Doak VZ-4

Doak VZ-4
Land	Usa
Role	VTOL onderzoek convertiplane
Eerste vlucht	25 februari 1958
Gebouwd	1

De Doak VZ-4 (of Doak Model 16) was een Amerikaans prototype Vertical Takeoff and Landing (VTOL) vliegtuig gebouwd in de jaren 1950 voor dienst in het Amerikaanse leger. Slechts één prototype werd gebouwd, en het Leger van de V.S. trok het van actieve proeven in 1963 terug.

Bron: Doak VZ-4 op Wikipedia

Doak 16 VZ-4DA Walk Around
Photographer	Vladimir Yakubov
Localisation	US Army Transportation Museum, Fort Eustis
Photos	39

[

Doak 16 VZ-4DA 01

Doak 16 VZ-4DA 02

Doak 16 VZ-4DA 03

Doak 16 VZ-4DA 04

Doak 16 VZ-4DA 05

Doak 16 VZ-4DA 06

Doak 16 VZ-4DA 07

Doak 16 VZ-4DA 08

Doak 16 VZ-4DA 09

Click on a photo and use the mouse scroll to view all photos

Wacht, Zoeken Doak VZ-4 voor u...

Zie ook:

General Characteristics and Role

The Doak 16, designated VZ-4DA by the U.S. Army, was an experimental Vertical Takeoff and Landing (VTOL) aircraft developed in the late 1950s. It was designed to explore the concept of a “convertiplane” that could take off and land vertically like a helicopter, but transition to forward flight like a conventional fixed-wing aircraft for faster cruise speeds. The Doak 16 used a unique propulsion system: a single engine drove two large, tilting ducted fans located at the wingtips. The entire fan assemblies could be rotated 90 degrees, a configuration known as a ducted fan tilt-wing. This technology was highly experimental, part of a push by the U.S. military to find practical VTOL solutions for observation and utility roles.

Property	Typical Value (VZ-4DA)
Role	Experimental VTOL Research Aircraft
National Origin	United States (U.S. Army)
Fabrikant	Doak Aircraft Company
First Flight	February 1958 (Conventional), February 1959 (Vertical)
Bemanning	2 (Pilot and Observer)
Lengte	9.75 m (32 ft 0 in)
Spanwijdte	4.88 m (16 ft 0 in)
Hoogte	3.05 m (10 ft 0 in)
Gross Weight	1,450 kg (3,200 lb)

Powerplant and Propulsion System

Engine: 1 x Lycoming T53-L-1 turboshaft engine (later used in the Bell UH-1 Huey).
Power Output: 825 shp (615 kW).
Propulsion: Two tilting ducted fans (impellers), each connected to the engine via a transmission system to ensure synchronous rotation and thrust.
Flight Control: In vertical mode, control was provided by vanes located in the ducted fan exhaust. In forward flight, conventional rudder, elevator, and ailerons were used.
Maximum Speed (Cruise): Approximately 370 km/h (230 mph).
Service Ceiling: 6,096 m (20,000 ft).

Program Outcome and Legacy

Test Program: The VZ-4DA successfully demonstrated the transition from vertical to horizontal flight and back, validating the ducted fan tilt-wing concept.
Performance: Although the tests were successful, the VZ-4DA suffered from complex mechanical systems required to articulate the fans and transfer power, and it had a limited payload capacity.
Conclusion: The U.S. Army concluded the program in 1960. While the ducted fan concept showed promise, the Army ultimately shifted focus to lighter turboshaft helicopters (like the Bell UH-1) and other VTOL concepts that were considered more mechanically simple and scalable.
Preservation: The single prototype built, tail number 56-6942, is preserved and on display at the U.S. Army Transportation Museum at Joint Base Langley-Eustis, Virginia.