Engines of Our Ingenuity

No. 1004:
NORDEN'S BOMBSIGHT

by John H. Lienhard

Click here for audio of Episode 1004.

Today, the story of the not-so-secret bombsight. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

As I grew up during WW-II, the words secret weapon summoned up only one image: the Norden Bombsight was America's highly touted secret weapon. Meanwhile, the real military secret was the atom bomb. It caught us all by surprise when it fell.

Norden managed to surround his bombsight with a remarkable wall of hype. Bombardiers had to carry a pistol to shoot the device like a lame horse if they crash-landed over enemy territory. WW-II movies told about spies trying to learn its secret -- of heroes giving their lives to protect the secret. Only years later did I learn that there'd hardly been any secret at all.

But let's go back to the beginning. Carl Norden came to America in 1904. He was Dutch -- raised in Java and educated in Switzerland. First, he worked with Elmer Sperry on gyro-stabilizers. He and Sperry were a pair of temperamental geniuses -- difficult people. Norden left in 1913 to set up his own business.

He began designing the bombsight for the Navy in 1920. He finally had a pretty good version in 1928. At the same time, his old boss, Sperry, was developing the Army's bombsight.

It was 1932 before the Army compared notes with the Navy and found that Norden's instrument was far better. But Norden regarded the Army as plebian and he wouldn't deal with them. To get his bombsight, the Army had to buy it from the Navy.

It was a superb piece of design -- an analog computer that calculated the trajectory of the bomb, given crosswind, altitude, and airspeed. It also released the bomb. In a plane moving 300 feet per second, the bombardier's reaction time was too slow to tolerate.

I didn't know it then, but a Norden worker named Lang had stolen the plans in 1937 for the Germans. Göring gave him $3000 -- a huge sum in those days. Later, Lang was caught and sent to jail for 18 years. The irony is, Germany never used the device.

The Germans committed to dive-bombing, while we pursued high-altitude precision bombing. The trouble was, precision was another Norden myth. From 20,000 feet, 2/3 of American bombs fell 1/5 of a mile or more from their targets -- even with the best of bombsights.

Meanwhile, the bombsight itself had been reclassified from secret to merely confidential two years before Lang's infamy. In 1942 it was downgraded to restricted, the lowest classification.

By then we were switching to the English tactic of saturation bombing. A bomber armada flew over a city. The lead plane signaled the drop and they pulverized everything below -- hoping to catch occasional military targets in the general carnage.

It was a nasty war, and, I suppose, we needed to make heroes of machines as well as people. Norden give us our mechanical hero.

I'm John Lienhard at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


Sherman, D., The Secret Weapon. Air & Space, March 1995, pp. 78-87.

I am grateful to architect B. Caroll Tharp of Montgomery, Texas, for suggesting the topic and providing the source.


The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.

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