The politics of procurement

In the 1930s, the U.S. Army was building up its own airborne fighting arm, known as the General Headquarters (GHQ) Air Force, which had been established in 1922. The Army was structured so thee the GHQ Air Force had to arrange training and procure supplies through another arm, the Army Air Corps.    

The GHQ Air Force, as impressed with the Norden bombsight as the Navy, made it standard equipment on its own bombers by 1934. But because the Norden company was a dedicated source to the Navy, the only way the Army Air Corps could get Norden bombsights was by ordering them through the Navy, a pass-along arrangement that complicated design development and delivery.    

Since the Norden bombsight had been developed primarily for the medium altitudes and slow speeds of small Navy flying boars, such as the PBY bombers, it needed to be modified for the higher speeds and extremely high and low altitudes of the heavy, long- range Army GHQ Air Force bombers. For Air Force purposes, the Norden's optical field of the telescope was too limited, giving insufficient forward and thwartship vision. The Norden bombsight also did not allow bombs to be accurately targeted if the plane were descending in a glide a maneuver preferred to level flight during bombing runs because changing altitude made the bomber a more elusive target for antiaircraft guns and its trail settings were too limited to accommodate the wind resistance encountered by the faster Air Force planes. These shortcomings could only be overcome if Air Force bombardiers fudged the data they entered into the bombsight by levers and knobs.    

The design problems became moot, however, when despite the pressure from both Navy and Army, Carl L. Norden Inc. could not deliver. One reason may have been the fact that the firm relied on old-world artisans in its various plants to manufacture he Norden Mark XV by hand, fitting the parts according to qualitative tolerances as "free-running fit, no play.

In January 1936, the Navy suspended all deliveries of the Norden sight to the Army Air Corps until the Navy's own requirements were satisfied. At that point, the commander of the GHQ Air Force, Major General Frank M. Andrews, expressed his concern in a memo to the Chief of the Air Corps and to the Navy. He then openly encouraged the Sperry Gyroscope Co. to develop the O-1 bombsight to meet Air Force specifications.

A bombsight had to determine in real time both the range and the course of the plane so as to calculate the proper moment for releasing a bomb. It had to compensate for air resistance, which caused the bomb to trail behind the plane (top), and cross winds, which made it drift downwind to the side of the plane's path (bottom). Other factors included the bombs ballistics and the target's altitude, which affected, the time of fall.