The Conroy Turbo-Three was a series of two Douglas DC-3s 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 converting ...

. 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 Vi ...

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

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 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 Conroy Tri-Turbo-Three was a Douglas DC-3 fitted with three Pratt & Whitney Canada PT6A turboprop engines by Conroy Aircraft; the third engine was mounted on the nose of the aircraft. Design and development First flown on 2 November 1977,'' ...

. 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 located on the Thames River. It is the home of General Dynamics Electric Boat, which is the major contractor for submarine work for the United States Navy. The Naval Submarine Base New London i ...

where on February 19, 1984 its cockpit was hit by a wing from a Trans American

Lockheed L-100 Hercules The Lockheed L-100 Hercules is the civilian variant of the prolific C-130 Hercules military transport aircraft made by the Lockheed Corporation. Its first flight occurred in 1964. Longer L-100-20 and L-100-30 versions were developed. L-100 pr ...

. 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 a ...

(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

See also

References