Why not indeed, Dorothy?

Since the Montgolfier Brothers had conquered the problem of lighter-than-air flight with their helium-filled balloons in 1872, scientists, engineers, adventurers, inventors, pioneers and crack-pots all around the world had been trying to solve the next obvious problem, how to lift heavier-than-air machines from the ground, or simply put, how to achieve controlled, powered flight. 

While a hot-air balloon could allow Joseph and Etienne Mongolfier to achieve their dream of “floating amongst the clouds”, to go that bit further and fly over the rainbow would take nothing less than a curve-winged, thick leading edge aerofoiled, box-kite aeroplane, powered by a four-cylinder, petrol driven engine.

Lawrence Hargrave was an astronomer and natural history explorer who, through his self-funded experiments in New South Wales in the 1880’s and 1890’s, established the basic aeronautical theory that was to make heavier-than-air flight a reality.

Hargrave was born in Greenwich, England, in 1850, and when he was fifteen his father, Attorney-General of New South Wales, had him brought him out to Australia. Hargrave then lived with his father and brother in Rushcutter’s Bay. Lawrence’s father wanted him also to be a lawyer and had him tutored with that aim in mind, but Lawrence’s scientific inclinations led him in other directions. Instead of passing the New South Wales matriculation examinations, at sixteen, Lawrence instead got an education sailing around Australia. After several more expeditions through Australia and New Guinea and a stint as an Assistant Observer at the Sydney Observatory, at thirty-five he retired to his family property near Stanwell Park, on the coast south of Sydney as a man of independent means to concentrate on learning how to fly.

There he built box kites to help him hang-glide down the cliff-side but overtaken by the birds on his way, he realised they already did that. Seeing this, he took the obvious and easy path and studied what the natural world had already invented.

One thing he noticed was that bird’s wings are not flat, but that the leading edge is thicker than the trailing edge, and followed a curved design. Hargrave realised that this was the essential bit of engineering that made flight possible. The longer distance over the leading edge compared to the trailing edge reduced the air pressure above the wing and caused the air below at greater pressure to move upwards toward the zone of lower pressure, creating lift.

It was the revolutionary curved-wing design that made heavier-than-air flight possible and Lawrence immediately set about designing the aerofoil, the curved wing with a thick leading edge, which was the basis of the aeronautical theory underlying flight.

Lawrence studied the work of his predecessors, including Leonardo Da Vinci. However, unlike Da Vinci and many others who attempted to imitate nature directly, Hargrave took up where nature left off…

…Hargrave reasoned that man could fly, not so much by imitating birds, as by imitating worms, and, recognising the fluid properties of air, fish…

…The only problem left to overcome was the need for thrust and he began designing an engine that could power the flight. The main obstacle was weight. Birds overcame this by having hollow bones, but Hargraves realised it was necessary to construct an engine that was light but still gave enough thrust, i.e. a light engine with enough power would be needed. Hargrave designed a rotary compressed air engine, but did not construct it or try it out.

In 1893, the editor of the French international flight journal Progress of Flying Machines, Octave Chanute, stated 

If there be one man, more than another, who deserves to succeed in flying through the air, that man is Mr. Laurence Hargrave, of Sydney, New South Wales. He has now constructed with his own hands no less than 18 flying machines of increasing size, all of which fly, and as a result of his many experiments (of which an account is about to be given) he now says, in a private letter to the writer, that: ‘I know that success is dead sure to come.’

…

Hargrave’s curved wing and aerofoil research were published in the Progress of Flying Machines and the Aeronautical Annuals published by the dedicated American patron of flight research, James Means, whose publications communicated to a largely disinterested and very sensible US public, the state-of the-art in attempts at flight in the work of Chanute, Hargrave, Lilienthal and Cayley, among several others.

At this same time, Octave Chanute was corresponding with two equally “batty” pioneers who were also trying to emulate the principle in a barn in Dayton, Ohio.

In 1900, the Wright Brothers had corresponded with Hargrave and with his full blessing and best wishes he gave them permission to freely make use of any and all of his research, ideas and designs, including everything that had been published.

The Wright Brothers constructed a plane using the box-kite and curved wing design that had become standard. They added on a light-weight, four-cylinder, gasoline engine, and on December 17, 1903, the research of hundreds culminated in their legendary first successful powered flight across the windy sand-dunes at Kitty Hawk, North Carolina. Hargrave telegraphed his congratulations to the Wright brothers from New South Wales and declaring, “My work is for humanity”, Hargrave never gained financially from his work. Making his work freely available, he never took out any patents…

…In 1915, Hargrave died in the year that the first Australian-born scientist was awarded the Nobel Prize for Physics.