GREATER AIR RANGE

Evening Post, Volume CXXIV, Issue 61, 9 September 1937, Page 23

GREATER AIR RANGE

PROGRESS IN DESIGN

CIVIL AND MILITARY

SPEED & DISTANCE

The ever-widening network of international airlines, bringing with it the further need for long flights, nonstop over both land and water, has turned the attention of aircraft designers to the development of long range types, writes I*'. A. Kiernan in the "New York Times." The 5288-mile flight of the Soviet pilots Shkaloff, Baidukoff, and Beliakoff, from Moscow to the State line of Oregon, clearly indicates the value of aeroplanes capable of long range. Had their ship not been of that type the flight could never have been attempted, for they had to pass over thousands of miles of uncharted and undeveloped territory where a forced landing would spell disaster. The full value of their flight, however, will be known only when it is determined how much of the data collected can be adapted to military, and commercial aviation. Like the development of a safety factor, such spectacular flights serve as laboratory experiments. It must follow that an aeroplane which can carry sufficient fuel for 5000 miles can be made to operate on a basis of airline economics for at least half that distance, regardless of terrain. GOAL OF 8000 MILES. In all air-active countries the trend is towards longer flying range development. England, France, and Germany are developing aircraft to be capable of flying across the North Atlantic on commercial routes. The military services of all the air powers likewise are concentrating on bombers of longer flight radius. Military services of all the air Powers likewise are concentrating on bombers of longer flight radius. Military aeroplanes use the term radius in place of range because on average missions N the bomber must have a theoretical ability to return to its base. In the United States a goal has^ been set at 8000 miles as the desirable range. No performance figures are available on aeroplanes of the latest types in test by the military services which might indicate how close they haye come to this goal. The adaptation of such heavy bombers to commercial design is still in the early stages. In Europe the building and placing in service of the heavy bomber is indicative of the trend. Russia, with its new 280-mile an hour TB-6, can carry a 2-ton bomb load 2000 miles non-stop. Italy has ordered squadrons of F. I. A. T. BR-20s, whose performance figures are said to be 260 miles an hour, a ton and a half bomb load, and a range of 1500 miles. A Savoia-Marchetti heavy bomber known as the S-79 is still.shrouded in secrecy as regards performance ■ data. England, whose policy of keeping in the van in military aviation is being put to the test, is still using bombers with 2000 miles of range and is sacrificing some range in the interest of greater speed. France, with its Bloch 131 dual-motored ship, carries ( 2204 pounds of bombs for about 2400 miles. CIVIL AIRCRAFT IN EUROPE. In the building of long xange European aircraft for commercial use Germany claims the lead because of the development of the Jumo 205 Diesel motor, cutting down fuel consumption and unit power plant weight. The German practice of catapulting the heavily-laden aeroplanes also adds to the range. France is building its aeroplane to bid for transatlantic work in the form of a Bloch flying boat with four engines. The motors to be.used in the aeroplane have not been announced. France, too, has been concentrating on Diesel development with some measure of success. Present estimated figures for the boat indicate twelve tons of useful load over a range of 2500 miles at a speed of 190 miles an hour. The aeroplane is being designed to carry twenty passengers in its cabin. Probably the greatest single improvement making possible the range increases of modern aircraft has been the wide adoption of the constantspeed propeller. By its use maximum power can be obtained at take-ofl' and fuel consumption lowered while cruising, thus reducing the required fuel load and increasing pay load. HEAVY WING LOADING HELPS. Second only to the constant-speed propellers comes the general practice of using high wing loading, a design feature which was impossible before the development of the new airscrew. The high wing load makes for greater speed, once aloft, and the use of flaps and other forms of airbrake or high lift device allows for greater useful load carrying. A third factor of importance, and one which limits the ultimate size of such aircraft, is the increase in horsepower in the individual power plant. Coupled with the improved propellers, the efficient wing and carefully streamlined aircraft itself, engines can now be cruised at points as low as 40 per cent, of their highest power, a practice which reduces by more'than 60 per cent. the. maximum fuel consumption per mile with a loss of a much smaller fraction of the maximum speed.