* This chapter provides an overview of UAV regulatory issues, as well as UAVs that proved deads ends or were strictly experimental.
* One of the less obvious issues concerning UAVs is integration of their operations into open "national airspace", where they may fly alongside private and commercial aircraft, in contrast to "special use" airspace, which includes "Restricted", "Warning", and "Military Operations" areas where airliners and private pilots are not allowed to fly. Currently, UAV operations in national airspace are considered on a case-by-case basis by the US Federal Aviation Administration (FAA), and lead times run to months.
There are projections that the US military could be operating thousands of UAVs in a decade, with some of these aircraft carrying munitions, and the number of US commercial UAVs could be even larger. Figuring out how these UAVs can operate safely alongside commercial traffic is a nasty bureaucratic issue. The US Department of Defense, the FAA, and NASA have been considering how UAV traffic over the US should be regulated, and what implications UAVs have for international air traffic agreements. International regulations for commercial UAVs are regarded as particularly important, to allow American businesses to operate and sell UAV technology in other countries. Initial work suggested that UAVs should be divided into three regulatory classes:
Measures under consideration are to allow a medium-altitude, long-range UAV into the US national airspace if it were escorted by a piloted chase plane, or if it has adequate sensors to "see and avoid" commercial traffic and is monitored at all times by a ground operator. The ground operator will likely have to be a qualified pilot who knows the rules of the airways, and would be in two-way communications with the air-traffic control network.
UAVs would likely not be allowed to operate on a normal basis in high-volume "Class B" airspace around major airline hubs such as Chicago, New York, and Los Angeles. The FAA would also require certification that the communications link to a UAV be reliable and resistant to interference.
There are a large number of confusing issues to consider, since the possibilities for UAVs are open-ended. Small, long-range UAVs like the Aerosonde that could be used for weather or traffic observation are one complication, as well as UAVs like the Scaled Composites Proteus used as relays for high-bandwidth communications.
NASA is working with industry on a 5-year "Integrated Systems Research (ISR)" program, to begin in 2011, the intent of which will be to sort out the issues and provide recommendations to the FAA, which will formally establish the rules. European UAV vendors have formed their own consortium to provide data to the European aviation regulatory body, the European Aviation Safety Agency (EASA). The UK has been conducting their own program, the "Autonomous Systems Technology Related Airborne Evaluation & Assessment (ASTRAEA)". Global progress on the issue has been slow, an indication of its complexity.BACK_TO_TOP
* A good number of UAVs have been developed that were built in small numbers or nobody bought, and are discussed here mostly out of historical interest.
The "SkyEye" series of UAVs was developed by Developmental Sciences Corporation, which was originally apparently part of Lear Astronautics but which is now a component of BAE Systems. In any case, Developmental Sciences was one of the first US companies to investigate battlefield UAVs, flying the first prototype of their "SkyEye" series in 1973, leading to the first flight of the improved "R4E" variant in 1978.
The SkyEye had the common pusher-propeller twin-tailboom configuration, but it had distinctive slightly-swept wings and antennas on top of the tailfins. It was powered by a rotary engine and could carry two underwing stores, along with its primary payload. It landed on a retractable centerline skid or can be recovered by parachute. The SkyEye was sold to a number of countries for battlefield surveillance, and were used commercially for pesticide spraying.
* DRS Technologies, previously S-TEC, developed a "Sentry" UAV, in roughly the same class as the Dragon drone. The Sentry looked something like a Dragon with a twin-boom raised tail. It was built of carbon composites and Kevlar, and powered by a 19.5 kW (26 HP) piston engine in a tractor configuration.
The Sentry was introduced in 1986. DRST followed it up with the more capable "Sentry HP", with a broad wing and a vee tail. DRST built another follow-on to the Sentry, a mini-UAV named the "Neptune", which had the interesting feature, as its name implied, that it could be operated off water -- think of it as a "flying boat" UAV. The 11.2 kW (15 HP) pusher engine was mounted high to keep it dry during takeoffs and landings. Although DRST was promoting their UAVs as late as 2009, photos circulating of a Sentry HP at a trade show carrying four tiny smart munitions, DRST never sold their UAVs in large numbers, and at last notice the product list on the DRST website did not include any UAVs.
* In the late 1980s, Sikorsky Aircraft flew a small UAV named "Cypher", with coaxial rotors inside a doughnut-shaped airframe. The doughnut-shaped shroud not only improved safety in handling the machine, it also helped increase lift. The initial Cypher was strictly a demonstrator that lacked full flight capability, with work leading to a true flight demonstrator and then a "Cypher II" , which was evaluated by the US Marines as the "Dragon Warrior". The service did not adopt it.
* An interesting tactical UAV was developed by a company associated with the University of Maryland, Freewing Aerial Robotics Corporation. Working with well-known small-aircraft designer Burt Rutan, Freewing designed a series of piston-powered short-takeoff-and-landing UAVs, based on a design where the fuselage pivoted relative to the wing surfaces. There was considerable buzz over the design for a time, with a production arrangement set up with Matra of France, but no one bought the Freewing and the effort evaporated.
* Bell developed a turboshaft-powered tiltrotor UAV named the "Eagle Eye", which performed its first flight in 1993. Bell pushed the machine for a decade without finding a buyer, but finally obtained a contract in 2002 to produce Eagle Eyes for the US Coast Guard's "Deepwater" modernization program. The program's name turned out to be only too appropriate, however, since it proved more than the service could smoothly manage, and the result was cutbacks and schedule slipouts.
The Eagle Eye was one of the casualties, with the USCG regrouping to consider a cheaper UAV. It appears the Eagle Eye was an impressive machine, but it suffered from a problem that has long plagued VTOL technology development: potential customers just couldn't see that the machine offered enough advantages over a helicopter to justify the higher price tag.BACK_TO_TOP
* New concepts for UAVs keep appearing and disappearing, sometimes becoming visible as flight demonstrator prototypes for a time. It is hard to be certain if these programs are dead, or may resurface in the future as production machines.
DARPA conducted a program with the Army on development of prototypes for an "Uninhabited Combat Armed Rotorcraft (UCAR)", originally given the snappy name of "Robotic Rotary Wingman". A requirement was issued in the spring of 2002, specifying a robot rotorcraft to be armed with missiles, unguided rockets, guns, and nonlethal directed energy weapons.
Northrop Grumman and Lockheed Martin were selected in the summer of 2003 to come up with detailed designs. Ironically, Northrop, Grumman, Lockheed, and Martin had never built a full-production rotorcraft. The Northrop Grumman design used the twin-two-blade-rotor "eggbeater" scheme usually associated with Kaman helicopters while the Lockheed Martin design used a four-blade rotor with a "no-tail-rotor (NOTAR)" jet exhaust in the tail to cancel torque. Both were "stealthy" designs with weapon stores in internal bays; both eliminated the tail rotor, which is the noisiest element on a conventional helicopter.
The Army seemed very enthusiastic about the program, but then pulled out abruptly late in 2004, to eventually adopt -- and later discard -- the Fire Scout. The UCAR designs were simply too whizzy and futuristic, overkill for actual needs. It's hard to say the UCAR effort was a failure, however, since DARPA's mission is to evaluate next-generation technologies. Sometimes they lead to operational systems, sometimes they don't, but even when they don't the technologies developed can prove useful down the road.
* From 2003, the US military conducted experiments in lightweight VTOL UAVs for tactical cargo delivery. Aurora Flight Sciences developed a series of "GoldenEye" UAVs under a DARPA contract, apparently for SOCOM operations. The GoldenEyes were "tailsitter" or "pogo" machines that took off and landed straight up. They were barrel-looking machines with landing gear on the bottom of the "barrel, and a wing that pivoted, allowing it to be aligned with the aircraft centerline in cruise flight and at a right angle to the centerline in hover flight. The initial variant was the "GoldenEye 100", built of composites and with a rotary engine. Aurora also developed smaller "GoldenEye 80" and "GoldenEye 50" variants.
BAE Systems developed a demonstrator UAV similar to the GoldenEye, named the "AirWolf", as part of a DARPA experiment in which the UAV delivered "Wolfpack" battlefield sensors and other payloads. The Airwolf prototype performed its initial flights in the spring of 2005. These DARPA projects eventually ran their course, and little more was heard of the GoldenEye and AirWolf.
In addition, AeroVironment developed a pogo UAV named the "SkyTote" under an Air Force contract. Details are unclear, but illustrations of the SkyTote show it to be another pogo-type tailsitter, with a surprising resemblance to the pogo fighters of the 1950s. It was powered by a rotary engine.
* Along with the Goldeneyes, Aurora Flight Sciences also built a demonstrator for a tactical UCAV under a US Army contract awarded in 2005. Initial flight of the "Excalibur" was in the summer of 2009.
Excalibur had a weight of 325 kilograms (720 pounds). It looked like a plastic sled with two booms running back to a straight wing in the rear. It was 4 meters (13 feet) long and has a wingspan of 3 meters (10 feet). There was a small turbofan on a pivot mount between the booms, with the engine tilting up for vertical take-off and then tilting back to the horizontal for forward flight. There were electrically driven lift-fans in the nose and each wingtip to help with vertical flight; the lift-fans were driven by batteries, which could provide surge power for short durations and then be recharged by a turbofan-driven generator in flight.
The Excalibur could take off and land vertically, but was not capable of sustained hover. Maximum speed in forward flight was about 550 KPH (300 KT). Concepts for a follow-on production machine envisioned a vehicle twice as big, with a warload of 180 kilograms (400 pounds). However, the program was apparently purely experimental, with little mention of it in recent years.
* DARPA has worked with a company named NextGen Aeronautics of Torrance, California, to develop a "morphing-wing" UAV. An initial demonstrator, the 45 kilogram (100 pound), piston-powered "MFX-1", was flown in the summer of 2006. The morphing wing could not only change its sweep -- nothing new there -- but could shift fore and aft along the wingroot, and adjust its chord. At the moment, it appears to be a pure technology-development exercise, with no particular operational use in mind.
DARPA has also worked on a particularly interesting program codenamed "RapidEye", which was o be a small UAV to be launched as a payload on a solid-fuel rocket booster that would deliver it quickly to anywhere in the world. The RapidEye UAV would have a folding configuration, along the lines of those of the NASA Mars UAVs. The delivery system would not only provide rapid response, it would also permit overflights of any territory on Earth without violations of airspace: by international agreement, space is open territory where rights of navigation cannot be enforced. However, there have been loud concerns over the idea of using a long-range missile for carrying a conventional warload, since the Russians would have difficulty telling it from a missile carrying a nuclear warhead.BACK_TO_TOP
* I never really intended to write this document, at least not to the level of detail and length it has reached. It was just a case of one thing leading to another. It all started with a short document on the BQM-74 Chukar that I released in 1998. I had intended to incrementally add new documents on UAVs following the Chukar article, but I was sidetracked by development of the companion documents in this series, DUMB BOMBS & SMART MUNITIONS and CRUISE MISSILES. By the spring of 2000 I had such a "critical mass" of information on UAVs that I decided to simply go ahead and put together a full survey of the topic.
It is a reflection on the level of activity in the UAV field that getting the first version of this document out the door proved to be such an extended exercise. New information popped up continuously, requiring constant additions and rewrites. AVIATION WEEK had something new almost every week, and even as I was polishing for release I was still adding details. Once released, new information kept trickling in, demanding updates. The subject's so open-ended that each time I perform an update, there's always loose ends since I just don't have the time to track all the details down.
After a few years I learned to be selective, since there are a lot of UAV projects coming and going, with proposals appearing and disappearing, and even those proposals that seem to be on track for development tend to shift like a mirage. It turns out to be more bother than it's worth to discuss a UAV development program unless it's on a fairly solid track. It's also completely useless to incorporate sketchy information on existing but obscure UAVs, since such materials often turn out to be very misleading or dead wrong.
There came a time when I finally had to simplify this document just to weed out some of the more dubious information. It seems to "breathe" through revisions, expanding as more examples are added, then shrinking again as the text is streamlined and the junk thrown out. It still managed to grow until I finally decided to break it down into multiple documents, organized by region -- USA, Europe, Israel / Middle East, Russia / Far East. It was just too difficult to maintain.
* Sources include:
* Although this is a long list of sources it is by no means padded, and in fact I have not bothered to list many sources where all I got was a comment or two. Various editions of JANE'S ALL THE WORLD'S AIRCRAFT back to 1960 were consulted as well, and proved valuable resources. JANE'S now publishes UAV details in a stand-alone volume, but its price is far beyond my means, and though it would provide a tremendous number of details on the latest technology, I do not have access to it.
I found a large number of details on the Web, though mostly in tiny bits and pieces. I won't include URLs of websites here because they break so often and maintaining them would be a nuisance out of proportion to their value, but a search engine should find them pretty quickly. Useful sites included AAI; Freewing Corporation; AeroVironment; BAI Aerosystems; Silver Arrow in Israel; CAC Systemes in France; the Federation of American Scientists (FAS) website; and many excellent materials from NASA on their UAV programs. With each revision I found more high-quality photographs for illustrations as well.
Recent revisions of this document have been assisted by Andreas Parsch's excellent website, DIRECTORY OF US MILITARY ROCKETS & MISSILES. Mr. Parsch is clearly attempting to provide a definitive reference on the topic and goes into maximum detail, and those who want more data than provided here, at least on US UAVs, would certainly find it very interesting. I find it difficult to keep up with him, and certainly am not trying to compete with him for level of detail!
* Revision history:
v1.0 / 01 feb 01 v1.1.0 / 01 feb 02 / General cleanup and update. v1.2.0 / 01 jan 03 / General update. v1.3.0 / 01 jan 05 / General update, added 3 chapters, new pix. v1.4.0 / 01 apr 06 / General polishing, updates, more drawings. v1.4.1 / 01 mar 08 / Cleanup and simplification. v1.5.0 / 01 jan 09 / Considerable streamlining, illustrations update. v1.6.0 / 01 mar 10 / General cleanup. v2.0.0 / 01 feb 12 / Cut out non-US UAVs for release elsewhere.BACK_TO_TOP