I am going to attempt to unsettle your elementary understanding of aviation history and in the process also contradict every general knowledge books you’ve ever read as a child! I am sure you will asnwer one of the basic questions differently from now on!
The first thing that might probably pop up in your mind when asked,“who invented the heavier than air aircraft ?” would be the Wright Brothers. Agreeable, but behind the screens, there was a man, who actually laid down the physics behind flight.
The world got Sir George Cayley on 27th December 1773 in Scarborough, Yorkshire in a small town called in the north of England. People considered him as the English Leonardo, for he was the one who gave insights on the physics of aviation. For the article let us look at the three major inventions of Cayley.
The 1799 Silver Disk
Historians believed that this was Cayley’s seminal invention that changed the whole perspective of heavier than air aircraft. He modified the aircraft by replacing the rotating wings of earlier concepts by fixed wings. The only place where we don’t find fixed wings now, are helicopters. He also changed the wing shape and found out that, a curved wing produces more lift than a flat plate. Thus the concept of camber in wings and aspect ratio was born. By having a curved wing, we can create the necessary pressure distribution above and below the wing that produces the necessary lift.
At the back of the silver disk, we can find the scientist’s view on the forces that act on a flying body. Although he could not exactly give the direction of the air resistance force, Cayley understood its presence. Whether it was due to pure pressure difference or that which follow Newton’s rare medium concept was unknown to him.
The Whirling Arm Experiment, 1804
Cayley comprehended the corollary that resistance is proportional to the characteristic area of the body, square of the velocity, and the air density as his axiomatic terms for his whirling arm experiment. He adapted the first whirling arm that was demonstrated by Robins in 1746. To this Cayley added a horizontal hinge at the arm’s junction and vertical drive shaft so that the arm acts like a lever. By using a paper plate (0.093 sq m) the height the driving weight descended down was sufficient for the plate to travel a distance of 600 ft. At this juncture, he realised that the centre of pressure lies outside the plate’s mid span position. He calculated the centre of pressure location by numerical integration. The results of this experiments has given to rise to the lift coefficient term CL which is what we use as a performance parameter for every aircraft now. He measured this by placing weights at the computed centre of pressure so as to keep the arm rotating in the horizontal plane.
The Coach Carrier, 1853
Cayley made use of a slightly cambered (thick and curved) aerofoil, rectangular planform (wing area) and a low aspect ratio. The tail plane was depressed by about 8 degrees. His’s flight was designed in such a way that the centre of gravity was ahead of the neutral point. This ensures that the aircraft is longitudinally stable, i.e. the nose doesn’t pitch up and down unnecessarily. He also made use of two tail surfaces, one horizontal and the other vertical. All this adding more stability to the aircraft.
The brave soul who tested the first flight at Brompton Dale, crash landed and came out crying saying that he was hired to drive and not to fly.
One must not forget that his basic sketches and models have paved the way to the huge A380s that fly today. The top 5 takeaways of the article are the basic things Cayley found out
Serious flight missions can be achieved with fixed wing aircrafts
Curved surface produces more lift
Tail placed behind, at an angle adds stability to the aircraft
The silver disc contains the basic outline of any flight
He could not integrate a propulsion system to his glider.
Remember one thing, apart from aviation, history, legends, science and the world’s celebration of inventors,
The most famous are not always the most important, the least famous are not the most forgotten. At the end of the day it is what you have lived and loved that defines you. History books which describe histories of legends only have pages while the readers who read them have heart. Always capture hearts, for what you make as a man is least important than what you become as one!
Leave a Reply