Before the DC-3 became a marketing success for the Douglas Aircraft Company - produced in some 16,000 total examples - the concern developed and delivered their DC-2. The DC-2 was born in a 1933 requirement from Transcontinental and Western Air (Trans World Airlines - otherwise remembered as "TWA") for a metal-skinned, tri-motor passenger transport. The all-metal requirement was something of note for it came at a time when the civilian aviation industry was beginning its move away from the more hazardous wooden passenger aircraft with origins in the post-World War 1 world.
For its submission to the TWA need, Douglas developed a twin-engine monoplane of all-metal design. It sported large low-wing assemblies with rounded wingtips. The cockpit was set at the extreme front end of the tubular fuselage that was capped by a short nose cone assembly. The fuselage tapered off into a conventional tail unit showcasing a single large vertical tail fin and rounded horizontal plane surfaces. The engines were set within streamlined nacelles along each wing leading edge. The retractable undercarriage consisted of two single-wheeled main landing gear legs and a small tail wheel at the rear. This gave the model a distinct "nose up" appearance. The main landing gear legs retracted into the underside of each engine nacelle. Internally, the machine was piloted by two crew in the cockpit and internal space was such that the aircraft could transport up to 12 passengers in relative comfort with windows dotting the sides of the fuselage. The engines of choice became a pair of Wright air-cooled, radial piston engines developing up to 690 horsepower each and powering three-bladed variable pitch metal propeller assemblies. For its time, the DC-2 was as modern as passenger transport came. First flight was recorded on May 11th, 1934.
Power from the Wright R-1820-F53 Cyclone series of 9-cylinder air-cooled radial piston engines (730 horsepower) netted the airframe a top speed of 210 miles per hour (at approximately 6,800 feet). Operational range was nearly 1,100 miles with a service ceiling maximizing at 22,750 feet. Rate-of-climb was a solid 1,030 feet per minute.
After formal review of the Douglas concept, TWA took on the DC-2 as its newest airliner, destined to bring Americans - and the world - to whatever destinations needed finding. The original Douglas design was slightly modified with internal seating for up to 14 passengers and uprated Wright radial piston engines were selected to complete the specifications. An initial order for 20 aircraft was then placed with the initial production mark being simply "DC-2". The DC-2 was first introduced on May 18th, 1934.
The DC-2 proved a very sound, reliable and safe vehicle for its time. So much so, in fact, that the aircraft was tapped as the next passenger airliner for a variety of operators including some in Europe. Of these, Polish LOT and SwissAir proved the most notable. KLM of the Netherlands was also noteworthy for the time. Those DC-2s destined for Europe were produced locally through license-production handled by the Dutch Fokker concern - a firm having made a name for itself building World War 1 fighters for Germany and finding much success in the civilian market in during the Interwar period thereafter. Douglas also sold local production licenses to British Airspeed and Japanese Nakajima though only the latter utilized the right to a high degree, building some five aircraft. Airspeed never took advantage of their license and failed to produce a single examples (these would have been designated as AS.23 by the company). Overtime, many were whisked away to preferred destinations in the relative comfort of the DC-2 - which helped to open people's minds to the safety and comfort of airline travel in number.
The United States military naturally saw value in the multi-faceted DC-2 design as both a cargo transport and VIP passenger transport and eventually ordered both of the type in number. The "militarized" prototype form of the civilian model became the "XC-32" and this was a single example fitted with 2 x Wright R-1820-25 series radial piston engines of 750 horsepower each with seating for 14. The production model became the C-33 of which 18 were produced. The C-39 became a 16-seat variant and combined features of the existing DC-2 with the new DC-3. These were powered by a pair of Wright R-1820-55 series radials delivering 975 horsepower each. A single C-39 with 2 x Pratt & Whitney R-1830-21 radial engines became the VIP transport to US General Hap Arnold as the C-41. Another VIP transport existed under the designation of C-42 and completed with Wright R-1820-53 series radials of 1,000 horsepower. The United States Navy and Marine Corps both operated a version of the DC-2 and knew it as the R2D-1. These were delivered with 2 x Wright R-1820 series radials. At least 24 DC-2s in civilian guises were pressed into service at the start of World War 2, becoming the C-32A.
Beyond US and the aforementioned European nations utilizing the DC-2, other civilian operators included Australia, Nazi Germany (Lufthansa), Italy and Mexico among others. Military and official government operators also included Argentina, Australia, Austria, Finland, France, Nazi Germany, Japan, Spain and the United Kingdom (Royal Air Force). All told, some 200 DC-2s were produced with production spanning from 1934 to 1939. The airframe also served as the basis for the military-minded B-18 "Bolo" medium bomber accepted into service by the USAAC prior to World War 2. The more successful DC-3 held origins in the DC-2 and proved to essentially be a much improved version of the latter.