Miniature UAVs
Encyclopedia
A miniature UAV or Small UAV (SUAV), is an unmanned aerial vehicle
Unmanned aerial vehicle
An unmanned aerial vehicle , also known as a unmanned aircraft system , remotely piloted aircraft or unmanned aircraft, is a machine which functions either by the remote control of a navigator or pilot or autonomously, that is, as a self-directing entity...

 small enough to be man-portable.

Miniature UAVs range from micro air vehicle
Micro air vehicle
A micro air vehicle , or micro aerial vehicle , is a class of unmanned aerial vehicles that has a size restriction and may be autonomous. Modern craft can be as small as 15 centimetres...

s (MAVs) that can be carried by an infantryman, to man-portable UAVs that can be carried and launched like an infantry anti-aircraft missile
Surface-to-air missile
A surface-to-air missile or ground-to-air missile is a missile designed to be launched from the ground to destroy aircraft or other missiles...

.

MAVs & mesicopters

The notion that small, even very small, UAVs might have practical uses arose in the early 1990s. In 1992, DARPA
Defense Advanced Research Projects Agency
The Defense Advanced Research Projects Agency is an agency of the United States Department of Defense responsible for the development of new technology for use by the military...

 conducted a workshop titled "Future Technology-Driven Revolutions In Military Operations". One of the topics in the workshop was "mobile microrobots". The idea of using very small "microdrones" was discussed, and after initial skepticism the idea started to gain momentum.

The RAND
RAND
RAND Corporation is a nonprofit global policy think tank first formed to offer research and analysis to the United States armed forces by Douglas Aircraft Company. It is currently financed by the U.S. government and private endowment, corporations including the healthcare industry, universities...

 Corporation released a paper on the microdrone concept in 1994 that was widely circulated. DARPA conducted a series of "paper studies" and workshops on the concept in 1995 and 1996, leading to early engineering studies by the Lincoln Laboratories at the Massachusetts Institute of Technology
Massachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...

 (MIT), and the U.S. Naval Research Laboratory (NRL) in Washington DC.

The studies demonstrated that the concept was feasible. In 1997, DARPA then began a multi-year, $35 million USD development program to develop "micro air vehicle
Micro air vehicle
A micro air vehicle , or micro aerial vehicle , is a class of unmanned aerial vehicles that has a size restriction and may be autonomous. Modern craft can be as small as 15 centimetres...

s (MAVs)". The MAV project's goals was to develop a microdrone whose largest dimension was no more than 15 centimeters (6 inches); would carry a day-night imager; have an endurance of about two hours; and be very low cost. It would operate with a high degree of autonomy to be used in the squad-level combat environment. MAVs capable of hovering and vertical flight would be used to scout out buildings for urban combat and counter terrorist operations. A MAV could be included in a pilot's survival kit
Survival kit
A survival kit is a package of basic tools and supplies prepared in advance as an aid to survival in an emergency. Military aircraft, lifeboats, and spacecraft are equipped with survival kits....

. A downed pilot could use it to keep track of enemy search parties, or relay communications to search and rescue
Search and rescue
Search and rescue is the search for and provision of aid to people who are in distress or imminent danger.The general field of search and rescue includes many specialty sub-fields, mostly based upon terrain considerations...

 units.

Phase-two MAVs

This phase-one DARPA study ended in 2001, and was followed by a phase-two study that focused on particular vendors with an intent to develop MAVs closer to operational specification. A number of different MAVs were developed as part of these DARPA efforts:

Lockheed Sanders "Microstar"
The Lockheed Sanders MicroSTAR series of prototypes. The battery-operated MicroSTAR designs resembled kid's toys. An initial design had a fat teardrop body with stubby cropped-delta wings running along most of the body, along with a single vertical tailplane and a pusher propeller
Pusher configuration
In a craft with a pusher configuration the propeller are mounted behind their respective engine. According to Bill Gunston, a "pusher propeller" is one mounted behind engine so that drive shaft is in compression...

. A later version had winglets instead of the single vertical tailplane, and a nose mounted propeller
Propeller (aircraft)
Aircraft propellers or airscrews convert rotary motion from piston engines or turboprops to provide propulsive force. They may be fixed or variable pitch. Early aircraft propellers were carved by hand from solid or laminated wood with later propellers being constructed from metal...

. The MicroSTAR featured a five-gram navigation system that could be given directions by the ground station, but could also automatically keep on a heading or orbit a target.


CIT, AeroVironment and UCLA "MicroBat" ornithopter
The MicroBat ornithopter
Ornithopter
An ornithopter is an aircraft that flies by flapping its wings. Designers seek to imitate the flapping-wing flight of birds, bats, and insects. Though machines may differ in form, they are usually built on the same scale as these flying creatures. Manned ornithopters have also been built, and some...

 from the California Institute of Technology
California Institute of Technology
The California Institute of Technology is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering...

 (Caltech), working with AeroVironment
AeroVironment
AeroVironment Inc. is a technology company in Monrovia, California, and Simi Valley, California, that is primarily involved in energy systems, electric vehicle systems, and unmanned aerial vehicles . Paul B. MacCready, Jr., a famous designer of human powered aircraft, founded the company in 1971...

 and the University of California, Los Angeles
University of California, Los Angeles
The University of California, Los Angeles is a public research university located in the Westwood neighborhood of Los Angeles, California, USA. It was founded in 1919 as the "Southern Branch" of the University of California and is the second oldest of the ten campuses...

. The ornithopter design concept followed experiments conducted in the mid-1990s by Charles Ellington, a zoologist at the University of Cambridge, and his colleagues, in which mechanical analogues of insect wings were tested in a wind tunnel. The group was only interested in studying the biomechanics of insects and was extremely surprised that somebody seemed interested in them. The CalTech / AeroVironment MicroBat ornithopter was test-flown for short distances under battery power. Researchers performing flight tests with the MicroBat said it tended to attract small birds when it ran low on power and fell to the ground. The birds clustered near the floundering ornithopter in what seemed to be a desire to help.

Other research groups also worked on ornithopters. A Georgia Tech Research Institute
Georgia Tech Research Institute
The Georgia Tech Research Institute is the nonprofit applied research arm of the Georgia Institute of Technology in Atlanta, Georgia, United States...

 group built a rubber-band powered entomopter
Entomopter
The Entomopter is a multimode insect-like robot developed by Prof. Robert C. Michelson and his design team from the Georgia Tech Research Institute , University of Cambridge , ETS Labs and others. The name 'Entomopter' is derived from entomo + pteron...

 and also did research on a chemically powered Reciprocating Chemical Muscle
Reciprocating Chemical Muscle
The Reciprocating Chemical Muscle is a mechanism that takes advantage of the superior energy density of chemical reactions. It is a regenerative device that converts chemical energy into motion through a direct noncombustive chemical reaction.-Function:...

 propulsion system.


Lutronix Corporation "Kolibri" micro-helicopter
The Kolibri micro-helicopter built by Lutronix Corporation of Del Mar, California. The Kolibri (German for "Hummingbird") was larger than the other DARPA MAV prototypes, with a weight of about 300 grams. The Kolibri was built as a cylinder with rotors at one or both ends, using vanes moved through the rotor airflow by piezoelectric actuators for flight control. It was powered by electric motors or a tiny, highly efficient multi-fuel engine developed by a company named D-STAR.


Micro Craft "SLADF" ducted fan micro-helicopter
The Small Lift Augmented Ducted Fan (SLADF) ducted-fan micro-helicopter, built by Micro Craft of San Diego, California, and Ontario, Canada. The SLADF was a ducted fan
Ducted fan
A ducted fan is a propulsion arrangement whereby a fan, which is a type of propeller, is mounted within a cylindrical shroud or duct. The duct reduces losses in thrust from the tip vortices of the fan, and varying the cross-section of the duct allows the designer to advantageously affect the...

 helicopter
Helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...

 with a diameter of about 15 centimeters (6 inches) and a weight of 1.8 kilograms (4 pounds), with payload. Interestingly, the SLADF did not appear to use a contra-rotating rotor design, using a single rotor with aerodynamic deflection surfaces inside the duct to cancel torque. First flight test of the SLADF was in late 2000. The SLADF could be fitted with an optional wing to provide useful lift to increase loiter time, and also provided additional fuel storage.


AeroVironment "Black Widow" flying-wing
The AeroVironment Black Widow MAV. Developed by a team led by Matt Keenon, the Black Widow was powered by electric motor driving a small propeller in the nose, with a lithium battery permitting about 20 minutes of flight. It carried an off-the-shelf camera chip giving it a color video resolution of 510 by 492 pixels. While the first Black Widow prototype was a flat disk with a single vertical stabilizer
Vertical stabilizer
The vertical stabilizers, vertical stabilisers, or fins, of aircraft, missiles or bombs are typically found on the aft end of the fuselage or body, and are intended to reduce aerodynamic side slip. It is analogical to a skeg on boats and ships.On aircraft, vertical stabilizers generally point upwards...

 and a propeller in the front, it was followed by an improved Black Widow that looked a little like a thin portable CD player with tapered edges and cut-off corners; a propeller in front; and three fins on the back. It did not have autonomous navigation capabilities, and was controlled essentially like a hobbyist's RC airplane.

Subsystems design

Along with the flight prototypes, the DARPA effort considered subsystems design. A useful operational MAV would need a lightweight, highly efficient engine with a power source with high energy density. Electric motors were becoming available that met the requirement, but power sources were more troublesome. Lithium batteries were marginal. New compact fuel cells were in development but weren't expected to be available for several years.

One particularly intriguing option for both propulsion and power was a button-sized silicon microturbine ("jet") engine developed by Dr. Al Epstein at MIT during the 1990s. Silicon was actually a good structural material at such scales, though increasing operating temperature
Operating temperature
An operating temperature is the temperature at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the device function and application context, and ranges from the minimum operating temperature to the...

 would have dictated use of silicon carbide.

A production device was envisioned as a centrifugal-flow engine about two centimeters across burning natural gas, with a single turbine disk for compression and a single disk for exhaust rotation. The design didn't look much like a conventional turbojet, resembling more a tiny flat cylindrical box with an inlet hole on one side and an exhaust hole on the other. It was expected to have a thrust-to-weight ratio of about 100—incredible compared to any "macroscale" engine but a logical consequence of scaling the technology down in size—and run at about 1.2 million RPM, making bearings a tricky issue. Since it could "spool up" in about a millisecond, it was envisioned as operating in a pulsed mode to conserve fuel and also provide a throttling scheme. A functioning gas turbine was never successfully implemented at this scale after years of development.

Other tricky issues were control systems, since an MAV couldn't be flown like a model airplane and would have to be able to tolerate turbulence and wind gusts, and miniaturizing navigation, communications, and sensor systems, as well as ensuring that they didn't interfere with each other. DARPA specified that the payload would be no more than 15 grams.

Stanford "Mesicopter"

As extreme as MAV specifications were, a team under Ilan Kroo at Stanford University
Stanford University
The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...

 worked on an even more extreme design in the form of a centimeter-wide four-rotor mesicopter using microcircuit fabrication techniques. The work was funded by NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

. Design of such a small aircraft was constrained by the fact that at such scales, the air becomes a highly viscous medium, or in aerodynamic terms a mesicopter had a low Reynolds number. Basic aerodynamics of the mesicopter were defined by a cycle of computer simulation, followed by tests of model components. The research led to mesicopter rotor designs where the rotor looked much more like the blades of an ordinary room fan than the rotor of a conventional helicopter. Propeller designs did not achieve desired efficiency and the Mesicopter was never able to lift the weight of its own energy source.

MAVs rethought

The DARPA MAV effort ended in 2000 and the results of the effort were somewhat negative, demonstrating that a 15 centimeter UAV was simply too small to be useful or even workable, at least over the short run. However, though the size was unrealistic, the basic concept seemed valid even if a larger machine were needed.

DARPA did begin a follow-on effort in the spring of 2002, working with the US Army on a larger ducted fan vehicle as a follow-on to SLADF under the "Organic Air Vehicle (OAV)" program. Allied Aerospace, which had bought out Micro Craft, demonstrated a scaled-up SLADF, while Honeywell performed tests with their own ducted-fan vehicle, named iSTAR. However, neither vehicle seemed particularly promising and the program was cut short.

It was revived as OAV-2 in 2004, with DARPA specifying a diesel
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...

-powered ducted-fan vertical-takeoff UAV with a weight of 51 kilograms (112 pounds), including a payload of 10 kilograms; a range of 10 kilometres (6.2 mi); a top speed of 92 km/h (50 knots); the ability to hover in a 37 km/h (20 knots) wind; an endurance of two hours; and a ceiling of 3,350 meters (11,000 ft).

The OAV was to be carried, launched, and recovered on a Humvee, using a crew of two soldiers, who would be able to get it flying in five minutes. Its sensor systems will be able to provide targeting data to within 10 meters (33 feet) to support non-line-of-sight weapons. The UAV would have autonomous flight capabilities with the ability to maneuver in cluttered terrain using an all-weather obstacle-avoidance system, and DARPA wanted it to have the ability to land and conduct observations from its landing site. Other possibilities were use of the UAV for communications relay, SIGINT, countermeasures, or even armed attack. The Army was interested in the program, but its current status is uncertain. It may have disappeared again; and if so it may reappear once more.

Black Widow "Wasp" and "Hornet"

AeroVironment has also worked on follow-ons to its Black Widow, named the Wasp and the Hornet. The Wasp is a flying wing
Flying wing
A flying wing is a tailless fixed-wing aircraft which has no definite fuselage, with most of the crew, payload and equipment being housed inside the main wing structure....

, with the wing in the form of a rectangle with a slightly swept leading edge. It is propeller driven, with the propeller in front. The Wasp's main improvement over the Black Widow is that the lithium-ion battery and wing structures are one and the same, allowing maximum battery capacity relative to MAV size. The Wasp has a wingspan of 33 centimeters (13 inches) and a weight of 210 grams (6 ounces). Like the Black Widow, the Wasp is radio controlled.

In the spring of 2003, AeroVironment performed the first flight of the Hornet, which is similar to the Wasp but has a straight rectangular wing with a slightly greater span of 38 centimeters (15 inches) and, more significantly, is powered by fuel cell
Fuel cell
A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...

s. The fuel cells are built into the top of the wing, where they combine oxygen in the ambient air with hydrogen produced internally by the MAV through reaction of a hydride material with water.

The fuel cell system is expected to provide three times the endurance of batteries of comparable weight, though early flights were limited by the tendency of the fuel cells to dry out. DARPA is actually more interested in the battery powered Wasp, but other interested parties in the US defense establishment, particularly the NRL, are very intrigued by fuel cells, and so DARPA is hedging its bets. Ultimately, AeroVironment engineers want to fit their MAVs with an autopilot and a color video camera.

French "Mirador"

The French have done work along similar lines, with the French defence procurement agency (DGA
Délégation Générale pour l'Armement
The Direction générale de l’armement, which could be translated as “General Directorate for Armament”, or DGA, is the French Government Defence procurement agency responsible for the program management, development and purchase of weapon systems for the French military.-Armament programs...

 in its French acronym) sponsoring a flight demonstrator, the Mirador. It was a fixed-wing, propeller-driven aircraft 25 centimeters (9.84 inches) long and was powered by miniature fuel cells that gave it an endurance of about 20 minutes. It was built by the French defense aerospace research agency ONERA
Office National d'Etudes et de Recherches Aerospatiales
Office National d'Études et de Recherches Aérospatiales or Onera is the French aerospace research center. It is a public establishment with industrial and commercial operations, and carries out application-oriented research to support enhanced innovation and competitiveness in the aerospace and...

, working with the Royal Military Academy of Brussels, and is primarily intended to be a testbed for miniature sensor technologies.

The DGA envisions an operational MAV as about 40 centimeters (16 inches) long, with a weight of less than 1.5 kilograms (3.3 pounds), an endurance of 15 minutes or more, a ceiling of 100 meters (330 feet) and an operating radius of a kilometer (0.6 mile). For the moment, the concept seems strictly experimental.

Future smaller MAVs

The notion of bird-sized or even insect-sized MAVs has not disappeared, it is just that it is now seen as a project for a future generation. The DARPA effort did get a lot of people thinking about tiny aircraft. MAVs have attracted a hobbyist and amateur community, somewhat along the lines of the "robot war" competitions that make it onto TV, and yearly competitive events have been conducted. These home-built MAVs are of course relatively unsophisticated, but have demonstrated a great deal of ingenuity. It is possible that in the near future someone will develop an idea that will catch on.

Recent research (as of 2005) includes a model utilizing ground effect
Ground effect
As it pertains to fixed wing aircraft, "ground effect" refers to the increased lift and decreased drag that an aircraft airfoil or wing generates when an aircraft is about one wingspan's length or less over the ground...

 at NPS
Naval Postgraduate School
The Naval Postgraduate School is an accredited research university operated by the United States Navy. Located in Monterey, California, it grants master's degrees, Engineer's degrees and doctoral degrees...

(http://www.aa.nps.navy.mil/~jones/), DelFly at TUDelft
Delft University of Technology
Delft University of Technology , also known as TU Delft, is the largest and oldest Dutch public technical university, located in Delft, Netherlands...

 and Wageningen University
Wageningen University
Wageningen University and Research Centre is a Dutch public university in Wageningen, The Netherlands. It consists of Wageningen University, the Van Hall-Larenstein School of Higher Professional Education, and the former agricultural research institutes of the Dutch Ministry of Agriculture...

, etc. Some also consider using a Reciprocating Chemical Muscle
Reciprocating Chemical Muscle
The Reciprocating Chemical Muscle is a mechanism that takes advantage of the superior energy density of chemical reactions. It is a regenerative device that converts chemical energy into motion through a direct noncombustive chemical reaction.-Function:...

 for actuating flapping wing MAVs such as the Entomopter
Entomopter
The Entomopter is a multimode insect-like robot developed by Prof. Robert C. Michelson and his design team from the Georgia Tech Research Institute , University of Cambridge , ETS Labs and others. The name 'Entomopter' is derived from entomo + pteron...

 pioneered by Prof. Robert C. Michelson
Robert C. Michelson
Robert C. Michelson is an American engineer and academic widely known for inventing the entomopter, a biologically inspired flapping-winged aerial robot, and for having established the International Aerial Robotics Competition. He has received degrees in electrical engineering from the Virginia...

 at the Georgia Tech Research Institute
Georgia Tech Research Institute
The Georgia Tech Research Institute is the nonprofit applied research arm of the Georgia Institute of Technology in Atlanta, Georgia, United States...

.

MIT "WASP"

The US Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...

 has been interested in developing MAVs that could be deployed as munitions, fired from artillery or unguided rocket launcher pods. A research team at the Massachusetts Institute of Technology (MIT) has developed a prototype artillery-launched UAV. The UAV, named the Wide Area Surveillance Projectile (WASP), no relation to the AeroVironment Wasp, is fired out of a 127 millimeter (5 inch) naval gun.

The MIT group modified a standard illumination flare round to serve as the external case. After firing, the shell popped out six fins to keep it from tumbling. Once the shell was 20 kilometres (12.4 mi) downrange, a parachute popped out of the tail to extract the drone. The parachute slowed the drone, which then unfolded into flight configuration. The WASP had a folding vee tail, a folding two-blade propeller up front, and two straight folding wings. The wings were folded into six sections and unfolded into a total span of 94.5 centimeters (3.1 feet). Once unfolded, the right wing was higher on the fuselage than the left, a result of the packaging scheme.

The WASP drone had a flight endurance of fifteen minutes, including ten minutes of powered flight and five minutes of glide. It had a tiny camera in its lower fuselage, and relayed both imagery and its own current GPS
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...

 coordinates back to the warship or artillery battery that fired it. At least two WASP prototypes were built and tested. After initial announcements of the effort, the whole thing went quiet, but it certainly remains an interesting possibility.

"Wing-store UAV" and Raytheon "SilentEyes"

The Army has also worked on a UAV that can be launched out of a 70 millimeter (2.75 inch) unguided rocket pod mounted on a helicopter and could also be carried by larger UAVs. This wing-store UAV is 1.8 meters (6 ft) long, and is fired out of the launch tube with a solid-rocket booster. It then deploys wings, tail, and propeller, and cruises for up to two hours on electric power at a speed of 185 km/h (100 knots). It can carry a small daylight or infrared camera.

Details of the wing-store UAV are unclear, but it may have some resemblance to the Raytheon
Raytheon
Raytheon Company is a major American defense contractor and industrial corporation with core manufacturing concentrations in weapons and military and commercial electronics. It was previously involved in corporate and special-mission aircraft until early 2007...

 SilentEyes UAV. SilentEyes looks like a simple metal cylinder with a rounded cap, straight folding wings mounted in the middle of the UAV and with a noticeable dihedral, and a folding inverted-vee tail. The UAV is 46 centimeters (18 inches) long and less than 7 centimeters (2.75 inches) in diameter.

Raytheon calls SilentEyes a "parasite" UAV, as it would be dispensed from a larger UAV, like a Predator
RQ-1 Predator
The General Atomics MQ-1 Predator is an unmanned aerial vehicle used primarily by the United States Air Force and Central Intelligence Agency...

; a gliding submunitions dispenser; or a cruise missile
Cruise missile
A cruise missile is a guided missile that carries an explosive payload and is propelled, usually by a jet engine, towards a land-based or sea-based target. Cruise missiles are designed to deliver a large warhead over long distances with high accuracy...

. The baseline version of the SilentEyes would be strictly a glider
Glider aircraft
Glider aircraft are heavier-than-air craft that are supported in flight by the dynamic reaction of the air against their lifting surfaces, and whose free flight does not depend on an engine. Mostly these types of aircraft are intended for routine operation without engines, though engine failure can...

, but its glide ratio of 11:1 would allow it to stay in the air for a half hour if released from typical Predator operational altitudes. It would be used for close-up examination of targets spotted by SAR to ensure that they are valid targets, or for post-strike target damage assessment.

The little UAV can carry a gimbaled infrared or color TV camera, with the video compressed for transmission by a UHF communications link over line-of-sight ranges. It could also carry a jammer payload, or a small warhead. Since multiple SilentEyes would be deployed at the same time, each could be assigned a different code or "telephone number" to minimize confusion in communications.

Raytheon is shooting for a target price of about $5,000 to $10,000 USD. The company is considering a powered version of SilentEyes with a microjet engine, as well as "stretched" versions of the UAV.

Italian "MALP"

Galileo Avionica of Italy is currently working on their own "parasite" UAV, called simply the Miniature Air Launched Payload (MALP), to be carried on a Falco or similar UAV. The MALP has large cruciform tailfins, small cruciform nosefins, and "switchblade" wings stowed back along the fuselage that pop out straight when the UAV is released. It is intended to carry imaging or other sensors to probe dangerous targets.

Man-portable UAVs

There is actually a great deal of activity in the small UAV field, with a number of systems now being acquired and some being used in combat.

AeroVironment "Pointer" and "Raven"

In 1999, the US Army bought four AeroVironment Pointer small UAVs for testing in the service's "Military Operations In Urban Terrain" and was enthusiastic about the usefulness of the Pointer. The Pointer system is too large to be conveniently carried by soldiers and is normally hauled around in a Hummer vehicle or the like, and so the Army asked AeroVironment if the company could come up with a more portable solution. AeroVironment agreeably developed a half-sized control system and a cut-down version of the Pointer called the RQ-11 Raven (no relationship to the Flight Refueling Raven).

The Raven has the same configuration and central pod of the Pointer, but a shorter tail and a wing reduced to a 52% span of 1.34 meters (4 feet 5 inches). The Raven has an endurance of 90 minutes on rechargeable batteries. A 4-mission loadout can be carried by a single soldier along with all of his other standard battle gear. Following the Afghanistan campaign in 2001-2002, the US SOCOM ordered 80 Ravens from AeroVironment, which was more than the total number of Pointers that had been sold to that time. The US Army also placed orders for up to 105 Ravens in the late summer of 2003 after the US occupation of Iraq led to persistent insurgent attacks on US forces. Since then, the RQ-11B Raven B has become the official standard SUAS (Small Unmanned Aircraft System) for USSOCOM, US Army, US Marines, and several international countries. As of early 2008, over 8000 Raven airframes have been shipped to customers worldwide. Ravens have been operational in combat in Afghanistan, Iraq, and other undisclosed locations.

Encouraged by such successes, AeroVironment is also working on a newer version of the Pointer, named the "Puma", with greater endurance and payload. In addition, they have disclosed that they are in late development of a small lethal UAV.

AeroVironment "Switchblade"

In September 2011 it was reported that the US Army had signed a contract with AeroVironment for the supply of the Switchblade miniature drone. Switchblade is the first tactical armed drone for use by a soldier as part of their backpack kit and weighs around 2.5kg.

The mini-drone has a small warhead and is launched from a 60cm long container/launcher tube. As it launches its small wings unfold and can be guided to its target via a nose-mounted camera. The operator looks through a viewer that displays video from the drone. Switchblade can also be directed to co-ordinates using Global Positioning System (GPS). Powered by an electric motor it can reach speeds up to 80km/h and loiter for up to 40 minutes.

Lockheed Martin "Desert Hawk"

US forces are also using another mini-UAV in Iraq, the Lockheed Martin
Lockheed Martin
Lockheed Martin is an American global aerospace, defense, security, and advanced technology company with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta in March 1995. It is headquartered in Bethesda, Maryland, in the Washington Metropolitan Area....

 Desert Hawk. It weighs 3.2 kilograms (7 pounds), has a wingspan of 1.32 meters (52 inches) and a length of 86.4 centimeters (34 inches). It is made mostly of plastic foam, suggesting something like a Nerf toy, and uses an electric motor driving a pusher propeller as a powerplant, making it very quiet. It is launched with a bungee cord, carries three small CCD
Charge-coupled device
A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...

 cameras, has an endurance of about an hour. It flies mostly under autonomous control, with the "pilot" keeping track of what's going on with a laptop computer.

The Desert Hawk was designed by Lockheed Martin
Lockheed Martin
Lockheed Martin is an American global aerospace, defense, security, and advanced technology company with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta in March 1995. It is headquartered in Bethesda, Maryland, in the Washington Metropolitan Area....

's Skunk Works
Skunk works
Skunk Works is an official alias for Lockheed Martin’s Advanced Development Programs , formerly called Lockheed Advanced Development Projects. Skunk Works is responsible for a number of famous aircraft designs, including the U-2, the SR-71 Blackbird, the F-117 Nighthawk, and the F-22 Raptor...

 for the Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...

 FPASS (Force Protection Airborne Surveillance System
Force Protection Airborne Surveillance System
The Desert Hawk is a small unmanned aerial vehicle used for base perimeter protection.It was designed by Lockheed Martin's Skunk Works for the Air Force FPASS Program on a quick-reaction contract issued late in the winter of 2002, with the first system delivered in the early summer...

) Program on a quick-reaction contract issued late in the winter of 2002, with the first system delivered in the early summer. It was designed quickly because it leveraged heavily off of technology and design studies developed for the MicroStar MAVs.

However, in 2007, the US Air Force FPASS office switched all of their UAV systems over to the RQ-11 Raven B (http://www.af.mil/news/story.asp?id=123071292). Desert Hawk did make the short-list for the recent Netherlands Army Mini-UAV program, but ultimately lost to the RQ-11B Raven B (http://www.avinc.com/pr_detail.asp?ID=75). The only military forces still using Desert Hawk are the UK Army.

NRL "Dragon Eye", "Swallow" and "Finder"

The U.S. Naval Research Laboratory (NRL) has developed a man-portable UAV of roughly the same size as the AeroVironment Raven, named the RQ-14 Dragon Eye (no relationship to the BAI Aerosystems Dragon). The Dragon Eye is a tailless design with a rectangular wing and twin props. It is designed to fit into a backpack, with a weight of 2.25 kilograms (5 pounds) and a span of 1.14 meters (3 feet 9 inches). It can be lanched by hand or bungee slingshot and has a GPS-INS-based waypoint navigation system.

One of the interesting features is that the operator monitors Dragon Eye operation through "video goggles" connected to a laptop computer. The control system weighs about 5.4 kilograms (12 pounds). The Dragon Eye's endurance is an hour. The production contract for Dragon Eye was awarded to AeroVironment in 2003, and over 1000 aircraft were built before the Marines switched over to the RQ-11B Raven B for the remainder of the Dragon Eye production contract.

The NRL has also built at least two other small UAVs. The Swallow is of more conventional configuration than the Dragon Eye, roughly comparable to the AeroVironment Pointer, with long sailplane wings and a tail-mounted propeller. Details are unclear, but it has been used in NRL experiments to develop anti-sniper sensors for base security applications.

The Finder (Flight Inserted Detector Expandable for Reconnaissance), with a weight of 26 kilograms (57 pounds), can carry a small imager, or an atmospheric sampling sensor to check for radiological / chemical / biological contaminants
Pollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...

, and other sensor payloads are being considered. Other details of the Finder are unclear.

The Finder has been evaluated as a payload for the Predator UAV, with one Finder carried under each wing, acting as a parasite UAV like the Raytheon SilentEyes. Initial flight tests of the Finder with the Predator were performed in the summer of 2002.

Turkish Baykar MiniUAV

Baykar Machine Inc.'s (Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...

) Bayraktar Mini UAV
Bayraktar Mini UAV
The Bayraktar Mini UAV is an unmanned aerial vehicle produced by Turkey's Baykar Makine. The system is designed for aerial reconnaissance and surveillance activities to serve Turkish Land Forces' small units and is currently operational on the field.-Overview:...

 system with 1.2m length and 1.6 m wing span body, currently still in development, can be hand launched and land on its body or through a parachute deployment. The inverse Vtail, fixed wing platform has 5 kg maximum take off weight, can reach up to a 95 km/hour airspeed and has a flight envelope of 10000 feet. Integrated with its own avionics and payload systems, it has an endurance of 1-1.5 hour.

Russian UAV ZALA 421-08 and ZALA 421-12

ZALA 421-08
ZALA 421-08
ZALA 421-08 is a micro unmanned aerial vehicle developed and produced by the Izhevsk-based ZALA Aero company. It is a small, portable and reliable UAV platform. Weighing only 9 kg it includes 2 aerial vehicles, compact ground control station, 2 spare power supply kits and backpack container...

 developed by A-Level Aerosystems, Izhevsk, Russia is a flying wing UAV featuring a weight of 1.7 kg and a wing span of mere 0.8 m. The payload consists of color forward-looking and side-looking cameras. The plug-in cameras module can be easily replaced with the infrared camera. Its range is 15 km, maximum flight duration is 90 minutes. ZALA 421-08 is powered by an electric motor. The UAV is launched by hand and landed on a 30×100m ground using parachute. Small sizes make it indispensable in urban areas and busy air spaces.
Being operated by all power ministries of Russia, ZALA 421-08 has proved itself as an extremely useful surveillance tool when capturing the terrorists and smugglers.

ZALA 421-12
ZALA 421-12
ZALA 421-12 is a micro unmanned aerial vehicle developed and produced by the Izhevsk-based company ZALA Aero. It is a small, portable and reliable UAV platform. ZALA 421-12 is designed for front-line reconnaissance, overground and oversea surveillance. It takes 3 minutes to prepare ZALA for launching...

 is a flying wing UAV specially designed by A-Level Aerosystems, Izhevsk, Russia for Federal Security Service. It features a weight of approximately 4 kg and a wingspan of 1.6 m. The UAV carries EO equipment weighing up to 1 kg which may include gyro-stabilized down-looking video camera, 10 MPix photo camera or infrared camera. The UAV is powered by electric motor driving a small propeller in the nose, with rechargeable batteries permitting an hour of continuous flight at the range of 40 km. Its takeoff and landing is performed in fully automatic mode. The range of application is rather wide, including monitoring of emergencies and natural disasters, remote monitoring of fuel and energy complex, patrolling of land and sea borders, industrial and environmental monitoring, and protection of security-critical facilities.

EADS "Tracker"

European EADS
EADS
The European Aeronautic Defence and Space Company N.V. is a global pan-European aerospace and defence corporation and a leading defence and military contractor worldwide...

 organization is developing a small UAV named the Tracker, which features a wide-span wing, twin boom
Twin boom
Twin-boom aircraft have their tailplanes and vertical stabilizers mounted on the tail of either two fuselages or on two booms fixed to either both sides of the single fuselage, the wings or the engine nacelles.The reason for this design choice may be:...

s for payload and so on, and a central pod with tractor and puller propellers. It has a weight of 7.5 kilograms (16.5 pounds), a span of 1.4 meters (4 feet 7 inches), and an endurance of an hour.

EMT "Aladin"

German manufacturer EMT has produced the Aladin Mini-UAV for German forces. It has a range of more than 15 km and an endurance of 30–60 minutes.

China "CATIC"

CATIC of China is working on their own hand-launched man-portable UAV, the "ASN-15", with an endurance of an hour and a payload of 6.5 kilograms (14.3 pounds).

Elbit "Skylark I" and "Seagull"

In the spring of 2003 Elbit
Elbit Systems
Elbit Systems Ltd. is one of the world's largest defense electronics manufacturers and integrators. Established in 1967, and based in Haifa, Israel, Elbit employs 11,000 people worldwide....

 of Israel introduced two electrically powered man-portable UAVs, the Skylark and the Seagull. Both of these UAVs have a launch weight of about 5.5 kilograms (12 pounds), a speed of from 35 to 70 km/h (20 to 40 knots), and can carry either a color daylight imager or an infrared imager. The Skylark I is of conventional configuration, resembling nothing so much as a large kid's rubber-band airplane with a pod under the fuselage. It has an endurance of 1.5 hours.

The Seagull is much less conventional, in the form of a boomerang
Boomerang
A boomerang is a flying tool with a curved shape used as a weapon or for sport.-Description:A boomerang is usually thought of as a wooden device, although historically boomerang-like devices have also been made from bones. Modern boomerangs used for sport are often made from carbon fibre-reinforced...

-shaped flying wing with wingtip fins and a pusher propeller. Size, performance, and payload details of the Seagull are similar to those of the Skylark, but the endurance is stretched to six hours.

Rafael "SkyLite"

Rafael of Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...

 has built a man-portable UAV also named the SkyLite
Skylite
Skylite is a Memphis based gospel music label started by The Statesmen Quartet and The Blackwood Brothers in 1959. Along with The Blackwood Brothers and The Statesmen Quartet, Skylite signed, among others, The Speer Family and the Oak Ridge Quartet...

, which is fired out of a tube like an antitank missile, and has an endurance of about an hour. It can be launched from a vehicle mount or shoulder-launched by a soldier. Skylite B is the newest version, and is rail-launched. In October 2008, Rafael announced that a SkyLite B had achieved an altitude of 36,000 feet (11,000 m).

The SkyLite has a certain general resemblance to the Raytheon SilentEyes, being a tube a 110 centimeters (3 feet 7 inches) long with a glass sensor nose; a pusher propeller powered by an electric motor; pop-out straight wings with a span of 150 centimeters (4 feet 11 inches); and a cruciform pop-out tail. It has a launch weight of 6 kilograms (13.2 pounds). It was originally named "Skylark" but Rafael decided to change the name to avoid confusion with the Elbit Skylark
Skylark
The Skylark is a small passerine bird species. This lark breeds across most of Europe and Asia and in the mountains of north Africa. It is mainly resident in the west of its range, but eastern populations are more migratory, moving further south in winter. Even in the milder west of its range,...

.

IAI Malat "BirdEye"s and "Mosquito"

IAI
Israel Aircraft Industries
Israel Aerospace Industries or IAI is Israel's prime aerospace and aviation manufacturer, producing aerial systems for both military and civilian usage. It has 16,000 employees as of 2007...

 Malat has also introduced their own small UAV line, designated BirdEye
IAI Bird-Eye
IAI Bird-Eye - family of mini-UAV by Israel Aerospace Industries Malat division.- Sources :* http://www.deagel.com/Tactical-Unmanned-Air-Vehicles.htm BirdEye section...

, which includes the 5 kilogram (11 pound) BirdEye 500 and the 500 gram (1.1 pound) BirdEye 100. Sources also mention a Malat micro-UAV, the Mosquito, though this may be the same as the BirdEye 100. Malat has been promoting the BirdEye 500 for both military and civilian uses, with civilian uses including urban security, crime-fighting, and traffic observation.

YellowPlane "Voyager" and "Manta"

High wing electric powered, 1.4m wingspan the Voyager is a conventional pusher airframe with a maximum AUW of 3.5KG with a wide CG range useful for different payload configurations. The Manta, 1.2m wingspan flying wing is used for vertical NVIR imaging.

Aeryon Labs "Scout"

The Aeryon Scout is a man-packable quadrotor UAV designed for aerial reconnaissance by users with minimal training. Weighing just 1.3 kg, it features onboard intelligence, all-digital communications and a map-based touch-screen control which enables new users to operate the vehicles with only minutes of training. This map-based control allows the system to be easily controlled beyond line-of-sight and at night, a unique feature of this system.
Its unique modular design allows for quick-connect payloads of different types and its arms and legs are changeable in the field, with no tools. This allows the user to repair damages easily and return to operation quickly. The Scout is approximately 0.8 m from propeller tip to tip and operates using 4 brushless DC motors, making it very quiet. It has an endurance of approximately 20 minutes. It is capable of flying in winds up to 50 km/h and designed for all-weather operation, with an industrial temperature range. It has a payload capability of approximately 250 grams. It has been designed for both military and civilian use, with specific focus to remain dual-use compliant.

TriggerComposites Pteryx UAV

In 2010, the company introduced a novel UAV that can fly diverse pre-programmed missions
using only the simplest mission selector and a single takeoff button. The UAV features
automatic takeoff and parachute landing,
allowing reduction of workload and reducing configuration mistakes,
identified as a major hazard in day-to-day civilian photomapping operations.
No groundstation nor laptop is required as missions are defined relative to takeoff position.
Despite featuring parachute, a sturdy fuselage, under 5 kg TOW and up to 1 kg payload, the UAV can fly 1h missions (2h with reduced payload).

MAVinci "SIRIUS UAS"

The SIRIUS UAS is a completely autonomous small airplane with a wingspan of two meters. The UAV combined with the image post processing software enables one to simply obtain aerial images and calculate orthofotos and three dimensional elevation models out of the image data.
The flight planning is done automatically after selecting the aerial image area. The flightplan can be altered before and during the flight. No catapult or launching device is necessary because the UAV is hand-launched. During the flight aerial images are recorded automatically. Manual control during the flight in case of emergencies is possible with assisted flight mode supported by the autopilot. In this mode landing is also possible on very small areas. Autonomous landing is also available.

See also

  • Unmanned aerial vehicle
    Unmanned aerial vehicle
    An unmanned aerial vehicle , also known as a unmanned aircraft system , remotely piloted aircraft or unmanned aircraft, is a machine which functions either by the remote control of a navigator or pilot or autonomously, that is, as a self-directing entity...

  • Micro air vehicle
    Micro air vehicle
    A micro air vehicle , or micro aerial vehicle , is a class of unmanned aerial vehicles that has a size restriction and may be autonomous. Modern craft can be as small as 15 centimetres...

  • Bird flight
    Bird flight
    Flight is the main mode of locomotion used by most of the world's bird species. Flight assists birds while feeding, breeding and avoiding predators....

  • Insect flight
    Insect flight
    Insects are the only group of invertebrates known to have evolved flight. Insects possess some remarkable flight characteristics and abilities, still far superior to attempts by humans to replicate their capabilities. Even our understanding of the aerodynamics of flexible, flapping wings and how...

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