Images of various Artifacts of the Month's

July 2021

Artifact of the Month

VZ-4DA DOAK Model 16

Doak Model 16 was the first vertical take-off and landing (VTOL) aircraft to demonstrate the tilt duct concept. It was proposed to the military in the early 1950s by Doak Aircraft Company. In 1956 the U.S. Army Transportation Research and Engineering Command purchased one Doak 16 and designated it VZ-4DA. The Army was looking for a utility and observation aircraft that combined the VTOL capabilities of a helicopter with the higher speed and greater maneuverability of a conventional fixed-wing airplane. The Doak made its first flight in February 1958.

The research aircraft had ducted propellers on the wing tips which rotated 90 degrees to convert flight from vertical take-off and hovering to normal flight. The Doak 16 demonstrated conventional, vertical, and short take-offs and landings. Although the aircraft exhibited some undesirable flight characteristics, only a few were considered fundamental to the tilt-duct system, and they were solvable.

The VZ-4 was the end product of Doak’s many years of research and development in the VTOL field, and the aircraft proved reasonably useful in exploring the military potential of non-helicopter VTOL vehicles. After three years of joint testing by the Army and NASA the sole VZ-4, number 56-9642 was withdrawn from the Army inventory and subsequently operated solely by NASA before being turned over to the Transportation Museum in 1973.