Aerodynamics: HISTORY OF AEROSPACE

SIR GEORGE CAYLEY (1773-1857)

SIR GEORGE CAYLEY (1773-1857)
Sir George Cayley introduced the concept of a fixed wing for generating lift, combined vertical &horizontal tail for stability and another separate mechanism for propulsion.
Sir George Cayley was born at Scarborough in Yorkshire, England on December 27/1773. He was educated at York and Nottingham and later studied chemistry and electricity under several noted tutors. He was a scholarly man of some rank, a portrait of Cayley is shown below. He lived a long life of 84 years.

He engraved his revolutionary fixed-wing the concept on the silver disk in 1799 (see Fig) in 1804, he built a whirling-arm apparatus, shown in Fig, for testing airfoils this was simply a lifting surface (airfoil) mounted on the end of a long rod, which was rotated at some speed to generate a flow of air over the airfoil. In modern aerospace engineering, wind tunnels now serve this function, but in his time the whirling arm was an important development, which allowed the measurement of aerodynamic forces and the centre of pressure on a lifting surface

Cayley’s states that the basic principle of a flying machine is “to make a surface support a given weight by the application of power to the resistance of air.” He notes that a surface inclined at some angle to the direction of motion will generate lift (upwards force acting on an airfoil) and that a cambered (curved) surface will do this more efficiently than a flat surface. He also states that lift is generated by a region of low pressure on the upper surface of the wing. He was the first one to suggest such multiplanes (i.e. biplanes and triplanes).

SIR OTTO LILIENTHANL

Lilienthal was born on May 23, 1848, at Anklam, Prussia (Germany). He did his schooling in Potsdam and Berlin, the latter at the Berlin Technical Academy, graduating with a degree in mechanical engineering. Lilienthal designed and flew the first successful controlled gliders in history. He designed a glider in 1889, and another in 1890—both were unsuccessful. However, in 1891, Lilienthal’s first successful glider flew from a natural hill at Derwitz, Germany. He used cambered (curved) airfoil shapes on the wing and vertical and horizontal tail planes in the back for stability. He made over 2000 successful glider flights. On August 9, 1896, He was gliding from the Gollenberg hill near Stollen in Germany. A temporary gust of wind brought Lilienthal’s monoplane glider to a standstill, he stalled and crashed to the ground. Only the wing was crumpled; the rest of the glider was undamaged. However, Lilienthal was carried away with a broken spine. He died the next day in the Bergmann Clinic in Berlin. In 1893, he built a powered machine; the prime mover was a carbonic acid gas motor that twisted six slats at each wing tip. In 1895, he built a second, but larger, powered machine neither one of these aeroplanes was ever flown with the engine operating.

WILBUR WRIGHT & ORVILLE WRIGHT

Wilbur Wright was born on April 16, 1867, in Millville, Indiana. Orville Wright was born on August 19, 1871, in Dayton, Indiana. Both the brothers have never officially received a high school diploma.

Orville Wright was a prize-winning cyclist, and this prompted the brothers to set up a bicycle sales and repair shop in Dayton. Three years later they began to manufacture their own bicycle designs, using homemade tools. These enterprises were profitable and helped to provide the financial resources for their later work in aeronautics.

They built a wind tunnel in their bicycle shop in Dayton and tested more than different airfoil shapes. They designed a force balance to measure accurately the lift(a force acting opposite to weight) and drag(a force acting opposite to thrust )They made a glider 3 glider was a classic. It was constructed in 1902. It was a biplane glider with a 32-ft 1-in wingspan. This number 3 glider is shown in Fig Note that, after several modifications, the Wrights added a vertical rudder behind the wings. This rudder was movable, and when connected to move in unison with the wing warping, it enabled the number 3 glider to make a smooth, banked turn. This combined use of rudder with wing warping (or later, ailerons) was another major contribution of the Wright brothers to flight control in particular, and aeronautics in general.