THE FIRST FORTRESS: The Air Corps called for a "battleship of the skies," Boeing offered the "299" (later the XB-17); observers called it a "regular fortress with wings." It exceeded expectations, later crashed — victim of pilot error.
THE STORY OF THE B-17
In 1934 the U. S. Army Air Corps asked for a battleship of the skies. The specifications called for a "multi-engine" bomber that would have a high speed of 200-250 mph at 10,000 feet, an operating speed of 170-200 mph at the same altitude, a range of 6 to 10 hours, and a service ceiling of 20,000-25,000 feet.
Boeing designers figured that with a conventional 2-engine type of airplane they could meet all specifications and probably better them. But such a design probably would not provide much edge over the entries of competitors. They decided to build a revolutionary type of 4-engine bomber.
In July 1935 an airplane such as the world had never seen before rolled out on the apron of the Boeing plant at Seattle, Wash. It was huge: 105 feet in wing span, 70 feet from nose to tail, 15 feet in height, It was equipped witn 4 Pratt & Whitney Hornet 750 Hp engines, and 4 Hamilton Standard 3-bladed constant-speed propellers. To eliminate air resistance, its bomb load was tucked away in internal bomb bays. Pilots and crew had soundproofed, heated, comfortable quarters where they could operate efficiently while flying in any kind of climate. And the big bomber bristled with formidable firepower.
"It's a regular fortress," someone observed, "fortress with wings."
Thus the Boeing 299, later designated the XB-17, was born — the grandfather of the Flying Fortress that was to become champion and pace-setter of all heavy bombardment aircraft in the World War II.
The XB-17 surpassed all Army specifications for speed, climb, range, and load-carrying requirements. Then, in October, 1935, it crashed at Wright Field when a test pilot neglected to unlock the elevator controls on takeoff.
But the Army Air Corps recognized in this first Fortress the heavy bomber of the future. Thirteen airplanes, designated Y1B-17, were ordered. While one airplane was held at Wright Field for experimental purposes, the other 12 went out to set new range and speed records, cruising the Western Hemisphere, and confounding skeptics who said that the Flying Fortress was "too much airplane for any but super-pilots." Not one of the 12 was ever destroyed by accident.
With experience, the Fortress acquired new strength, virtues, possibilities. The Y1B-17A, equipped with Wright G Cyclone engines and General Electric turbo-superchargers, gave astonishing performances at altitudes above 30,000 feet. The B-17B, flight tested in 1939, had 1000 Hp Wright Cyclone engines and hydro-matic full-feathering propellers.
In the spring of 1940, when Hitler had overrun Norway, Denmark, Holland, Belgium, and France, the B-17C made its debut with more armor plate for crew protection, more power in its engines. The B-17D took on leakproof fuel tanks, increased armament, better engine cooling in fast climbs, and a speed increase to more than 300 mph.
When the Japs attacked Pearl Harbor, the B-17C's and B-17D's were the first Fortresses to see action. But soon the B-17E's were on their way to join them in even greater numbers-faster, heavier, sturdier Fortresses, packing .50-cal. waist and tail guns, with a Sperry ball turret under the fuselage, and another power turret on top.
By the spring of 1942, still another Fortress — the B-17F—with longer range, greater bomb load capacity, more protective armament and striking power, was streaking across both Atlantic and Pacific in enormous numbers to provide what General Arnold called "the guts and backbone of our world-wide aerial offensive."
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