PAYLOAD 9 CREW MEMBERS, ONE TON OF BOMBS, AND FIVE 30-CALIBER MACHINE GUNS.
THE 299, OFFICIALLY DESIGNATED THE XB-17, WEIGHED 16 TONS. ITS GREAT WINGS WERE CONSTRUCTED OF ALUMINUM ALLOY METAL BRACED INTERNALLY BY A BRIDGE-LIKE TRUSS STRUCTURE. THE 299 WAS HIGHLY STREAMLINED AND ITS LANDING GEAR RETRACTED INTO WELLS IN THE ENGINE NACELLES. ITS ENGINES WHIRLED 3-BLADED CONSTANT-SPEED PROPELLERS. IT WAS EQUIPPED WITH WING FLAPS TO REDUCE ITS LANDING SPEED. GUNNERS WERE PROTECTED BY PLASTIC GUN BLISTERS AND BOMBS WERE CARRIED INSIDE THE FUSELAGE.
THE INTRODUCTION OF THE _FLYING FORTRESS_ MARKED A GREAT STEP FORWARD IN THE DESIGN OF BIG MILITARY AIRPLANES. IT CAME AS THE RESULT OF THE BOEING COMPANY’S DEVELOPMENT OF LOW-WING, ALL-METAL, MULTI-ENGINED PLANES. IT ALSO PROVED THAT PROPER STREAMLINING REDUCED _DRAG_ AND INCREASED SPEED.]
The pioneering of unusual airplanes like the _Monomail_, the B-9, and the 247 transport were steps toward the Boeing 299. It was a courageous step from two-engined to four-engined bombers, but the Boeing Company made it so successfully that almost instantly the United States Army Air Corps won world leadership in long-range, heavy bombardment aviation.
The exceptional speed, range, armament, and bomb capacity of the 299 quickly resulted in the dramatic name _Flying Fortress_. As the B-17 it flew across the country at 232 miles per hour. In 1938, six B-17 _Flying Fortresses_ set unofficial world records for speed and range in a mass flight from Langley Field, Virginia, to Buenos Aires, Argentina, and return.
From 1930 to 1940 the small but efficient air arm of the United States Navy continued to make progress. Since the introduction of the radial engine, the Navy had worked closely with manufacturers of this type of power plant. All types of Navy airplanes were powered with either Wright or Pratt & Whitney air-cooled, radial engines. Many problems peculiar to naval aircraft were worked out through the close co-operation of Navy technicians and manufacturers. Corrosion-resistant metals were developed for cylinders. Stronger engine parts were introduced to withstand the stress of dive-bombing. Continual progress was made in increasing the power of the engine without increasing its weight per horsepower. Thus engine power increased from 200 horsepower in 1925 to 1,000 horsepower in 1940.