CHAPTER III – Flying Machines Construction And Operation

To grasp the fundamentals of modern flying machines, one must delve into the dynamics of bird and wind action. A straightforward experiment involving a circular cardboard piece illustrates this concept vividly. When dropped, the cardboard falls due to gravity; however, if thrown edgewise against the wind, it sails, mimicking flying machine behavior. This experiment underscores how motion—whether generated by the force of an arm or a motor—keeps the object afloat. The motor’s continuous and powerful propulsion differentiates it from the temporary thrust provided by human effort.

Furthering the understanding of flight mechanics, another experiment uses a piece of cardboard with a paper attached to one edge. By bending the paper into a curve and blowing across its convex surface, the paper lifts instead of collapsing. This is contrary to naive expectations, as air flow over the curved surface raises the paper. Conversely, when the paper is curved with the concave side up and blown across, it moves downward, emphasizing that the direction of curvature significantly impacts the air’s effect on the object.

These principles are central to all flying machines. The construction of monoplanes and biplanes relies on curved surfaces for sustentation. Initially, straight planes were tested but proved inefficient in sustaining flight. By adopting curved planes with the concave side facing downward, air is trapped and creates buoyancy. The optimal curvature degree remains debated among engineers, with variations from one to three inches per foot showcasing different designs’ attempts to harness air effectively.

This insight parallels the initial actions of a bird commencing flight. Like a bird flaps its wings to gain altitude, a flying machine’s motor propels it into the sky. However, unlike birds, flying machines require constant propulsion from the motor to remain airborne, highlighting the mechanical principle: a flying machine, to sustain flight, must continuously move forward.

The term “plane” traditionally suggests a flat surface, yet in aviation, it incorrectly describes the curved supporting surfaces of flying machines, leading to the common but technically imprecise usage of “aeroplane.” Despite the terminological inaccuracy, its widespread acceptance ensures its continued use in discussions related to flight mechanics.