206 



NATURE 



[April 14, 1910 



of variability.; but -beyond this margin merely to point the 

 elevating rudder at an increased angle is insufficient. 

 You can obtain ascensional power at the expense of speed, 

 but there is a point below which the speed must not be 

 reduced. 



There is, as we have seen, a natural speed for. an aero- 

 plane, and this natural speed is only elastic within limits. 

 A remarkable variation on one machine was shown by 

 M. Delagrange at Doncaster. With a cross-Channel 

 Bl^riot, to which he had attached a 50 horse-power Gnome 

 motor, flying with the wind, he flew at a rate of forty 



Fig. 4.— Position of Pilot, a, Antoinette, R.E.P. 



miles per hour. On the very next daj', in a dead calm, 

 with the same machine, he flew at the rate of fifty miles 

 an hour. The difference, which was equivalent to 20 per 

 cent., was due to the fact that he was getting more work 

 out of the motor. On the same type of machine, with a 

 25 horse-power Anzani motor, the best speed was only 

 about thirty-three miles per hour. M. Delagrange said 

 he could vary the speed 30 per cent. Another instance of 

 driving a flying machine with 

 increased power has been pro- 

 vided by M. Santos-Dumont, 

 who put a 40 horse-power 

 motor to his little monoplane, 

 which gives about 300 per 

 cent, more than the usual 

 proportion of power to lifting 

 area. 



' Now to obtain great vari- 

 ability of speed we shall have 

 to have lifting surfaces that 

 can be enlarged and diminished 

 at will, and correspond with 

 different engine-power. 



The most scientific attempt 

 to obtain the variable plane 

 area is on the Chauviere 

 monoplane, in which, while, 

 in present designs, the lead- 

 ing edge remains rigid, the 

 plane is quite flexible, and 

 the rear edge can be let for- 

 ward or pulled back by the 

 tightening or slackening of 

 cords, so that the width of 

 the plane is either narrow or 

 broad. , When narrow, • for 

 high speed, the pressure of 

 the air bulges the plane to 

 an increased curve. 



As to the development of 

 the flying machine, differentia- 

 tion will, in the main, re- 

 spond to certain demands. 

 We can clearly foresee de- 

 velopment with both mono- 

 plane and biplane. 



The racing aeroplanes will probably be monoplanes with 

 comparatively small lifting surface, high speed giving the 

 necessary lifting-power. The racing aeroplane will not 

 carry a great weight, and the power of the engine will be 

 required for driving at a great speed without more waste 

 of energy than is unavoidable. It is, of course, an axiom 

 that the greater the speed the less the waste of power. 

 Monoplanes will very probably develop into a permanent 

 racing type. 



NO. 211 1, VOL. 83] 



The near future will sec machines in which three or 

 four passengers can be carried, and in which, the. control 

 can be .in the hands of two pilots. Sooner or later w 

 shall get the machine attempted with two molo: 

 instead of one; and quite certainly we shall hav 

 the machine with variable lifting surface and variable; 

 power. , 



We know that an aeroplane can descend safely on Id 

 water. M. Latham did that in his attempt to cross th' 

 Channel. Soon we shall have machines that can ascend 

 from water, . . ...... 



The use of dirigible balloons, especially in this 

 country, where strong breezes are common, calls 

 for airship harbours at frequent intervals. Prob- 

 ably shelter walls capable of being turned round 

 to the wind in any direction will be used. Each 

 will have a staff of attendants, and the walls will 

 not always be standing erect, but will be so made 

 that they can be run up in a few minutes when- 

 ever an airship approaches and signals its need. 

 To have them every ten miles or so all over the 

 country always standing would be intolerable. 



.-\n airship has nothing to fear from any wind 

 while she is in the air, but on landing even an 

 ordinary breeze may wreck her. It is all very 

 weH for the Germans to show us what they 

 can do with dirigible balloons, but in the 

 great central plain of Europe there is Comparatively little 

 wind. They are not handicapped as we are ; but in this 

 country so frequently and quickly do strong winds spring 

 up that it may be doubted whether any airships that could 

 not be quickly deflated would be of use. \\'e may dis- 

 cover that we can.only employ the semi-rigid and the non- 

 rigid balloon. The rigid balloon at Barrow may be a big 

 blunder after all. 





PiQ_ 5. Xhe Chauviere Monoplane. An attempt to embody the principle of the variable lifting surface. The 



plane has a rigid leading edge, but is itself simply a .sail. In flight the pressure of air underneath gives it a 

 camber. The rear edge can be slackened and tightened at will to suit different speeds, the sides alternately 

 or in unison. 



'T'HE problem of remedying the admitted inefficiency of 

 our present methods of technical education, and of 

 invigorating the industries of this country with' progressive 

 scientific spirit, while at the same time increasing the 

 1 From a paper read before the A.ssociation of Teachers in Technical 

 In.stitutions (West Yorkshire Branch) at Letds, on April 2, by Dr. Robert 

 Pohl. 



