as the Model 166) had two 900 hp R-1820-G102 and single long dorsal canopy, 39 built. The 139W-3A (also known as the Model 166A) as WH-3 with equipment changes, 40 built. A total of 166.[4]
- Model 139WS
- Single demonstrator to the Soviet Union.[8][4]
- Model 139WSM
- Export version for Siam, 23 built.[4]
- Model 139WSP
- Proposed licence built version to be built by CASA of Spain, not built.
- Model 139WT
- Export version for Turkey, 20 built[1]
Operators
- Argentine Air Force received 27 Model 139W aircraft.
- Argentine Navy received 13 Model 139W aircraft. [9]
- Indonesian Air Force took over several numbers of B-10, passed to Indonesian guerillas from Netherlands East Indies in 1945.[citation needed]
- Royal Thai Air Force received six Model 139W aircraft in April 1937 and used them during the 1942 invasion of Burma.
- Turkish Air Force received 20 Model 139W aircraft in September 1937.
- Soviet Air Force bought one aircraft for evaluation.
Survivors
The only known B-10 to still be intact is at the National Museum of the United States Air Force at Wright-Patterson Air Force Base near Dayton, Ohio. The aircraft on display is painted as a B-10 used in the 1934 Alaskan Flight. It was an export version sold to Argentina in 1938 and donated by the Government of Argentina to the U.S. Government for display in the museum in 1970. It was restored by the 96th Maintenance Squadron (Mobile), Air Force Reserve, at Kelly Air Force Base, Texas, in 1973-1976. [10]
Various parts of crashed B-10s, such as turrets and wings, were retrieved from the jungle of Borneo and are now on display in the Militaire-Luchtvaartmuseum (Military Aviation Museum) at Soesterberg, the Netherlands.[11]
Specifications (B-10B)
Data from United States Military Aircraft Since 1909[12]
General characteristics
- Crew: 3
Performance
Armament
- Guns: 3× .300 in (7.62 mm) Browning machine guns
- Bombs: 2,260 lb (1,030 kg)
References
- Notes
- ^ a b c Jackson 2003, p. 246.
- ^ a b c d Eden and Moeng 2002, p. 931.
- ^ a b c Cite error: The named reference
fitz46
was invoked but never defined (see the help page). - ^ a b c d e f g h i j k l m n Eden and Moeng 2002, p. 932.
- ^ Swanborough and Bowers 1964, p. 331.
- ^ a b Fitzsimons 1967/1969, p. 1845.
- ^ Swanborough and Bowers 1964, p. 332.
- ^ a b Baugher, Joe. "Martin B-10". Encyclopedia of American Aircraft Accessed 4 July 2007.
- ^ Donation of the Martin B-10
- ^ Martin B-10 USAF Fact Sheet
- ^ Netherlands Military Aviation Museum
- ^ Swanborough and Bowers, 1964, p. 333.
- Bibliography
- Eden, Paul and Moeng, Soph, eds. The Complete Encyclopedia of World Aircraft. London: Amber Books Ltd., 2002. ISBN 0-7607-3432-1.
- Fitzsimons, Bernard, ed. The Illustrated Encyclopedia of the 20th Century Weapons and Warfare. New York: Purnell & Sons Ltd., 1967/1969. ISBN 0-83936-175-0.
- Jackson, Robert, The Encyclopedia of Military Aircraft, London: Parragon Publishing, 2003. ISBN 1-40542-465-6.
- Swanborough, F. Gordon and Bowers, Peter M.United States Military Aircraft Since 1909. Putnam New York, 1964. ISBN 0-85177-816-X.
- Taylor, John W. R. "Martin B-10". Combat Aircraft of the World from 1909 to the Present. New York: G.P. Putnam's Sons, 1969. ISBN 0-425-03633-2.
External links
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