Aircraft developments leave pilots grounded
Three aircraft have dominated the news pages more than any others in recent years, namely the AirbusA380, the Boeing787 Deamliner and the EurofighterTyphoon. All of these have cost many millions of Euros to get to where they are today, and all three have been designed for their specific target markets. But there is an altogether different class of aircraft that has seen considerable investment in recent years, albeit without the same level of publicity.
Unmanned aerial vehicles – or UAVs – come in various formats and sizes, depending on the roles for which they are intended. In the main, they are aimed at tasks that are deemed to be ‘too dull, dirty or dangerous’ for humans. UAVs are being developed around the world, with the USA being the clear leader in terms of the number of aircraft in development, production and operation. It has been reported that Europe's market share is less than five per cent but, as this present article will show, there is plenty of work in progress.
One of the most active European organisations in this field is EADS Defence and Security. Towards the end of 2007, the German Ministry of Defence named EADS Defence and Security as the prime contractor role for the research and technology programme known as Agile UAV within Network-Centric Environments (Fig.1). The Agile UAV-NCE programme aims to analyse and refine enabling technologies and operational concepts for unmanned agile reconnaissance operations using UAVs. EADS Defence and Security is the lead partner for the tri-national Advanced UAV study in France, Germany and Spain. The company’s prime objectives are to study system-of-systems approaches and the network-centric operations context for its UAV portfolio.
As the Finnish Defence Forces see similar technological and operational requirements, they are also contributing to the Agile UAV-NCE programme via their established national Finnish Unmanned Vehicle Systems (FinUVS) project and its recently launched follow-up UAV Data Link technology programmes. The Finnish industrial participants are Patria as national prime contractor and Insta as co-contractor, both funded by the Finnish Defence Forces. The contribution of the Nordic partners centres on secure networking data links. RUAG Aerospace of Switzerland will also be involved.
The Agile UAV-NCE programme is intended to be executed in subsequent phases and to run until 2013, covering demonstrations by simulation as well as by real flight tests. The main features will be risk-reduction processes, the evaluation of key technologies and the generation of operational concepts for future UAV systems. As a consequence, the most prominent tasks are the definition and simulation of missions, of communication links and of platform control under NCE conditions. Flight trials will focus on verification and validation of the Agile UAV-NCE concept by performing reconnaissance and
sensor-to-shooter missions.
Technology demonstrator
EADS Defence and Security is responsible for the complete system design and will contribute to the programme with its Barracuda technology demonstrator. This vehicle is seen as a decisive step towards the next generation of interoperable modular Advanced UAV systems.
While Barracuda is a fixed-wing aircraft, EADS is also developing a coaxial dual-rotor unmanned helicopter, known as Sharc, which commenced test flights in 2007 (Fig.2). This UAV demonstrator, which is approximately 2.5m long, has a maximum take-off weight of 190kg and can accommodate 60kg of mission equipment in its payload compartments. Sharc is equipped with a redundant flight control unit, a laser altimeter, and control and data links.
The modular design of the avionics facilitates the integration of a broad range of different mission equipment. For example, tests will be conducted on electro-optical and infrared sensors, and Sharc can also accommodate a compact synthetic aperture radar system.
With its autonomous vertical take-off and landing capability, together with its substantial payload capacity, EADS believes the Sharc UAV will be attractive to navies for unmanned reconnaissance and surveillance, as well as aerial target designation and damage control missions. Its dual-rotor configuration is said to make the Sharc especially suitable for ship-based missions, as it provides thirty per cent more lift at equal weight than conventional helicopters with tail booms. This enables a heavier payload to be carried with comparable flight performance. The dual-rotor design also provides greater attitude stability, which makes it easier to compensate for the rolling movement of the ship – a prerequisite for autonomous deck landings. Dual counter-rotating rotors are mutually torque-compensating and therefore negate the need for a tail rotor. This, in turn, has a favourable effect on the overall dimensions of the UAV. The innovative overall design of the UAV is also said to present new technical possibilities, such as the integration of antenna in the outer skin.
While navies are clearly an important target market for EADS, the company also states that the Sharc has potential applications in industrial monitoring.
Good all-rounder
Saab has already developed an unmanned helicopter, the Skeldar V-150, which is designed for military and civil applications, national and international missions, and day and night operations (Fig.3). Viewed as a complete system, the Skeldar V-150 can form part of a command and control system, and would readily operate as a component within a network-based defence structure.
Anders Carp, the deputy programme manager for UAV operations at Saab, comments: "Skeldar V-150 can, for example, be used for surveillance, reconnaissance, target acquisition and designation, and electronic warfare. The system is incredibly flexible; it is the sensors used that shape the mission."
A basic system might contain two UAVs, a control station and electro-optics and infrared (EO/IR) payloads, but the Skeldar V-150 is designed to carry a range of payloads, such as high-performance synthetic aperture radar sensors combining radar and target indicator capabilities, as well as an advanced electronic warfare suite.
Surveillance and reconnaissance
Helicopter-based UAVs are certainly very useful, but there is a huge amount of research ongoing into
fixed-wing autonomous UAVs. One example of this is the BAE Systems Herti aircraft, which is being developed for military and civilian surveillance and reconnaissance operations. According to BAE Systems, Herti is cost-effective and flexible, providing high-quality imagery using a safe, reliable platform that can integrate seamlessly with current and future information networks.
Herti is a highly adaptable, fully autonomous, platform-based system providing robust, cost-effective surveillance and reconnaissance capability to support a range of military and civil requirements. High-quality images can be captured, processed and relayed to ground stations, forward deployed units and command centres in a variety of operational environments with very low network bandwidth demand.
The aircraft has already completed performance flight test missions, plus the autonomous ICE (image collection and exploitation) mission system has successfully completed autonomous target searches.
At the larger end of the scale, BAE Systems is also leading the
E166million (£124million) Taranis UAV technology demonstrator programme. Taranis will be the largest UAV yet built in the UK and, as part of the UK Ministry of Defence’s Strategic Unmanned Air Vehicle (Experiment) (SUAV(E)) programme, the project will explore and demonstrate how emerging technologies and systems can deliver battle-winning capabilities for the UK armed forces. BAE Systems is the industry lead and prime contractor, with Qinetiq, Rolls-Royce and Smiths Aerospace being the other industry partners.
European Neuron
Another unmanned combat air vehicle (UCAV) technology demonstrator under development in Europe is the Neuron, led by Dassault Aviation at the prime contractor, with Alenia Aeronautica, Saab, EADS CASA, HAI and RUAG Aerospace as other industrial partners. So far the Neuron project has reached the stage where a 1:16 scale model is being wind tunnel tested by Saab at facilities belonging to the Forces Research Institute (FOI:s) in Stockholm. The Neuron’s first flight is planned for 2011.
As well as its involvement with the Neuron project, Alenia Aeronautica is investing heavily in the Male (medium altitude long endurance) class of UAV. Indeed, towards the end of 2007, its Sky-Y surveillance aircraft completed a flight of eight hours duration in Vidsel, Sweden, thereby setting the continental endurance record for aircraft of this class weighing over one tonne. This flight, which was aimed at checking the full payload performance and operational procedures of both the aircraft and ground station, was one of a series to check the aircraft’s performance and behaviour at altitude and at full payload, and to test its diesel propulsion system, all on-board systems, self-pilot and self-navigation systems, as well as automatic take-off and landing functions.
Solar power
Little progress has so far been made towards air-to-air refuelling of UAVs, which could ultimately restrict their flight duration capabilities. However, the Zephyr UAV is an ultra-lightweight carbon fibre aircraft, weighing just 30kg, that uses solar power generated by paper-thin amorphous silicon arrays covering the wings (Fig.4).
The brainchild of Qinetiq, the hand-launched Zephyr carries lithium-sulphur batteries that are recharged during the day using solar power, then used to power the aircraft at night. The aircraft features a bespoke autopilot system to navigate between waypoints and to remove the requirement for permanent manual operation.
Already Zephyr has secured a place in the history of UAV development by exceeding the world record for the longest duration unmanned flight. The high-altitude long-endurance (Hale) aircraft achieved a 54-hour flight and reached an altitude of 58,355feet (17786m) in August 2007, though the record is not official, as there was no FAI observer present. A second flight lasted for 33 hours 43 minutes, with the aircraft climbing to 52,247feet (15925m).
