Science of Flight

Balloons were the first vehicles to fly and Archimedes' principle is the secret of their lift-carrying power. Use the ideal gas law to determine air density and the hydrostatic equation to chart air pressure versus altitude. Then apply these concepts to lighter-than-air craft to learn how the Breitling Orbiter balloon was able to circumnavigate the globe non-stop.

Lift is the fundamental force involved in winged flight. It is also fraught with misunderstanding. Debunk a popular but incorrect explanation of lift, known as the equal-time theory. Then gain a deep appreciation for the power of air flowing around an airfoil at differing angles of attack. Also examine Albert Einstein's misguided attempt to design a better airfoil.

Focus on parasitic drag, a byproduct of moving an aircraft through the air, which has no practical benefit and is therefore like a parasite. Zero in on two aspects of parasitic drag: skin friction and pressure. Observe how these phenomena arise and how they can be reduced, which is a key goal of aircraft design. Learn about laminar flow as well as golf ball design.

Aerodynamic stall occurs when lift suddenly decreases, causing drag to rise steeply. Consider the role of stall in several notable air accidents, and see a demonstration in which Professor Gregory deliberately pilots a plane through a stall, showing how to recover. Also look at technological measures to combat stall and the problem of induced drag.

Starting with the Wright brothers, trace the role of wind tunnels for studying lift and drag on aircraft structures, which sparked the rapid advancement of aviation. Aerodynamic research also involves analysis and computations. Get a taste of this process by analyzing conservation of mass, momentum, and energy as they relate to lift and drag.

Apply concepts of lift and drag to propulsion, focusing on the internal combustion engine and propeller, which is still the most efficient power plant for aircraft flying at low speeds. Study the four-cycle engine and the design of propellers, which are rotating wings twisted to present an optimum angle of attack across their entire length.

Propeller-driven aircraft drop sharply in efficiency at high fractions of the speed of sound. For sustained high-speed flight, a different propulsion system is needed: the jet engine. Trace the history of jets and their super-efficient variant used on commercial airliners: the high-bypass turbofan, a machine so intricate and beautiful that a piece of one is on display at the Museum of Modern Art.

For anyone who gets the jitters during heavy turbulence, fear not: the plane is designed to take it! Follow the evolution of airframes from wood to metal to today's composite materials. Consider the problem of designing a sturdy structure that is still light enough to fly efficiently. Also look at tragic accidents that revealed the limits of certain materials and led to safer planes.

Trace the quest for stable, controlled flight back to aviation pioneers Samuel P. Langley, the Wright brothers, and Glenn Curtiss. Stability means producing forces that restore an aircraft to equilibrium when perturbed, while control entails deflection of control surfaces to alter the pitch, roll, or yaw effects that act on the aircraft's center of gravity.