858 The Outline of Science 



As a representative type of a two-seater fighting machine, 

 the Bristol "Fighter" undoubtedly stands first among the world's 

 aircraft. This machine carries a pilot and observer and is fitted 

 with a 275 h.p. Rolls-Royce, or a 300 h.p. Hispano-Suiza engine ; 

 it has a full speed of 124 m.p.h. and can climb to 10,000 feet in 

 21.3 minutes, whilst the ultimate height to which it can attain is 

 about 20,000 feet. Its armament consists of a machine-gun, 

 firing forward through the propeller and operated by the pilot, 

 and a second machine-gun operated by the observer, which can 

 be moved about to command the whole of the rear of the machine. 

 The device which enables the pilot to fire his machine-gun abso- 

 lutely between the revolving blades of the air-screw is exceed- 

 ingly ingenious. It is known as the Constantinesco Interrupter 

 Gear. By means of a communication between the engine of the 

 machine and the gun itself, the gun is timed not to fire on those 

 occasions when the blades of the propeller would be in the path 

 of the bullet. As the propeller revolves at the rate of about 750 

 revolutions per minute, the ingenuity of this arrangement can 

 well be imagined. 



For a representative single-seater the Sopwith "Snipe" may 

 be taken as an example. This machine was produced shortly 

 before the end of the war and is fitted with a 200 h.p. Bent- 

 ley Rotary 2 engine, which gives the machine a full speed of 

 135 m.p.h. It can climb to 10,000 feet in 8.8 minutes, and the 

 armament consists of three machine-guns, all firing forward be- 

 tween the blades of the air-screw. To protect himself from attack 

 in the rear the pilot depends entirely upon the flying qualities 

 of his machine. 



For a typical bomber, one may take the Vickers "Vimy." 

 This carries a pilot, gunner, and bomber together with a load 

 of 1,146 Ib. of bombs. It also carries four Lewis guns for defence 

 in case of attack, two being placed in the nose of the machine 

 and two in the fuselage (the body of the machine). Though 

 fitted with two 360 h.p. Rolls-Royce engines, it does not travel 



