DISCOVERY 



Helicopter Flying 

 Machines 



By " Rafex " 



The aeroplane is the only heavier-than-air machine 

 which has reached a practical stage of development 

 at the present time. Yet there are two other forms 

 which have been experimented with at different times, 

 and are still the subject of research. One, the Omi- 

 thopter, has a flapping-wing mechanism intended to be a 

 close representative of the flight of a bird ; the other, 

 the Helicopter, is able to rise into the air directly from 

 the vertical downward thrust of a helical screw revolv- 

 ing in a horizontal plane. The helicopter is the subject 

 of the present article. It has lately aroused a revival 

 of interest owing to the zealous work of several en- 

 thusiasts, some of whom have met with partial success. 

 Until a few years ago its possibilities had been over- 

 shadowed by the achievements of the aeroplane, and 

 indeed it had become difficult to realise that for many 

 decades, if not centuries, the devotees of the heavier- 

 than-air school had been divided into three sects, 

 followers of the aeroplane, the omithopter, and the 

 helicopter, so far had the aeroplane outstripped the 

 two others in practical results. 



It may be asked, and somewhat pertinently, why, 

 in view of the success of the aeroplane, anyone still 

 contimies in the endeavour to produce a practicable 

 helicopter, since the aeroplane appears to fulfil all 

 requirements. The answer is to be found partly in 

 the native pertinacity of the hiunan mind, particularly 

 when of an inventive turn, in its refusal to desert a 

 thing in which faith has once been put, and its glorious 

 determination to overcome the obstacles to the solution 

 of a problem once set ; partly in the fact that the 

 aeroplane does not in all respects satisfy the require- 

 ments of heavier-than-air flight. The chief point in 

 which the aeroplane fails is that it does not bring aerial 

 locomotion to the ordinary man's door. It is, in fact, 

 more closely analogous to the train than to the motor- 

 car, because it is necessary to travel by some other 

 means of locomotion in order to reach the aeroplane's 

 point of departure. (In parenthesis, it may be noted 

 that if this comparison between the aeroplane and the 

 train be true, the airship appears to be the equivalent 

 of the steamship in its capacity to extend from continent 

 to continent the trans-continental internal transport 

 services provided by the aeroplane. ) But why can an 

 aeroplane not start at one's door ? Simply because it 

 requires an aerodrome of considerable extent over whirh 

 to run as a land-borne macliine before it takes or leaves 

 the air. It is not even in as favourable a position as a 

 railway train, as the space required for an aerodrome 



is greater than that required by a railway station, 

 and cannot be provided within the precincts of a town. 

 Before a jouniey by aeroplane can be commenced, it is 

 therefore necessary to undertake a journey of, in most 

 cases, some miles from one's own front door to the 

 aerodrome ; and it is this disadvantage which is seized 

 upon by the helicopter enthusiast as the justification 

 for his continued efforts. His point is that the heli- 

 copter could start from the roof of a house or any 

 convenient fiat space, in the very centre of a town if 

 need be, and so combine the functions of train and motor- 

 car. It is mainly this feature which spurs the inventor 

 to persevere in his efforts. 



The history of the helicopter is at least as old as that 

 of the aeroplane, and, in fact, if models be considered, 

 it may even be said that the helicopter achieved 

 success, first, because many model helicopters of a toy 

 form had risen into the air long before the first model 

 aeroplane left the ground. In 1784, for example, two 

 Frenchmen named Launoy and Bienvenu exhibited to 

 the Academic des Sciences a primitive model helicopter 

 which consisted of two four-bladed feather "screws" 

 placed one above the other and caused to rotate by the 

 untwining of a bow-string twisted round the connect- 

 ing stick. In a famous paper contributed to Nicholson's 

 Journal in 1809, and subsequently reprinted on two 

 occasions by the Aeronautical Society, Sir George 

 Cayley described the method of making a toy of this 

 sort, which he called a " Chinese top." Incidentally, 

 it may be mentioned that Sir George Cayley has fre- 

 quently been described as the " Father of British 

 Aeronautics," and, in fact, the papers contributed by 

 him to Nicholson's Journal and the Mechanic's Maga- 

 zine contain all the essential principles of both heavier- 

 and lighter-than-air flight. His foresight was amazing, 

 and there seems little reason to doubt that, had the 

 petrol engine existed in his day, he would have succeeded 

 in producing both a navigable airship and an aeroplane 

 capable of flight. He was bom in 1773, and, as he men- 

 tions in his paper of 1809 referred to above, his first 

 aeronautical experiment was made in 1796 with the 

 toy helicopter, and he was still writing on the sub- 

 ject of aeronautics up to a year or two before his death 

 in 1857. Indeed, in a letter dated 1854 to Depuis 

 Delcourt, secretary of the Societe Acrostatique et 

 Meteorologique de France, he gives a description, 

 accompanied by a rough sketch, of an improvement on 

 " the clumsy structure of the toy called the Chinese 

 top," produced by " Mr. Cooper of the London Univer- 

 sity," which he was "mounting, say, 20 or 25 feet." 

 He goes on to state that he himself had had a still 

 better model made of which he says : " It is the best 

 I have ever seen, and will mount upward of 90 feet 

 into the air." This consisted of three blades of sheet- 

 tin, mounted on a box-wood nut, which was threaded 



