Doak VZ-4

The Doak VZ-4 (or Doak Model 16) was an American prototype VTOL aircraft built in the 1950s for service in the United States Army.

Development
The aircraft was originally powered by an 840 shp Lycoming YT53 turboprop engine. It was replaced with a 1000 shp Lycoming T53-L-1 turbine. The turbine engine is mounted in the fuselage driving two wing-tip mounted tilting ducted fan propellers.

Only one aircraft was produced. Given serial number 56-6942, it is on display at the U.S. Army Transportation Museum located at Fort Eustis, Virginia.

Operators

 * USA
 * NASA
 * United States Army