The Secret of Flight

Dr. Alexander Lippisch introduces his series and the basic laws of fluid motion by means of new methods of visualizing the flow phenomenon. He also introduces the Smoke Tunnel (a type of wind tunnel) which is so designed as to make it possible to observe the entire flow field and to see clearly the action of the aircraft components. He shows how the first man-made flying vehicle, the kite, is a primitive application of the dynamic lift of the flat plate.

Dr. Lippisch points out the main problems of flight: lift and drag, control and stability, and propulsion. He explains the correlation between flow velocity, the local pressure, and the distance between streamlines. A picture of a light plane in flight is projected into the wind tunnel so that viewers may have a side view of such a plane and the streamlines around it. He explains velocity distribution and demonstrates how increasing speed diminishes the pressure on a surface and vice versa.

Dr. Lippisch's theme is the historical development of the flying machine. He begins his lecture with a short demonstration of Penaud's model. He shows how the invention of the cambered wing led to the first man-carrying aircraft, the glider. The next problem, the problem of control, was not conceived until the Wright Brothers began their pioneering glider experiments in Kitty Hawk, and Dr. Lippisch shows a scale model of their last (1902) glider and its control arrangement is demonstrated. As he shows film clips of the Wright Brothers' airplane, he explains the function of this first power aircraft.

The Wright Brothers solved three problems with their first plane: lift, control, and propulsion. The problem of lift was the one which caused the most controversial opinions between scientists and engineers. Dr. Lippisch traces the development of the cambered wing section until a streamlined cambered plate led to the development of the modern wing profile.

Even before the improved lift devices were designed, the stability and control problems had to be solved and further improvements incorporated into the original systems. Dr. Lippisch illustrates how the stability and control system of the Wright brothers' glider differs from the system on the conventional aircraft of today.

After the lift, stability and control problems were solved, a propulsive system was needed to make the aircraft fly. The first propulsion device - the propeller - is still in use today. Dr. Lippisch explains the design of the propeller and demonstrates the lifting propeller - the Helicopter Rotor.