Chapter 5
To a large extent, the winning aircraft of World War II were designed and developed either just before the outbreak of hostilities or shortly after the war began. Also, these aircraft were conceived from the outset as military platforms to be wielded as instruments of air power. Exceptions were few and far between, none more prominent than the twin-engine Douglas civil airliner that was transformed into a mainstay of the Allies’ cargo and troop transport operations.
On 17 December 1935, the thirty-second anniversary of the Wright brothers’ success at Kitty Hawk, the Douglas DC-3 rose from Clover Field in Santa Monica, California, on its maiden flight. Little could the Douglas Aircraft design team, including company founder Donald W. Douglas, have known then that their creation would not only revolutionize commercial air travel but also give the Allied forces a distinct advantage over their Axis foes in the coming war.
Indeed, after the war, General Dwight Eisenhower opined that the majority of senior officers considered the militarized version of the Douglas transport to be among the four pieces of equipment most important to winning the war in Africa and Europe. The others were the bulldozer, Jeep, and 2½-ton truck, none of which, curiously enough, was designed for use in warfare.
The almost instant success of the DC-3, which enabled the airlines to turn a profit for the first time without reliance on airmail contracts, drew the interest of the US Army Air Corps. The aircraft’s impressive performance was owed to the specifications laid down for the DC-3’s precursor by Transcontinental & Western Air in a letter of 2 August 1932. The letter called for the new Douglas airliner, the DC-1, to be able to take off with one engine inoperable from the airport with the highest field elevation on the airline’s cross-country route. Donald Douglas referred to this requirement as the ‘birth certificate of the modern airliner’. The requirement was later changed to include the ability to climb on a single engine above the route’s mountain peaks.
With a pre-war civilian gross weight certification of 25,200 pounds and the capacity to carry twenty-one passengers, the DC-3 represented an excellent ‘off-the-shelf’ military transport, subject, of course, to modification for cargo and troops. The aircraft was rugged, too. Airlines were discovering that even when severe turbulence struck or mid-air collisions occurred with chunks of the wings sheared off, the aircraft usually forged ahead.
Perhaps the best example of the type’s durability was illustrated by an incident in the summer of 1941. The starboard wing of a parked China National Airways Corporation DC-3 sustained major damage during a Japanese air assault. Only a DC-2 wing was available as a replacement. Though five feet shorter than the DC-3 wing, it was installed and, according to reports, ‘the airliner flew splendidly.’ Under the circumstances, ‘this aircraft was christened the DC-2½.’
By the time America entered World War II, 507 DC-3s had been produced, of which 434 went to commercial operators. A total of 289 were being flown by US airlines. Soon, production of military versions would eclipse the prior civil airliner output. Douglas was impelled to supplement its Santa Monica operation by establishing new factories at Long Beach, California, and Oklahoma City, Oklahoma. By mid-1944, the company was completing a C-47 and similar military variants at the rate of one every thirty-four minutes.
When war erupted and the Allies needed a general-purpose transport, it was fortunate that the DC-3 was there. In its C-47 military designation, it proved to be an exceptionally capable and adaptable aircraft, a true wartime workhorse. The crews who flew the aircraft showered the type with praise.
Other transports besides the C-47 provided valuable service, too. Douglas produced the C-54 Skymaster based on its four-engine DC-4 airliner. The C-54 was bigger than the C-47. It also had a longer range. The first production model flew in early 1942, but only 1,242 were built. Notably, the first dedicated Presidential transport was a modified C-54A named the Sacred Cow. It was equipped with an electric lift in the tail section to accommodate President Franklin Roosevelt in his wheelchair.
The Curtiss C-46 Commando was the remaining major transport aircraft operated by the US during the war. The first C-46 was delivered to the Army Air Forces in the summer of 1942. Because of its long range and double-lobe fuselage which gave it a greater load capacity than the C-47, the type was used mainly in the Far East. The C-46 developed a deserved reputation for sustaining the Allied effort in China by flying with regularity over the hazard-laden ‘Hump’.
Though the supply function has often been neglected in warfare, the more astute commanders have recognized it as essential to victory. The pilots and crews of the transports are not typically in the forefront of air combat histories, but without their service those at the tip of the spear could hardly survive let alone triumph.
Sometimes the transports had to run the gauntlet of enemy fire and they generally lacked armament with which to shoot back. Airfield conditions and the operating environments were frequently anathema to flight, yet the transport crews had a job to do and they performed it in spite of the ominous peril. The contributions of the transport crews were no less heroic than those of their fighter and bomber counterparts.
Hump Hurdler: Curtiss C-46 Commando
The C-46 originated from a Curtiss-Wright airliner concept meant to compete with the sine qua non of the airliners of the 1930s, the standard-setting Douglas DC-3. Curtiss had a presence in the commercial airliner business, but by the mid-1930s its lumbering Condor was clearly antiquated and being surpassed by all-metal monoplanes from Lockheed, Boeing and the aforementioned Douglas. To keep up with the other companies, Curtiss designed the Model CW-20, which was larger with a bigger payload capacity, though it was, like the competitors, a taildragger configuration powered by twin radial engines.
A sense of the load capacity of the C-46 is evident in this image of troops boarding through the port cargo door. The C-46 had a voluminous cabin because of its two-lobe configuration. Its flights ‘over the Hump’ between India and China were noteworthy.
Designed to carry thirty-six passengers, the US Army Air Corps saw the potential for a cargo/transport version. This made sense since the Curtiss design was stockier and, at least in theory, could carry a heavier load than the first-generation of twin-engine, all-metal airliners which already operated on commercial routes. The CW-20’s extra cabin capacity came from the fact that its fuselage was configured as two circular sections, sometimes called lobes, joined longitudinally.
To smooth over the crease at this longitudinal joint, a fairing was inserted. But the fill-in cover did not provide any performance improvement, so it was removed. The windscreen and cockpit side windows were flush with the nose, a fairly distinctive design feature that made the type instantly recognizable. A batch of C-46B production units had a more traditional stepped windscreen, but the manufacturer returned to making its original nose in the C-46D, which was distinguishable from earlier models in that it had double cargo doors. The windscreen changes occurred again between the E and F models.
In the spring of 1940, the prototype’s twin-finned tail proved to be inefficient in flight testing. The solution came in the adoption of a more conventional single fin/rudder arrangement. On 21 June 1941, the US Army bought the subsequent test article, which it designated the C-55. After three months of further evaluation, the aircraft was sold to a foreign airline.
These C-46As are depicted in an all-metal finish and a painted finish. By mid-1944, it was decided to forgo the painted exterior. Doing so saved money and time. An additional benefit was increased speed because of the reduction in weight.
The C-46 production models, which had been ordered in quantity in September 1940, would utilize the C-55 tail design. First deliveries began to arrive on 12 July 1942. Soon, the transport was modified with a cargo door in the aft port fuselage to accommodate oversize equipment like big aircraft engines, Jeeps and supplies stacked on pallets. Nicknamed the Commando, the aircraft could haul up to forty fully equipped troops.
C-46s served in many theatres during World War II, but they were used most extensively in Asia where their greater load-carrying ability was desperately needed to supply American and Chinese forces confronting the diffuse Japanese presence. It was in the China-Burma-India area of operations that the type established its enduring reputation as an indispensable component in the do-or-die lifeline to Chunking, the principal destination where supplies were offloaded.
Negotiating the unforgiving terrain of the Himalayan range, barely clearing craggy bluffs at 14,000 feet in adverse weather with a full load of flammable aviation fuel, required nerves of steel. The transport pilots and crew persevered to keep the air bridge open. The experience gave rise to the expression ‘flying over the Hump’.
The type was employed as a troop carrier in Europe and a small number went to the Marine Corps as the R5C- 1. The aircraft remained in US Air Force service for years to come, albeit in declining numbers. Its last notable role, eminently appropriate for an aircraft called the Commando, was during the Vietnam War as a counterinsurgency platform with the famed 1st Air Commando Wing.
Specifications (for C-46A)
Manufacturer: Curtiss-Wright
Type: troop/cargo transport with a typical crew of four
Powerplant: two 2,000-horsepower Pratt & Whitney R-2800-51 Double Wasp 18-cylinder radial piston engines
Wingspan: 108 ft 1 in
Length: 76 ft 4 in
Height: 21 ft 9 in
Maximum take-off weight: 56,000 lb
Maximum speed: 269 miles per hour
Cruising speed: 183 miles per hour
Service ceiling: 27,600 ft
Range: 1,200 miles
Load: cargo of 10,000 lb or fifty troops or thirty-three litters and four medics
Old Reliable: Douglas C-47 Skytrain
Donald Douglas and his talented team of designers could hardly have imagined in the mid-1930s as they put the finishing touches on the DST (Douglas Sleeper Transport), the third in a new family of commercial airliners, that with relatively minor modification the aircraft would become the most widely used transport in the looming war or that it would emerge as a shining symbol of freedom’s triumph over tyranny. The step toward glory occurred when American Airlines asked Douglas Aircraft for a bigger version of its existing all-metal twin, the DC-2. The new airliner would have to accommodate fourteen passengers with sleeping berths and provide the safety of single-engine performance should one of the two engines quit.
The Army Air Corps took delivery of its first Douglas DC-3 on 14 September 1939. It was designated the C-41A. That aircraft, pictured here, was used initially as the transport for Secretary of War Henry Stimson and later as a regular staff transport. The highly successful DC-3 airliner was the basis for the US Army’s C-47 and the US Navy’s R4D. These cargo/troop transports were among the most important aircraft of the war.
Because there wasn’t much demand for berths, Douglas converted the cabin for day operations, installing twenty-one passenger seats. This modified DST became the DC-3. When the airliner started plying commercial routes in 1936, it caught the attention of other airlines which were mindful of the aircraft’s advantages. Within three years, more than 90 per cent of US airline passengers flew on the type or its smaller predecessor, the DC-2.
The US Army Air Corps had tracked the development of the family of Douglas twin-engine airliners and, in July 1936, bought some DC-2s. With the introduction of the bigger DC-3 around that time, the US Army saw the value in a militarized version of the new Douglas design. As need for that type of aircraft grew, Douglas got word that an Army version would have to have more powerful engines, a reinforced floor and a strengthened tail section to accommodate a cargo door.
First production deliveries of the C-47 occurred in 1941, but these arrived at a crawling pace because of the company’s strained assembly line capacity and start-up adjustments at a new plant. Because of its urgent need for transports, the US Army requisitioned many existing civil DC-3s. A priority was placed on ramping up the military transport’s production rate.
After the baseline C-47 production model, the company made the C-47A, which contrasted with the forerunner by having a higher voltage electrical system. The RAF began to take significant deliveries of the A model, known in RAF parlance as the Dakota Mk III. This moniker differed markedly from the prosaic official US name of Skytrain. The remaining major production model was the C-47B, which had two-stage superchargers to improve high-altitude performance for the China supply route over treacherous mountain ridges.
The C-47’s success had much to do with the simplicity of its design. A stressed-skin aircraft made of light alloy and with a low cantilevered wing, it was a sturdy structure, destined in some cases to last for many decades. A nearly circular fuselage enabled carriage of wide and tall loads. Because of a decent thrust-to-weight ratio the transport had a payload capacity of 6,000 pounds.
The modern equipment that went into the construction of the C-47 was, by and large, readily available from suppliers, which meant that proven technologies like pneumatic wing deicing boots, hydraulically operated split-type flaps, cowl flaps and constant-speed propellers ensured reliable operation. During the war and long afterwards, C-47 pilots and crew praised the transport, often remarking that the aircraft gave them an extra margin of performance, providing a little more in the way of climb and cruise in tight spots when those attributes were sorely needed.
The type’s most memorable service came on 6 June 1944 when a total of over 1,000 C-47s participated in the D-Day invasion, the long-anticipated Allied offensive to liberate continental Europe. Some carried paratroopers while others towed gliders which carried yet more troops. Many of the more than 24,000 Allied soldiers who were flown to the battle arrived via these transports.
In fact, a version of the C-47 was made expressly for the paratroop mission. Designated the C-53 Skytrooper, this model abandoned the hardened floor and oversize cargo doors. Instead, its cabin was lined with seats for twenty-eight paratroopers.
The US Navy’s equivalent of the Army’s Air Transport Command was the Naval Air Transport Service, which operated about 600 C-47s with the designation R4D followed by the pertinent model number. During the war, US production of the C-47 totalled 10,048. An estimated 2,700 were built in the Soviet Union as the Lisunov Li-2. About 500 were constructed by Japan and coded ‘Tabby’ by the Allies.
After World War II, the C-47 continued in Air Force service for many years, notably during the Berlin Airlift, delivering vital supplies to break the Soviet blockade, and during the Vietnam War as the AC-47 gunship, which was known as Puff the Magic Dragon. Other variants have remained in civil operation, hauling freight, servicing skydivers at jump schools and giving scenic aerial tours. Some have even undergone turboprop conversions.
The type has outlasted virtually all the military transports that have been introduced since it first flew in Air Corps livery. The Gooney Bird’s predominant virtue was that it came through when needed. Flight crews could count on the pre-war airliner, modified for military service, to finish the mission and get them home safely.
Specifications (for C-47A)
Manufacturer: Douglas Aircraft
Type: troop/cargo transport and glider tug with a typical crew of three
Powerplant: two 1,200-horsepower Pratt & Whitney R-1830-93 Twin Wasp radial piston engines
Wingspan: 95 ft 0 in
Length: 64 ft 2 in
Height: 16 ft 11 in
Maximum take-off weight: 26,000 lb
Maximum speed: 229 miles per hour
Cruising speed: 185 miles per hour
Service ceiling: 23,200 ft
Range: 1,500 miles
Load: cargo of 10,000 lb or 28 troops or 18 litters