"The Anatomy of the Aeroplane." "It is the petrol engine which has made possible...

"The Anatomy of the Aeroplane."

"It is the petrol engine which has made possible the modern airplane. It is mechanically impossible to have aeroplane wings flap like birds, and therefore the craft must be pulled through the air by airscrews (propellers). It will be realised that the great art of aero engine making is to centre the maximum power in the smallest space with the smallest weight. Here is one of the modern miracles of engineering. It is the Rolls Royce Merlin engine. The wonderful compactness of this 1200 horse power plant is well shown in the nearer engine. In order to reduce resistance against the wind aero engines are cowled when in flight as in the other engine shown. The large spinner over the propeller boss covers the ingenious mechanism which alters the pitch at which the blades strike the air, thus allowing maximum efficiency with various speeds and loads. The aircraft shown is a Lancaster."