Applied Science 849 



before commencing a flight, to find out weather conditions along 

 the route; he reports progress by wireless from the air as he 

 flies at 100 m.p.h. ; he announces the time of his probable arrival 

 if he wants the ground illuminated for a night landing; he is 

 guided on his way by wireless if he flies in fog; he converses 

 with the pilots of other aircraft by means of his wireless tele- 

 phone. In the future it is quite possible that aircraft will be 

 entirely controlled by wireless from the ground, whilst motive- 

 power may well be transmitted from ground stations to the 

 machine in flight. The future of flying and wireless are bound 

 together. 



The first requisite of a good commercial aeroplane is the 

 ability to carry a heavy load at a low cost. In other words, the 

 weight carried must be kept up whilst the engine-power is kept 

 down. The next essential is speed; then comes slow landing, so 

 that the machine may be brought down safely at any spot in the 

 event of a forced landing. Rapidity of climbing power, the 

 quality of being easy to manoeuvre, and ability to fly to great 

 altitudes need not be considered when commercial aircraft are 

 being designed. 



One of the best commercial aeroplanes at the present time 

 (1922) is the D.H. 34. This machine with a Napier engine of 

 450 h.p. carries ten passengers in an enclosed cabin in addition 

 to the pilot and steward. Another machine is the D.H. 29. 

 This is a monoplane fitted with a 450 h.p. Napier engine, having 

 accommodation for twelve passengers in an enclosed cabin. The 

 D.H. series of machines illustrate excellently the improvements 

 in design of commercial machines; the engine-power remains 

 about the same, but the revenue load increases. This is made 

 possible by improvements in the design of the machine itself. 



Abroad, the Farman "Goliath" is a good illustration of 

 present-day commercial aircraft. This machine carries twelve 

 passengers in addition to a pilot and a mechanic and is fitted 

 with two 260 h.p. Salmson engines. Many people are of opinion 



