The unusual Helio AU-24 ''Stallion'' was Utility Transport Plane, modified into a ''Gunship''. Only (20) AU-24s were built by The Helio Company. The primary purchaser of The AU-24 ''Stallion'' The US Central Intelligence Agency (CIA). During The early phases of The Vietnam War (1964), The US Air Force purchased (18) of The AU-24 for use. Both a Counter Insurgent and Surveillance Craft, The ''Stallion'' was overshadowed by the more powerful US Douglas AC47D ''Spooky'' and later ''Puff, The Magic Dragon'' Airships. Most were exported tp The Khmer Air Force (Cambodia, 1972). The AU-24 was in limited service there until 1993. The ''Stallion'' was 40-feet in length with a wingspan of 41-feet. Crewed by (2), The AU-24 could transport up to (9) Passengers (when in a Transportation configuration). Power came from a single Pratt and Whitney (Canada) PTA6 Turboprop Engine. It produced an airspeed of 216-mph. The AU-24 had an operational ceiling of 25,000-feet. As a Gunship, The ''Stallion'' was armed with with (1) 20mm Rotary Barrel Cannon and the capability to support up to (5) Air to Surface Missile of Rockets (roughly 5-inch Fragmentation Warheads).