The Norden Bombsight

by Kurt Rand

The Navy lifts the veil of censorship a little on facts concerning our prime secret weapon

Delicate as a pharmacist's balances, fine as a thoroughbred colt, closely guarded as a Sultana — but sturdy as a stone barn — the Norden bombsight is the most discussed yet least known of all the tools of today's war.

For more than 10 years it has been surrounded with the most elaborate and spectacular secrecy, such a ritual of hiding with armed escorts and oath-swearing guardians that the forms of protection became a legend, and the bombsight's mere existence a propaganda.

Now, at last, the wall of jealous silence has been cracked — slightly. A little bit has been disclosed about its appearance, a little about how it is used. Is it because, at last, the Air Forces have ruefully discovered that it's not as good as they thought it was? Not at all — if anything, it's even better.

No weapon in daily use can long remain a secret. Sooner or later, the enemy inevitably will come into possession of it, take it apart, find out how it operates. And that has happened to the bombsight. The strange thing is that nobody cares much that Germany now has had an opportunity, almost beyond question, to examine a number of the devices at her leisure. The loss of men, that's serious. The loss of equipment is regretted. But Germany will not profit by what she learns from the bombsights recovered in American bombers lost over Europe.

That is because the Norden bombsight is more than an instrument. It is also a system of training and a technique. Rather, it has imposed a system of training, and created a technique — the Army Air Forces technique of high-altitude, precision, daylight bombing. To use the bombsight, even if they could manufacture it — a matter of considerable doubt — the Germans would have to abandon their entire system of bombardier training and start afresh. This is almost an unthinkable decision in the midst of war.

To an innocent bystander, the bombsight does not present a particularly impressive appearance. But it does a very, very impressive job. Give the bombardier clear weather, or even a few seconds to squint at his target, and the properly trained man just can't miss.

Bombardier cadets learn enough about its complicated insides to make superficial repairs, but it takes a carefully-trained specialist to perform a major operation on the Norden bombsight. Opened up, it becomes — to the layman — a bewildering confusion of gears, mirrors, cams, lenses, wires, prisms, bearings and a myriad of tiny parts.

This multiplicity of small parts, and the extremely fine tolerances to which they are machined, are two of the principal reasons why the enemy would encounter extreme difficulty in duplicating the Norden bombsight. Another is the scarcity of essential raw materials, for shortages are more critical in Germany than in this country.

Around the Air Forces schools where thousands of men have been taught to use the bombsight, one of the ancient but favorite jokes is the mock-solemn prediction that, any time now, the Army is going to start giving commissions to the bombsights and leave the bombardiers at home. It's a natural tribute to the results delivered by this mechanism, which seems to do just about everything but think, and comes close to doing that, too.

Approaching the target, but before beginning the bombing run, the bombardier sets the bombsight for operation at the predetermined altitude and airspeed of the plane, lines up the sight with the plane's true direction, and prepares the release mechanism for the bombs. When the bombing run begins, the bombardier takes command of the ship.

A good bombardier requires only a few seconds to get his sight lined up, but he's an extremely busy man during that time. He must allow nothing to distract him. The air around his plane may be filled with a hideous crescendo of the high whines of scores of engines, shattered and roaring with the staccato thunders of aircraft machine guns and cannon. Subconsciously, the bombardier may be aware of enemy fighters diving and spitting death at his bomber, may feel the rip and impact of bullets and shells that find their mark. But consciously he thinks only of his bombsight and its target.

Squinting through the telescope, he lines up two cross-hairs to intersect across the target, then adjusts the sight so that the cross-hairs remain fixed on the target. The bombsight, synchronized to the speed and altitude of the plane, does the rest. If the plane is put on the proper course, the hairs of the telescope follow the target — and the bombsight even puts the plane on the proper course and holds it there.

The bombsight, its self-contained computing mechanism "thinking" far more quickly than the human mind, automatically makes compensation for the plane's forward motion, its drift, and even — in the case of a moving target — for the target's motion. The course of the plane is controlled either automatically by the bombsight's operation of a gyropilot, or by the sight's operation of an indicator in the pilot's compartment to guide the pilot in handling the ship.

At the proper moment, the bombardier releases his deadly "eggs," and with his "bombs away!" the command of the plane returns to the pilot. Unless something has occurred completely beyond his control to interrupt the bombing run, it's almost a certainty that the bombs have landed squarely on the target — even if they were dropped from 30,000 feet or more.

For a long time, the effectiveness of this high-altitude precision strategic bombing technique was a matter of considerable controversy. The RAF was skeptical, and its skepticism was reflected in the assurances of "experts" that the technique, however valuable in the clear weather prevailing around most of the North American continent, was useless over western Europe where the weather often gets bad. But the AAF now has convinced the skeptics — at Vegesack, at Lorient, at Abbeville, at Wilhelmshaven, at many another target in Germany and German-occupied Europe. Reminded of the controversy, and asked his opinion, Lieut Col Pierpont M Hamilton, AC, said recently, "Well, I'd certainly hate to be occupying any spot selected by our bombers for a target."

Despite its fame, the history of the Norden bombsight is still obscure for the most part. Carl Ludwig Norden and Theodore H Barth were both consultant engineers for the Navy when Norden invented the mechanism in 1923. They formed a partnership. Five years later the partnership became a corporation, Carl L Norden, Inc, of which Barth is president and sole owner, and with which Norden is connected as a consultant. The company not only has but one owner — it has never had but one customer, the US Government. Originally occupying a single floor of a building in New York City, the company now occupies two entire buildings there, and has plants in Indianapolis, Northampton, MA and Danbury, CT.

None of the usual industrial information is available concerning Carl L Norden, Inc. No one at liberty to talk knows how many bombsights are being turned out now, how many have been manufactured in the company's history, or even whether the present bombsight is substantially like the original. The company's contracts are with the Navy, which supplies the sight to the AAF, and Barth is proud — and justifiably so — of the fact that the Navy inspectors have yet to reject a single bombsight delivered by his company.

The bombsight and the company are Barth's hobby as well as his business, and he has said that he would pay for the privilege of occupying his desk and running the show. Heavy, powerfully built, the 50-year-old executive is a man of tremendous personal force whose driving energy sets the pace for the entire organization.

He and his staff have examined captured German bombsights, and he finds them heavy and cumbersome affairs that he cannot imagine putting into any kind of mass production. He also holds that failure would meet any German attempt to put the Norden sight into production for the Luftwaffe.

Barth is interviewed rarely, but one of the rare occasions came along in April when his company got its third Army-Navy Production Award for outstanding performance of war contracts.

"Even if the Germans were given the Norden blueprints, it would take them a year and a half to tool up," said he at that time.

"Then they would have to teach people how to use the tools. Then their troubles would begin. It is comparatively easy to build two or three bombsights, but to get sizable production takes a terrific effort. And building the bombsight is only half the job.

"It took our Army and Navy nearly 10 years of organized schooling — all this before Pearl Harbor, mind you — to educate what was then believed to be a sufficient number of men to use and maintain the bombsight, only to find at the outset of the war that this was only a small fraction of the number that was required.

"After Pearl Harbor all the trained men that could be spared from combat duty became instructors. We had to spread our trained men pretty thin.

"The bombardier schools operated around the clock to produce the bombing crews and, particularly, the bombardiers who now are obtaining pretty good results. Even today, with our long-established setup, it takes up to eight months to train maintenance men, and we have the finest kind of talent to begin with."

Of course, the Germans do not have the Norden blueprints, and those who know say it would take them considerable time — a minimum of two months — before their skilled technicians could dive into the bombsight's complications and come out with a reasonably accurate picture of how it works, and why. Give them another two months to achieve their modifications to meet German techniques and production methods. Then, as Barth points out, another year and a half would be required to tool up, additional time for training workers and, assuming that after all that the enemy actually succeeded in producing the bombsights in quantity, a complete changeover in training methods for bombardiers, adding more months to the process. It all adds up to "no use" by the Germans of the Norden bombsight.

Although the Norden company has expanded enormously, and all of the expansion obviously is for military bombsight production, Barth is prepared to shift to the manufacture of other things when the military requirements decline with the end of hostilities.

Furthermore, he predicts that after the war the world's precision instrument industry will be centered in the United States. Knowledge and facilities developed under the stress of conflict will be available for peacetime uses, he says. For the company he owns and directs and for the bombsight it produces, Barth gives full credit to Mr. Norden. "He is an amazing man and a modest one. I was lucky to meet up with him," he asserts.

"We make a good team, like Gilbert and Sullivan. He was interested in the scientific end and I was able to put his ideas into metal — make them a practical possibility. We've always worked perfectly together, and we've never 'had words'."

This article was originally published in the July, 1943, issue of Flying magazine, vol 33, no 1, pp 37-38, 148.
The PDF of this article [ PDF, 7.2 MiB ] includes photos of a Beech Wichita and a B-17F.
Photos credited to US Army, Boeing.