TRAVEL FORECAST

Evening Post, Volume CXXI, Issue 21, 25 January 1936, Page 8

TRAVEL FORECAST

HEIGHT AND SPEED

STRATOSPHERE PROSPECTS

(From "The Post's" Representative.) LONDON, January 4.

Cruising at a height of 40,000 feet and at a speed of nearly 300 miles an hour is forecast by Professor G. T. R. Hill, Kennedy Professor of Engineering at London University, as a possibility of ahvline travel in the near future. Professor Hill is famous as the designer of the Westland-Hill Pterodactyl tailless aeroplanes, of which the latest, a military two-seat fighter powered with a Rolls-Royce steam-cooled engine, is under test at Martlesham Heath, landplane experimental station of the Royal Air Force.

Professor Hill is conscious that his forecast may disappoint those enthusiasts of stratosphere flying who like to contemplate speeds of the order of 2000 m.p.h. He states, in anticipation of their criticisms, that he does not expect an immediate transference of long-distance travel in the stratosphere, but rather a gradual raising of the cruising height. His figures are based on available research and reasonable of engine supercharger development in the next year or two.

He takes as a basis a passenger transport aeroplane of relatively small size, weighing 90001b fully laden and carrying up to five passengers over a distance of 2500 miles. He limits maximum power to 800 h.p. and assumes that airscrew efficiency is 80 per cent. He goes a short step further in the direction of fuel economy than is yet achieved. Engines are assumed to be fully supercharged to a height of 30,000 feet, after which the normal loss of power in a further 10,000 feet will enable the craft to cruise economically at full throttle, but only twothirds power, at the required height of 40,000 feet.

Professor Hill has picked out five imaginary designs. The most efficient cruises at 296 m.p.h. at operational height of 40,000 feet, and takes less than seven hours for the journey of 2500 miles—sufficient for a transAtlantic crossing and with a margin beyond. Its useful load, fuel excepted, is 9301b and it carries five passengers in addition to the crew of two. The cabin and pilots' compartment are sealed and carry their own atmosphere at pressures not far below ground level pressures. In other words, human beings as well as engines must be supercharged for "stratosphere" flying.

Much useful information which bears upon Professor Hill's prophecy should be gained in trial flights of the "stratosphere" machine which the Bristol Aeroplane Company is building for the Air Ministry. Many novel ideas are embodied in its construction, and heights of 50,000 to 60,000 feet may be brought by it within the reach of the power-driven aircraft. Up to the present the remoter levels of the atmosphere have been invaded only by balloon, the record standing at about 72,000 feet