NotesHargrave's flapping wing machine models formed part of his earliest experiments between 1884 and 1892. They were conceived from a theoretical study conducted by Hargrave into the movement of animals like fish, snakes and jellyfish, as well as the movement of waves (a theory he famously dubbed at a Royal Society meeting as 'The Trochoided Plane'). This theory prompted him further into the study of birds and their anatomy and the use of flapping wings as a means for propulsion, hence the development of the flapping wing model.
Hargrave's initial models of this type were powered by clockwork, but he later replaced this with rubber bands and then compressed air and steam. The decision to use compressed air came about after Hargrave conducted a comparative experiment into a flapping wing and screw propelled model (B113 and B114), where he discovered that both methods of propulsion seemed to be equally efficient.
This particular model shows a combination of the screw propulsion with compressed air. It was tested on January 2, 1891 and was found to fly 128 feet by 144 ft pounds of energy at the rate of 10.34 mph (it took 8 seconds). Compared to Hargrave's earlier experiment with compressed air and flapping wings (B116), this model was much slower. The engine made 49 revolutions with a reduced pressure of 45 pounds per square inch and the engine was .29 efficient. The machine was also found to fly in a curved course caused by the amount of torque produced by the rotating propeller.
The second of four children of John Fletcher and Ann, Lawrence Hargrave was born at Greenwich, London on January 29, 1850. In 1856, Lawrence's father, eldest brother Ralph and uncle Edward emigrated to Australia in what appears to be a consensual marital separation between John and Ann. They were bound for Sydney to join a third brother of John and Edward, who was a member of the Legislative Assembly for New England (named Richard), while Ann, Lawrence and her two other children, Alice and Gilbert, stayed in Kent, England.
During his early years, Lawrence was educated at the Queen Elizabeth's School in Kirkby Lonsdale, Westmoreland, before he sailed to Australia in 1865 to join his father, brother and two uncles. John Fletcher, who was a distinguished judge in the New South Wales Supreme Court living at Rushcutters Bay House, anticipated a career for Lawrence in law. Despite organising tuition for him, Lawrence failed to matriculate, but was subsequently accepted to begin an apprenticeship with the Australasian Steam Navigation Company (ASN Co) in 1867. For five years he worked as an apprentice, gaining invaluable skills in woodworking, metalworking and design.
The circumnavigation voyage of Australia aboard the 'Ellesmere' (offered to Lawrence by another passenger en route to Australia from London) obviously stimulated an interest for Lawrence in exploration. From 1871, Lawrence joined the Committee of Management of J.D. Lang's New Guinea Prospecting Association and in 1872 was on board the brig 'Maria', bound for New Guinea in search of gold, when it sunk off Bramble reef, north Queensland, causing great loss of life. After returning to Sydney to work for the ASN Co, and later the engineers P.N. Russell & Co, Lawrence participated in several more exploratory voyages to the Torres Strait and New Guinea, accompanying figures like William Macleay, Octavius Stone and Luigi d'Albertis along the Fly River. These voyages continued until 1876, at which time Lawrence worked at the foundries of Chapman & Co, before choosing to settle down with new wife, Margaret Preston Johnson in September, 1878 with whom he had six children (Helen-Ann (Nellie), Hilda, Margaret, Brenda, Geoffrey and Brenda-Olive).
In January of the following year, Lawrence commenced work as an extra observer (astronomical) at Sydney Observatory under the Government astronomer H.C. Russell. In this role, Lawrence was able to make a number of important observations and inventions, including the transit of Mercury in 1881, the Krakatoa explosion in 1883 and the design and construction of adding machines. The income made from land bestowed to Lawrence by his father in Coalcliff, however, meant that in 1883 Lawrence was able to resign from his position at the Observatory to pursue his fascination and study into artificial flight. This interest came about from his observation of waves and animal motion, including fish, birds and snakes.
Lawrence's earliest experiments, spanning 1884-1892, involved propulsion with monoplane models built from light wood and paper. He first attempted to build a full-size machine capable of carrying a human in 1887 and in 1889 he built his most influential engine - a three cylinder radial rotary engine. Lawrence's later experimental phase, 1892-1909, involved the use of curved surfaces in his models. This research subsequently led to the development of the box kite, the most famous invention associated with his name.
Lawrence always conducted his experiments in his local area (i.e. Rushcutters Bay, Woollahra Point and Stanwell Park). He was against patenting his inventions for fear of stifling the development of aviation in the bigger picture and therefore published his results quickly and widely, particularly through the Royal Society of New South Wales. This Society helped Lawrence to gain an international reputation and brought him into contact with other aviation pioneers like Octave Chanute and Otto Lilienthal. The very first paper he gave was "The Trochoided Plane" (delivered August 6, 1884).
In Lawrence's later years he conducted research into early Australian history, postulating the theory that two Spanish ships found their way into Sydney Harbour in the late 16th century. Apart from this and of course his interests in aeronautics, Lawrence also concerned himself with the contemporary issues of patent laws, free competition, Darwinism, a bridge for Sydney Harbour, pensions, strikes and conscription.
Lawrence Hargrave died of peritonitis at Lister Hospital on July 6, 1915. Lawrence's death came only nine weeks after the death of his youngest son, Geoffrey, at Gallipoli.