The Douglas Commercial Model Number 2 (DC-2) entered U.S. commercial airline service in May 1934 and immediately began breaking speed records. [In U.S. Navy (USN) service, the DC-2 was designated R2D, q.v.] Even before they received their first DC-2, American Airlines had approached the Douglas Aircraft Company and requested that the DC-2 be stretched and developed as a sleeper transport. American Airlines was operating a transcontinental sleeper service using Curtiss T-32 Condors and they wanted an aircraft that had the roominess and comfort of the Condor with the performance and economy of the DC-2. American was looking for an aircraft that (1) had a greater payload, (2) a larger cabin for the installation of sleeping berths, (3) greater range, and (4) more directional control to correct the DC-2's fish tailing. The DC-2 could accommodate 14-passengers in seven rows. Douglas designed a new aircraft that had a wider fuselage, was longer, had a larger wing accommodating more fuel and more powerful engines. This new aircraft was the Douglas Sleeper Transport (DST).
The DST was a twin-engined, all-metal, low-wing monoplane with retractable landing gear. The crew of two, pilot and copilot, sat side-by-side in the cockpit. The main landing gear retracted into the nacelles but about one-third of the tire was left exposed as a precaution in the event of a wheels up landing; the tail wheel was full swivelling but did not retract. The wing extended beneath the fuselage and served as a mounting for both engine nacelles. The entire aircraft, except for the control surfaces, was made of high-tension strength aluminum alloy known as Alclad; the control surfaces, i.e., ailerons, rudder and elevators, were metal framed covered with fabric. The cabin of the DST had fourteen 36-inch (91.44 cm) wide double seats which converted to seven lower berths and seven 30-inch (76.20 cm) wide upper berths which folded into the ceiling when not in use. For daytime operations, the aircraft could carry 21-passengers; for sleeper operations, 14-passengers could be accommodated in the 14-berths. The first flight by the DST-114 was made on 17 December 1935. The DST could be identified by four small rectangular windows on each side of the fuselage above the first, third, fifth and seventh passenger windows.
American Airlines also ordered a "daytime" version of the DST without berths and the four small rectangular windows and this was identified as the Douglas Commercial Model Number 3 (DC-3). The DC-3, which could accommodate 21-passengers in seven rows, made its first flight on 16 August 1936.
When World War II started on 1 September 1939, the DC-2 and DC-3 were being operated by every major U.S. airline and by 18 foreign airlines. On 11 September 1939, the U.S. Army Air Corps (USAAC), which was superseded by the U.S. Army Air Forces (USAAF) on 20 June 1941, took delivery of their first DC-3, a DC-3A-253A, which was designated C-41A. On 16 May 1940, President Franklin D. Roosevelt called for the production of 50,000 aircraft annually by the U.S. aviation industry. The DC-3 was an obvious choice because it could be purchased off-the-shelf and on 16 September 1940, the USAAC and the USN ordered 147 and 30 DC-3's respectively for military use to be built at Douglas' new Long Beach, California plant. These aircraft were designated C-47 by the USAAC and R4D by the USN.
On 11 March 1941, the Lend-Lease Bill was signed by the President and the U.S. Army took over ordering all DC-3's for military service, whether they be for the USN or Lend Lease. (In USAAF service, the DC-3's were designated C-41A, C-47, C-48 through C-53, C-68, C-84, C-117 and YC-129.) By the end of World War II, a total of 10,245 DC-3's had been produced for the military and were in use by the USAAF, USN, U.S. Marine Corps (USMC), U.S. Coast Guard (USCG) and foreign military air forces. The USN accepted 570 DC-3's during the war. All of these aircraft had a crew of two to four, i.e., pilot, copilot, radio operator and/or navigator. All aircraft built for the USAAF were powered by two Pratt & Whitney R-1830 fourteen-cylinder, twin-row, air-cooled, radial engines driving three-bladed Hamilton-Standard constant speed propellers.
Soon after the U.S. entered World War II, there were concerns that American industry could not produce enough aluminum and aircraft to win the war and the USN ordered the Budd RB-1 Conestoga, q.v., made of stainless steel. However, by the time the RB-1 was ready to enter mass production, it became evident that it was not needed.
After World War II, the American aircraft industry began a search for the DC-3 replacement and Douglas undertook a project to modernize the DC-3. Douglas purchased two second-hand DC-3's and strengthened and stretched the fuselage, added new horizontal and vertical tail surfaces with squared tips, added new squared wing tips and smoother engine nacelles with doors that completely enclosed the landing gear and used more powerful engines. This new aircraft became known as the DC-3S or the Super DC-3. Unfortunately for Douglas, the project failed because (1) there was an excess of war surplus C-47's/R4Ds available and (2) Convair introduced the more modern, faster and pressurized Convair CV-240. In 1950, Douglas sold the first DC-3S prototype to the U.S. Air Force (USAF); the aircraft was first designated YC-129-DO but later redesignated YC-47F-DO. After testing the aircraft, the USAF decided to purchase the Convair CV-240 and transferred the aircraft to the USN where it was redesignated R4D-8. The USN was impressed with the aircraft and signed a contract with Douglas to convert 100 R4D-5's, -6's and -7's to the R4D-8 configuration.
In 1962, the U.S. Department of Defense adopted a new, standard designation system based on the USAF system that was to be applied to all military aircraft. The R4D-5's, -6's and -7's were redesignated C-47H, J and K respectively and a prefix, rather than a suffix letter was used for aircraft that had been modified. The R4D-8's were redesignated C-117Ds and also used a prefix letter for modified aircraft. The old and new designations are listed below in the Production History section.
R4D-1: The 101 DC-3A-360's were ordered in three different groups; 30 were ordered directly by the USN on16 September 1940, followed by an order for 33 more; these were delivered between February and October 1942. The next 34 were ordered by the USAAF as C-47-DLs and transferred to the USN between November 1942 and February 1943. The last aircraft was transferred from the Royal Air Force (RAF) to the USN in March 1946 for service with the U.S. Naval Attache in London, England. These aircraft, built at the Douglas Long Beach, California plant and powered by two 1,200 hp (894.8 kW) Pratt & Whitney R-1830-92 engines, were cargo and passenger transports with a large cargo doors, on the port (left) side of the fuselage aft of the wing, a reinforced metal floor with tie-down fittings and a 12-volt electrical system. The cargo doors consisted of two large panels, the forward portion incorporating a standard passenger door; the dimensions of the cargo openings were 7 feet inch (2.146 meters) wide and 5 feet 10 inches (1.791 meters) high at the front and 4 feet 7 inches (1.41 meters) high at the rear. The interior had wooden seats folding against the sides of the cabin for 28-fully-armed paratroopers and fittings for 18-stretchers and a medical crew of three. The aircraft also had a glider-towing cleat in the tail. All were struck from the inventory by December 1949.
R4D-2: Two DC-3-388's originally ordered by Eastern Air Lines but completed for the USN and delivered in March and April 1941. These aircraft were built at the Douglas Santa Monica, California plant and lacked the reinforced floor of the R4D-1. Powered by two 1,200 hp (894.8 kW) Wright R-1820-71 nine-cylinder, single-row, air-cooled, radial engines, they were used as VIP transports; both were subsequently redesignated as flagships, R4D-2Fs and later R4D-2Zs. Since they were VIP transports, they had a standard airliner passenger door mounted aft of the wing on the port (left) side of the fuselage. They were struck from the inventory in May and December 1946. These aircraft were similar to the USAAFs C-49 series of impressed airliners.
R4D-2F: The two R4D-2's redesignated as flagship (VIP) aircraft.
R4D-2Z: The two R4D-2Fs redesignated as VIP transports in 1945.
R4D-3: Twenty DC-3A-405's, built at the Santa Monica, California plant, were ordered by the USAAF as C-53-DOs and transferred to the USN between January and November 1942. Unlike the R4D-1, these aircraft were troop transports and as such had (1) a normal wooden floor instead of a reinforced metal floor, (2) a 26-inch (66.04 cm) wide door instead of the large cargo door, and (3) fixed metal seats for 28 fully-armed paratroopers. They also had a towing cleat for use as a glider-tug. Powered by two 1,200 hp (894.8 kW) Pratt & Whitney R-1830-92 engines, these aircraft had a 12-volt electrical system. All were stricken from the inventory by December 1948.
R4D-4: Ten DC-3A-447's, originally ordered by Pan American World Airways but completed for the USN and delivered in December 1942 and January 1943, were built as personnel transports at the Santa Monica, California plant. As personnel transports, they had a standard airliner passenger door mounted aft of the wing on the port (left) side of the fuselage. Powered by 1,200 hp (894.8 kW) Pratt & Whitney R-1830-92 engines, these aircraft were similar to the USAAFs C-53C-DO. They were struck from the inventory between October1946 and March 1956.
R4D-4Q: One R4D-4 converted post World War II to radar countermeasures aircraft.
R4D-5: The 238 DC-3A-456's were ordered by the USAAF as C-47A-DLs and transferred to the USN between March and November 1943 . These aircraft, built at the Long Beach, California plant, were identical to the R4D-1 except being equipped with a 24-volt electrical system and improved cabin heating. In 1962, the remaining R4D-5's were redesignated C-47Hs.
R4D-5E: Unknown number of R4D-5's converted for special electronics operations.
R4D-5L: At least six R4D-5's modified post World War II with extra fuel and higher gross weight for use in Antarctica. In 1962, the remaining aircraft were redesignated LC-47Hs.
R4D-5Q: At least four R4D-5's modified post World War II as electronic countermeasures (ECM) trainers with three crew, eleven students and an instructor. In 1962, the surviving aircraft were redesignated EC-47H.
R4D-5R: At least seven R4D-5's converted to a 21-seat passenger transport. Redesignated TC-47H in 1962.
R4D-5S: Unknown number of R4D-5's converted post World War II to antisubmarine warfare (ASW) trainers with space for nine students and one instructor. Redesignated SC-47H in 1962.
R4D-5T: Unknown number of R4D-5's converted to navigational trainers.
R4D-5Z: Unknown number of R4D-5's converted post World War II to VIP transports. Redesignated VC-47H in 1962.
R4D-6: The 157 DC-3A-467's were ordered by the USAAF as C-47B-DLs and transferred to the USN between August 1944 and March 1945. These aircraft, built at the Long Beach, California plant, were identical to the R4D-5 but were equipped with two 1,200 hp Pratt & Whitney R-1830-90C engines with two-stage, two-speed superchargers, provisions for fuel tanks in the fuselage and improved heaters. These aircraft had been developed for high-altitude flights over the "Hump" in the China-Burma-India (CBI) Theater. In all probability, the superchargers were removed after World War II. Aircraft remaining in the inventory in 1962 were redesignated C-47Js.
R4D-6E: R4D-6's converted for special electronics operations.
R4D-6L: At least three R4D-6's modified post World War II with extra fuel and higher gross weight for use in Antarctica. In 1962, the remaining aircraft were redesignated LC-47Js.
R4D-6Q: R4D-6Qs modified post World War II as electronic countermeasures (ECM) trainers with three crew, eleven students and an instructor. In 1962, the surviving aircraft were redesignated EC-47J.
R4D-6R: R4D-6's converted to a 21-seat passenger transport. Redesignated TC-47J in 1962.
R4D-6S: R4D-6's converted post World War II to antisubmarine warfare (ASW) trainers with space for nine students and one instructor. Redesignated SC-47J in 1962.
R4D-6T: R4D-6's converted to navigational trainers.
R4D-6Z: R4D-6's converted post World War II to 15-17 passenger VIP transports. Redesignated VC-47J in 1962.
R4D-7: The 43 DC-3A-467's were ordered by the USAAF as TC-47B-DKs and transferred to the USN between March and May 1945. These aircraft, built at the Oklahoma City, Oklahoma plant, were C-47B-DKs converted to navigational trainers and were redesignated TC-47Ks in 1962.
R4D-8: The 101 Super DC-3's or DC-3Ss consisted of (1) the USAF's YC-47F transferred to the USN in 1951 and (2) 100 R4D-5's, -6's and -7's converted to the DC-3S standard. These aircraft were powered by two 1,475 hp (1,100 kW) Wright R-1820-80 nine-cylinder, single-row, air-cooled radial engines and were redesignated C-117D in 1962.
R4D-8L: At least six R4D-8's converted with skis and other cold weather equipment for operations in the Arctic and Antarctic. The aircraft had additional fuel tanks and a higher gross weight. Redesignated LC-117D in 1962.
R4D-8T: At least six R4D-8's converted to navigational trainers for eight students. Redesignated TC-117D in 1962.
R4D-8Z: R4D-8's converted to 16-passenger VIP transports. Redesignated VC-117D in 1962.
C-47H: R4D-5's redesignated in 1962.
EC-47H: R4D-5Qs redesignated in 1962.
LC-47H: R4D-5Ls redesignated in 1962. One converted to LC-47M.
SC-47H: R4D-5Ss redesignated in 1962.
TC-47H: R4D-5Rs redesignated in 1962.
VC-47H: R4D-5Zs redesignated in 1962.
EC-47J: R4D-6Qs redesignated in 1962.
LC-47J: R4D-6Ls redesignated in 1962.
SC-47J: R4D-6Ss redesignated in 1962.
TC-47J: R4D-6Rs redesignated in 1962.
VC-47J: R4D-6Zs redesignated in 1962.
LC-47M: One LC-47H reequipped with electronic countermeasures (ECM) equipment.
C-117D: R4D-8's redesignated in 1962.
LC-117D: R4D-8Ls redesignated in 1962.
TC-117D: R4D-8Ts redesignated in 1962.
VC-117D: R4D-8Zs redesignated in 1962.
The first two R4Ds used by the Navy were the two R4D-2s. In December 1941, these two aircraft were at Naval Air Station (NAS) Anacostia, District of Columbia and NAS Pensacola, Florida. The primary user of the R4Ds in the USN was the Naval Air Transport Service (NATS). NATS was established on 12 December 1941 under the Chief of Naval Operations (CNO) to provide rapid air delivery of critical equipment, spare parts, and specialist personnel to naval activities and fleet forces all over the world. To accomplish its mission, NATS was authorized to establish three wings, the Pacific, West Coast and Atlantic Wings. Like the USAAF's Air Transport Command (ATC), NATS flew the longer supply routes to deliver needed material to the war zones. On the return trips, they frequently flew wounded back to hospitals. NATS also operated with the ATC in flying between India and China over the "Hump" and operated a route between India and the U.S. carrying important raw materials.
The first NATS R4D squadron was Transport Squadron One (VR-1) established at NAS Norfolk, Virginia on 9 March 1942 and tasked with operating between Boston, Massachusetts and Corpus Christi, Texas; Argentia, Newfoundland and Trinidad, British West Indies and later to Iceland and Rio de Janeiro, Brazil. VR-1 moved to NAS Patuxent River, Maryland on 19 July 1943 and subsequently operated both R4Ds and Douglas R5D Skymasters, q.v. Other NATS transport squadrons operating the R4D were
- VR-2, formed at NAS Alameda, California on 1 April 1942 and tasked with operating from California to NAS Kodiak, Territory of Alaska and NAS Corpus Christi, Texas. VR-2 made the first transoceanic flight by NATS when they initiated air transport service between NAS Alameda and NAS Pearl Harbor, Territory of Hawaii on 15 May 1942. VR-2 established a detachment at NAS Pearl Harbor and began survey flights to the South Pacific on 7 September 1942. Starting in March 1943 when VR-4 was activated at NAS Oakland, California, VR-2 became a NATS seaplane squadron operating Consolidated PB2Y Coronados, q.v., Martin PBM Mariners, q.v., and the single Martin PB2M-1R Mars, q.v.
- VR-3, formed at Fairfax Field, Kansas City, Kansas on 15 July 1942, was tasked with operating within the U.S. In late 1942, VR-3 moved to NAS Olathe, Kansas and starting in 1944, began operating a small number of Douglas R5D Skymasters, q.v.
- VR-4 formed on 4 March 1943 at NAS Oakland, California with R4Ds received from VR-1. The squadron later acquired a limited number of Douglas R5D Skymasters, q.v. to augment the R4Ds.
- VR-5, formed at NAS Seattle, Washington on 24 June 1943 from a VR-2 Detachment, took over the routes from the U.S. to the Territory of Alaska. VR-5 primarily operated R4D=92s but also flew Douglas R5D Skymasters, q.v.
- VR-7, formed at NAS Miami, Florida in April 1943 but operating from Miami Municipal Airport; these two airports were separated by railroad tracks. VR-7 assumed VR-1's missions to the Caribbean and South America.
- VR-11 formed at Naval Auxiliary Air Station (NAAS) Oakland, California on 1 September 1943 with R4Ds. The squadron moved to NAS Honolulu, Territory of Hawaii on 15 December 1943 and, in addition to R4Ds, became NATS' largest user of the Douglas R5D Skymaster, q.v.
- VR-13, formed at NAAS Oakland, California on 16 June 1944, moved to Los Negros Island, Admiralty Islands (2-03S 147-25E) in the spring of 1945.
Other USN squadrons that operated R4D=92s included Air Transport Evacuation Squadrons One, Two and Three (VRE-1, -2 and -3); Rescue Squadrons Two, Three, Five and Fourteen (VH-2, -3, -5 and -14); Utility Squadrons Four and Seven (VJ-4 and -7); Utility Transport Squadron Two (VRJ-2); Air Ferry Transport Squadrons One to Four (VRF-1 to -4); and Air Ferry Service Squadron One (VRF-1).
The USMC equipped six squadrons with R4D=92s in 1942/43. The first squadron to receive the new R4D-1's was Marine Utility Squadron One Hundred Fifty Two (VMJ-152) at Marine Corps Air Station (MCAS) Quantico, Virginia. The other five squadrons were VMJ-153, -252, -253, -352 and -353. All of these squadrons were redesignated Marine Transport Squadron (VMR) in June 1944.
The first Marine R4D-1 unit to enter a combat area was VMJ-253 which moved from MCAS Ewa, Territory of Hawaii to New Caledonia Island (21.30S 165.70E) on 1 September 1942 to support the Marine operations on Guadalcanal Island (9.32S 160.12E) in the Solomon Islands. In November, VMJ-152 moved from the U.S. to New Caledonia and on 24 November 1942, these two squadrons and the USAAFs 13th Troop Carrier Squadron were assigned to a new command on New Caledonia, the South Pacific Combat Air Transport Command (SCAT). SCAT was responsible for providing air transport to Guadalcanal and later, Bougainville Island (6.00S 155.00E). The two Marine squadrons were joined by VMJ-153 which moved from the U.S. to New Caledonia in March 1943. VMR/VMR-152 and -153 moved to Bougainville Island and remained there until the end of the war providing transport in the South and Southwest Pacific and eventually to the Phillippines and Okinawa Island, Ryukyu Islands (26.39N 128.00E).
VMR-253 moved to Guam (13.28N 144.47E) and Tinian Islands (15.00N 145.38E) in the Mariana Islands in August 1944 to support the Marines in their drive across the Central Pacific. They also became one of the units assigned to the Transport Air Group (TAG) which was responsible for aerial transportation in the Central Pacific. Because of inadequate facilities, the squadron moved to Naval Air Base (NAB) Abemama Atoll (0.21N 173.51E), Gilbert Islands and then to Hawkins Field on Betio Island, Tarawa Atoll (1.25N 173.00E), Gilbert Islands on 4 September 1944. The squadron returned to Guam on 10 October 1944 and began supply and evacuation missions to and from Iwo Jima Island in the Volcano Islands (26.47N 141.20E) in February and March 1945. The squadron was re-equipped with Curtiss R5C-1 Commandos, q.v., in March 1945.
VMJ-252, based at MCAS Ewa, Territory of Hawaii, was equipped with R4Ds in 1942 and began the first air transport service to Midway Island (28.13N 177.22W) and other outlying Pacific bases. The squadron began re-equipping with the Curtiss R5C-1 Commando, q.v., in August 1944.
The last Marine R4D squadron was VMJ-352 the was activated at MCAS Cherry Point, North Carolina on 1 April 1943. This squadron also transitioned to the Curtiss R5C-1 Commando, q.v., in 1944.
The USCG received a total of eight R4D-5's during World War II; the first batch was delivered in May 1943 and the last batch in July 1944. These aircraft were used for search and rescue (SAR) missions and logistical support.
R4D-8: 90 feet (27.43 meters)
All others: 95 feet 6 inches (29.11meters)
R4D-1 through -4: 64 feet 6 inches (19.66 meters)
R4D-5 through -7: 63 feet 9 inches (19.43 meters)
R4D-8: 67 feet 9 inches (20.65 meters)
R4D-1, -2, -3 and -4: 16 feet 11 inches (5.16 meters)
R4D-5, -6 and -7: 17 feet (5.18 meters)
R4D-8: 18 feet 3 inches (5.56 meters)
R4D-8: 969 square feet (90.02 square meters)
All others: 987 square feet (91.70 square meters)
R4D-1, -2, -3 and -4: 16,600 pounds (7,530 kg)
R4D-5: 17,057 pounds (7,737 kg)
R4D-6 and -7: 17,257 pounds (7,828 kg)
R4D-8: 19,537 pounds (8,870 kg)
R4D-1: 26,300 pounds (11,929 kg)
R4D-2: 25,200 pounds (11,431 kg)
R4D-3, -4 and -5: 29,300 pounds (13,290 kg)
R4D-6 and -7: 30,000 pounds (13,608 kg)
R4D-8: 31,000 pounds (14,061 kg)
R4D-1: 230 mph (370 km/h)
R4D-4 and -5: 230 mph at 8,800 feet (370 km/h at 2,682 meters)
R4D-6 and -7: 224 mph at 10,000 feet (361 km/h at 3,048 meters)
R4D-8: 270 mph at 5,900 feet (435 km/h at 1,798 meters)
R4D-4: 207 mph (333 km/h)
R4D-5, -6 and -7: 160 mph (257 km/h)
R4D-8: 251 mph (404 km/h)
R4D-5: 3,800 miles (6,116 km)
R4D-6 and -7: 3,600 miles (5,974 km)
R4D-8: 2,500 miles (4,023 km)