How the Douglas Aircraft Company Created the DC-3, Part 2

As recounted in Part 1, the DC-1 and DC-2 were developed after a request by Transcontinental and Western Airlines (TWA). What was then United Airlines (NASDAQ: UAL) was TWA's rival in transcontinental air service, using the Boeing 247. Because Boeing (NYSE: BA) (then named United Aircraft and Transport Corporation) also owned United, TWA sought an aircraft that would allow it to compete. 

Douglas and his talented team designed and built the DC-1 in 1932-33, and TWA requested several changes that led to the DC-2. After its introduction in 1934, the DC-2 was quickly considered the best passenger aircraft in the world. Other airlines soon began lining up after TWA to place orders. Douglas was not bound by the same constraints as Boeing and could take those orders freely, assuring a healthy production run. KLM Royal Dutch Airlines was the first non-U.S. carrier to order DC-2s and began operating them in the fall of 1934. 

KLM entered a DC-2 in the 1934 MacRobertson International Air Derby from London, England, to Melbourne, Australia. While it came in second place overall in speed (beaten by a specially- built de Havilland DH.88 Comet), it finished first in the handicap division, ahead of a 247D flown by American pilots Col. Roscoe Turner and Clyde “Upside-Down” Pangborn. Turner and Pangborn were no run-of-the-mill pilots—Turner was a record-breaking aviator and three-time winner of the Thompson Trophy air race, while  Pangborn and a copilot flew their airplane on the first non-stop flight across the Pacific Ocean.

Meanwhile, the KLM DC-2 flew the airline's regular route, which was 12,300 statute miles, in 71 hours and 28 minutes at an average speed of 160 mph. In addition, it had a crew of four, three paying passengers and 420 pounds of cargo—the mail. 

The DC-2 also demonstrated that a new era in commercial aviation had begun. While European aircraft manufacturers had been focused on building better military aircraft, U.S. OEMs had improved their aircraft for commercial aviation. By the mid-1930s, hundreds of commercial airliners plied the skies, and they were faster than any aircraft in regular service with the Royal Air Force. 

In 1935, the DC-2 became the first airplane built by Douglas Aircraft to be awarded the well-regarded Collier Trophy for outstanding achievements in flight. Douglas Aircraft built 156 DC-2s at its Santa Monica, California, facility; a total of 193 DC-2s were built. There was no question that the DC-2 was a success—and Douglas wanted to get the most from the company’s investment in R&D and tooling—but there was room for improvement.

The immediate success of the DC-2 led C.R. Smith—the 35-year-old president of the newly formed American Airlines (NASDAQ: AAL)—to Douglas Aircraft Company in 1934. The DC-3 was the result of a lengthy telephone call between Smith and Donald Douglas. Smith wanted a new aircraft; and according to the Museum of Flight, what he sought was an airplane that combined the “speed, reliability and profitability of the DC-2 with the comfort of the sleeping berth-equipped Curtiss T-32 Condor biplane.” In fact, Smith wanted two new airplanes—a longer version of the DC-2 that was capable of carrying more passengers on daytime flights, and another for overnight passengers that was outfitted with railroad-type sleeping berths.

Smith persuaded a reluctant Douglas to design a new sleeper aircraft based on the DC-2—the DC-2's cabin was 66 inches wide, too narrow for side-by-side berths. Douglas took on the project, but only after Smith agreed that American Airlines would purchase at least 20 aircraft. 

The engineering team for the new Douglas aircraft was led by chief engineer Arthur E. Raymond; the project took less than two years – an incredibly short timeline by modern standards. Originally envisioned as a relatively simple enlargement of the DC-2, the Douglas engineers soon realized that was not really possible and that the new airplane would need to be significantly redesigned from the DC-2.

Among the many differences between the two aircraft, the DC-3’s fuselage was lengthened and widened with rounded sides; “its wings and tail surfaces were enlarged and strengthened, the nose section and landing gear were modified, and new, more powerful Wright [1820] engines were installed,” according to the Museum of Flight.

Therefore, although the DC-3 was superficially similar to the DC-2, it eventually shared fewer than 10 percent of its parts with the DC-2, according to the Museum of Flight. 

The prototype Douglas Sleeper Transport, or DST, first flew on December 17, 1935, (the 32nd anniversary of the Wright Brothers' flight at Kitty Hawk) on a sunny afternoon in Santa Monica. Its cabin was 92 inches wide. To meet the American Airlines order, Douglas Aircraft manufactured the 14-passenger DST version of the DC-3 first. The first DST was accepted by American on April 29, 1936, and a total of seven DSTs were delivered to American Airlines by mid summer. 

The DST (also known as the “Sky Sleeper”) was the height of luxury for that time. Each had 14 plush seats in four main compartments that could be folded in pairs to form seven berths; seven more berths folded down from the cabin ceiling. 

The version of the new airplane (with 21 seats instead of the DST’s 14-16 sleeping berths) was given the designation DC-3. No prototype was built, and the first “day plane” DC-3 built for American Airlines followed in August 1936. 

Capt. Walter Braznell captained the inaugural flight of the DST Flagship Illinois for American Airlines on June 26, 1936, from Chicago to Newark. The initial flights were very successful, and American built its early reputation around them.

Just a few months after American Airlines’ initial order for DC-3s, United Airlines became the second airline to commission DC-3s (in November 1936). The DC-2 had been proven more economical than the Boeing Model 247 (which United had been flying, as a subsidiary of Boeing); the airline’s executives assumed the DC-3 would continue that lead. Following the initial orders from American and United, more than 30 other airlines placed orders for DC-3s during the next two years.

KLM received its first DC-3 in 1936; it replaced a DC-2 on what was then the world’s longest scheduled route, Amsterdam via Batavia (now Jakarta, Indonesia) to Sydney, Australia. KLM purchased more than 20 DC-3s before World War II began in Europe.

The DC-3 quickly established its reputation with the various airlines, and by 1939, more than 90 percent of U.S. airline passengers were flying in either DC-2s or DC-3s. The DC-3 dominated the  pre-World War II airline industry; by the mid-1940s all but 25 of the 300 airliners operating in the U.S. were DC-3s, according to Encyclopedia Britannica.

The Douglas DC-3 surpassed its competitors for many reasons. It was capable of taking off and landing on relatively short runways, was fast (a maximum cruising speed of up to 180 knots or 207 mph), had a good range (1,100 nm at 65 percent power and 142 knots), was more reliable, and carried between 14 to 32 passengers in greater comfort or a minimum of 6,000 pounds of cargo. A low-wing metal monoplane that had conventional landing gear, the DC-3 was originally powered by two Wright R-1820 Cyclone radial piston engines of between 1,000-1,200 hp. (Most DC-3s still in operation now use supercharged Pratt & Whitney R-1830 Twin Wasp engines of up to 1,200 hp.) The airplane crossed the continental U.S. from New York to Los Angeles in 18 hours with only three stops. Before the outbreak of World War II, the DC-3 pioneered many air travel routes. 

Along with its other qualities, the DC-3 was an efficient airplane; as noted by the Museum of Flight, most DC-3s were operated by two-pilot crews, and joined by a flight attendant, if operated in passenger service. Different versions and engine choices were introduced by Douglas Aircraft. The airplane’s efficiency led to airline profitability, as well as to the significant growth of civil air transport in the U.S. and worldwide prior to World War II. 

Production of DSTs ended in mid-1941, while civilian DC-3 production ended in early 1943. By  that time, more than 600 DC-3s had been built. However, dozens of the DSTs and DC-3s ordered by airlines that were built between 1941 and 1943 were designated for U.S. military service while they were still on the production line. In addition, many existing civilian DC-3s were converted to military use. 

But this was only the beginning. Like other manufacturers of aircraft, automobiles, and a myriad of civilian staples, Douglas Aircraft shifted to production for the U.S. and Allies’ war effort. 

The DC-3 was designated as the C-47 by the U.S. Army Air Forces, the R4D by the U.S. Navy, and the Dakota by the Royal Air Force of the United Kingdom. Whatever it was called, the world’s first successful commercial airliner readily adapted to military use—it was the most widely used transport aircraft of the war. 

Roughly 10,147 C-47s, C-53s, and other variants were manufactured by Douglas for use by the Allies at its facilities in Santa Monica and Long Beach, California, and in Oklahoma City, Oklahoma, and encompassing models built under license to Russia (as the Li-2) and Japan (as the L2D). The C-53 version of the DC-3 was a troop carrier. Peak production of the C-47 occurred in 1944, when roughly 4,853 were delivered to the armed forces. 

For both airline and military use, the DC-3 was easy to operate and maintain, and flexible enough to use in various flight conditions and for a variety of missions. The DC-3’s wartime adaptations were both simple and effective. According to the Encyclopedia Britannica, the airplanes were used to “transport passengers (28), fully armed paratroopers (28), wounded troops (18 stretchers and a medical crew of three), military cargo (e.g., two light trucks), and anything else that could fit through its cargo doors and weighed not much more than three tons.” 

C-47s were modified from the original DC-3 model; among other mods, they had strengthened floors to carry cargo and they were fitted with stronger landing gear. Another key difference was the C-47’s two-part doors, designed to facilitate cargo loading. You could push a ramp up to the door and drive a jeep inside.

C-47s were also used to tow gliders and some were also converted to an efficient, high-speed glider. Those aircrafts’ engines were removed, the empty cowls were faired over, and other nonessential weight was jettisoned. As a glider, a converted C-47 could carry 40 fully armed troops at a top towing speed of 290 mph, which was 90 mph faster than any other transport glider—and 26 percent faster than its top speed as a transport airplane. Though the converted C-47 gliders saw limited use in wartime, the stock C-47s themselves were used to great effect to tow WACO CG-4A gliders to drop behind enemy lines in Europe.

Military versions of the DC-3 were known colloquially as “Skytrains” and “Skytroopers.” DC-3s were used in all of the theaters of war, including notably during Operation Overlord and other missions collectively known as “D-Day” in Normandy, France, and subsequent assaults by Allied airborne forces. In addition, DC-3s/C-47s were used to ferry provisions during the Berlin Airlift of 1948-49.

In addition to converting the DC-3 to military use, Douglas Aircraft manufactured another 20,000 warplanes (primarily the SBD Dauntless and the A-26 Invader). Military versions of the DC-3 were manufactured until the end of the war. Moreover, approximately one-sixth of the U.S. airborne fleet was built by Douglas.

The global civilian market swarmed with surplus aircraft of all types following the close of World War II. Many C-47s were converted to passenger and cargo versions. Although the DC-3/C-47 models were no longer competitive with new larger and faster turboprop transports, the type still made for a dependable workhorse worldwide. All the positive traits of the DC-3 proved adaptable and useful on less glamorous routes for both passengers and cargo.

As just one of many examples, Cubana de Aviación was the first Latin American airline to offer scheduled service from Havana to Miami with a DC-3, shortly after the war ended. In addition, the airline used DC-3s on several of its domestic routes well into the 1960s.

In 1949, a larger, more powerful Super DC-3 was launched by Douglas Aircraft and garnered positive reviews. The airplane also had greater cargo capacity, and an improved wing, but with thousands of surplus aircraft available at cheap prices, the Super DC-3 failed to sell well in the civilian aviation market. Only five Super DC-3s were delivered, three of them to Capital Airlines. 

The Super DC-3 prototype was purchased by the U.S. Navy (designated as YC-129); the Navy also had 100 R4Ds upgraded to the Super DC-3 specifications during the early 1950s. Their designation was altered to R4D-8/C-117D. Like the DC-3/C-47, the R4D-8/C-117D was incredibly durable and dependable; the last U.S. Navy C-117 was retired on July 12, 1976. The last U.S. Marine Corps C-117 lasted even longer; it was retired from active service in June 1982. Perhaps even more of a testament to the DC-3, the U.S. Forest Service utilized the aircraft for smoke jumping and general transportation; the agency’s last DC-3 was retired in December 2015.

First flown in 1935, the Douglas DC-3 became the most successful airliner in the formative years of air transportation. The DC-3 and DST made air travel in the U.S. popular because of their speed, comfort, and reliability. Eastbound transcontinental flights crossed the nation in about 15 hours with three refueling stops; westbound trips (against the prevailing winds) took about 17.5 hours. Before the DC-3, such a trip entailed numerous short hops in slower and shorter-range aircraft during the day, with train travel overnight.

Early U.S. airlines—American, United, TWA, Eastern and Delta (NYSE: DAL)—purchased more than 400 DC-3s from Douglas Aircraft. These airlines’ fleets began the modern U.S. air travel industry, and by the 1950s and 1960s had replaced trains as the preferred way to travel across the U.S. (and then the world). 

The DC-3 was very comfortable by the standards of its time. It was also very safe because of its strong, multiple-spar wing and all-metal construction. Bottom line: airlines that purchased DC-3s favored it because it was  profitable. 

The DC-3 took off easily, cruised comfortably at 145 knots at 10,000 feet, had a cruising range of 1,100 nm or more, depending on the power settings used, had a service ceiling of 26,500 feet and a clean stall speed of 68 kias. 

A common saying among pilots and aviation enthusiasts is “the only replacement for a DC-3 is another DC-3.” Several aircraft companies attempted to design and build a replacement for the DC-3 for over 30 years after its introduction. However, no single airplane could match the versatility, rugged reliability, and economy of the DC-3. It remained a significant part of air transport systems well into the 1970s.

Airlines liked the DC-3 for its easy maintenance, its ability to take off and land on short runways, and its remarkable reliability. These factors combined to keep DC-3s flying in many regions of the world into the 21st century. There are still small operators using DC-3s in revenue service or as cargo aircraft. Current uses of the DC-3 include passenger service, aerial spraying, freight transport, military transport, missionary flying, skydiver shuttling, and sightseeing. 

The oldest surviving DST is the sixth Douglas Sleeper Transport built, which was manufactured in 1936. The aircraft was delivered to American Airlines on July 12, 1936. Its most recent flight was on April 25, 2021. The oldest DC-3 still flying is the original American Airlines Flagship Detroit (the 43rd aircraft off the Santa Monica production line, which was delivered on March 2, 1937). It appears at air shows around the country and is owned and operated by the Flagship Detroit Foundation.

It’s very likely that neither Donald Douglas nor any of the employees at Douglas Aircraft Company could have imagined that the DC-3 would be as successful as it was, much less that a number of DC-3s would still be in service more than 85 years after the airplane was first introduced. 

Author’s note: Among the sources of information for this article were Boeing, the Smithsonian Institution, the Museum of Flight, Encyclopedia Britannica, aviation.history.com, museumofflying.com, pearlharboraviationmuseum.org, and Honest Vision: The Donald Douglas Story, by Julie Boatman Filucci.