Technological Developments

By the mid-i930s many air power advocates believed that aerial technology had finally begun to catch up to air power theory. The outdated Keystone в-4, a two-engine, fabric-covered biplane that served as the Army’s primary bomber when the decade began, gave way to all-metal monoplanes, the Boeing в-9 and Martin b-io. The open-cockpit в-9 could fly at 186 miles per hour at six thou­sand feet, which made it 60 miles per hour faster than any cur­rent Air Corps bomber when it first flew in April 1931. At above twenty thousand feet—the estimated maximum range of antiair­craft artillery—it was faster than the Air Corps’ primary fighter aircraft, the P-26! The b-io was faster still, recording a speed of 207 miles per hour at twenty-one thousand feet in 1932, plus it sported internally carried bombs, enclosed crew compartments, and a retractable landing gear.6 Both aircraft had only two en­gines, however, which precluded them from carrying heavy bomb loads for long distances.

To overcome this deficiency, Air Corps Chief Major General Benjamin Foulois submitted a request to aircraft manufacturers for a design capable of flying 2,000 miles with a ton of bombs at a speed of 250 miles per hour. Three companies responded to the request, and one, Boeing, built a four-engine model designed for an eight-man crew. That prototype, the хв-17, could reach 250 miles per hour at fourteen thousand feet, could operate as high as thirty thousand feet, and could carry 2,500 pounds of bombs 2,260 miles or 5,000 pounds for 1,700 miles.7 For airmen it was the manifestation of nirvana. Hap Arnold recalled that the в-17 was “the first real American air power…. Not just brilliant proph­ecies, good coastal defense airplanes, or promising techniques; but, for the first time in history, Air Power that you could put your hands on.”8 The Air Corps wanted to purchase sixty-five B-17S, but the prototype’s crash in October 1935, stemming from locked flight controls—and the War Department’s desire for a bomber better suited for supporting ground troops—limited the order to thirteen. They began arriving at Langley’s Second Bombardment Group in March 1937.

Complementing the в-17 was a device that significantly im­proved bombing accuracy—the Norden bombsight. In October 1931 Air Corps observers witnessed use of the Navy’s new bomb – sight, the Mark XV. Carl L. Norden, a civilian consultant, and Navy Captain Frederick I. Entwistle had developed the device, and in 1932 Foulois requested twenty-five of them for the Air Corps. The main feature of the black metal bombsight was a gyro – stabilized, motor-driven telescope. The bombardier looked through it during the bomb run, after having inserted the wind speed, al­titude, and bomb ballistics information into the bombsight. Its primitive computer updated the aircraft’s speed over the ground, which enabled the bombardier to control lateral aircraft move­ments via an autopilot. Meanwhile, he synchronized the telescope’s vertical and horizontal crosshairs on the target. If he had inserted the proper data and aligned the crosshairs over the proper spot, the bombsight would identify the correct point to release bombs and drop them automatically. Under ideal conditions at twenty – one thousand feet, he might place one bomb out of all those that he dropped into a hundred-foot-diameter circle surrounding the center of the target, although conditions in combat would rarely be ideal. Still, the Norden bombsight dramatically increased the possibility that an air offensive could sever the strands of an in­dustrial web. In 1933 the Air Corps ordered seventy-eight more of the devices, and by the late 1930s the Tactical School had its stu­dents estimating the number of Norden-equipped bombers needed to destroy particular targets. The bomber type used in those ex­ercises was the в-17.9