Doak VZ-4
1958 experimental VTOL aircraft model by Doak Aircraft Company
The Doak VZ-4 (or Doak Model 16) was an American prototype Vertical Takeoff and Landing (VTOL) aircraft built in the 1950s for service in the United States Army. Only a single prototype was built, and the U.S. Army withdrew it from active trials in 1963.
Development
Edmund R. Doak, Jr., a self-taught engineer and vice president of Douglas Aircraft Company, founded Doak Aircraft Company in Torrance, California, in 1940. The company grew to 4,000 employees during World War II, with subcontracts from every major American aircraft manufacturer. These included molded plywood fuselages for trainers such as the AT-6 and Vultee BT-13, and doors, hatches and gun turrets for a multitude of aircraft.
Doak proposed a VTOL aircraft to the U.S. Army's Army Transportation and Research and Engineering Command at Fort Eustis in Newport News, Virginia, in 1950. He touted the aircraft as able to take off and land in a small area, hover and loiter over a target area, and fly backwards like a helicopter without the noise and vibration of a helicopter, while also having the horizontal cruising ability, high speed, wing-mounted weapons, and mission flexibility of a conventional fixed-wing fighter aircraft. Knowing that a Soviet attack on airbases would interdict takeoffs and landings by conventional aircraft, the Army found Doak's proposal attractive, and on 10 April 1956, it awarded Doak a contract to produce a single prototype for use as a research aircraft.
The aircraft, designated the Doak Model 16 by the Doak company and assigned the serial number 56-9642, was originally powered by an 840 shp (630 kW) Lycoming YT53 turboprop engine mounted in the fuselage, later replaced by a 1,000 shp (750 kW) Lycoming T53-L-1 turbine. The engine drove two wingtip-mounted fiberglass tilting ducted fan propellers through a "T" box on the engine that transmitted power to the propellers via a 4-inch (102-mm) aluminum tubular shaft and two smaller shafts.
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The record creator and administrative purpose are central evidence, because official documentation reflects both action and institutional priorities. The source revision retrieved here is dated Sep 8, 2026. The linked authority identifier is Q1144651. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1963, 1940, 1950 and 1956.
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This entry incorporates text from “Doak VZ-4” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.