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Aviation History
1941
1941 - 1374.PDF
Ft/GH] DOU( THE world's largest aeroplane is about to fly. The DouglasB-19, leviathan bomber, has been wheeled out of thefactory and is being carefully groomed for its first test flight in the'hands of a U.S. Army Air Corps pilot. This flight is expected very shortly. Needless to say, this bomber is not yet a production type ; it will not, in the words of the overworked phrase, be "rolling off the end of the production line" for a long time. In fact, before it can become a real aeroplane, larger engines than any yet announced will have to be developed, as its present power plant of four Wright Duplex Cyclones, though they develop about 2,000 h.p. for take-off, are not very adequate for pulling its great weight of 140,0001b. (or i6o,ooolb. for overload con dition) through the air. The maximum power rating of these two-row, 18-cylinder, air-cooled radials is 1,700 h.p. at 2,300 r.p.m. at 6,500ft. pressure altitude, and they drive three-bladed airscrews of 16ft. diameter. This gives a power loading of 20.5 lb. per h.p., or 17.5 for take-off at the loaded weight of 140,0001b. But the advance in size in the construction of this Douglas giant is so great that many problems in development will arise and much time will be required to solve them all. By this time -a * 1 it is likely that more powerful engines will be available, and the company has da^P well to design with this in view, so that their bomber will not be outmoded before it has become a real weapon. The giant's span is 210ft., approaching twice that of the Ensign, which is 123ft., and still much larger than the Dornier Do X, which was 157ft. The contract for its con- struction was signed in 1935, and since then wofk has gone on behind enormous canvas screens draped from the roof trusses of the Douglas factory at Santa Monica, California. It is of all-metal aluminium alloy stressed- skin construction, and typically "Douglas" in appearance with its single fin and rudder. The fuselage is thin, as befits a military craft not intended to carry passengers, and this will help to keep drag to a minimum, though with modern aircraft drag is becoming much more a question of skin friction than of head resistance. This is apparent in the flush The wing and part of the fuselage were con« structed vertically before lowering horizontallyfor assembly.
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