Showing posts with label Norden bombsight. Show all posts
Showing posts with label Norden bombsight. Show all posts

Tuesday, March 24, 2009

Remembering the Norden Bombsight


My friend Maurice Rockett, a B-17 bombardier with the 95th, sent me this article today. It's very good.


Story by Walt Sehnert

Monday, March 23, 2009
One of the most closely guarded secrets of World War II was the Norden bombsight. This was the invention of a Dutch-born American, Carl Norden, who had come to the United States in 1904, after completing his University studies in Switzerland. In the United States, Norden went to work for the Sperry Corp., which was developing gyroscopes for improving ship stabilization for the U.S. Navy. Carl Norden and Elmer Sperry really never got along with each other very well. Sometime after World War I, Norden left the Sperry organization to start his own company, with the idea of making bombsights for the U.S. Navy. But with the advent of World War II Norden's bombsights were adopted by the United States Army Air Corps, and later the USAF. It was here, with the growing importance of the big bombers in the war that the Norden bombsight gained its exalted reputation, not just for the United States, but all countries of the world that were engaged in World War II, both Allies and Axis forces.
The Norden bombsight was just one step, but a giant step, in the evolution of bombsights, dating back to World War I, when pilots used a simple crosshairs telescope to help bring their bombs close to their designated target.
The World War II Norden bombsight consisted of two main parts, a stabilizer and a sight-head. The stabilizer was a platform that was kept level by a series of gyroscopes, and was attached to the plane's autopilot, so that during the last stages of a bombing run the stabilizer actually flew the plane, to keep it on target.
The sight-head consisted of three primary parts. 1. A primitive analog computer calculated the impact point of the bombs, relative to the flight pattern of the plane. 2. A small telescope lined up the target initially. 3. A series of electric motors and gyroscopes automatically moved the bombsight so that the target remained stationary in the bombsight as the plane moved closer to its target. Proponents of the Norden bombsight claimed that it was foolproof. Using that bombsight, (they said), a bombardier "could drop a bomb into a pickle barrel from 20,000 feet."
By the end of World War II 45,000 USAAF and USAF bombardiers had been checked out on the Norden bombsight, and all of them had signed papers promising to protect the bombsight with their lives, and to destroy it if they were forced to abandon their plane.
The ritual of using a Norden bombsight at air bases was rigid, (including its use at the McCook Army Air base). The bombsight was kept in a fortified storage building. When it was to be used, it would be brought out of the storage building by a contingent of armed guards. It was kept in a zippered bag until it was put in its place aboard a bomber (B-25, B-17, or B-29), by the plane's bombardier. Returning from a mission, the bombsight was again placed in its zippered bag, removed from the plane under the watch of an armed guard, and deposited back into its storage building, which was also under a constant guard.
Despite the claims of the bombsight's champions, the Norden bombsight was less than foolproof. Tests on the bombsight were made in level flying aircraft, flying at constant airspeeds. In combat, bombers flying bombing runs in enemy territory under these conditions were very likely to be shot down. Instead, U.S. pilots preferred to approach their targets in a gliding path, which made the planes harder to hit with anti-aircraft fire, but meant a great deal of manual input by the bombardiers, and a much greater risk of human error -- thus a great variance in the dependability of the bombsight in pinpointing the bomb's target.
Never the less, stealing the secrets of the Norden bombsight was a top priority of German spies during the war, even though it has since been learned that the Germans already knew the basic secrets of the bomb sight, but had decided that it did not fit in with their preferred method of bombing -- dive bombing attacks as opposed to high altitude precision bombing, which the Americans preferred.
Capturing the secrets of the Norden bombsight was the primary goal of the largest German spy ring to be successfully captured and prosecuted by the Americans during World War II.
Nineteen-year old Herman Lang was a German engineer who immigrated to the United States in 1927 (and became a U.S. citizen in 1939). He took a job with Carl Norden and was soon assigned work making gyroscopes for the Norden bombsight. He apparently did good work, and learned the intricacies of the bombsight very well. On a trip to Germany in 1938 Lang had a meeting with Herman Goering, Hitler's right hand man, and negotiated a deal (for $3,000) to reproduce from memory his recollections of the bombsight. During World War II German bombsights used many of the same principles of the American Norden device.
Upon his return to the United States and the Norden Corp., Lang continued to feed sensitive military information to the Germans through his involvement with the Duquesne Spy Ring, a key German spy organization, under the leadership of Fritz Joubert Duquesne, a U.S. citizen from South Africa, whose hatred of the British had led him to spy for the Germans in both World War I and World War II.
FBI agents were aware of the Duquesne organization in the U.S. for some time. For nearly two years, from 1939-1941, the FBI ran a covert radio station for the organization, intercepting information from Germany and controlling messages sent from the German spies in the U.S.
In late 1941, through the use of a "double agent," Wm. Seybold, the FBI was able to capture, jail, and convict 32 German agents of the Duquesne Spy Ring. (Herman Lang was in this group and received a sentence of 18 years, and then was deported to Germany). FBI head, J. Edgar Hoover, called this the greatest roundup of enemy agents in the history of the U.S.
It was, indeed, an important coup. After the war a former German spy stated that the capture of the Duquesne group had effectively destroyed the German spy network in the United States. (The story of the Duquesne Spy Ring was the theme of the 1945 Academy Award film "House on 92nd Street".)
Toward the end of World War II the weaknesses of the Norden bombsight were overcome somewhat when the USAF adopted the principle of "saturation bombing" of a target and pinpoint accuracy was of less importance for our bombers. Never the less, throughout the war the United States put great effort in protecting the secrets of the Norden bombsight, making the bombsight the greatest "non-secret" of the war. Some have described the extreme efforts of the U.S. in preserving the secrets of the Norden bombsight during World War II as a gigantic smokescreen, designed to divert attention away from the "Manhattan Project," the making of and finally using the atomic bomb, which certainly did end World War II. Atomic Bomb secrets, though the subject of many rumors, were largely preserved by the U.S. to the end of World War II.
It is probably fitting that Tom Ferebee, the bombardier aboard the Enola Gay, used a Norden bombsight to drop the atomic bomb on Hiroshima, thus combining the two great secrets of the war, the Norden Bombsight and the Atomic Bomb, to end World War II.
Source: Various Internet sources, Dale Cotton of the "Friends of the McCook Airbase."

Wednesday, November 7, 2007

Remembering the Norden Bombsight and Its Creator


Marilyn Walton sent me some good links dealing with the famous Norden bombsight, which legend has it could drop a bomb into a pickle barrel from twenty thousand fee (though only under ideal conditions and rarely when an aircraft was in less than perfect weather or was being shot at or flakked up. At the end of the article are two websites Marilyn recommended on the Norden bombsight. I checked them both and they are very interesting. According to Marilyn, Carl Norden sold his invention to the war effort for one dollar.
In the wiki story below, if you click on the blue hyperlinks, you can get additional information on the topics:

"Design and operation

The Norden sight was designed for use on US Navy aircraft by Carl Norden, a Dutch engineer educated in Switzerland who emigrated to the US in 1904 and worked on bombsights at the Sperry Corporation before starting his own company. The Norden was initially built at the Norden plant in New York City before the start of WWII and then at several other companies during the war. The device used a mechanical analog computer comprising electric motors, gyros, mirrors, bubble levels, gears and a small telescope.





The bombardier would input the necessary information, such as airspeed and altitude, and the bombsight would calculate the trajectory of the bomb being dropped. Near the target the aircraft would fly on autopilot to a precise position calculated by the bombsight and release the ordnance. Using this device, bombardiers could, in theory, drop their bombs within a 100-foot (ca 30m) circle from an altitude of well over 20,000 feet (ca. 7km). In combat, this accuracy was never achieved — because the Norden had been tested under "artificial conditions" at the US proving grounds, for example in the absence of anti-aircraft fire or adverse weather. An additional factor was that the shape and even the paint of the bomb mantle greatly changed the aerodynamic properties of the weapon; and, at that time, nobody knew how to calculate the trajectory of bombs that reached supersonic speeds during their fall.

Under perfect conditions only 50 percent of American bombs fell within a quarter of a mile of the target, and American flyers estimated that as many as 90 percent of bombs could miss their targets.

Operational efficiency

The "Norden" was marketed as the tool to win the war; and it was often claimed that the bombsight could drop bombs into pickle barrels. As noted above, the bombsight's effectiveness is debated. Some argue that over typically cloud-covered Europe the Norden was nearly useless, and the British Bomber Command focused on nighttime bombing anyway. However, the United States Army Air Forces (USAAF) did both day and night bombing runs, depending on the distance; and many veteran B-17 and B-24 bombardiers swore by the Norden.
In the European theater, the US introduced an Automatic Flight Control Equipment (AFCE) and a radar system called the H2X (Mickey), which were used directly with the Norden bombsight. The AFCE served as the mechanical computer “autopilot” of the plane. The radar proved most accurate in coastal regions, as the water surface and the coastline produced a distinctive radar echo.


Over Japan, bomber crews soon discovered strong winds at high altitudes, the so-called jetstreams — but the Norden bombsight worked only for wind speeds with minimal wind shear, under which testing had been done. Additionally, the bombing altitude over Japan reached up to 30,000 feet — but most of the testing had been done well below 20,000 ft.
In both theaters of war, one vulnerability was that, when the bombardier auto-piloted the aircraft using the bombsight, the aircraft was more susceptible to anti-aircraft fire and collisions with other allied aircraft.

As a mechanical device, the Norden bombsight used complex machinery consisting of many gearwheels and ball bearings, which were prone to produce inaccuracies if not properly maintained. In fact, many bombsights were rushed to war use without thorough testing. Often the bombardier had to oil and repair failures himself – for some time into the war, equipped and qualified groundcrew technical staff were just not available in sufficient numbers (see below).

Wartime security

As a critical wartime instrument, bombardiers were required to take an oath during their training stating that they would defend the Norden secret with their own life if necessary. In case the bomber plane should make an emergency landing on enemy territory, the bombardier would have to shoot the important parts of the "Norden" with a gun, disabling it; but as this method still would leave a nearly intact apparatus to the enemy, something like a thermite gun was installed – the sheer heat of the chemical reaction would melt the "Norden" into a lump of metal.

After each completed mission, bomber crews left the aircraft with a bag which they deposited in a safe ("the Bomb Vault"). This secure facility ("the AFCE and Bombsight Shop") was typically in one of the base's Nissen hut (Quonset hut) support buildings. The Bombsight Shop was manned by enlisted men who were members of a Supply Depot Service Group ("Sub Depot") attached to each USAAF bombardment group. These shops not only guarded the bombsights but performed critical maintenance on the Norden and related control equipment. This was probably the most technically skilled ground-echelon job, and certainly the most secret, of all the work performed by Sub Depot personnel. The non-commissioned officer in charge and his staff had to have a high aptitude for understanding and working with mechanical devices.
As the end of World War II neared, the bombsight was gradually downgraded in its secrecy; however, it was not until 1944 that the first public display of the instrument occurred.
Its last use in combat was by the Naval Air Observation Squadron Sixty-Seven (VO-67), during the Vietnam War. The bombsights were used in Operation Igloo White for dropping Air-Delivered Seismic Intrusion Detectors (ADSID) along the Ho Chi Minh Trail. " ---End Wikipedia article
Further reading at these websites: http://www.nordenretireesclub.org/norden_bio.htm