Helio Stallion

AU-24 Stallion
Helio AU-24A Stallion in storage at Davis-Monthan AFB, July 1972
Role	Armed gunship, counter-insurgency, utility transport
National origin	United States
Manufacturer	Helio Aircraft Company
First flight	5 June 1964
Primary users	United States Air Force Khmer Air Force
Number built	20

The Helio AU-24 Stallion was an American armed gunship, counter-insurgency, and utility transport developed for the United States Air Force. A total of 20 were built during the Vietnam War. Most aircraft were later sold to the Khmer Air Force.

The Helio HST-550 Stallion was an STOL utility aircraft developed in the United States in 1963. The prototype flew in July 1964. Initially conceived by the Helio Aircraft Company as a turboprop-powered variant of the Helio Courier, it eventually emerged as a completely new design of the same general configuration and much of its design was initiated from components used in the Helio H-500 Twin. It was a much larger aircraft than the Courier, and Helio soon discovered that it was too expensive for the market.

The United States Air Force however, emerged as a buyer for the design, purchasing the aircraft for the Credible Chase programme as the AU-24A. This was the gunship version of the Stallion, with a PT6A-27 680 shp (510 kW) turboprop, equipped with a General Electric M197 three-barrel 20x102mm rotary cannon mounted in the left cargo door. It also had five underwing and fuselage hardpoints.

Of the 18 aircraft purchased, fourteen or fifteen were eventually sold to the Khmer Air Force.

Data from Jane's All The World's Aircraft 1976-77

General characteristics

Performance

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