The Bird Dog is a light observation aircraft, generally used for artillery fire observation and direction. It was based on the Cessna 170 high-wing general aviation aircraft design; the prototype was designated Model 305. The design has a high wing braced by struts attached to the landing gear mounts in the fuselage. The trailing edge has split flaps inboard of ailerons. In most Bird Dogs, the tail as a gentle curve to both the fin and rudder as well as curved horizontal stabilizers and elevators. A horizontally opposed piston engine drives a 2-blade propeller. A two-seat tandem cockpit under the wing has all-round glazing for maximum possible observation. The fixed "taildragger" landing gear has spring-steel main gear forward and a castoring tail wheel. Some models are equipped with underwing hardpoints for smoke marker rockets.