Lawrence Hargrave: His Role in the Development of the Successful Aeroplaneby Ian Debenham1, 1998
The approaching millennium and the centenary of aviation should provide the impetus for aviation historians to begin the serious interpretation of their field of interest.
My motivation to embark on this particular line of thought was a determination to reconcile the 'exalted' position Lawrence Hargrave held in world aviation during his lifetime to his current disregarded role as merely a maker and flier of kites. Gibbs-Smith is dismissive of Hargrave and Tom Crouch echoes Gibbs-Smith. Why then did Octave Chanute laud Hargrave as the man most likely to fly and why did Alexander Graham Bell visit him in his Woollahra Point home? The Wright brothers regarded him as one of the great pioneers of aviation even though they claimed that he made no contribution to their success. More precisely, what affect, if any, did Hargrave have on the development of the successful aeroplane?
I have developed the hypothesis that the basic biplane structure with parallel wing leading and trailing edges of the successful Wright Flyer should owe some debt to Hargrave and his boxkite. Otto Lilienthal is generally cited as the major influence on the early development of aviation. While not wishing to downgrade his role, the Wright brother's 'Flyer' and Alberto Santos Dumont's '14bis', recognised as the first to achieve powered, controlled flight in Europe, owe nothing to the general layout of the Lilienthal gliders.
In my opinion Lilienthal proved that aviation was possible but fatal, Hargrave proved that it was possible and safe and thus Hargrave's stable boxkite structure was used as a basis for flying machines rather than the 'cranky' Lilienthal glider.
The hypothesis has much evidentiary support especially in regard to the development of the first successful aeroplane in Europe. However the evidence becomes perilously superficial in regard to the Wright 'Flyer' and it will take further searching for stronger evidence and much learned discussion before the hypothesis is accepted (or rejected).
It should be no surprise to aviation historians that Hargrave was a major influence on the development of the first successful heavier-than-air craft to fly in Europe. Even to the casual observer Alberto Santos-Dumont's '14bis' is a collection of Hargrave box kites flying in tight formation. It is claimed, perhaps with some justification that the design of '14bis' was developed from the successful 1905 floatplane glider designed and built by Gabriel Voisin while an employee of the Syndicat d' Aviation.
Gabriel Voisin, with his brother, Charles, had built his first 'Hargrave', as he called his box-like structures, in 1898. He was astonished by its remarkable stability. Thus, despite Voisin's knowledge and admiration of Lilienthal's efforts and research, his earliest attempts at gliding flight in 1899 were made by modifying their 'Hargrave'. The attempts were considered by the brothers to be unsuccessful and Gabriel drew the conclusion that the wood-braced box kite created too much drag to make forward motion. Photographs of a Voisin glider at Neuville sur Saone dated to 1899, show this craft to be more sophisticated than the basic 'Hargrave'. It is missing the side curtains between the wings and the strutting and bracing is minimal. This craft must have allowed them greater success than their slightly modified box kite.
In May 1900 Gabriel Voisin began preliminary drawings for his first powered aircraft. The lessons learned in gliding coupled with the information provided by the late Otto Lilienthal influenced the design but Voisin abandoned the Lilienthal curved planform in favour of the Hargrave box kite that he "knew so well".
Voisin's first knowledge of Octave Chanute, the French-born American railway engineer, came in 1902 when articles about Chanute's gliding experiments of 1896 complete with "clear photographs" appeared in the French journal La Locomotion. Using the photographs as a guide and, recognising a similarity between the Chanute glider and their Hargrave kites, Gabriel and Charles built a glider. Finding the tail unit too heavy they retrieved one of their old Hargrave kites from storage and affixed this to the craft. In Gabriel's words: -
"the effect was instantaneous. Our glider stopped flying tail-down and took up in the wind stream, even when loaded, a nearly horizontal position."
Voisin's next machine, the 1904 glider was towed un-manned into the air by a car but crashed soon after takeoff when the empennage broke off. He does not make clear whether this was a Chanute type wing structure or a Hargrave. He merely states that the: -
"glider kite left the ground just as our Hargrave kites had done"
The 1905 floatplane glider completed in June provides the link between the Voisin gliders and Santos Dumont's '14bis', the aircraft generally accepted as the first powered aircraft to fly in Europe. This glider, in Gabriel Voisin's words: -
"was a true Hargrave with vertical partitions which gave it the characteristic box kite look."
He has no hesitation in attributing his successful glides in this aircraft as the inspiration for Santos Dumont: -
"Everybody in Paris who was interested in heavier-than-air craft had been at our trial which had been photographed. Santos Dumont was there. He had not, until then, begun to think about aviation. Yet on the same day as we did our experiment, he dismantled his last dirigible and began the work which eventually brought him to the aircraft of 1906. The comparison of the two machines and of the dates, which can readily be checked, proves immediately that my old friend was inspired by my glider of the Seine experiment."
Following an unsuccessful business venture with Louis Bleriot, and following Santos Dumont's successful flight of 1906 Gabriel Voisin joined his brother Charles in a business producing the first commercially available powered aircraft that actually flew. Voisin would have classified a number of their early products as 'Hargraves' because of their cellular design.
It must be borne in mind that most of this work carried on in Europe was done so in ignorance of the success of the Wright brothers. Their aircraft was not demonstrated there until 1908 and prior claims of their achievement that had leaked out to Europe, especially to France, were treated with great scepticism.
Chanute had tried to disseminate information in France about the Wright brother's aircraft but attempts to construct a machine based on the interpretation of Chanute's information had resulted in failure. This sowed the seed of doubt, nurtured by Gallic nationalism, into a disbelief in the claim of successful flight by the Wright brothers prior to 1908.
Finding the historical 'truth' about Hargrave's influence on the development of the first successful aeroplane is made difficult by the Wright brother's seeming intuitive grasp of aeronautical problem solving and their habit of testing all information after they discovered the error in Lilienthal's lift/drag figures. Further `smoke screening' is provided by their need to protect their patents by secrecy and their long battle with Langley, Curtiss and the Smithsonian Institution about recognition of their achievement. Thus they became defensive about acknowledging any debts to anyone. Octave Chanute, a major link in the chain between Hargrave and the Wright brothers, was somewhat of an egotist, not always acknowledging debt and sometimes posturing as a leading player. His personality frustrates the search for evidence about Hargrave's role.
At the most basic level of inquiry the Wright brothers had, as their inspiration, Otto Lilienthal. Samuel Langley was a contemporary experimenter as was Octave Chanute; the latter becoming closely involved with the development of their flying machine. Both Lilienthal and Langley had experimented primarily with monoplane aircraft although the former had tried multiplane types. From the outset the Wright brothers selected the Chanute type biplane as their favoured layout and this was retained throughout. The did not vary from the parallel leading and trailing edge to try the curved planform of the German's wing nor try the tandem monoplane layout proved so successful in model form by Langley. It is my guess that, initially, they would have sought a stable lifting device as Chanute had done and as Voisin had done.
The activities of Lilienthal and the reporting thereof had shown that his flights were unstable and in the mid-1890s aviation experimenters were seeking a stable lifting platform. The kite lift of Hargrave carried out on November 12, 1894 had impressed Hargrave on the stability of his box kites; a characteristic Gabriel Voisin realised in 1898 and subsequently incorporated into all his successful aircraft.
Octave Chanute had been a correspondent of Hargrave's and much impressed with his work. In his book Progress in Flying Machines published in 1894 Chanute stated that he thought that Hargrave was going to be the first man to fly. This judgement, however, was made prior to the kite lift experiment.
With the success of his kite lift Hargrave, as was his habit, began to disseminate the information via articles to engineering journals and a paper to the Royal Society of New South Wales. Reprints of this paper were sent to Hargrave who sent them to his correspondents.
The information was picked up by various non-aviation people in the USA who built Hargrave kites and subsequently wrote articles about their stable characteristics and good lifting ability.
The Powerhouse Museum fortunately preserves a considerable quantity of Hargrave's correspondence. It was hoped that this correspondence would provide a solid indication of Hargrave's box kite as an influence on the development of Chanute's glider, which, in turn is known to be an influence on the layout of the Wright's aircraft including the successful 'Flyer'.
Unfortunately the solid indication eludes. Information on the stability of the box kite is abundantly available to Chanute but he appears not to acknowledge this. The letters from Hargrave contain numerous references linking cellular kites and stability.
In a letter to Hargrave dated September 26, 1893 Chanute wrote: -
"I had already reached the conclusion that longitudinal stability was best to be obtained by placing aeroplanes behind each other" "the cellular kite idea is new to me. Do you find that the vertical planes between the horizontal surfaces add very much to the stability and more than keel cloths would do?"
On November 18, 1893 Hargrave responded: -
"Re the Cellular Kites: I think the vertical planes between the horizontal surfaces are more economical as to material and stiffen the fabric more than keel cloths would do. I had a keel cloth on Kite Z but abandoned it."
Hargrave sent a photo of some "new kites and descriptions of an experiment" to Chanute on December 12, 1894 undoubtedly about the recent kite lift experiment but despite this and the other evidence available to Chanute about the stability of the kites he seems to disregard it all.
On February 12 1896 Chanute advised Hargrave: -
"I have come to the conclusion that the problem of automatic stability can not be solved by experimenting with soaring machines and am having two built to test the value of an idea of my own. I will advise you as to the results."
This appears to have been the last letter Hargrave received prior to Chanute carrying out his aviation experiments in the Indiana dunes in 1896. The next letter received by Hargrave was sent September 30 1896 and gives a short description of the experiments: -
"I began in June with a Lilienthal machine. I found it 'cranky' and hard to manage in a gusty wind and presently discarded it. Then I tried mine, grouping the wings in various ways and got some very steady but not long glides. Then I came back here and with the acquired experience rebuilt the machine, and built another in which the stability is obtained in a different manner. Both proved successful and they have taken hundreds of glides 150 to 350ft without the slightest accident."
Frustratingly Chanute does not directly acknowledge any debt to Hargrave although the successful Chanute glider, the one that also influenced Voisin in 1902, looks remarkably like a modified Hargrave box kite, even to the addition of side curtains which, admittedly were removed later. The glider is referred to as a Chanute-Herring glider as Augustus Herring, according to Chanute, designed the `automatic device' which secured the rudder to the sustaining surfaces.
According to Tom Crouch, however, this glider was derived from a model glider designed and built by Herring in 1892. This assertion is difficult to understand as Chanute, in a letter to James Means in 1897, stated that he, Chanute, was responsible for the general design. Furthermore, in the face of criticism about his lack of acknowledgment of Herring made against him in 1900 by Matthias Arnot Chanute wrote to Herring in 1901 and set out the facts as he remembered them: -
"1st. While we were still in camp I made and gave you, on cross-section paper, a sketch of the two-surfaced machine with a Penaud tail to serve in building the 1896 machine."
The incorporation of the Pratt truss as a means of separating the planes and providing a solid box-like structure is undoubtedly a Chanute innovation. This type of truss was commonly used in railway bridges and Chanute was a railway engineer of great repute.
A fact which hinders the search for Hargrave's input into Chanute's glider is that originally the two-surfaced machine was made as a triplane. Instability in flight caused the early removal of the lower plane leaving the familiar biplane layout.
The lack of concrete evidence linking the Hargrave box kite to the Chanute glider is further frustrated by subsequent commentators over several decades alluding to Chanute's glider as Hargrave box kite-like: the visual evidence is there but the proof is not.
Further research is required to answer the questions posed.
Did Chanute develop his glider from Herring's 1892 model as Crouch asserts? What did this model look like and why did Chanute credit Herring only with the design of the aerodynamic hinge for the tail? If not from Herring, where did Chanute get his layout for the planes? Although the precedent existed for multiplanes with parallel leading and trailing edges and some of these were under test at the time only Hargrave had tested and disseminated the information on their stability at the time of the building of Chanute's glider. Chanute must have been aware that the Hargrave box kite was stable, a feature that had priority in his quest for a flying machine.
It seems probable, albeit unproven at this time, that the basic layout of the Chanute glider was influenced by Hargrave's box kite. In turn the Chanute glider influenced the layout of the Wright 'Flyer'.
This paper is reproduced with the permission of the author