Flight. Diagrams illustrating the flight of a pigeon viewed from three standpoints ; 



side; C, obliquely from side and front 



E. J. Marty in " Movement," by permission of Wm. Heinema 



from above; B, from the 



France, Italy, 



After the diagrai 



Germany, and 



pushes the joy stick forward, and in contradistinction to the forcing 



Russia. Many problems await an the aeroplane tends to dive ; he of the air past a curved surface and 



answer, but in the main it may 

 be stated that the great problem 

 of safe flight has been solved. 



moves back, pulling the joy stick so downwards by means of an air- 

 back, and the aeroplane puts its screw as in the aeroplane, 

 nose up. Moving the joy stick to Soaring flight calls for some 



The problem of stability in flight the right makes the aeroplane roll attention here. It is well known 



is one which has been for all practi- 

 cal purposes solved, though the 

 actual mechanical contrivances for 

 maintaining that stability have not 



to the right, and conversely for a that certain birds, as the albatross, 



left-hand movement. The rudder are able to keep in the air for long 



bar is worked by the feet, and periods without any appreciable 



pressure on it with the right foot flapping of their wings. This soar- 



yet reached the state of perfect causes the aeroplane to move to ing flight is not peculiar to birds or 



automatic response found in birds. 

 The problem is complicated in 

 that, though the surfaces, both 

 main and control, may be sufficient 

 to maintain equilibrium for a par- 



the right, and conversely. The insects, aeroplanes soaring in an 



joy stick is connected by wiring to exactly similar way. Soaring flight 



the ailerons and elevators, and the is possible where there are currents 



rudder bar similarly to the rudder, of air moving upwards, as Lord 



FLIGHT IN NATURE. In nature Rayleigh_and Prof. Langley have 



ticular speed of flight, they are not the power of flight is possessed by sh own. These currents act as the 

 sufficient at some other speed. mO st birds, most insects, and all necessary source of energy to sup- 

 Many of the aeroplanes used during the bats. The flying fish springs P ort tne bird or tne aeroplane, 

 the Great War, for example, were out of the water and skims along though naturally they must be 

 stable at some flying speeds, but f or some distance by the aid of its much stronger for the latter. Such 

 not at others. The rudder of an winglike fins, but it is very doubt- upward currents, usually very local, 

 aeroplane is used to give directional f u l if any true propulsive move- exist round coasts, mountainous 

 control, i.e. for turning ; the me nt is made by them. The so- country, hot ground, etc., and an 

 ailerons or wing-flaps to bank called flying squirrels, lemurs and upward wind of 5 m. an hour is not 

 the aeroplane when turning in lizards do not really fly. Thev are uncommon. Soaring flight is, 

 order to prevent it side-slipping; merely able to stretch out the loose however, only possible for short 

 the elevators for altering the 8 ki n of their sides to form a kind distances in aeroplanes. The speed 

 incidence of the main planes and o f parachute by the help of which of an upward current for soaring 

 so altering the speed of flight. If they are able to take long flying fli 8 ht is proportional to the speed 

 all or any of these control surfaces leaps through the air from one tree of fll g nt of the aeroplane or bird, 

 are insufficient, the aeroplane will to another. The principles of flight so that the latter with their slower 

 be unstable or uncontrollable at i n birds, bats, and insects are iden- flying speeds are able to soar where 



tical with those of the aeroplane, 



some particular speed. 



The control system of the 

 modern aeroplane is so arranged 

 that the natural movements made 

 by the pilot are those which make 

 the aeroplane manoeuvre as he 

 would expect from those move- 

 ments. He leans forward and 



an aeroplane cannot. 



though manifested in different Bibliography. Military Aeroplanes, 



ways. In all there is the cardinal G.L.Loening, 19 18; Aeroplane Struc- 



principle that air is forced down- g^/ ^ f >%$*. 



wards in order that the bird or namics> L Bairstow. 1020 | Aero- 



insect may sustain itself in flight. nau tics in Theory and Experiment, 



This forcing down of air is accom- w. L. Cowley and J. H. Levey, 



plished by the beating of the wings, 2nd ed. 1920. 



