King George County Schools is a school division that serves students in King George County, Virginia . The district administers 3 elementary schools, 1 middle school, and 1 high school.
93-556: It serves all parts of the county for grades PK-12, except for those within Naval Surface Warfare Center Dahlgren Division , which are served by the Department of Defense Education Activity (DoDEA), for grades K-8. The superintendent of King George County Schools is Robert Benson. Before being appointed in 2012, he was an assistant superintendent for Cobb County School District . There are five members of
186-469: A Civil War Navy commander, who is the acknowledged "father of modern naval ordnance." Prior to 1918, the Navy operated a proving ground at Indian Head, Maryland, but it became inadequate as advances in gun designs and ordnance made its range obsolete. During World War I, a range of 90,000 yards (82,000 m) was sought by the Navy to prove its new battleship guns. The range was required to be over water but inside
279-403: A circle into which 50% of the bombs would fall, was 34 meters (110 ft) wide from only 910 meters (3,000 ft) altitude. This was an error of over 3.6%, somewhat worse than existing systems. Moreover, bombardiers universally complained that the device was far too hard to use. Norden worked tirelessly on the design, and by 1928, the accuracy had improved to 2% of altitude. This was enough for
372-553: A final total of six factories took several years. The USAAF demanded additional production to meet their needs, and eventually arranged for the Victor Adding Machine company to gain a manufacturing license, and then Remington Rand . Ironically, during this period the U.S. Navy abandoned the Norden in favor of dive bombing, reducing the demand. By the end of the war, Norden and its subcontractors had produced 72,000 M-9 bombsights for
465-459: A means to conduct successful high-altitude bombing. For example, an invasion fleet could be destroyed long before it could reach U.S. shores. To protect these advantages, the Norden was granted the utmost secrecy well into the war, and was part of a production effort on a similar scale to the Manhattan Project : the overall cost (both R&D and production) was $ 1.1 billion, as much as 2/3 of
558-499: A mechanical computer, and an autopilot for the first time to not merely identify a target but fly the airplane to it. The bombsight directly measured the aircraft's ground speed and direction, which older types could only estimate with lengthy manual procedures. The Norden further improved on older designs by using an analog computer that continuously recalculated the bomb's impact point based on changing flight conditions, and an autopilot that reacted quickly and accurately to changes in
651-676: A number of brilliant young scientists and engineers to the area during the war, and some were tapped to help with the ongoing Manhattan Project and the development of the atomic bomb. Two such people include Dr. Norris E. Bradbury , who later became the Director of the Los Alamos National Laboratory, and Deak Parsons , the weaponeer on the Enola Gay , the aircraft which dropped the Little Boy atomic bomb on Hiroshima, Japan in 1945. In
744-553: A report stated that the Norden's results were three to four times as good as their own bombsights, the Air Ministry decided to sweeten the pot and suggested they offer information on radar in exchange. This too was rebuffed. The matter eventually worked its way to the Prime Minister, Neville Chamberlain , who wrote personally to President Roosevelt asking for the Norden, but even this was rejected. The reason for these rejections
837-402: A stabilizer system to a vector bombsight would roughly double the accuracy of the system. This would allow the bombsight to remain level while the aircraft maneuvered, giving the bombardier more time to make his adjustments, as well as reducing or eliminating mis-measurements when sighting off of non-level sights. However, this would not have any effect on the accuracy of the wind measurements, nor
930-540: A stabilizer to the Mark III, the Mark III-A, also included a separate contract to develop a new automatic PDI. Norden proposed removing the electrical switches used to move the pointer and using the entire bombsight itself as the indicator. In place of the thin metal wires that formed the sights on the Mark III, a small low-power telescope would be used in its place. The bombardier would rotate the telescope left or right to follow
1023-657: A variety of Navy aircraft to excellent reviews. By connecting the outputs of the S-1 bombsight to the A-5 autopilot, Sperry produced a system similar to the M-4/SBAE, but it reacted far more quickly. The combination of the S-1 and A-5 so impressed the Army that on 17 June 1941 they authorized the construction of a 186,000 m (2 million sq ft) factory and noted that "in the future all production models of bombardment airplanes be equipped with
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#17330855668471116-457: A working prototype. Lieutenant Frederick Entwistle, the Navy's chief of bombsight development, judged it revolutionary. The new design, the Mark XV, was delivered in production quality in the summer of 1931. In testing, it proved to eliminate all of the problems of the earlier Mk. XI design. From 1,200 meters (4,000 ft) altitude the prototype delivered a CEP of 11 meters (35 ft), while even
1209-734: Is located in King George County , Virginia , in close proximity to the largest fleet concentration area in the Navy. NSWCDD is part of the Naval Surface Warfare Centers under the Naval Sea Systems Command (NAVSEA). NSWCDD was initially established 16 October 1918 as a remote extension of Maryland's Indian Head Proving Ground used for testing naval guns. The Dahlgren site was named the Lower Station, Dahlgren Naval Proving Ground when it first opened. The location on
1302-643: Is still commonly used to refer to the base. There are a few other major tenant commands on the base such as the Joint Warfare Analysis Center and the Aegis Training and Readiness Center (ATRC) involved in the training and development for the Aegis Combat System, and training and development for other future shipboard combat systems. NSF Dahlgren was also previously home to Naval Space Surveillance System Command ( NAVSPASUR ) before that function
1395-747: Is the local county high school. Norden bombsight The Norden Mk. XV , known as the Norden M series in U.S. Army service, is a bombsight that was used by the United States Army Air Forces (USAAF) and the United States Navy during World War II , and the United States Air Force in the Korean and the Vietnam Wars . It was an early tachometric design, which combined optics,
1488-429: The 2010 Census was 599. It is entirely distinct from Dahlgren CDP , to the west. Dahlgren was established in the spring of 1918 as a Naval Proving Ground. Its recorded first work, the firing of a 7-inch (178-millimetre)/45 caliber tractor-mounted gun, occurred on 16 October 1918, which is recognized as the official founding date. The proving ground was named Dahlgren in honor of Rear Admiral John Adolphus Dahlgren ,
1581-466: The E6B calculator used to this day. In operation, the bombardier would first take a measurement of the wind speed using one of a variety of methods, and then dial that speed and direction into the bombsight. This would move the sights to indicate the direction the plane should fly to take it directly over the target with any cross-wind taken into account, and also set the angle of the iron sights to account for
1674-519: The Estoppey D-series , as it automatically levelled the sight during use. Navy experiments showed these roughly doubled accuracy, so they began a series of developments to add a gyroscopic stabilizer to their bombsights. In addition to new designs like the Inglis (working with Sperry) and Seversky , Norden was asked to provide an external stabilizer for the Navy's existing Mark III designs. Although
1767-684: The Standard missile used on modern United States Navy warships, and the warhead for the AIM-54 Phoenix . Current projects include the majority of US research into directed-energy weapons , railgun technology and weapons integration for the Littoral combat ship . NSWCDD scientists and engineers share their technological expertise by participating in science, technology, engineering, and mathematics (STEM) activities to inspire students to pursue technical careers. NSWCDD mentors support summer academies, such as
1860-649: The Tomahawk missile , which improved the Navy's capacity to perform attacks on land targets from a distance that decreased the risk to ships. Dahlgren also was critical in work to protect Navy ships from enemy missile and air attacks with programs such as the Standard missile and the Aegis Combat System . That work continues in 2017, along with the electromagnetic railgun , DDG 1000 , Littoral Combat Ship (LCS), and Chemical Biological and Radiological Defense . Because of
1953-564: The 2,000-part machine. Between 1932 and 1938, the company produced only 121 bombsights per year. During the first year after the Attack on Pearl Harbor , Norden produced 6,900 bombsights, three-quarters of which went to the U.S. Navy. When Norden heard of the U.S. Army's dealings with Sperry, Theodore Barth called a meeting with the U.S. Army and U.S. Navy at their factory in New York City. Barth offered to build an entirely new factory just to supply
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#17330855668472046-460: The 50 needed for the Mk. XI to measure its ground speed. In most cases, the bomb run needed to be only 30 seconds long. Despite this success, the design also demonstrated several serious problems. In particular, the gyroscopic platform had to be levelled out before use using several spirit levels , and then checked and repeatedly reset for accuracy. Worse, the gyros had a limited degree of movement, and if
2139-719: The A-5 Automatic Pilot and have provisions permitting the installation of either the M-Series [Norden] Bombsight or the S-1 Bombsight". By 1938, information about the Norden had worked its way up the Royal Air Force chain of command and was well known within that organization. The British had been developing a tachometric bombsight of their own known as the Automatic Bomb Sight, but combat experience in 1939 demonstrated
2232-497: The British Air Ministry and Royal Navy to increasingly anti-American attitudes when they considered sharing their own developments, notably newer ASDIC systems. By 1940 the situation on scientific exchange was entirely deadlocked as a result. Looking for ways around the deadlock, Henry Tizard sent Archibald Vivian Hill to the U.S. to take a survey of U.S. technical capability in order to better assess what technologies
2325-540: The CSBS and similar designs allowed the calculation of the proper flight angle needed to correct for windage , they did so by looking downward out of the aircraft. Very simple bombsights could be operated by the pilot, but as their sophistication grew they demanded full-time operators. This task was often given to the front or rear gunner. In Army aircraft they would sit near enough to the pilot to indicate any required directional adjustments using hand signals, or if they sat behind
2418-463: The CSBS as their standard inter-war bomb sight, including the U.S. Navy, who used a modified version known as the Mark III . It was already realized that one major source of error in bombing was levelling the aircraft enough so the bombsight pointed straight down, even small errors in levelling could produce dramatic errors in accuracy. The US Army did not adopt the CSBS and instead used a simpler design,
2511-563: The King George County School Board: There are 5 schools in King George County. King George Elementary School Potomac Elementary School Sealston Elementary School King George Middle School King George High School Naval Surface Warfare Center Dahlgren Division The United States Naval Surface Warfare Center Dahlgren Division ( NSWCDD ), named for Rear Admiral John A. Dahlgren ,
2604-496: The M-4 model. In 1937 the Army, faced with the continuing supply problems with the Norden, once again turned to Sperry Gyroscope to see if they could come up with a solution. Their earlier models had all proved unreliable, but they had continued working with the designs throughout this period and had addressed many of the problems. By 1937, Orland Esval had introduced a new AC-powered electrical gyroscope that spun at 30,000 RPM, compared to
2697-614: The Mark XI was so secret that Gillmore was not aware Fechet was referring to the Norden. Gilmore produced contracts for twenty-five examples of an improved version of the Seversky C-1, the C-3, and six prototypes of a new design known as the Inglis L-1. The L-1 never matured, and Inglis later helped Seversky to design the improved C-4. The wider Army establishment became aware of the Mark XI in 1929 and
2790-464: The Material Division at Wright Field , stating: I cannot too strongly emphasize the importance of a bomb sight of precision, since the ability of bombardment aviation to perform its mission of destruction is almost entirely dependent upon an accurate and practical bomb sight. He went on to request information on every bombsight then used at Wright, as well as "the Navy's newest design". However,
2883-656: The NSWCDD include physicists Albert Einstein , Edward Teller , Carl Norden , and computer pioneers Howard Aiken and Grace Hopper . Engineering projects of historical or military significance developed at NSWCDD include the triggering device on the Hiroshima atomic bomb , the Norden Bombsight used on most American bombers such as the B-17 Flying Fortress , B-24 Liberator and B-29 Superfortress during World War II ,
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2976-478: The Naval Space Surveillance Center, which selected Dahlgren to be at the center of the laboratory's growing computer advances. It was around this time that Dahlgren became heavily involved with the development of Fleet Ballistic Missiles , later called Submarine-Launched Ballistic Missiles. In the 1970s and 1980s, Dahlgren was on the leading edge of naval surface weapons work with programs such as
3069-458: The Navy and Air Forces had to give up using pinpoint attacks. The Navy turned to dive bombing and skip bombing to attack ships, while the Air Forces developed the lead bomber procedure to improve accuracy, and adopted area bombing techniques for ever-larger groups of aircraft. Nevertheless, the Norden's reputation as a pin-point device endured, due in no small part to Norden's own advertising of
3162-399: The Navy developed the concept of the pilot direction indicator , or PDI, an electrically-driven pointer that the observer used to indicate which direction to turn. The bombardier used switches to move the pointer on his unit to indicate the direction of the target, which was duplicated on the unit in front of the pilot so he could maneuver the aircraft to follow suit. Norden's attempt to fit
3255-411: The Navy's Bureau of Ordnance to place a US$ 348,000 contract (equivalent to $ 6.17 million in 2023) for 80 production examples. Norden was known for his confrontational and volatile nature. He often worked 16-hour days and thought little of anyone who did not. Navy officers began to refer to him as "Old Man Dynamite". During development, the Navy asked Norden to consider taking on a partner to handle
3348-807: The Navy's arsenal. Most of the work was done at the Main Range Gun Line, which faces down the Potomac River. During the World War II years, Dahlgren became involved with new computational devices (computers) because of its ordnance requirements. Ground-breaking early computers were sent to Dahlgren to help with ballistic work and other directives, including the Aiken Relay Calculator and the Naval Ordnance Research Calculator (NORC). The computer and ordnance work going on attracted
3441-449: The Norden's 7,200 , which dramatically improved the performance of the inertial platform. The use of three-phase AC power and inductive pickup eliminated the carbon brushes, and further simplified the design. Carl Frische had developed a new system to automatically level the platform, eliminating the time-consuming process needed on the Norden. The two collaborated on a new design, adding a second gyro to handle heading changes, and named
3534-465: The PDI work, and the contract was allowed to continue. Norden suggested that the only solution to improve accuracy would be to directly measure the ground speed, as opposed to calculating it using the CSBS's wind triangle. To time the drop, Norden used an idea already in use on other bombsights, the "equal distance" concept. This was based on the observation that the time needed to travel a certain distance over
3627-553: The Potomac River was specifically chosen for the development of a long ballistic test range on the Potomac River, required for the testing of modern, high-powered munitions. The NSWCDD employs approximately 4,700 scientists, engineers and support personnel at the Dahlgren organization and more than 350 at NSWCDD DNA. Prior to 2007, Panama City Coastal Systems Station located at the Naval Support Activity Panama City
3720-463: The U.S. Army Air Force alone, costing $ 8,800 each. Typical bombsights of the pre-war era worked on the "vector bombsight" principle introduced with the World War I Course Setting Bomb Sight . These systems consisted of a slide rule -type calculator that was used to calculate the effects of the wind on the bomber based on simple vector arithmetic . The mathematical principles are identical to those on
3813-470: The U.S. Army, but the U.S. Navy refused this. Instead, the U.S. Army suggested that Norden adapt their sight to work with Sperry's A-5, which Barth refused. Norden actively attempted to make the bombsight incompatible with the A-5. It was not until 1942 that the impasse was finally solved by farming out autopilot production to Honeywell Regulator , who combined features of the Norden-mounted SBAE with
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3906-456: The U.S. would be willing to exchange. This effort was the start on the path that led to the famous Tizard Mission in late August 1940. Ironically, by the time the Mission was being planned, the Norden had been removed from the list of items to be discussed, and Roosevelt personally noted this was due largely to political reasons. Ultimately, although Tizard was unable to convince the U.S. to release
3999-741: The USAAF. After investing more than $ 100 million in Sperry bombsight manufacturing plants, the USAAF concluded that the Norden M-series was far superior in accuracy, dependability, and design. Sperry contracts were cancelled in November 1943. When production ended a few months later, 5,563 Sperry bombsight-autopilot combinations had been built, most of which were installed in Consolidated B-24 Liberator bombers. Expansion of Norden bombsight production to
4092-561: The Virginia Demonstration Project, where they introduce robotics and basic engineering principles to area middle and high school students through hands-on activities. NSWCDD also has educational partnerships with several universities across the U.S. The Department of Defense Education Activity (DoDEA), which serves as the local school district for the base, has a K-8 school , Dahlgren Elementary Middle School. The school first opened in 1921. The school's principal facility
4185-416: The aim point. This not only reduced the time needed for the bombsight setup but also dramatically reduced the chance for errors. This attack on the accuracy problem was by no means unique; several other bombsights of the era used similar calculators. It was the way the Norden used these calculations that differed. Conventional bombsights are set up pointing at a fixed angle, the range angle, which accounts for
4278-492: The aircraft-mounted A-5 to produce what the U.S. Army referred to as "Automatic Flight Control Equipment" (AFCE); the unit would later be redesigned as the C-1. The Norden, now connected with the aircraft's built-in autopilot, allowed the bombardier alone to fully control minor movements of the aircraft during the bombing run. By May 1943 the U.S. Navy was complaining that they had a surplus of devices, with full production turned over to
4371-619: The best-known bombsights. The Norden sight was designed by Carl Norden , a Dutch engineer educated in Switzerland who immigrated to the U.S. in 1904. In 1911, Norden joined Sperry Gyroscope to work on ship gyrostabilizers, and then moved to work directly for the U.S. Navy as a consultant. At the Navy, Norden worked on a catapult system for a proposed flying bomb that was never fully developed, but this work introduced various Navy personnel to Norden's expertise with gyro stabilization. World War I bomb sight designs had improved rapidly, with
4464-465: The business and leave Norden free to develop the engineering side. They recommended former Army colonel Theodore Barth, an engineer who had been in charge of gas mask production during World War I. The match-up was excellent, as Barth had the qualities Norden lacked: charm, diplomacy, and a head for business. The two became close friends. In December 1927, the United States Department of War
4557-412: The calculation of the vectors. The Norden attacked all of these problems. To improve the calculation time, the Norden used a mechanical computer inside the bombsight to calculate the range angle of the bombs. By simply dialing in the aircraft's altitude and heading, along with estimates of the wind speed and direction (in relation to the aircraft), the computer would automatically, and quickly, calculate
4650-420: The calculations were common. The second problem was that the sight was attached to the aircraft, and thus moved about during maneuvers, during which time the bombsight would not point at the target. As the aircraft had to maneuver in order to make the proper approach, this limited the time allowed to accurately make corrections. This combination of issues demanded a long bomb run. Experiments had shown that adding
4743-520: The company was owned by the Navy. In 1934 the newly-forming GHQ Air Force, the purchasing arm of the U.S. Army Air Corps , selected the Norden for their bombers as well, referring to it as the M-1. However, due to the dedicated source contract, the Army had to buy the sights from the Navy. This was not only annoying for inter-service rivalry reasons, but the Air Corps' higher-speed bombers demanded several changes to
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#17330855668474836-593: The consolidations of naval laboratories into one headquarters center, it became the Dahlgren Division of the Naval Surface Warfare Center. NSWCDD conducts basic research in all systems-related areas and pursues scientific disciplines including biotechnology , chemistry , mathematics , laser and computer technology, chemical, mechanical, electrical and systems engineering , physics and computer science . Distinguished figures who have worked for
4929-431: The design, he was able to request information about its external dimensions and details on the mounting system so it could be easily added to British bombers if it were released in the future. The conversion of Norden Laboratories Corporation's New York City engineering lab to a production factory was a long process. Before the war, skilled craftsmen, most of them German or Italian immigrants, hand-made almost every part of
5022-486: The design, notably the ability to aim the sighting telescope further forward to give the bombardier more time to set up. The Navy was not interested in these changes, and would not promise to work them into the production lines. Worse, Norden's factories were having serious problems keeping up with demand for the Navy alone, and in January 1936, the Navy suspended all shipments to the Army. Mk. XV's were initially installed with
5115-572: The design. The Navy brass was concerned that giving the Norden to the RAF would increase its chances of falling into German hands, which could put the U.S.'s own fleet at risk. The UK Air Ministry continued increasing pressure on Pirie, who eventually stated there was simply no way for him to succeed, and suggested the only way forward would be through the highest diplomatic channels in the Foreign Office. Initial probes in this direction were also rebuffed. When
5208-537: The device after secrecy was reduced late in the war. The Norden saw reduced use in the post–World War II period after radar-based targeting was introduced, but the need for accurate daytime attacks kept it in service, especially during the Korean War. The last combat use of the Norden was in the U.S. Navy 's VO-67 squadron, which used it to drop sensors onto the Ho Chi Minh Trail in 1967. The Norden remains one of
5301-481: The device as it was owned by the U.S. Navy. The matter was not helped by a minor diplomatic issue that flared up in July when a French air observer was found to be on board a crashed Douglas Aircraft Company bomber, forcing President Roosevelt to promise no further information exchanges with foreign powers. Six months later, after a change of leadership within the U.S. Navy's Bureau of Aeronautics , on 8 March 1939, Pirie
5394-425: The ground would remain relatively constant during the bomb run, as the wind would not be expected to change dramatically over a short period of time. If you could accurately mark out a distance on the ground, or in practice, an angle in the sky, timing the passage over that distance would give you all the information needed to time the drop. Norden's version of the system was very similar to the Army's Estoppey D-4 of
5487-434: The highly specialized work force required, the Navy promised to supply housing, food and medical services, schools, recreation, and other socially needed infrastructure. In the 1920s and 1930s, Dahlgren was involved in testing bombsights, including the Norden bombsight , for the Navy's fledgling air forces. But, until World War II, much of the principal work at Dahlgren surrounded the proofing and testing of every major gun in
5580-411: The interior of the device, and the positioning of the control knobs, which meant the bombardier could only adjust side-to-side or up-and-down aim at a time, not both. But despite all of these problems, the Mark XV was so superior to any other design that the Navy ordered it into production. Carl L. Norden Company was incorporated in 1931, supplying the sights under a dedicated source contract. In effect,
5673-581: The laboratory's broad-based growth in research and development and with its new missions, Dahlgren's name officially changed to the Naval Weapons Laboratory in 1959. It was later changed to the Naval Surface Weapons Center in 1974 with the merger of the former Naval Ordnance Laboratory at White Oak, Maryland. In 1987, the name was changed again to the Naval Surface Warfare Center as new and expanded missions were added. And, in 1992, with
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#17330855668475766-466: The latest production Mk. XI's were 17 meters (55 ft). At higher altitudes, a series of 80 bomb runs demonstrated a CEP of 23 meters (75 ft). In a test on 7 October 1931, the Mk. XV dropped 50% of its bombs on a static target, the USS Pittsburgh , while a similar aircraft with the Mk. XI had only 20% of its bombs hit. Moreover, the new system was dramatically simpler to use. After locating
5859-522: The latter or over a quarter of the production cost of all B-17 bombers . The Norden was not as secret as believed; both the British SABS and German Lotfernrohr 7 worked on similar principles, and details of the Norden had been passed to Germany even before the war started. Under combat conditions the Norden did not achieve its expected precision, yielding an average CEP in 1943 of 1,200 feet (370 m), similar to other Allied and German results. Both
5952-428: The middle section of the bridge finally fell on the last day. However, the effort as a whole was clearly a failure in any practical sense. About the same time as the operation was being carried out, General James Fechet replaced General Mason Patrick as commander of the USAAC. He received a report on the results of the test, and on 6 January 1928 sent out a lengthy memo to Brigadier General William Gillmore, chief of
6045-411: The need for it to be stabilized. Work was underway as the Stabilized Automatic Bomb Sight (SABS), but it would not be available until 1940 at the earliest, and likely later. Even then, it did not feature the autopilot linkage of the Norden, and would thus find it difficult to match the Norden's performance in anything but smooth air. Acquiring the Norden became a major goal. The RAF's first attempt, in
6138-399: The pilot, using strings attached to the pilot's jacket. The Navy's first bombers were large flying boats , where the pilot sat well away from the front of the fuselage, and one could not simply cut a hole for the bombsight to view through. Instead, the bombs were normally aimed by an observer in the nose of the aircraft. This made communications with the pilot very difficult. To address this,
6231-401: The plane banked far enough the gyro would reach its limit and have to be re-set from scratch – something that could happen even due to strong turbulence . If the gyros were found to be off, the levelling procedure took as long as eight minutes. Other minor problems were the direct current electric motors which drove the gyroscopes, whose brushes wore down quickly and left carbon dust throughout
6324-399: The proper dropping angle. While the Mk. XI was reaching its final design, the Navy learned of the Army's efforts to develop a synchronous bombsight, and asked Norden to design one for them. Norden was initially unconvinced this was workable, but the Navy persisted and offered him a development contract in June 1929. Norden retreated to his mother's house in Zürich and returned in 1930 with
6417-412: The result the Sperry S-1 . Existing supplies of Nordens continued to be supplied to the USAAC's B-17s, while the S-1 equipped the B-24Es being sent to the 15th Air Force. Some B-17s had been equipped with a simple heading-only autopilot, the Sperry A-3. The company had also been working on an all-electronic model, the A-5, which stabilized in all three directions. By the early 1930s, it was being used in
6510-399: The same automatic PDI as the earlier Mk. XI. In practice, it was found that the pilots had a very difficult time keeping the aircraft stable enough to match the accuracy of the bombsight. Starting in 1932 and proceeding in fits and starts for the next six years, Norden developed the Stabilized Bombing Approach Equipment (SBAE), a mechanical autopilot that attached to the bombsight. However, it
6603-425: The same era, differing largely in the physical details of the actual sights. The D-4 used thin wires as the sights, while Norden's would use the small telescope of the Mark III-A. To use the system, the bombardier looked up the expected time it would take for the bombs to fall from the current altitude. This time was set into a countdown stopwatch , and the sights were set to the angle that the bombs would fall if there
6696-538: The spring of 1938, was rebuffed by the U.S. Navy. Air Chief Marshal Edgar Ludlow-Hewitt , commanding RAF Bomber Command , demanded Air Ministry action. They wrote to George Pirie , the British air attaché in Washington, suggesting he approach the U.S. Army with an offer of an information exchange with their own SABS. Pirie replied that he had already looked into this, and was told that the U.S. Army had no licensing rights to
6789-424: The target in the sighting system, the bombardier simply made fine adjustments using two control wheels throughout the bomb run. There was no need for external calculation, lookup tables or pre-run measurements – everything was carried out automatically through an internal wheel-and-disc calculator . The calculator took a short time to settle on a solution, with setups as short as six seconds, compared to
6882-455: The target, and then a flight of a dozen Douglas B-18 Bolos placed most of their bombs in a separate 550 m × 550 m (600 yd × 600 yd) square outlined on the ground. Another change of management within the Bureau of Aeronautics had the effect of making the U.S. Navy more friendly to British overtures, but no one was willing to fight the political battle needed to release
6975-528: The target. This motion would cause the gyros to precess , and this signal would drive the PDI automatically. The pilot would follow the PDI as before. Norden initially delivered three prototypes of the stabilized bombsight without the automatic PDI. In testing, the Navy found that while the system did improve accuracy when it worked, it was complicated to use and often failed, leaving the real-world accuracy no better than before. They asked Norden for suggestions on ways to improve this. They were still interested in
7068-482: The territorial waters of the United States. The area from Machodoc Creek to Point Lookout on the Potomac River was selected because of its relative straight lines and accessibility. The climate and relative calm of the river were also factors as the Navy sought an ice and rapids free testing area. At the time of Dahlgren's establishment, the area was extremely remote and relatively unpopulated. Thus, to recruit and retain
7161-539: The ultimate development being the Course Setting Bomb Sight , or CSBS. This was essentially a large mechanical calculator that directly represented the wind triangle using three long pieces of metal in a triangular arrangement. The hypotenuse of the triangle was the line the aircraft needed to fly along in order to arrive over the target in the presence of wind, which, before the CSBS, was an intractable problem. Almost all air forces adopted some variation of
7254-404: The various effects on the trajectory of the bomb. To the operator looking through the sights, the crosshairs indicate the location on the ground the bombs would impact if released at that instant. As the aircraft moves forward, the target approaches the crosshairs from the front, moving rearward, and the bombardier releases the bombs as the target passes through the line of the sights. One example of
7347-400: The wind or other effects. Together, these features promised unprecedented accuracy for daytime bombing from high altitudes. During prewar testing the Norden demonstrated a 150 feet (46 m) circular error probable (CEP) , an astonishing performance for that period. This precision would enable direct attacks on ships, factories, and other point targets. Both the Navy and the USAAF saw it as
7440-406: The wind's effect on ground speed. These systems had two primary problems in terms of accuracy. The first was that there were several steps that had to be carried out in sequence in order to set up the bombsight correctly, and there was limited time to do all of this during the bomb run. As a result, the accuracy of the wind measurement was always limited, and errors in setting the equipment or making
7533-406: The winter of 1939, at which point a number of articles about the Norden appeared in the U.S. popular press with reasonably accurate descriptions of its basic workings. But when these were traced back to the press corps at the U.S. Army Air Corps, the U.S. Navy was apoplectic. Instead of accepting it was now in the public domain, any discussion about the Norden was immediately shut down. This drove both
7626-492: The years immediately after the war, Dahlgren's work force was cut back. But the laboratory's strong computer and ordnance expertise kept the base open and Navy work flowing. Subsequently, the onset of the Cold War and Korea again placed demands for new offensive and defensive ship systems. In 1958, with the former Soviet Union's launching of Sputnik I, a space race began. Dahlgren opened its gates that year to its first tenant activity,
7719-431: Was built during World War II . In 2011 a review of the building found that it was in "poor" shape. King George County Public Schools operates non-DoDEA public schools in King George County. Most off-post persons associated with NSF Dahlgren send their children to King George County schools. The King George County school Potomac Elementary School is in proximity to the entrance to NSWC Dahlgren. King George High School
7812-400: Was eventually able to buy an example in 1931. Their testing mirrored the Navy's experience; they found that the gyro stabilization worked and the sight was accurate, but it was also "entirely too complicated" to use. The Army turned its attention to further upgraded versions of their existing prototypes, replacing the older vector bombsight mechanisms with the new synchronous method of measuring
7905-548: Was granted permission to use a bridge over the Pee Dee River in North Carolina for target practice, as it would soon be sunk in the waters of a new dam. The 1st Provisional Bombardment Squadron , equipped with Keystone LB-5 bombers, attacked the bridge over a period of five days, flying 20 missions a day in perfect weather and attacking at altitudes from 6,000 to 8,000 feet (1,800–2,400 m). After this massive effort,
7998-523: Was invited to watch an air demonstration at Fort Benning where the painted outline of a battleship was the target: At 1:27 while everyone was still searching [the sky for the B-17s] six 300-pound (140 kg) bombs suddenly burst at split second intervals on the deck of the battleship, and it was at least 30 seconds later before someone spotted the B-17 at 12,000 feet (3,700 m) The three following B-17s also hit
8091-443: Was more political than technical, but the U.S. Navy's demands for secrecy were certainly important. They repeated that the design would be released only if the British could demonstrate the basic concept was common knowledge, and therefore not a concern if it fell into German hands. The British failed to convince them, even after offering to equip their examples with a variety of self-destruct devices. This may have been ameliorated by
8184-406: Was no wind. The bombardier waited for the target to line up with a crosshair in the telescope. When it did, the timer was started, and the bombardier rotated the telescope around its vertical axis to track the target as they flew toward it. This movement was linked to a second crosshair through a gearing system. The bombardier continued moving the telescope until the timer ran out. The second crosshair
8277-452: Was not a true "autopilot", in that it could not fly the aircraft by itself. By rotating the bombsight in relationship to the SBAE, the SBAE could account for wind and turbulence and calculate the appropriate directional changes needed to bring the aircraft onto the bomb run far more precisely than a human pilot. The minor adaptations needed on the bombsight itself produced what the Army referred to as
8370-494: Was now at the correct aiming angle, or range angle , after accounting for any difference between groundspeed and airspeed. The bombardier then waited for the target to pass through the second crosshair to time the drop. In 1924, the first prototype of this design, known to the Navy as the Mark XI, was delivered to the Navy's proving grounds in Virginia. In testing, the system proved disappointing. The circular error probable (CEP),
8463-539: Was once again instructed to ask the U.S. Navy about the Norden, this time enhancing the deal with offers of British power-operated turrets. However, Pirie expressed concern as he noted the Norden had become as much political as technical, and its relative merits were being publicly debated in Congress weekly while the U.S. Navy continued to say the Norden was "the United States' most closely guarded secret". The RAF's desires were only further goaded on 13 April 1939, when Pirie
8556-563: Was part of Dahlgren Division, but in 2008, it became its own division within the NAVSEA Naval Surface Warfare Center structure. The physical base where NSWCDD is located became officially known as the Naval Support Activity Dahlgren (NSA Dahlgren) in 2003 when Naval Installations Command assumed all base operating functions, leaving NSWCDD as an installation tenant, however, the name NSWCDD or NSWC
8649-532: Was transferred to the Air Force in 2004. In 2006, the installation's name was changed to its current iteration of Naval Support Facility Dahlgren when Naval District Washington merged it and Naval Support Activity Indian Head under the combined command of Naval Support Activity South Potomac . The base is recognized by the Census Bureau as a census designated place (CDP), Dahlgren Center. Its population as of
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