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Conroy Aircraft of Santa Barbara, the developer of the Aero Spacelines Guppy oversized cargo planes, also produced a series of turboprop DC-3 conversions.
The first was the Turbo-Three, N4700C. The Douglas airframe ID of the Turbo-Three was 4903. It was equipped with a pair of 1,600 shaft horsepower Rolls Royce Mk. 510 turboprops from a crashed United Airlines Viscount. The cruise speed of the Turbo-Three was increased from 170 miles per hour to 215 milse per hour.
The Turbo-Three made its first flight with the new powerplants on May 13, 1969. It appeared at the Paris Airshow later that month. It is seen here at the Santa Barbara Airport on April 12, 1972.
The Turbo-Three was followed by the Super-Turbo-Three, N156WC, seen here at the Santa Barbara Airport on June 12, 1974. Its Douglas airframe ID was 43193. The Super DC-3 had larger wings and tail surfaces than the DC-3, and its main landing gear were fully enclosed. Although very few Super DC-3s had been purchased by the airlines, the Navy and Marine Corps were retiring several R4D-8s about that time. Note the Viscount engine donor parked at the left.
The small diameter Rolls Royce Dart engines were grafted onto the rear portion of the original engine nacelle. The airflow behind a large part of the small-diameter propellers from the Viscount was obstructed by the nacelle and landing gear fairing. The Super-Turbo-Three required a 6,000-foot long runway, limiting its practicality as a commuter airliner.
The Super-Turbo-Three ended up rotting at the Groton, Connecticut Airport. Its cockpit was seriously damaged when it was hit by the wing of a taxiing Trans American Lockheed Hercules on February 24, 1984.
The Super-Turbo-Three put in an appearance at the Mojave Air Races on June 18, 1975.
The original Turbo-Three airframe was converted by John Conroy's Specialized Aircraft Company into the Tri-Turbo-Three. It was equipped with three 1,174-horsepower, Pratt & Whitney Canada PT6A-45 turboprops driving five-bladed propellers. Its registration was changed to N23SA. The cruise speed of the Tri-Turbo-Three was increased to 230 miles per hour. The nose engine could be shut down to increase its range at a reduced cruise speed of 180 miles per hour.
It made its first flight with three engines on November 2, 1977 and appeared at the 1978 Farnborough Airshow. It is seen here at the Camarillo Airport on December 7, 1981.
In early May 1986 workers at the Santa Barbara Airport accidentally ignited a fire in the cockpit of the Tri-Turbo-Three. The cockpit section of the airplane was destroyed in the blaze. This photograph was taken on May 9, 1986.
The wings and tail surfaces were removed from the fire damaged fuselage of the Tri-Turbo-Three. It is seen here in February 1987.
The Tri-Turbo-Three was re-assembled with a replacement fuselage.
Conroy also created a single engine turboprop conversion of Cessna 337 Super Skymaster, N1414G called the Stolifter. The rear engine was deleted and the forward engine was replaced with a 575-shaft horsepower Garrett AiResearch TPE 331-25A turboprop. The fuselage was extended to nearly double the volume available for cargo. The short take-off characteristics of the Stolifter were improved by the incorporation of a Robertson Aircraft Corporation high-lift system. This picture was taken on June 12, 1974.
John Conroy also developed the Pregnant and Super Guppies.
Much of the information on this page is from the book Douglas Propliners: DC-1 - DC-7, by Arthur Pearcy.
More of my photographs of Douglas DC-3s.
You can buy a 2009 calendar featuring my photographs of Douglas DC-3 Variants.
A dozen photos of variants of Douglas DC-3s, taken over a span of thirty years. DC-3s pictured include:
PCA DC-3 N50CE, San Francisco International Airport, August 6, 1974
DC-3 N25CE Puff, Santa Barbara Airport, October 1985
DC-3C N403JB Pegasus, Santa Barbara Airport, October 16, 1985
Salair DC-3C, N3FY, Santa Barbara Airport, May 10, 1988
Douglas Historical Foundation DC-2-118B NC1934D in TWA livery Marine Corp Air Station el Toro, April 29, 1989
Lisunov Li-2T Yellow 03, Zhukovsky, Russia, September 5, 1993
Royal Air Force Dakota, Farnborough Airshow, September 11, 1994
Air Atlantique DC-3 G-AMPO, Farnborough Airshow, September 11, 1994
DC-3-253 NC41HQ (C-41 38-0502), Nellis Air Force Base, April 25, 1997
DC-3 N101KC Rose, Hawthorne Airport, Friday, July 9, 2004
DC-3 N20TW, Edwards Air Force Base, August 19, 2005
DC-3C N814CL Mainliner O'Connor, Camarillo, June 12, 2006
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Go to home page of the Goleta Air and Space Museum.