Editing Martin B-10 (section)

=== Martin Model 139, 139A and 139B ===
Army Air Corps versions, 165 built.
;YB-10
:Model 139A, test and production version of the XB-10 with crew reduced to three members, and two {{cvt|675|hp|kW}} R-1820-25, 14 built, some flown temporarily as float planes.<ref name="world2"/>
;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 {{cvt|236|mph|kph}}. This made it the fastest aircraft of the B-10 series. Despite this advantage, only one was built, as a test aircraft.<ref name="world2"/>
;B-10
:According to one source, two additional aircraft ordered in 1936.<ref name="world2"/>
;B-10B
:Model 139, main production version with two {{cvt|775|hp|kW}} R-1820-33 engines, 105 built, delivered August 1936.<ref name="world2"/>
;B-10M
:According to one source this was, these were B-10Bs converted as target tugs.<ref name="world2"/> According to Martin's own archive, this was the designation of the YB-10 after testing, then used for airmail and Alaska missions, 13 of the 14 built were still in service in April 1940.
;RB-10MA
:One former NEIAF Model 139WH-3A model impressed in July 1942 and flown from Australia to the United States.<ref name="world2"/>
;YB-12
:Model 139B. With {{convert|250|or|500|USgal|L}} flotation chambers for safety on overwater flights, and two [[Pratt & Whitney R-1690]]-11 "Hornet" radial engines. These {{cvt|775|hp|kW}} engines gave similar performance to those on the B-10B ({{cvt|218|mph|kph}}), seven built, five still in service in April 1940.<ref name="world2"/>
;(Y)B-12A
:The production version of the YB-12 with provision for a {{cvt|365|USgal|L}} fuel tank in the bomb bay, giving the B-12A a combat range of {{cvt|1240|mi|km}}, 25 built, 23 still in service in April 1940.<ref name="world2"/>
;YB-13
:Re-engined version of the YB-10 powered by two {{cvt|700|hp|kW}} [[Pratt & Whitney R-1860|Pratt & Whitney R-1860-17 Hornet B]] radial engines. Ten were on order but cancelled before production started, not built.<ref name="world2"/>
;XB-14
:To test the new {{cvt|900|hp|kW}} [[Pratt & Whitney R-1830|Pratt & Whitney YR-1830-9]] "Twin Wasp" radial engines, one built which was converted back to YB-12 after testing.<ref name="world2"/>
;A-15
:Proposed attack variant of the YB-10 with two {{cvt|750|hp|kW}} R-1820-25 engines, was never built. The contract fell to the [[A-14 Shrike]].<ref name="ohnine2">Swanborough and Bowers 1964, p. 332.</ref>
;YO-45
:With two {{cvt|750|hp|kW}} Wright R-1820-17, proposed high-speed observation role, one B-10 was beginning to be converted in 1934 and another in 1935 but both were stopped before being completed and were converted back into B-10s.