The Douglas O-2 was a 1920s

American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, pe ...

observation aircraft built by the

Douglas Aircraft Company The Douglas Aircraft Company was an American aerospace manufacturer based in Southern California. It was founded in 1921 by Donald Wills Douglas Sr. and later merged with McDonnell Aircraft in 1967 to form McDonnell Douglas; it then operated as ...

Development

The important family of Douglas observation aircraft sprang from two XO-2 prototypes, the first of which was powered by the 420 hp (313 kW)

Liberty V-1650-1 The Liberty L-12 is an American water-cooled 45° V-12 aircraft engine displacing and making designed for a high power-to-weight ratio and ease of mass production. It saw wide use in aero applications, and, once marinized, in marine use both i ...

V-engine and test-flown in the autumn of 1924. The second XO-2 was powered by the 510 hp (380 kW) Packard 1A-1500 Vee engine, which proved unreliable. The US Army ordered 45 O-2 production aircraft in 1925, these retaining the XO-2's welded steel tube fuselage, wooden wings and overall fabric covering but at the same time introducing aluminum panels on the forward fuselage. The XO-2 had been flown with short and long-span wings, the latter giving improved handling and therefore being specified for the production aircraft. The fixed tailskid landing gear included a main unit of the divided type, the horizontal tail surface was strut braced, and the engine was cooled by a tunnel

radiator Radiators are heat exchangers used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in cars, buildings, and electronics. A radiator is always a ...

. The O-2 proved to be a conventional but very reliable

biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While ...

which soon attracted orders for 25 more aircraft: 18 O-2A machines equipped for night flying and six O-2B dual-control command aircraft for the US Army, plus one civil O-2BS modified specially for James McKee, who made a remarkable trans-Canada flight in September 1926. In 1927 the O-2BS was adapted as a three-seater with a radial engine. The O-2Hs were an entirely new design but continued the same basic model number. Major differences were heavily staggered wings, a more compact engine installation, and clean landing gear secured to the fuselage. Up to 2011 there were no O-2's known to exist. However, in 2011 the wreckage of O-2H 29-163 that crashed out of Kelly Field Texas on March 16, 1933 has been positively identified. The rear and central/forward portion of the fuselage behind the firewall, wing attachments and landing gear parts, tailplane and many engine parts and eight of the twelve pistons are now recovered. Research is continuing on this aircraft. It is known it was flown by Aviation Cadet Charles D. Rogers on a night recon advanced training mission. Apparently flying low, the aircraft hit a hill and burned after the crash leaving only the found wreckage today. Weather was not considered a contributing factor. Cadet Rogers was instantly killed in the crash by the impact. His body was recovered but the wreckage was abandoned due to the airframe and engine both being a writeoff. The only similar aircraft known to exist are a restored Douglas M-2 mailplane and a follow-on derivative of the O-25 variant, an

O-38 The Douglas O-38 was an observation airplane used by the United States Army Air Corps. Between 1931 and 1934, Douglas built 156 O-38s for the Air Corps, eight of which were O-38Fs. Some were still in service at the time of the Pearl Harbor Attack ...

Operational history

Douglas O-2M variants were deployed by the Chinese Air Force's 6th, 7th and 8th Bomber-Attack and Scouting-Attack Groups in combat against the Imperial Japanese forces during the early years of the War of Resistance-World War II. O-2Ms (sometimes mislabeled as Douglas ''O-38''s) were heavily deployed in the Battle of Shanghai, the

Battle of Nanjing The Battle of Nanking (or Nanjing) was fought in early December 1937 during the Second Sino-Japanese War between the Chinese National Revolutionary Army and the Imperial Japanese Army for control of Nanking (Nanjing), the capital of the Rep ...

and the Battle of Taiyuan. As their slow speed made the O-2Ms vulnerable to fast Japanese fighters, they either flew clandestine night missions solo or day missions escorted by Hawk IIs or Hawk IIIs. Japanese ace fighter pilot Akio Matsuba flying an A2N from the aircraft carrier ''Kaga'' in his first aerial combat engagement, claimed his first (shared) victory over an O-2M while providing air-cover for Japanese troop-landings in Shanghai on third day in the airwar of the War of Resistance/WWII, 16 August 1937.

Variants

;XO-2 : Two pre-production prototypes. ;O-2 : Initial production model - 45 built. ;O-2A : O-2 with night flying equipment - 18 built. ;O-2B : Dual control version of O-2 - six built. ;O-2C : These differed from the O-2 in having frontal radiators for their

Liberty L-12 The Liberty L-12 is an American water-cooled 45° V-12 aircraft engine displacing and making designed for a high power-to-weight ratio and ease of mass production. It saw wide use in aero applications, and, once marinized Marinisation (also m ...

engines and modified oleo-strut landing gear. The USAAC took delivery of 18 aircraft, while the remaining 27 went to reserve National Guard units - 45 built and one later conversion from O-9. ;O-2D : Unarmed staff transport versions of the O-2C - two built. ;O-2E : A one-off aircraft which replaced the wire link between upper and lower wing ailerons of production aircraft by rigid struts. ;O-2H : The fuselage was redesigned and a new tailplane was fitted, with staggered wings of unequal span. The O-2H incorporated the rigid- strut aileron interconnections of the O-2E. An improved split-

axle An axle or axletree is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, bearing ...

landing gear was standard. The USAAC received 101 O-2Hs between 1928 and 1930, and the National Guard a further 40 - 141 built. ;O-2J : Unarmed dual control version of the O-2H for service as USAAC staff transports - three built. ;O-2K : A slightly modified version of the O-2J for US Army staff transport and liaison duties. 30 built for the USAAC and 20 for the National Guard - 50 built. ;O-2M : various export versions of O-2 that saw services with Republic of China Air Force. These aircraft were used as scout-bombers by the Chinese in the Second Sino-Japanese War with some success against ground targets of the Empire of Japan. It was also used by the Mexican Air Force with Lewis and Vickers machine guns, with very good results. ;O-2MC : Export version for China, powered by a Hornet radial engine - ten built ;O-2MC-2 : Export version for China, with the Hornet radial engine surrounded by a Townend ring - 20 built ;O-2MC-3 : Export version for China, fitted with an uprated Pratt & Whitney Hornet radial engine - five built ;O-2MC-4 : Export version for China - 12 built ;O-2MC-5 : Export version for China, fitted with the less powerful Pratt & Whitney Wasp C1 engine - 12 built ;O-2MC-6 : Export version for China, fitted with the

Wright R-1820-E The Wright R-1820 Cyclone 9 is an American radial engine developed by Curtiss-Wright, widely used on aircraft in the 1930s through 1950s. It was produced under license in France as the Hispano-Suiza 9V or Hispano-Wright 9V, and in the Soviet Un ...

radial engine - 22 built ;O-2MC-10 : Export version for China, fitted with a

Wright R-1820-F21 The Wright R-1820 Cyclone 9 is an American radial engine developed by Curtiss-Wright, widely used on aircraft in the 1930s through 1950s. It was produced under license in France as the Hispano-Suiza 9V or Hispano-Wright 9V, and in the Soviet Un ...

radial engine - one built ;XO-6 : Five all-metal O-2s, built in the mid-1920s by Thomas-Morse. ;XO-6B : Radically altered (smaller and lighter) version of the XO-6 - one built. ;O-7 : Three O-2s refitted with the Packard 2A-1500 direct-drive engine. Two were later converted to O-2 standards, and one to the O-2C standard. ;O-8 : One O-2 with the Curtiss R-1454 radial engine instead of the intended Packard inverted-Vee engine. It later became an O-2A. ;O-9 : One O-2 refitted with the

Packard 3A-1500 The Packard 1A-1500 was an American 12-cylinder liquid-cooled 60-degree Vee piston aircraft engine designed in 1924.Gunston 1989, p.109. Test flown in the second prototype Douglas XO-2 it proved to be unreliable. Only 29 engines w ...

geared engine. It resembled the O-7 but had a four- rather than two-bladed propeller. It later became an O-2A. ;XO-14 : One reduced-scale O-2H, with a Wright J-5 engine, and the first Douglas aircraft with wheel brakes. ; XA-2 : The 46th aircraft of the original O-2 contract was completed as an attack machine with the powerplant of one V-1410 Liberty inverted-Vee engine, and with a total of eight machine-guns (two in the engine cowling, two each in the upper and lower wings, and two on a ring-mounting operated by the observer). It was remarkably well armed for its day, and competed against the

Curtiss A-3 The Curtiss Falcon was a family of military biplane aircraft built by the American aircraft manufacturer Curtiss Aeroplane and Motor Company during the 1920s. Most saw service as part of the United States Army Air Corps as observation aircraft ...

in 1926 but was not selected for production. ;OD-1 : Two O-2Cs for service with the US Marine Corps from 1929. ;O-22 : O-2H airframe with a swept-back upper wing and a Pratt & Whitney Wasp engine. ;O-25 : O-2H airframe with a Curtiss Conqueror engine, and a revised nose. Later redesignated as the XO-25A ;O-25A : Forty-nine production versions of the O-25. ;O-25B : Three unarmed O-25As fitted with dual controls. Used as staff transport aircraft ;O-25C : 29 production O-25s with Prestone cooling system ;Y1O-29 : Later designated O-29A: Two O-2K airframes fitted with a

Wright R-1750 Cyclone Wright Cyclone was the name given to a family of air-cooled Radial engine, radial piston engines designed by the Wright Aeronautical Corporation and used in numerous United States, American aircraft in the 1930s and 1940s. Background The Wright ...

engine. ;O-32 : O-2K conversion with Pratt & Whitney R-1340-3 Wasp engine, most later fitted with anti-drag rings. ;O-32A : Production O-32, 30 built. ;YO-34 : O-22 re-fitted with a Curtiss Conqueror engine. Douglas BT-1 and BT-2

;BT-1 : O-2K conversion to basic trainer, 30 converted. ;BT-2 : O-32 airframe converted to basic trainer. ;BT-2A : O-32A conversion to basic trainer, 30 converted. ;BT-2B : First production model, 146 built. 58 later converted to BT-2BI instrument trainers. Two converted to BT-2BR and 15 to BT-2BG radio-controlled aerial target drones. ;BT-2C : Second production model, 20 built. 13 converted to BT-2CI instrument trainers. Seven became BT-2CR drone controllers. ;A-4 : Seventeen BT-2BRs and BT-2BGs converted in 1940 as radio-controlled aerial target drones. These had tricycle gear (a steerable nosewheel was added) with main gear moved aft, faired-over rear cockpit, and single controls, allowing the aircraft to be test-flown.Home Video of flying K model (around 6 min)
/ref> ; MO-2B: Three seat general purpose biplane derived from the M series of mail-planes, despite the O-2 designation

Operators

; * Republic of China Air Force ; * Mexican Air Force ; * United States Army Air Corps * United States Marine Corps

Specifications (O-2H)

References

External links

{{DEFAULTSORT:Douglas O-02 Biplanes 1920s United States military reconnaissance aircraft

O-2 O2, O-2, o2, O2, O2, O2− or O2+ may refer to: Science and technology * or dioxygen, the common allotrope of the chemical element oxygen * , the ion oxide * , the ion superoxide * , the ion dioxygenyl * , doubly ionized oxygen * O2, an EEG ...

Single-engined tractor aircraft Aircraft first flown in 1924