Aeronautics
Hargrave had been interested in experiments of all kinds from an early age, particularly those with aircraft. When his father died in 1885, and Hargrave came into his inheritance, he resigned from the observatory to concentrate on full-time research. and for a time gave particular attention to the flight of birds. He chose to live and experiment with his flying machines in Stanwell Park, a place which offers excellent wind and hang conditions and nowadays is the most famous hang gliding and paragliding venue in Australia.
In his career, Hargrave invented many devices, but never applied for a patent on any of them. He needed the money but he was a passionate believer in scientific communication as a key to furthering progress. As he wrote in 1893:
"Workers must root out the idea by keeping the results of their labors to themselves a fortune will be assured to them. Patent fees are much wasted money. The flying machine of the future will not be born fully fledged and capable of a flight for 1000 miles or so. Like everything else it must be evolved gradually. The first difficulty is to get a thing that will fly at all. When this is made, a full description should be published as an aid to others. Excellence of design and workmanship will always defy competition."
Among many, three of Hargrave's inventions were particularly significant:
- Study of curved aerofoils, particularly designs with a thicker leading edge.
- The box kite (1893), which greatly improved the lift to drag ratio of early gliders.
- Work on the rotary engine, which powered many early aircraft up until about 1920.
He made endless experiments and numerous models, and communicated his conclusions in a series of papers to the Royal Society of New South Wales. Two papers which will be found in the 1885 volume of its Journal and Proceedings show that he was early on the road to success. Other important papers will be found in the 1893 and 1895 volumes which reported on his experiments with flying-machine motors and cellular kites.
Of great significance to those pioneers working toward powered flight, Hargrave successfully lifted himself off the ground under a train of four of his box kites at Stanwell Park Beach on 12 November 1894. Aided by James Swain, the caretaker at his property, the kite line was moored via a spring balance to two sandbags (see image). Hargrave carried an anemometer and clinometer aloft to measure windspeed and the angle of the kite line. He rose 16 feet in a wind speed of 21 mph. This experiment was widely reported and established the box kite as a stable aerial platform. Hargrave claimed that "The particular steps gained are the demonstration that an extremely simple apparatus can be made, carried about, and flown by one man; and that a safe means of making an ascent with a flying machine, of trying the same without any risk of accident, and descending, is now at the service of any experimenter who wishes to use it." This was seen by Abbott Lawrence Rotch of the meteorological observatory at Harvard University who constructed a kite from the particulars in Engineering. A modification was adopted by the weather bureau of the United States and the use of box-kites for meteorological observations became widespread. The principle was applied to gliders, and in October 1906 Santos Dumont in a box-kite aeroplane made the first officially recorded flight. As late as 1909 the box-kite aeroplane was the usual type in Europe.
Hargrave had not confined himself to the problem of constructing a heavier than air machine that would fly, for he had given much time to the means of propulsion. In 1889 he invented a rotary engine which appears to have attracted so little notice that its principle had to be discovered over again by the brothers Seguin in 1908. This form of engine was much used in early aviation until it was superseded by later inventions. His development of the rotary engine was frustrated by the weight of materials and quality of machining available at the time, and he was unable to get sufficient lift from his engines to build an independent flying machine.
Hargrave's work inspired Alexander Graham Bell to begin his own experiments with a series of tetrahedral kite designs. However, Hargrave's work, like that of many another pioneer, was not sufficiently appreciated during his lifetime. His models were offered to the premier of New South Wales as a gift to the state, and it is generally incorrectly stated that the offer was not accepted. It is not clear what really happened, but there appears to have been delays in accepting the models, and in the meantime they were given to some visiting German professors who handed them to the Munich museum. Hargrave also conducted experiments with a hydroplane, the application of the gyroscopic principle to a "one-wheeled car", and with 'wave propelled vessels'.
Hargrave's only son Geoffrey was killed at Battle of Gallipoli in May 1915 during World War I. Hargrave was operated on for appendicitis but suffered peritonitis afterwards and died in July 1915. He was interred in Waverley Cemetery on the cliffs overlooking the open ocean.
Hargrave was an excellent experimenter and his models were well crafted. He had the optimism that is essential for an inventor, and the perseverance that will not allow itself to be damped by failures. Modest, unassuming and unselfish, he always refused to patent his inventions, and was only anxious that he might succeed in adding to the sum of human knowledge. Many men smiled at his efforts and few had faith that anything would come of them. An honourable exception was Professor Richard Threlfall who, in his presidential address to the Royal Society of New South Wales in May 1895, spoke of his "strong conviction of the importance of the work which Mr Hargrave has done towards solving the problem of artificial flight". Threlfall called Hargrave the "inventor of human flight", and the debt supposed to be owed by the Wright brothers to Hargrave. The step he made in man's conquest of the air was an important one with far-reaching consequences, and he should be remembered as an important experimenter and inventor, who "probably did as much to bring about the accomplishment of dynamic flight as any other single individual".
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