In order to avoid the horror of trench warfare, which had been the hallmark of World War I, U.S. war planners were settling on the idea of precision strategic bombing to capitalize on the potential of air power. It would soon become very apparent that control of the skies would win the war. However, in order to carry out strategic bombing missions required precision bomb sights that would work from higher altitudes and speeds for the new generation of bombers being designed. The machine Dutch immigrant Carl L. Norden would create was so revolutionary that the design would be used throughout World War II and up to the Vietnam War.

Practically every news article of the day referred to the claim that the Norden bomb sight bombardiers could hit a pickle barrel from 20,000 feet. Though it is simply a myth and that amount of accuracy is absurd, the idea of its assistance in precision persists. Before the Norden came along, bombardiers, using a simple sight, could miss their targets by miles. With this new bomb sight, many bombardiers became so accomplished that they could hit their target nine out of ten times and when they missed, it was only a matter of about a hundred feet. One difficulty in its use was that when the bombardier turned it on, he had control of the plane for the time it took to calculate and drop the bomb load. This meant that for up to 5 minutes, the pilots could not avoid the antiaircraft shots and flak being fired at them. Nor could they avoid any enemy aircraft. It could take a matter of seconds for an enemy to lock on to them. The math favored the enemy.

“Leading up to and during the war, bombardiers trained in the use of two bomb sights. At that time, the military was experimenting with dive-bombing tactics for heavy bombers. For dive-bombing training, they had a $1 handheld sight consisting of an aluminum plate with a peg and a dangling weight. For flat runs, they had the Norden bomb sight, an extremely sophisticated analog computer that, at $8,000, cost more than twice the price of the average American home. On a bombing run with the Norden sight, bombardiers would visually locate the target, make calculations, and feed information on air speed, altitude, wind, and other factors into the device. The bomb sight would then take over flying the plane, follow a precise path to the target, calculate the drop angle, and release the bombs at the optimal moment. Once the bombs were gone, the bombardier would yell “Bombs away!” and the pilot would take control again. Norden bomb sights were so secret that they were stored in guarded vaults and moved under armed escort, and the men were forbidden to photograph or write about them. If his plane was going down, the bombardier was under orders to fire his Colt .45 into the bomb sight to prevent it from falling into enemy hands, then see about saving himself. It was the second most guarded secret in the nation at the time, the number one secret being the Manhattan Project and the atomic bomb” (Hillenbrand, 2010).

During missions, the Norden sight computed information fed in by the bombardier on bomb ballistics, ground speed, drift, and trail (the airplane’s distance from the target at bomb impact). Using a telescope attachment on the sight, the bombardier established and compensated for deflection to synchronize the instrument. Bombs were then released automatically when the bomber reached the point computed by the sight. The sight linked to the autopilot enabled the bombardier to control lateral movement of the plane through his adjustments of the sight.

Until late 1943, the Norden bomb sight was always protected by exceptionally heavy security. Sights were normally stored in air-conditioned, dust proof vaults that were patrolled by armed guards. During training, Army Air Corps bombardiers had to swear a solemn oath to guard the secret weapon with their lives, and they were responsible for destroying it in the event of an emergency landing behind enemy lines. Whenever a bombardier or ordnance technician carried a sight out to an aircraft, two armed guards accompanied him.

After hundreds of Norden-equipped bombers were shot down over enemy territory during 1943, Allied officials knew that the Germans had surely studied the bomb sight and learned its secrets. As a result, security was finally relaxed. When the war ended, details of the ingenious device were finally made public. But U.S. intelligence experts received a shock when they interrogated Luftwaffe personnel: The Germans had known the bomb sight’s secrets even before the war, thanks to a spy at Norden.

Sweeting, C.G. Not-So-Secret Weapon: The Norden Bombsight. Aviation History Magazine, 2017.

Hillenbrand, Laura. Unbroken. Random House, 2010.