Conroy Turbo-Three

The Conroy Turbo-Three was a series of two

Douglas DC-3 The Douglas DC-3 is a propeller-driven airliner manufactured by Douglas Aircraft Company, which had a lasting effect on the airline industry in the 1930s to 1940s and World War II. It was developed as a larger, improved 14-bed sleeper versi ...

s modified with

turboprop A turboprop is a turbine engine that drives an aircraft propeller. A turboprop consists of an intake, reduction gearbox, compressor, combustor, turbine, and a propelling nozzle. Air enters the intake and is compressed by the compressor. ...

engines by

Conroy Aircraft Conroy Aircraft was an American aircraft manufacturer founded by John M. Conroy in Goleta, California, in 1968 after he resigned as president of Aero Spacelines. The company imitated Aero Spacelines' success with its Guppy aircraft by convertin ...

. The first conversion first flew on May 13, 1969. Two Rolls-Royce Dart Mk. 510 engines from a crashed

Vickers Viscount The Vickers Viscount is a British medium-range turboprop airliner first flown in 1948 by Vickers-Armstrongs. A design requirement from the Brabazon Committee, it entered service in 1953 and was the first turboprop-powered airliner. The Visc ...

previously operated by

United Airlines United Airlines, Inc. (commonly referred to as United), is a major American airline headquartered at the Willis Tower in Chicago, Illinois.

were used to replace the original

Pratt & Whitney Pratt & Whitney is an American aerospace manufacturer with global service operations. It is a subsidiary of Raytheon Technologies. Pratt & Whitney's aircraft engines are widely used in both civil aviation (especially airlines) and military avi ...

radial engine The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is ...

s. Because the new turboprops were much lighter than the radial engines, they had to be mounted further forward to maintain the aircraft's center of gravity. The replace