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Drones-Unmanned Aerial Vehicle

 
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BerichtGeplaatst: 27 Mrt 2009 5:20    Onderwerp: Drones-Unmanned Aerial Vehicle Reageer met quote

Unmanned Aerial Vehicle, also known as a drone, an aircraft without a human operator on board. The largest modern unmanned aerial vehicles (UAVs) have a wingspan of more than 30 m (100 ft); the smallest UAVs can be carried in a backpack. UAVs originated during World War I (1914-1918), but modern UAVs were first developed in the 1970s.

Dayton Wright/Kettering Liberty Eagle ("Bug")

Other than the U.S. Navy, which became interested in using unmanned aeroplanes as "aerial torpedoes" as early as 1915 (see Sperry "Flying Bomb"), the U.S. Army was more reluctant to enter this field. However, this changed after an Army Major General watched a demonstration of a Curtiss N-9 flying several miles under automatic control in November 1917. Inventor Charles F. Kettering, member of a board which had been tasked with evaluating the possibilities of the "aerial torpedo" concept, argued in favour of building and testing a flying bomb design. With the help of others, Kettering designed such a machine, which was to be built by the Dayton Wright company. In January 1918, the Army ordered 25 examples of the aircraft. It was officially named the Liberty Eagle, but was generally referred to as the Kettering "Bug". The performance goal was to carry a 90 kg (200 lb) high-explosive payload over a distance of 80 km (50 miles).



The Kettering Bug was a small biplane of decidedly cheap construction. It used a wooden framework, which was covered with pasteboard on the fuselage and tail surfaces, and with doped paper and muslin on the wings. The wings had 10° of dihedral, which was intended to improve stability on take-off. Flight distance was measured by counting air-impeller revolutions, and when the preset distance was reached, the engine was cut, the wings detached, and the Bug fell to the ground. For testing purposes, a slightly larger manned version of the aircraft was flown a few times, beginning in July 1918. The unmanned Bug had no undercarriage, and was launched on a four-wheel dolly running on a track. The first flight attempt on 2 October failed, but a second try two days later was more successful. The Bug remained in the air for about 45 minutes, but did fly in large circles instead of the intended straight line. The flight was impressive enough to secure an order for 75 additional Bugs.

After the end of the war, the Army continued the experiments with the Kettering Bug, but the overall results were disappointing and the program was terminated in late 1919. Out of a total of 24 attempts at unmanned flights, only 7 could be considered at least partially successful. In the end, these early flying bombs failed because of the limited reliability of key components (engine and automatic pilot) as well as the incomplete knowlegde of aerodynamics at that time. The Army nevertheless continued experimenting with unmanned flight during the 1920s, using manned aircraft fitted with improved gyrostabilizers and radio-control systems.
Specifications

Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!

Data for Liberty Eagle (Kettering "Bug"):
Length 3.8 m (12 ft 6 in)
Wingspan 4.6 m (15 ft)
Weight 240 kg (530 lb)
Speed 185 km/h (115 mph)
Ceiling 3650 m (12000 ft)
Range > 100 km (60 miles)
Propulsion Wills/DePalma 4-cyl. piston engine; 27 kW (37 hp)
Payload 80 kg (180 lb) high-explosive
Main Sources

[1] Kenneth P.Werrell: "The Evolution of the Cruise Missile", Air University Press, 1985
[2] Laurence R. Newcome: "Unmanned Aviation: A Brief History of Unmanned Aerial Vehicles", AIAA, 2004
[3] Frederick I. Ordway III, Ronald C. Wakeford: "International Missile and Spacecraft Guide", McGraw-Hill, 1960
[4] Bill Gunston: "The Illustrated Encyclopedia of Rockets and Missiles", Salamander Books Ltd, 1979

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Laatst aangepast door Yvonne op 02 Apr 2013 10:12, in toaal 2 keer bewerkt
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BerichtGeplaatst: 27 Mrt 2009 5:23    Onderwerp: Reageer met quote

Curtiss/Sperry "Flying Bomb"

The Curtiss/Sperry "Flying Bomb" was the first of two American efforts during the First World War to develop what would today be called a cruise missile. The other was the Dayton Wright Liberty Eagle, better known as the Kettering "Bug".

Between 1909 and 1914, Elmer Ambrose Sperry developed a gyrostabilizer, which could keep aeroplanes flying straight and level without pilot intervention. In 1915, Sperry was approached by the U.S. Navy to use his gyrostabilizer to build a pilotless aircraft to be used as a flying bomb. The device was frequently called an "aerial torpedo" at that time, but contemporary official Navy reports appear to prefer the name "Flying Bomb".

The "Flying Bomb" was to fly in a straight line to a preset distance (measured in flight by a "distance gear", which counted engine revolutions), and then automatically dive to the ground. The principle was first demonstrated successfully in September 1916 with a manned aircraft. An on-board pilot handled take-off and landing, but didn't touch the controls during the automatic portion of the flight. In May 1917, the Navy ordered five Curtiss N-9 seaplanes to be modified for systematic manned trials of the "Flying Bomb" technology. Flight tests began in September, and were generally successful. The accuracy was about 3.2 km (2 miles) after a distance of 50 km (30 miles). This was apparently regarded as good enough, because the Navy subsequently ordered six examples of a purpose-built "Flying Bomb" airframe from Curtiss. The device was to have a range of 80 km (50 miles) at 145 km/h (90 mph) with an explosive payload of 450 kg (1000 lb).

]

The "Flying Bomb" (which had no other name or designation) was launched from a catapult, but on the initial three attempts in November/December 1917 the device failed to get airborne at all. On the next two flights in January 1918, the "Flying Bomb" crashed very shortly after take-off. To find out more about the stability problems at lift-off and in flight, Lawrence Sperry (Elmer's son) flew the aircraft twice in February (crashing on the second flight). As a result, several modifications were made, including lengthening the fuselage by 60 cm (2 ft). Further stability and control tests without risking to wreck the airframe were made by mounting it on top of a car and driving down a straight highway. Finally, on 6 March, an unmanned "Flying Bomb" flew successfully over the planned distance of 900 m (1000 yds). This was the first ever successful flight of a powered unmanned heavier-than-air craft in history.


Unfortunately, this remained the only success for the "Flying Bomb", and by the end of September all "Flying Bomb" airframes had been expended in crashes. The last flights had used a new type of catapult, which had also uncovered further structural and stability deficiencies in the "Flying Bomb" airframe. Tests then continued with the N-9 aircraft, and in October one of these possibly set a distance record when the distance mechanism (set at 12800 m (14000 yds)) failed and the aircraft flew on over the sea and disappeared.

After the war had ended, the Navy nevertheless decided to continue the flying bomb experiments, and ordered five examples of a new airframe design from Witteman-Lewis. It first flew in March 1919. However, tests with this aircraft, and another flying bomb built by the Naval Aircraft Factory, were not really successful, and the whole program was terminated in 1922. The U.S. Navy did not re-enter the field of unmanned aircraft in earnest until the mid-1930s, when several manned aircraft of different types were converted to radio-controlled drones. These experiments eventually lead to the TDR and TDN "assault drones" of World War II.
Specifications

Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!

Data for Curtiss/Sperry "Flying Bomb":
Length 4.6 m (15 ft)
Wingspan 7.6 m (25 ft)
Weight 680 kg (1500 lb)
Speed 145 km/h (90 mph)
Range 80 km (50 miles)
Propulsion Curtiss OX-5 piston engine; 74 kW (100 hp)
Payload 450 kg (1000 lb) high-explosive
Main Sources

[1] Kenneth P.Werrell: "The Evolution of the Cruise Missile", Air University Press, 1985
[2] Laurence R. Newcome: "Unmanned Aviation: A Brief History of Unmanned Aerial Vehicles", AIAA, 2004

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BerichtGeplaatst: 02 Apr 2013 10:11    Onderwerp: Reageer met quote

Unmanned Drones Have Been Around Since World War I

Quote:
Recently, the United States’ use of unmanned aerial vehicles (UAVs) has been the subject of much debate and scrutiny. But their history dates back a lot further than the war on terror. The first true UAVs, which are technically defined by their capability to return successfully after a mission, were developed in the late 1950s, but the American military actually began designing and developing unmanned aircraft during the first World War.

This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported

Military aviation was born during the years preceding the World War I, but once the war began, the industry exploded. Barely more than a decade after Orville and Wilbur Wright successfully completed the first documented flight in history –achieving only 12 seconds of air time and traveling 120 feet– hundreds of different airplanes could be seen dogfighting the skies above Europe. Mastering the sky had changed the face of war. Perhaps due to their distance from the fighting, the United States trailed behind Europe in producing military fliers but by the end of the War, the U.S. Army and Navy had designed and built an entirely new type of aircraft: a plane that didn’t require a pilot.

The first functioning unmanned aerial vehicle was developed in 1918 as a secret project supervised by Orville Wright and Charles F. Kettering. Kettering was an electrical engineer and founder of the Dayton Engineering Laboratories Company, known as Delco, which pioneered electric ignition systems for automobiles and was soon bought out by General Motors. At GM, Kettering continued to invent and develop improvements to the automobile, as well as portable lighting systems, refrigeration coolants, and he even experimented with harnessing solar energy. When the U.S. entered World War I, his engineering prowess was applied to the war effort and, under Kettering’s direction, the government developed the world’s first “self-flying aerial torpedo,” which eventually came to be known as the “Kettering Bug”.

this image is in the public domain.

The bug was a simple, cheaply made 12-foot-long wooden biplane with a wingspan of nearly 15 feet that, according to the National Museum of the U.S. Air Force, weighed just 530 pounds, including a 180 pound bomb. It was powered by a four-cylinder, 40-horsepower engine manufactured by Ford. Kettering believed that his Bugs could be calibrated for precision attacks against fortified enemy defenses up to 75 miles away – a much greater distance than could be reached by any field artillery. The accuracy of this early “drone” was the result of an ingenious and surprisingly simple mechanism: after determining wind speed, direction, and desired distance, operators calculated the number of engine revolutions needed to take the Bug to its target; the Bug was launched from a dolly that rolled along a track, much like the original Wright flier (today, smaller drones are still launched from a slingshot-like rail), and, after the proper number of revolutions, a cam dropped into place and released the wings from the payload-carrying fuselage – which simply fell onto the target. To be sure, it wasn’t an exact science, but some would argue that drones still aren’t an exact science.

The Dayton-Wright Airplane Company built fewer than 50 Bugs but the war ended before any could be used in battle. That might be for the best. Much like today, there was a lot of doubt about the reliability and predictability of the unmanned aircraft and the military expressed concern about possibly endangering friendly troops. After the war, research into unmanned aircraft continued for a short time, but development halted in the 1920s due to the scarcity of funding and research on UAVs wasn’t seriously picked up again until the outbreak of World War II. Although by today’s standards, the Kettering Bug has more in common with a guided missile than a drone, its conception as a pilotless plane represents an important step in the historical development of unmanned aerial vehicles.



Read more: http://blogs.smithsonianmag.com/design/2013/02/unmanned-drones-have-been-around-since-world-war-i/#ixzz2PILya8LA
Follow us: @SmithsonianMag on Twitter

Meer info:
http://www.army.mil/aviation/
http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=320
http://airandspace.si.edu/collections/artifact.cfm?id=A19610048000
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