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Sir George Cayley

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1773 - 1857


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Sir George Cayley (1773-1857)

Sir George Cayley  1773 - 1857

George Cayley (1773-1857) is considered the father of aviation. Cayley was a relatively well to do baronet who lived on an estate in Yorkshire, England. An educated man, Cayley spent his life working intensely on engineering, social, and political problems in England. However, the dominant interest of his life was heavier-than-air flight, and in 1799 he set forth for the first time in history the concept of the modern airplane. Cayley had identified the drag vector (parallel to the flow) and the lift vector (perpendicular to the flow). It was this concept which was to be utilized by the Wright brothers in the first successful airplane more than a century later.1

In 1804 Cayley built a whirling arm apparatus just as John Smeaton (1724-1792) had done earlier to study the resistance of air on cloth surfaces.2 At the end of this whirling arm was a lifting surface (a portion of a wing) on which Cayley measured force of lift. represented the first modern configuration airplane in history, with a fixed wing, and a horizontal and vertical tail that could be adjusted. He found that setting the wings at a slight dihedral gave lateral stability and that a tail plane set behind the main wings gave longitudeal stability.3 In 1809 and 1810 Cayley published three papers on his aeronautical research where he quite correctly pointed out for the first time that: (1) lift is generated by a region of low pressure on the upper surface of the wing and; (2) cambered wings (curved surfaces) generate lift more efficiently than a flat surface. These results, among many others, can be found in his papers entitled "On Aerial Navigation" published in the November 1809, February 1810, and March 1810 issues of Nicholson's Journal of Natural Philosophy.
4 This "triple paper" by Cayley ranks as one of the most important aeronautical documents in history.5 In 1849, he designed, built, and tested a full-size triplane glider, which during some of its tests carried a ten-year-old boy through the air several yards on a descending hill. For this reason, the machine is sometimes called "Cayley's boy carrier." One of Cayley's other designs appeared in Mechanics Magazine in 1852.6 Cayley never achieved his final goal--sustained heavier-than air, powered, manned flight. However, his contributions clearly furthered advancement to the modern airplane.

1. Anderson, JR., John D. The Wright Brothers, The First True Aeronautical Engineers.
2. Becker, Beril. Dreams and Realities of the Conquest of the Skies. New York: Atheneum, 1967. Page 37.
3. The American Heritage History of Flight. ed Josephy Jr., Alvin M. Simon & Schuster, 1962. Page 80.
4. Becker, Beril. Dreams and Realities of the Conquest of the Skies. New York: Atheneum, 1967. Page 46.
5. Anderson, JR., John D. The Wright Brothers, The First True Aeronautical Engineers.
6. Ibid.


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Sketch by George Cayley Of His Model Monoplane Glider - 1804

The Cayley Model Monoplane Glider (reconstruction) - 1804

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The Cayley Medallion, depicting (left) a Monoplane Glider and (right) Lift and Drag - 1799

Sir George Cayley is one of the most important people in the history of aeronautics. Many consider him the first true scientific aerial investigator and the first person to understand the underlying principles and forces of flight. His built his first aerial device in 1796, a model helicopter with contra-rotating propellers. Three years later, Cayley inscribed a silver medallion (above) which clearly depicted the forces that apply in flight. On the other side of the medallion Cayley sketched his design for a monoplane gliding machine.

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"Sir Cayley's Governable Parachute" Glider - 1852

In 1804 Cayley designed and built a model monoplane glider of strikingly modern appearance. The model featured an adjustable cruciform tail, a kite-shaped wing mounted at a high angle of incidence and a moveable weight to alter the center of gravity. It was probably the first gliding device to make significant flights.

The following year Cayley discovered that dihedral (wings set lower at their center and higher at their outer ends) improved lateral stability. He continued his research using models and by 1807 had come to understand that a curved lifting surface would generate more lift than a flat surface of equal area. By 1810 Cayley had published his now-classic three-part treatise "On Aerial Navigation" which stated that lift, propulsion and control were the three requisite elelments to successful flight, apparently the first person to so realize and so state.

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Sketch By George Cayley Of The Monoplane Glider - 1848

By 1816 Cayley had turned his attention to lighter-than-air machines and designed a streamlined airship with a semi-rigid structure. He also suggested using separate gas bags to limit an airship's lifting gas loss due to damage. In 1837 Cayley designed a streamlined airship to be powered by a steam engine.

In 1849 Cayley built a large gliding machine, along the lines of his 1799 design, and tested the device with a 10-year old boy aboard. The gliding machine carried the boy aloft on at least one short flight.

Soon thereafter, in 1853, Cayley built an even larger gliding machine and had his coachman aboard when he tested the device that same year. An oft-repeated story holds that after the short flight Cayley's coachman stated that he had been hired to drive a coach not to fly a glider. It appears the names of both the boy and the coachman have been forgotten. However, Sir George Cayley's endeavors (including in areas other than aeronautics) have hardly been forgotten, for he is seen as, perhaps, the single most important aerial researcher and theoretician of his time. His theories and activities inspired the next wave of aeronauticists, which included William S. Henson and  John Stringfellow.



Sir George Cayley Bt.

 (1773 - 1857)



 Sir George Cayley

Sir George Cayley, born in 1773, is sometimes called the 'Father of Aviation'. A pioneer in his field, he is credited with the first major breakthrough in heavier-than-air flight.

Cayley literally has two great spurts of aeronautical creativity, separated by years during which he did little with the subject.

He was the first to identify the four aerodynamic forces of flightùweight, lift, drag, and thrustùand their relationship and also the first to build a successful human-carrying glider.

Cayley described many of the concepts and elements of the modern airplane and was the first to understand and explain in engineering terms the concepts of lift and thrust. Before him, researchers thought that the propulsion system should generate both lift and forward motion at the same time, as birds were able to do. So they constructed their flying machines with flapping wings (called ornithopters) to resemble the motion of birds. Cayley realized that the propulsion system should generate thrust but that the wings should be shaped so as to create lift. Finally, Cayley was the first investigator to apply the research methods and tools of science and engineering to the solution of the problems of flight.

In his experiments, Cayley would first test his ideas with small models and then gradually progress to full-scale demonstrations. He also kept meticulous records of his observations. One of his first experiments as a young man was to build a small helicopter model. This toy was rooted deep in European history. The earliest ancestors of the device date to the 14th century. Cayley was inspired by a version developed in 1784 by the Frenchmen Launoy and Bienvenu. It had two rotors consisting of feathers stuck in corks and was driven by a string from a bow.

The design demonstrated an understanding of how a propeller worked. It also addressed CayleyÆs interest in finding a means of powering an aircraft. He attempted to use an engine fueled by gunpowder but it was unreliable. His inability to find a means of propulsion caused him to revert temporarily to Leonardo da VinciÆs concept of using flapping wings as a means of propulsion. This resulted in his 1843 convertiplane model called the ôAerial Carriage.ö Cayley reverted to ornithoptering propulsion and vertical flight ideas on several occasions in his career.

In 1799, Cayley designed a configuration that was basically in the form of a modern airplane with a fuselage and wings. Etched on a silver disk this design bears a close relationship to the modern flying machines of more than a century later. On one side of the disc he showed the forces that govern flight. On the reverse side, he engraved an aircraft that illustrated how those forces operated.

It had a fixed main wing, a fuselage, a cruciform tail unit with surfaces for vertical and horizontal control, a cockpit for the pilot, and a rudimentary means of propulsion that consisted of revolving vanes, a precursor to the propeller. Thus, one hundred years before the Wright brothers flew their glider, Cayley had established the basic principles and configuration of the modern airplane, complete with fixed wings, fuselage, and a tail unit with elevators and rudder, and had constructed a series of models to demonstrate his ideas.

Experiments that he began to carry out in 1804 allowed him to learn more about aerodynamics and wing structures using a whirling arm device. He observed that birds soared long distances by simply twisting their arched wing surfaces and deduced that fixed-wing machines would fly if the wings were cambered. This was the first scientific testing of airfoilsùthe part of the aircraft that is designed to produce lift.

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George Cayley, Gliders, 1804 -1852

After these experiments, he constructed what is considered to be the first real airplane in history. This glider, which was basically a kite on top of pole, was about 5 feet (1.5 meters) long, with a fixed wing set at an angle of incidence of 6 degrees and a cruciform tail that was attached to the fuselage by universal joints. Movable ballast controlled the center of gravity. After this model successfully flew, Cayley designed a larger model glider with rigid wings.

By 1808, Cayley had constructed a glider with a wing area of almost 300 square feet (28 square meters). By the middle of 1809, Cayley had investigated the improved lifting capacities of cambered wings, the movement of the center of pressure, longitudinal stability, and the concept of streamlining. He demonstrated the use of inclined, rigid wings to provide lift and roll stability, and the use of a rudder steering control. He even came to realize that an area of low pressure is formed above the wing. By 1809, he had advanced from model gliders to the building and successful flying of a glider with a total wing area of approximately 172 square feet (18.5 square meters).

Soon after, Cayley published a paper, On Aerial Navigation (1809-1810), which appeared in NicholsonÆs Journal of Natural Philosophy, Chemistry and the Arts. In this paper, he laid out the basis for the study of aerodynamics. However, this work was not known and acknowledged for some years.

After having built several models (with an interruption to explore the possibility of an Aerial Carriage of 1843), Cayley concentrated on experiments with full-size gliders. He built his first full-size glider in 1849 and initially carried out trials with ballast. Later that year, the ten-year-old son of one his servants became the first person in history to fly when he made a short flight in a Cayley glider.

Four years later, in 1853 and fifty years before the first powered flight was made at Kitty Hawk, North Carolina, Cayley built a triplane glider (a glider with three horizontal wing structures) that carried his coachman 900 feet (275 meters) across Brompton Dale in the north of England before crashing. It was the first recorded flight by an adult in an aircraft.

Throughout his long career, Cayley recognized and searched for solutions to the basic problems of flight. These included the ratio of lift to wing area, determination of the center of wing pressure, the importance of streamlined shapes, the recognition that a tail assembly was essential to stability and control, the concept of a braced biplane structure for strength, the concept of a wheeled undercarriage, and the need for a lightweight source of power. Cayley correctly predicted that sustained flight would not occur until a lightweight engine was developed to provide adequate thrust and lift, an event that did not take place until the flight of Orville and Wilbur Wright in 1903.




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George Cayley, aeroplane design, 1799 engraving

It had fixed wings for lift, a movable tail for control, and rows of "flappers" beneath the wings for thrust.

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George Cayley, aeroplane design, 1799, perspective sketch

In 1799, Sir George Cayley, a baronet in Yorkshire, near Scarborough, England, conceives a craft with stationary wings to provide lift and "flappers" to provide thrust. It also has a movable tail to provide control. So convinced is he that this idea is an earth-shaker, he engraves a drawing of this craft on a silver disk. Cayley is the first to separate the different forces that keep an aircraft in the air, and his engraving is the first recorded drawing of a fixed-wing aircraft -- an airplane.

It had fixed wings for lift, a movable tail for control, and rows of "flappers" beneath the wings for thrust



Airfoil Experiments 1804


Sir George Cayley


George Cayley, aerofoil testing device 'whirling arm'

Cayley was interested in reducing the 'direct resistance' (drag) of the spars in his gliders and developed the first instrument for testing streamlining. He cut the flat section of the spar to half the frontal area of the wider, curved part, to test the theory of the time that they would have the same drag.

On the End of a Whirling Arm

Sir George Cayley (1773-1857) also used a whirling arm to measure the drag and lift of various airfoils. His whirling arm was 5 feet long and attained tip speeds between 10 and 20 feet per second.


George Cayley, aerofoil testing device 'whirling arm' - Movie

Click the above image to download the Quicktime movie [2.9Mb]


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George Cayley, 'Helicopter', 1809

Based on design by Launoy and Bienvenu 1784.

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George Cayley, airfoil design, 1804

George Cayley, Glider, 1804

Armed with test data from the arm, Cayley built a small glider that is believed to have been the first successful heavier-than-air vehicle in history. In 1804 Cayley built and flew an unmanned glider with a wing area of 200 square feet.

By 1852 he had a triplane glider design that incorporated many features of modern aircraft, but manned, powered aircraft were still half a century away.

Although Cayley performed many aerodynamic experiments and designed precocious airplane models, his major contribution to flight was one of design philosophy. Before Cayley, would-be aeronauts believed that the propulsion system should generate both lift and forward motion at the same time, as birds and helicopters do.

Cayley said, "Make a surface support a given weight by the application of power to the resistance of air." In other words, use an engine to create forward motion and let the motion develop lift via the wings. This separation of propulsion and lift functions, simple though it sounds, was a revolutionary change in the way people thought about aircraft. One need not build planes with flapping wings! A whole new horizon in aircraft design opened up.


Progress in Flying Machines

Octave Chanute, Screws to Lift and Propel : Part I March 1892

In describing the various proposals and experiments which have been made to compass artificial flight by means of rotating screws, the latter will chiefly be considered as instruments from which to obtain support of a given weight in the air. There is no question that they can serve as propellers if the support be otherwise obtained, nor that if a screw can lift and sustain its own prime motor, it can also be made to progress horizontally, either by inclining it at the proper angle or by adding a vertical screw.

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Launoy and Bienvenu 'Helicopter', 1774

The first practical experiment known, however, is that of M. Launoy, a naturalist, and M. Bienvenu, a mechanician, who jointly exhibited before the French Academy of Sciences in 1784 the little apparatus shown below.

It consisted of two superposed screws, about one foot in diameter, each composed of four feathers inserted in sockets at the ends of a rotating axle. This axle was put into motion by the unwinding of a cord fastened to the two extremities of a bow and the report to the French Academy (May 1, 1784) says:

"The working of this machine is very simple. When the bow has been bent by winding the cord, and the axle placed in the desired direction of hight-say vertically, for instance- the machine is released. The unbending bow rotates rapidly, the upper wings one way and the lowerwings the other way, these wings being arranged so that the horizontal percussions of the air neutralize each other, and the vertical percussions combine to raise the machine. It therefore rises and falls back afterward from its own weight."

Launoy & Bienvenu proposed also to build a large machine, and to go up in it themselves. It is not stated whether this was ever attempted but probably not, as a brief investigation must have satisfied them that they had no adequate primary motive power at hand to lift even its own weight in that way, and that with a secondary or stored power tile machine would fly but for a few seconds. Practically the same device was constructed by Sir George Cayley in 1795, and described by him in Nicholson's Journal for April, 1810; but whether he reinvented it or borrowed the idea from Launoy & Bienvenu is not stated. He mentions it merely as a toy, and his writings seem to indicate that he expected success to be achieved instead with an aeroplane to be driven by some sort of propelling apparatus, if only a sufficiently light first mover could be contrived.

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George Cayley, wing experiments, 1809

George Cayley, Airship, 1816

George Cayley, 'Aerial Carriage', 1843

A biplane 'convertiplane' based on (but reportedly not accredited to) an idea by one Robert Taylor for a monoplane 'convertiplane' around the same time

George Cayley, 'Aerial Carriage', 1843

George Cayley, 'Aerial Carriage', 1843

George Cayley in later life, c.1850
George Cayley, Triplane, 'Boy Carrier' 1849



George Cayley, Triplane, 'Boy Carrier' 1849



George Cayley, 'Governable Parachute', 'Man Carrier' 1852

Mechanics Magazine, September 25, 1852

George Cayley, 'Governable Parachute', 'Man Carrier' 1852, Replica

George Cayley, 'Governable Parachute', 1852, Replica in flight

George Cayley, 'Governable Parachute', 1852, Replica in flight


other items...




George Cayley, Tensioned Wheels


George Cayley, FDC



Sir George Cayley


It is generally accepted that the aeroplane is the invention of Sir George Cayley in 1799 at Brompton, near Scarborough in Yorkshire. Indeed, in 1909 Wilbur Wright himself paid Cayley the following tribute:

"About 100 years ago, an Englishman, Sir George Cayley, carried the science of flight to a point which it had never reached before and which it scarcely reached again during the last century."

Restricted to gliders for lack of a light weight engine, for his designs of these Cayley employed the common rule, supplemented by results from his own whirling arm experiments which explored the improved lifting effect of increasing wing incidence. Because of his choice of low wing aspect ratio on structural grounds, such gliders achieved lift to drag ratios as low as 3, perhaps as high as 7. Initially, Cayley saw his gliders' cruciform tail units as supplying merely steering and re-trimming (for different flight speeds) but in his later designs -- notably the Governable Parachute of 1852 with its duplicated tail -- there began to emerge an appreciation of the stabilising function of the tail. Cayley introduced many innovations -- wing dihedral, the tension wheel undercarriage are diverse examples -- and, as early as 1809, the suggestion that the shape of the rear of a body is as important as the front in determining resistance so that a streamlined tail is beneficial.



A History of Aeronautics

Chapter III. Sir George Cayley by E. Charles Vivian

On the fifth of June, 1783, the Montgolfiers' hot-air balloon rose at Versailles, and in its rising divided the study of the conquest of the air into two definite parts, the one being concerned with the propulsion of gas lifted, lighter-than-air vehicles, and the other being crystallised in one sentence by Sir George Cayley:

'The whole problem,' he stated, 'is confined within these limits, viz.: to make a surface support a given weight by the application of power to the resistance of the air.'

For about ten years the balloon held the field entirely, being regarded as the only solution of the problem of flight that man could ever compass. So definite for a time was this view on the eastern side of the Channel that for some years practically all the progress that was made in the development of power-driven planes was made in Britain.

In 1800 a certain Dr Thomas Young demonstrated that certain curved surfaces suspended by a thread moved into and not away from a horizontal current of air, but the demonstration, which approaches perilously near to perpetual motion if the current be truly horizontal, has never been successfully repeated, so that there is more than a suspicion that Young's air-current was NOT horizontal.

Others had made and were making experiments on the resistance offered to the air by flat surfaces, when Cayley came to study and record, earning such a place among the pioneers as to win the title of 'father of British aeronautics.' Cayley was a man in advance of his time, in many ways. Of independent means, he made the grand tour which was considered necessary to the education of every young man of position, and during this excursion he was more engaged in studies of a semi-scientific character than in the pursuits that normally filled such a period.

His various writings prove that throughout his life aeronautics was the foremost subject in his mind; the Mechanic's Magazine, Nicholson's Journal, the Philosophical Magazine, and other periodicals of like nature bear witness to Cayley's continued research into the subject of flight. He approached the subject after the manner of the trained scientist, analysing the mechanical properties of air under chemical and physical action.

Then he set to work to ascertain the power necessary for aerial flight, and was one of the first to enunciate the fallacy of the hopes of successful flight by means of the steam engine of those days, owing to the fact that it was impossible to obtain a given power with a given weight. Yet his conclusions on this point were not altogether negative, for as early as 1810 he stated that he could construct a balloon which could travel with passengers at 20 miles an hour--he was one of the first to consider the possibilities of applying power to a balloon.

Nearly thirty years later--in 1837--he made the first attempt at establishing an aeronautical society, but at that time the power-driven plane was regarded by the great majority as an absurd dream of more or less mad inventors, while ballooning ranked on about the same level as tight-rope walking, being considered an adjunct to fairs and fetes, more a pastime than a study. Up to the time of his death, in 1857, Cayley maintained his study of aeronautical matters, and there is no doubt whatever that his work went far in assisting the solution of the problem of air conquest.

His principal published work, a monograph entitled Aerial Navigation, has been republished in the admirable series of 'Aeronautical Classics' issued by the Royal Aeronautical Society. He began this work by pointing out the impossibility of flying by means of attached wings, an impossibility due to the fact that, while the pectoral muscles of a bird account for more than two-thirds of its whole muscular strength, in a man the muscles available for flying, no matter what mechanism might be used, would not exceed one-tenth of his total strength.

Cayley did not actually deny the possibility of a man flying by muscular effort, however, but stated that 'the flight of a strong man by great muscular exertion, though a curious and interesting circumstance, inasmuch as it will probably be the means of ascertaining finis power and supplying the basis whereon to improve it, would be of little use.' From this he goes on to the possibility of using a Boulton and Watt steam engine to develop the power necessary for flight, and in this he saw a possibility of practical result.

It is worthy of note that in this connection he made mention of the forerunner of the modern internal combustion engine; 'The French,' he said, 'have lately shown the great power produced by igniting inflammable powders in closed vessels, and several years ago an engine was made to work in this country in a similar manner by inflammation of spirit of tar.' In a subsequent paragraph of his monograph he anticipates almost exactly the construction of the Lenoir gas engine, which came into being more than fifty-five years after his monograph was published.

Certain experiments detailed in his work were made to ascertain the size of the surface necessary for the support of any given weight. He accepted a truism of to-day in pointing out that in any matters connected with aerial investigation, theory and practice are as widely apart as the poles. Inclined at first to favour the helicopter principle, he finally rejected this in favour of the plane, with which he made numerous experiments.

During these, he ascertained the peculiar advantages of curved surfaces, and saw the necessity of providing both vertical and horizontal rudders in order to admit of side steering as well as the control of ascent and descent, and for preserving equilibrium. He may be said to have anticipated the work of Lilienthal and Pilcher, since he constructed and experimented with a fixed surface glider.

'It was beautiful,' he wrote concerning this, 'to see this noble white bird sailing majestically from the top of a hill to any given point of the plain below it with perfect steadiness and safety, according to the set of its rudder, merely by its own weight, descending at an angle of about eight degrees with the horizon.'

It is said that he once persuaded his gardener to trust himself in this glider for a flight, but if Cayley himself ventured a flight in it he has left no record of the fact. The following extract from his work, Aerial Navigation, affords an instance of the thoroughness of his investigations, and the concluding paragraph also shows his faith in the ultimate triumph of mankind in the matter of aerial flight:

'The act of flying requires less exertion than from the appearance is supposed. Not having sufficient data to ascertain the exact degree of propelling power exerted by birds in the act of flying, it is uncertain what degree of energy may be required in this respect for vessels of aerial navigation; yet when we consider the many hundreds of miles of continued flight exerted by birds of passage, the idea of its being only a small effort is greatly corroborated.

To apply the power of the first mover to the greatest advantage in producing this effect is a very material point. The mode universally adopted by Nature is the oblique waft of the wing. We have only to choose between the direct beat overtaking the velocity of the current, like the oar of a boat, or one applied like the wing, in some assigned degree of obliquity to it.

Suppose 35 feet per second to be the velocity of an aerial vehicle, the oar must be moved with this speed previous to its being able to receive any resistance; then if it be only required to obtain a pressure of one-tenth of a lb. upon each square foot it must exceed the velocity of the current 7.3 feet per second. Hence its whole velocity must be 42.5 feet per second.

Should the same surface be wafted downward like a wing with the hinder edge inclined upward in an angle of about 50 deg. 40 feet to the current it will overtake it at a velocity of 3.5 feet per second; and as a slight unknown angle of resistance generates a lb. pressure per square foot at this velocity, probably a waft of a little more than 4 feet per second would produce this effect, one-tenth part of which would be the propelling power.

The advantage of this mode of application compared with the former is rather more than ten to one. 'In continuing the general principles of aerial navigation, for the practice of the art, many mechanical difficulties present themselves which require a considerable course of skilfully applied experiments before they can be overcome; but, to a certain extent, the air has already been made navigable, and no one who has seen the steadiness with which weights to the amount of ten stone (including four stone, the weight of the machine) hover in the air can doubt of the ultimate accomplishment of this object.'

This extract from his work gives but a faint idea of the amount of research for which Cayley was responsible. He had the humility of the true investigator in scientific problems, and so far as can be seen was never guilty of the great fault of so many investigators in this subject--that of making claims which he could not support.

He was content to do, and pass after having recorded his part, and although nearly half a century had to pass between the time of his death and the first actual flight by means of power-driven planes, yet he may be said to have contributed very largely to the solution of the problem, and his name will always rank high in the roll of the pioneers of flight.



Further Reading

Sir George Cayley : On Aerial Navigation

"Arguably the most important paper in the invention of the airplane is a triple paper On Aerial Navigation by Sir George Cayley. The article appeared in three issues of Nicholson's Journal. In this paper, Cayley argues against the ornithopter model and outlines a fixed-wing aircraft that incorporates a a separate system for propulsion and a tail to assist in the control of the airplane. Both ideas were crucial breakthroughs necessary to break out of the ornithopter tradition."

I am apt to think that the more concave the wing to a certain extent, the more it gives support, and that for slow flights a long thin wing is necessary, whereas for short quick flights a short broad wing is better adapted.

Sir George Cayley is sometimes called the father of aeronautics. His contributions are mostly obscure, if nothing else because he came of age when the science of aerodynamics bordered the ludicrous in public's estimation. It was the age of Bonaparte, and Europe was concerned with more earthly matters.

His was also the time when the industrial revolution began, and there was still shortage of knowledge in propulsion systems. Besides, his achievements remained dormant for over half a century before being considered again by modern age pioneers, such as Lilienthal, Lanchester and the Wright Brothers. However, Cayley's writings clearly demonstrate that he had grasped fundamental concepts well ahead of anybody else. For example, writing about lift

The whole problem is confined within these limits, viz. To make a surface support a given weight by the application of power to the resistance of air.

He investigated the lift of cambered wings and the movement of the center of pressure. This led to understanding that a region of low pressure is established on the upper side of the wing.

Cayley's lifetime achievements are discussed concisely by CH Gibbs-Smith. His ideas spanned from helicopters to airships, from kites to birds, but his name is not formally linked to any of the aerodynamics advances, and certainly he was in no way able to build a heavier-than-air flying machine. Yet, it is also recognized that he made fundamental discoveries by great reasoning and imagination, such as :

  • Whirling arm for aerodynamic testing
  • Lift of cambered airfoils (quote above)
  • Wing streamlining (figure below)
  • Aerodynamics of the fixed wing airplane
  • Stabilizing effect of dihedral angle
  • Propeller-driven propulsion
  • Birds propulsion
  • Concept of powered fixed-wing aircraft
  • Concept of airship navigation
  • External ballistics

Many of his contributions remained in the form of drawings and hand sketches. These included "inventions" such as the tandem wing configuration, the convertiplane, the helicopter with two counter-rotating propellers. He did devise methods for testing airfoils at angle of attack, and he built and tested several unmanned gliders.

His experimental system consisted of a whirling arm (the precursor to the modern wind tunnel) to measure the drag and lift of various airfoils. The hurling arm was 5 feet long (about 1.65 m) and attained tip speeds between 10 and 20 feet per second (3.3-6.6 m/s).


Cayley's life was the subject of at least two biographies (listed below). His private journals are the most important source of his thinking. These became available to the public through the Royal Aeronautical Society some seventy years after his death. Some of his fundamental discoveries were published in the Mechanics' Magazine.

George Cayley

( 27 December 1773  -  15 December 1857 )


 Sir George Cayley

Sir George Cayley  was an exuberant polymath from Brompton-by-Sawdon, near Scarborough in Yorkshire. He was a naturalist, physical scientist, engineer, inventor and politician. His most celebrated achievement was to design and build a functional piloted (though un-powered) aeroplane, nearly fifty years before the Wright Brothers. He was the uncle of the mathematician Arthur Cayley.

Sir George inherited Brompton Hall and its estates on the death of his father, together with the title of Baronet. Though born into a life of privilege and immense wealth, he could not be characterized as an idle aristocrat. Free from any concern about money, and in the optimistic spirit of the times, he launched himself into a bewildering variety of projects, mostly aimed at improving the world through science and technology.

He was a keen observer and chronicler of the natural world throughout his life. He was a Member of Parliament (for the Whig party). He was a founder member of the Polytechnic Institution (a national organization set up in 1838 to educate the public on artistic and scientific matters), and for many years he served as its chairman. He was also a highly prolific inventor, although his ideas often made little impact because they were so far ahead of their time.

A number of his inventions were forgotten and then "re-invented" by others, many years later. Among the many things that he invented are self-righting life-boats, tension-spoke wheels, caterpillar tractors (which he called the Universal Railway), cow-catchers for railway locomotives, automatic signals for railway crossings, seat-belts, experimental designs for helicopters, and a kind of prototypical internal combustion engine fuelled by gun-powder. He also made contributions in the fields of prosthetics, heat engines, electricity, theatre architecture, ballistics, optics and land reclamation.

He is mainly remembered, however, for his flying machines. He is the first person known to have made a systematic study of the way air flows over wings. He built an alarming-sounding "whirling-arm apparatus" so that he could measure the force of the air on variously shaped specimens at various air-speeds and angles of attack. He also experimented with free-flying model gliders of various wing sections, in the stairwells at Brompton Hall. (Apparently he was forbidden from doing this while his wife was in the house.) These meticulously documented scientific experiments led him to develop an efficient cambered aerofoil and to identify the four vector forces that influence an aircraft: thrust, lift, drag, and weight. He discovered the importance of dihedral for lateral stability in flight, and he deliberately set the centre-of-gravity of many of his models well below the wings, for this reason. He also identified and investigated many other theoretical aspects of flight, and he is now widely acknowledged as the inventor of the science of aerodynamics.

By 1804 he was producing model gliders of a pattern that is startlingly similar to that of modern aircraft; a pair of large monoplane wings towards the front, with a smaller tail plane at the back comprising horizontal stabilizers and a vertical fin.

His experimental models became larger and larger until eventually he built a machine that could carry a person. After demonstrating that animals could fly in it safely, in late June or early July 1853 he persuaded his coachman to have a go. The glider was launched from a hill on the Brompton Estate by several teams of estate workers pulling on ropes and running downhill, and Sir George Cayley's coachman (his name is lost to history) flew the machine for a distance of between 100 and 200 meters across Brompton Dale into a meadow on the other side. This was the earliest recorded manned flight in a heavier-than-air machine. He landed safely, with no injury. It is often reported that as he stepped out of the machine he shouted at Sir George "I was hired to drive, not to fly!", and quit his job. Sir George was 79 years old at the time and not in the best of health, which perhaps to some extent excuses him for not risking his own neck in the glider.

Sir George is believed to have worked entirely alone on his development of a theory of flight. Although today we recognize his enormous achievements in this field, most of his contemporaries considered it to be no more than a whimsical hobby. Ultimately it can be argued that all his work on aerodynamics went to waste. Like his ideas for a caterpillar tractor or an internal combustion engine, his theories of aerodynamics sank into obscurity and had to be re-invented by others. Many of the advances made in the 1890s and 1900s by aviation pioneers such as Otto Lilienthal, Percy Pilcher and the Wright brothers were in fact rediscoveries of innovations that had been understood and described a half-century earlier by this extraordinary Yorkshireman.


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The Father of Flight

The world’s first aeroplane was designed and built at Brompton, England, a village ten miles west of Scarborough. The name of the man who undertook this task was Sir George Cayley (1773 - 1857) who lived at Brompton Hall.

George Cayley was born in Scarborough in 1773 and was always inquisitive. As a teenager he had measured how fast his thumb nail grew and discovered that it took one hundred days to grow half an inch (13 mm). He inherited the title of baronet on the death of his father, together with Brompton Hall and its land. Being a Member of Parliament and a very busy man did not prevent him from applying his mind to other problems. He witness the first railway accident and set about designing a cowcatcher, for locomotives and seat belts for the passengers. He invented the caterpillar tracks a hundred years before David Roberts reinvented them, which were eventually used on tanks and land moving equipment. A gunpowder engine was another of his experiments.

It was the theory of flight where he really excelled. He observed how fast crows flapped their wings in an endeavor to discover how to get lift off the ground and move forward. The consensus of opinion was that a machine would have to flap its wings to get lift and propulsion. George Cayley had observed the seagulls and realized they could get lift by gliding without flapping their wings and that the forward propulsion was a different problem.

Cayley set about investigating lift scientifically. As controlled conditions are required to carry out such experiments, due to wind variance, he chose to carry out these experiments on the staircase at Brompton Hall. His wife did not altogether approve of his experiments in the stairwell of the hall so he waited until she went to stay at her mother’s for the birth of their first baby before starting the tests. So having these controlled conditions he set about building a machine that had a whirling arm to simulated the wing of a bird and also allowed the angle of attack to be varied. He took as his model a crow’s wing and built a wing one foot square (350mm) and found that the best angle of attack was an incline of six degrees. So, using the knowledge that he had gained, he built his first model aircraft which took the form of a glider. The next step was to make a full size version that was able to carry a man.

The glider was built in a small stone building attached to the hall that served as George Cayley’s workshop. The aircraft was a flimsy affair as the weight had to be kept to a minimum. The wing was made in the shape of a diamond from linen sheet shaped by cane and held together with string with a tailplane at the back. Below the wing was seat with a three wheel undercarriage. The wheels, to be strong but light, consisted of rims tied to the axle with string and so Cayley had invented the bicycle wheel.

Now a site was required to fly the glider and Cayley chose Brompton Dale as it had a slope at its east end, near some trees. It was now 1853 and Cayley was 79 so he volunteered his coachman John Appleby to be the world’s first test pilot. The pilot sat in the glider and was pulled with ropes by farm workers down the slope until it flew into the air. It flew across the dale some two hundred yards (183 m) before it crashed landed, whereupon the coachman got out and is reputed to have said, “Sir George I wish to give notice. I was hired to drive, not to fly.”. John Appleby and Sir George Cayley had made history as the first men to fly and design a heavier than air machine — the aeroplane. This was fifty years before the Wright brothers fixed a propeller to an engine, put it in a glider and flew.


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