Built in 1961, this was the prototype of a turbine-powered transport heli-copter using dynamic components of the earlier Hiller models, but with an entirely new, more capacious fuselage (six seats).

G.Apostolo "The Illustrated Encyclopedia of Helicopters", 1984

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A private venture, the Ten 99 - "the smallest big helicopter flying" - is intended for a wide variety of roles, including fleet utility work, Marine Corps assault tasks, and general-purpose civil passenger and freight duties. Although no greater in overall dimensions than the Hiller 12E, it has twice the seating capacity; payload is in excess of 450kg.

Unique in the light-helicopter class is the provision of large aft-loading clamshell doors for the 2.83m³ box-like cargo compartment. In addition there are four doors for passengers and crew and to assist in through-loading of the cargo section.

Studies for the Ten 99 began late in 1958, and preparations for production have included market evaluation, wind-tunnel testing and the manufacture of a full-scale mock-up which has been transported to various places in order to obtain reactions from prospective customers. Application for type certification was made to the | FAA last summer.

"Flight", 16 November 1961

Technical data for 1099

Engine: 1 x Pratt & Whitney PT6 turboshaft, rated at 410kW, main rotor diameter: 10.86m, length: 12.57m, fuselage length: 8.05m, height: 3.18m, take-off weight: 1588kg, empty weight: 862kg