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 a ...

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 ...

. 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 a ...

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.

Operational history

Douglas O-2M variants were deployed by the

Chinese Air Force The People's Liberation Army Air Force (PLAAF; ), also known as the Chinese Air Force (中国空军) or the People's Air Force (人民空军), is an aerial service branch of the People's Liberation Army, the regular armed forces of the Peo ...

'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 Shanghai () was the first of the twenty-two major engagements fought between the National Revolutionary Army (NRA) of the Republic of China (ROC) and the Imperial Japanese Army (IJA) of the Empire of Japan at the beginning of the ...

, 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, in marine use both ...

engines and modified oleo-strut landing gear. The

USAAC The United States Army Air Corps (USAAC) was the aerial warfare service component of the United States Army between 1926 and 1941. After World War I, as early aviation became an increasingly important part of modern warfare, a philosophical r ...

took delivery of 18 aircraft, while the remaining 27 went to reserve

National Guard National Guard is the name used by a wide variety of current and historical uniformed organizations in different countries. The original National Guard was formed during the French Revolution around a cadre of defectors from the French Guards. Nat ...

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 An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll (or movement around ...

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 A strut is a structural component commonly found in engineering, aeronautics, architecture and anatomy. Struts generally work by resisting longitudinal compression, but they may also serve in tension. Human anatomy Part of the functionality o ...

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, beari ...

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 The Republic of China Air Force, retroactively known by its historical name the Chinese Air Force and unofficially referred to as the Taiwanese Air Force, is the military aviation branch of the Republic of China Armed Forces, currently based ...

. These aircraft were used as scout-bombers by the Chinese in the

Second Sino-Japanese War The Second Sino-Japanese War (1937–1945) or War of Resistance (Chinese term) was a military conflict that was primarily waged between the Republic of China and the Empire of Japan. The war made up the Chinese theater of the wider Pacific T ...

with some success against ground targets of the Empire of Japan. It was also used by the

Mexican Air Force The Mexican Air Force (FAM; es, Fuerza Aérea Mexicana) is the primary aerial warfare service branch of the Mexican Armed Forces. It is a component of the Mexican Army and depends on the National Defense Secretariat ( SEDENA). The objective of ...

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 The Pratt & Whitney R-1690 Hornet was a widely used American aircraft engine. Developed by Pratt & Whitney, 2,944 were produced from 1926 through 1942. It first flew in 1927. It was a single-row, 9-cylinder air-cooled radial design. Displacemen ...

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 The Pratt & Whitney Wasp was the civilian name of a family of air-cooled radial piston engines developed in the 1930s, 1940s, and 1950s.Gunston 1989, p.114. The Pratt & Whitney Aircraft Company (P&W) was founded in 1925 by Frederick B. Rentsc ...

C1 engine - 12 built ;O-2MC-6 : Export version for China, fitted with the Wright R-1820-E radial engine - 22 built ;O-2MC-10 : Export version for China, fitted with a Wright R-1820-F21 radial engine - one built ;XO-6 : Five all-metal O-2s, built in the mid-1920s by

Thomas-Morse The Thomas-Morse Aircraft Corporation was an American aircraft manufacturer, until it was taken over by the Consolidated Aircraft Corporation in 1929. History Founded in 1910 by English immigrants William T. Thomas and his brother Oliver W. T ...

. ;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 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 in 1926 but was not selected for production. ;OD-1 : Two O-2Cs for service with the

US Marine Corps The United States Marine Corps (USMC), also referred to as the United States Marines, is the maritime land force service branch of the United States Armed Forces responsible for conducting expeditionary and amphibious operations through com ...

from 1929. ;O-22 : O-2H airframe with a swept-back upper wing and a

engine. ;O-25 : O-2H airframe with a

Curtiss Conqueror The Curtiss V-1570 Conqueror was a 12-cylinder vee liquid-cooled aircraft engine. Representing a more powerful version of the Curtiss D-12, the engine entered production in 1926 and flew in numerous aircraft.Gunston 1989, p. 46. Design and de ...

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 piston engines designed by the Wright Aeronautical Corporation and used in numerous American aircraft in the 1930s and 1940s. Background The Wright Aeronautical Corporation was ...

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

engine.

;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

; *

United States Army Air Corps The United States Army Air Corps (USAAC) was the aerial warfare service component of the United States Army between 1926 and 1941. After World War I, as early aviation became an increasingly important part of modern warfare, a philosophical r ...

United States Marine Corps The United States Marine Corps (USMC), also referred to as the United States Marines, is the maritime land force service branch of the United States Armed Forces responsible for conducting expeditionary and amphibious operations through c ...

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