The Cessna L-19 was a popular Civilian aircraft designed in the 1950s. So popular and in wide usage, The US Military ordered the Model and identified it as The O-1 ''Bird Dog'' Observation Plane. It was used for aerial surveillance and artillery (gunnery) target spotting. The ''Bird Dog'' was also famed for being the first all-metal aircraft ordered by The US Army to replace similar loses incurred by the separation of it's air support branch in 1947 – known as The US Air Force. Close to 4,000 O-1 were built for The Military. They were first deployed as Observation platforms during The Korean War (1950-1953). Later, during The Vietnam War (1965-1975), The ''Bird Dog'' was used by The South Vietnamese Air Force. The Military Version was also a staple aircraft for The US Civil Air Patrol Service. Many examples are still in flying condition and used regularly. The Military O-1 crewed 2. They were 25-feet in length with a wingspan of 36-feet. The ''Bird Dog'' used a Single Continental 6-cylinder Engine. This produced 213-HP. They rated airspeed was 115-mph with an operational ceiling of 18,500-feet. They ranged over 500-miles.