By the late 1940s, the airlines were now losing money on the DC-3. The question was how long the airlines could wait before replacing it. Many reasoned the DC-3 had to wear out soon; after all, it was more than 20 years old. In addition, another pressing problem forced Douglas to look for a DC-3 replacement. The original certification of the DC-3 was under Bulletin 7A which was a pre-war litany of the performance characteristics necessary in the government’s eye to fly a safe airline. After the war the government came out with FAR 4B, “Transport Category Requirements.” The DC-3 did not measure up to many of these new requirements. To some there was only one answer. Douglas engineers concluded the DC-3 did so well that any replacement showing a vast improvement over it would be too costly. An improved version of the DC-3 would be the only solution.
Douglas Chief Engineer Malcolm K. Oleson thought his engineers had the answer. The Super DC-3 was a standard DC-3 airframe with major modifications. They stretched the fuselage, adding 39 inches to the nose section, and 40 inches to the rear cabin. This added six feet and seven inches of usable space. They increased the vertical and horizontal stabilizer surfaces in span and area, and replaced the power plants with the same engines used in the DC-4 (R2000). Shorter, jet ejection-type exhaust stacks increased the usable horsepower and they enlarged the engine nacelles, added wheel well doors, and a partially retractable tail wheel. They added smaller outer wing panels, swept back four degrees at the trailing edge to accommodate the rearward shift in the center of gravity. Flush rivets and low drag antennas decreased the drag. These changes allowed them to increase the seating capacity to 38. They also added an airstair and a retractable tail wheel. The plane offered an increased payload, and a top speed of 250 miles per hour, and met the FAR 4B requirements. It was, in fact, a 75 percent new airplane. The first flight of the Super DC-3 took place on June 23, 1949. The aircraft was designated DC-3S, c/n 43158. The U.S. Air Force first designated it the YC-129 but in recognition of its C-47 origins, it became the YC-47F. (The only major difference between the military Super DC-3 and the civilian model was the larger engines, 1,475 hp and the heavier metal floor.) The Air Force used the YC-47F as a test bed, but after extensive tests at Wright Patterson AFB, it did not impress them. They opted to use the new Convair C-131 instead.
The Navy had 100 of their R4Ds converted to R4D-8 (later the C-117D) at $300,000 each. (Note: All DC-3/Super DC-3 conversions received new construction numbers and this has added to the confusion as to how many DC-3s were actually manufactured.) It filled their need for an airplane with increased range, and 50 percent more payload. The Navy’s contract bailed Douglas out of a financial problem and kept the Super DC-3 alive, for a while. The Super DC-3 cost three million dollars in tooling, research, and development costs. Douglas claimed it was 75 percent new, and he could produce ten a month, in three different seating configurations. Initial response to the new plane was less than enthusiastic. In October 1949, Douglas took the Super DC-3 on a 10,000 mile demonstration tour. An advertisement promised it was, “capable of carrying on indefatigably in the noble tradition of its ancestor.”
The only operating restriction on the Super Three was altitude versus cargo. It had a ceiling of 25,000 feet, but the un-pressurized cabin prevented it from flying bottled goods, livestock and fresh fruit at altitude.
Since people were saying the only replacement for the DC-3 was another DC-3, Douglas decided to offer the Super DC-3 to the airlines in exchange for an original DC-3 and a fee for modifications. Douglas set the fee at $150,000. The airlines didn’t think much of the idea. The price tag was more than the pre-war DC-3, and the smaller airlines could not afford such capital investments.
Commercial success eluded the Super DC-3. Capital Airlines had used 23 regular DC-3s and they ordered three Super DC-3s. After they added their own features the cost increased to $250,000. They introduced the first one on their Washington to Atlanta run in July 1950.
Capital Airlines seemed pleased with the Super DC-3. They claimed its ground servicing time was significantly less than any other plane. They cited their Norfolk to Memphis run where a DC-3 took 1 hour and 16 minutes of ground time collectively at all the stops. The Super DC-3 took 45 minutes for the same servicing.
As pleased as they were initially, the later record speaks for itself. Capital Airlines never ordered more than three, although they had originally planned to replace their entire 23 plane fleet of DC-3s with Super DC-3s. The Douglas Aircraft Company used two Super DC-3s and one was fitted with two “Dart” turbo-props (N156WC) for Pilgrim Airlines, but they saw the licensing problems for passenger use and never accepted the model.
The published economies did not sway the airlines either. At 100 percent load, it cost $1.25 per seat mile, and was a decent buy. It was still attractive at $1.75 per seat mile with a 20-passenger load, and compared favorably to the DC-4, Convair-Liner and Martin 2-0-2. Perhaps Douglas should not have made that comparison for the airlines saw the obvious differences between new planes and a twenty-year-old DC-3. The airlines could see there were newer airplanes that appeared to do as well, at least economically.
The Super DC-3 was a good plane but even a modified and upgraded DC-3 could not replace the original. The Super DC-3, like all the other contenders eventually faded from the scene. Remarkably, in 1993, there were at least 19 still flying in the United States.