B-10

The B-10 was the first all-metal monoplane bomber to be produced in quantity. It also introduced such innovations as a monocoque fuselage, variable-pitch propellers, retractable landing gear, enclosed cockpits, and a rotating gun turret. A company- developed design, the prototype was found to have some deficiencies when testing began at Wright Field, Ohio, in the spring of 1932. It was modified to meet the Army's recommendations, and the XB-907A returned to Wright Field where it reached a speed of 207 mph with a full bomb load, which was considerably faster than any biplane bomber and as fast as most of the pursuit ships of the day. The Air Corps then bought the prototype (and redesignated it XB-10) along with 14 YB-10 service test aircraft. A total of 103 B-10B aircraft were built, and the type served in every AAC bomb group in the 1930s. Lt. Col. Henry H. "Hap" Arnold led a mass flight of B-10 crews from Washington, D. C., to Alaska for a six-week mapping mission that covered 18,000 miles. In 1935, B- 10s were used to test the Norden bombsight. Thirty-two YB-12/B-12A were built, which were essentially the same as the B-10, except for different engines, extra fuel, and flotation chambers for overwater flying as part of the AAC's coastal defense mission. Export versions (192 Martin Model 139s) were sold to the Soviet Union, the Netherlands, China, Siam, Argentina, and Turkey. Most of the B-10s were still in service in 1940, although relegated to target-towing duties. Only one B-10 exists today, a Model 139 on display at the US Air Force Museum at Wright-Patterson AFB, Ohio. (Specifications for B-10B.)

Contractors:	Glenn L. Martin Co.
Locations Built:	Baltimore, MD
Number Built: (USAF)	155 (155)
First Flight:	February or March 1932
First Flight Model:	Company Model XB-907
First Flight Location:	Baltimore, MD
First Flight Pilot:	Likely William K. "Ken" Ebel
Models/Variants:	B-10B
Powerplant:	Two Wright R-1820-33 Cyclone nine-cylinder radials of 775 hp each.
Wingspan:	70 ft 6 in.
Length:	44 ft 9 in.
Height:	15 ft 5 in.
Weight:	14,7000 lb gross.
Armament:	Three .30-cal. machine guns (one each in nose turret, aft cockpit, and ventral tunnel) and 2,260 lb of bombs internally.
Accommodation:	Four (pilot and copilot/radio operator in separate cockpits, bombardier/gunner, and gunner)
Cost:	$50,840
Max. Speed:	215 mph.
Range:	1,240 mi.
Ceiling:	24,200 ft.