The Conroy Turbo-Three was a series of two

Douglas DC-3 The Douglas DC-3 is a propeller-driven airliner manufactured by the 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 ...

s modified with

turboprop A turboprop is a Gas turbine, gas turbine engine that drives an aircraft Propeller (aeronautics), propeller. A turboprop consists of an intake, reduction drive, reduction gearbox, gas compressor, compressor, combustor, turbine, and a propellin ...

engines by Conroy Aircraft. 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 retired 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. T ...

previously operated by

United Airlines United Airlines, Inc. is a Major airlines of the United States, major airline in the United States headquartered in Chicago, Chicago, Illinois that operates an extensive domestic and international route network across the United States and six ...

were used to replace the original

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

radial engine The radial engine is a reciprocating engine, reciprocating type internal combustion engine, internal combustion engine configuration in which the cylinder (engine), cylinders "radiate" outward from a central crankcase like the spokes of a wheel. ...

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 replacement engines increased the aircraft's cruising speed from 170 mph to 215 mph. The prototype was later converted into the Conroy Tri-Turbo-Three. The second conversion was called the Super Turbo-Three because it was converted from a surplus Super DC-3. Unlike the first conversion, the Dart engines were mounted in the rear part of the engine nacelle. Due to the small diameter of the Viscount propellers, airflow was restricted by the bulky nacelles and landing gear fairings. This caused the takeoff distance to be 6000 feet, making it unappealing as a commuter aircraft. The aircraft ended up parked at Groton-New London Airport in

Groton, Connecticut Groton ( ) is a town in New London County, Connecticut, United States, located on the Thames River (Connecticut), Thames River. It is the home of General Dynamics Electric Boat, which is the major contractor for submarine work for the United St ...

where on February 19, 1984 its cockpit was hit by a wing from a Transamerica Airlines Lockheed L-100 Hercules. A similar conversion had been performed for

British European Airways British European Airways (BEA), formally British European Airways Corporation, was a British airline which existed from 1946 until 1974. BEA operated to Europe, North Africa and the Middle East from airports around the United Kingdom. The ...

(BEA) in the 1940s when a Dakota was converted to Dart power in order to obtain turboprop experience prior to the introduction of the Viscount.

References

{{Douglas DC-3 family 1960s United States airliners Turbo Three Low-wing aircraft Douglas DC-3 Aircraft first flown in 1969 Twin-turboprop tractor aircraft Aircraft with retractable conventional landing gear

See also

References