The never-built Douglas C-132, which would have been the world's largest turboprop aircraft. The C-132 was one of the first three USAF transport aircraft procured under the weapons system concept first implemented in 1949. Propjet efforts were made with the canceled Douglas C-132 and the C-133 Cargomaster. The C-132 was an early/mid-1950's concept for a turboprop, high-speed, swept wing cargo plane. It was to be capable of moving more than a half-million pounds of airplane faster than 460 mph.
The Douglas Model 1814 aircraft was started in 1951 under the title of program SS-402L Heavy Airlift Transport. On 14 February 1957, the U.S. Air Force announced a new transport aircraft. The Douglas C-132 was to be built at Douglas Aircraft Company's plant in Tulsa, Oklahoma. The mammoth C-132 transport was a new turboprop aircraft that was to carry 200,000 lbs. of cargo 3,500 miles at 450 m.p.h. speed. Instead of receiving a big contract, in early 1957 it appeared that Douglas may in the end produce only a few of the planes. But in the end there there was no funding in the budget for the C-132. The C-132 was ill-timed to go into service. The USAF decided to go to jets, first the C-135 and, later, the C-141.
The C-132 was proposed in two versions. The C-132A would have been a cargo transport, and the KC-132B would have served as a tanker. If built, the C-132 would have carried a maximum payload of 137,000 pounds a distance of 2,200 nautical miles, at a speed of 418 knots. The aircraft was to have an overall length of 179.3 feet and overall height of 57.9 feet, with a wingspan of 177.4 feet and an overall width of 193.3 feet in the tanker version with tip pods attached. The four-blade propellers were to be 20 feet in diameter, while the horizontal stabilizer would span 66.25 feet.
The tanker version was to have detachable tip pods, 34.5 feet long, with hose reels for probe and drogue refueling, plus auxiliary internal tanks in the cargo compartment. The refueling variant woud have been able to tank up three fighters simultaneously. The tip tanks and the internal tanks could be installed and removed at enroute bases, an idea that might have proven more difficult in practice than in theory.
Because of the Air Force type numbering system, the C-132 [possibly to be known as the Globemaster III] had been perceived as a predecessor to the C-133. The Douglas model numbers were quite distinct, however, being 1333 (C-133A) and 1430 (C-133B) and 1814 (C-132), respectively. The C-132 was, in fact, a separate project with no design commonality with the C-133, though it would have carried turboprop applications to a point not approached until the Antonov AN-22 Anteus debuted at the 1965 Paris Air Show.
The C-132 was not the first aircraft that contemplated using the T-57 turboprop. By August 1947, the Boeing team working ont he B-52 bomber had gone through several iterations, finally stabilizing for a while on the "Model 464-29", with a 20-degree swept wing, mounting four Pratt & Whitney (P&W) XT57 turboprops; landing gear consisting of four two-wheel assemblies in a row along the centerline; and defensive armament consisting solely of a tail turret.
In the end the C-132 progressed no further than a full-scale mockup and inflight testing of the Pratt & Whitney T57 turboprop engine mounted on a modified C-124C. The turboprop used power from a jet engine to drive a propeller. Turboprops drew attention between 1945 and 1960 but lost out because jet aircraft were faster. The turbopropeller, or turboprop engine, is basically derived by gearing a conventional propeller to the shaft of a gas generator composed of a compressor, burner, and turbine. The turboprop engine may therefore be thought of as a turbojet engine that transmits power to the air by means of a propeller rather than through the jet exhaust. The turboprop engine is light and relatively simple as compared with the large high-power reciprocating engines. For example, a modern turboprop engine may develop between 2 and 3 horsepower per pound of weight, as compared with a maximum of about 1 horsepower per pound for a reciprocating engine, and has been made in sizes of up to 15 000 horsepower. The specific fuel consumption of the turboprop engine, however, is somewhat higher than that of the best reciprocating engines. The turboprop engine has been used in a number of highly successful transport aircraft and is still in fairly widespread use, particularly for short-haul, commuter-type transports.
The C-132 was cancelled due to problems with the development of its Pratt & Whitney XT57 turboprop design of 15,000 shp each. The 15,000hp P&W T57 turboprop was cancelled in 1957, and the C-132 disappeared together with it. Some of the lessons learned with the T57 were applied to the C-133s T34 engine to raise its horsepower from 6,500 shp (T34-P-7WA) to 7,500 T34-P-9W).
Had the Air Force gone ahead with the project, the result would have been a turboprop transport and aerial refueler nearly twice as large as the C-133. The US Air Force would also have gained outsized cargo transport capabilities beyond even those of the C-133 that it did not enjoy until the Lockheed C-5 entered service in 1968. A number of highly successful turboprop aircraft have been developed for use as cargo carriers. The largest of these aircraft is the Russian Antonov AN-22, which weighs over 550 000 pounds and is equipped with four 15,000-horsepower engines. The largest American turboprop transport was the C-133 Cargomaster, powered by four 7,500 horsepower turboprops, just half the power anticipated for the C-132 or achieved on the AN-22.
The most important action to come out of the Air Force's 1958 modernization plan was the decision to begin developing from scratch a cargo jet to be fielded in the 1966-70 time frame. This aircraft became the C-141 Starlifter, perhaps the most significant transport aircraft brought into the USAF inventory to date.
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