Not only Le Bourget: given the number of new events in the field of unmanned aircraft announced at the Paris Air Show (see our report in this issue), one could have expected that little else had not been specifically 'earmarked' for this French grand aerospace meeting. What follows proves the contrary.
The use of blimps and airships controlled 'a la unmanned air vehicle' has been visited in past issues of Armada, but here comes a new breed of drone, courtesy of D-Star Engineering. Known as the Aerolenscraft, this new vehicle is designed for very long endurance (up to one year) operation at 65,000 ft, and therefore constitutes a first step in bridging the gap between hales and satellites.
The operating principle behind the Aerolenscraft is to gather solar energy during the day and store it as hydrogen for night operation. Due to its high internal volume the craft does without high-pressure tanks, compressors and heat exchangers. The gas provides both the necessary buoyancy to the craft as well as the energy to run its onboard systems, with thin-film, solid-oxide fuel cells converting the hydrogen into water during the night, which is stored onboard for conversion back to hydrogen during the daytime. Unfortunately, D-Star will not unveil at this stage any details regarding the structural components of the Aerolenscraft.
Although D-Star had announced the existence of this project in August 2007, work had been underway for some time, as indeed a company official told the author that the US Air Force Research Laboratories-sponsored project had completed its Phase 1 in June and was entering Phase 2. Phase 1 entailed conceptual development and preliminary design and analysis, while Phase 2 will cover design optimisation as well as hardware exploration of the ship's aerodynamics (which includes stability and control in a wind tunnel, as well as further work on energy harvesting and storage). Asked about the probable date of a maiden flight the same official was more evasive and disclosed that this could be part of Phase 3.
The advantage of such a concept is that the craft would be able to stay aloft for a year (or more), remain out of hales' and traditional aircraft's way and difficult to reach for anti-aircraft weapons, while being able to displace itself at a speed of 200 kts, loiter and provide better resolution images than satellites that orbit at altitudes ten times higher.
According to several e-mail messages received by the author just before print deadline, South Korea has yet another drone manufacturer. Wares from Ucon (Remoeyes series) and Korean Aerospace (Night Intruder) have already been covered in these columns, but the new entrant surprisingly comes under the name of Korean Air, which, apart from being the known airline, also licence-manufactures the Black Hawk.
The hitherto unnamed fixed-wing drone is apparently being developed with funding from the Ministry of Commerce, Industry and Energy with a view to eventually providing the military with a battlefield observation system. The drone has been under development for over three years, has an endurance of 2.5 hours and an operational (datalink) range of 40 km. A further model is envisaged to boost endurance and range to six hours and 80 km.
Proxy Flies for USAF
Proxy Aviation, which develops 'optionally piloted unmanned aircraft', performed an interesting experiment over a period of nine days at Creech Air Force Base in early July. Involving a Sky Watcher and a Sky Raider (see title picture) flying nine missions, the tests were aimed at demonstrating the capability of multiple drones to perform fully autonomous co-operative missions. The tests also involved two simulated unmanned aircraft managed by their own 'onboard' virtual pilot, meaning that all four elements had to communicate over a common mesh network, allowing one person to operate them through the use of the system's Sky Force network-centric software which actually is designed to simultaneously handle twelve drones and 20 ground nodes. Equipped with Flir Systems Saphire III gimballed sensors, the aircraft logged 49 flight hours during the nine missions. In the process the US Air Force, which had established the co-operative flight objectives, tested Proxy's systems in a series of <<complex and dynamic intelligence, surveillance and reconnaissance and hunter-killer scenarios>>. The flights included target search, simulated weapon and multiple sensor employment, dynamic mission re-tasking, formation flying, collision avoidance and automatic take-off and landing.
While the Sky Watcher is designed for medium-endurance, low- and medium-altitude ISR missions, the Sky Raider is engineered for heavy-payload missions requiring the carriage and release of external stores. It also features a retractable landing gear.
New from Italy
Selex has developed a new series of electrically powered mini-drones known as Strix, Otus and Asio that can be operated in automatic or semiautomatic modes. They are programmed by and operated from a common ground station and feature automatic take-off and landing. According to the company they can be operated independently or as part of a <<critical node in a fully integrated network surveillance system with payloads that can be controlled manually at any time during flight>>. The systems have recently been demonstrated at the Parc Aberporth range in Wales.
The Strix has a flying wing configuration and, in spite of its three-metre span, is man portable and can be carried in an ad-hoc backpack. Weighing 20 kg fully loaded the backpack holds the aircraft (ready to fly in 15 minutes), the cameras, the ground control module (which includes the datalink system) and the user manuals. The stabilised platform accommodates a 320 x 240 array sensor, 7.5-13.5 Im infrared camera with a 36[degrees] angle of view (with a x2 digital zoom), or a 537 x 597 pixel day/night camera with a x10 optical zoom proving a 62[degrees] to 7[degrees] field-of-view (the camera also has a x10 digital zoom).
Like the Strix, the smaller Otus can be enclosed in a backpack and can be launched by hand or from a catapult. At a mere eight kilos the fully-laden backpack is, however, less than half the weight of the Strix. The more conventionally pod-and-wing-configured aircraft is ready to fly in under ten minutes, but carries the same payloads as the Strix.
The vertical take-off and landing Asio is described as a 'hover and stare' drone for battlefield surveillance, forward scout and special operations missions but uses the same sensors as the Strix and the Otus. Like the latter, the structure of the backpack serves as a stand for the vertical aerial.
Selex has also unveiled a model of its latest creation, the Damselfly. This aircraft is reminiscent of a miniaturised Harrier as it also uses vectoring thrust nozzles to transition from vertical take-off to horizontal flight, a useful feature for operation in an urban environment, and when range and endurance are required. It goes without saying that some rather advanced avionics are required to stabilise the aircraft and synchronise the thrusters according to available wing lift. Due to the aircraft's potentially high resistance to lateral forces, Selex sees the Damselfly as an ideal system for use from ships and in 'urban canyons'.
The US Air Force has recently taken delivery of its first Aerovironment Batmav system as part of its Beyond Line of Sight programme. Aerovironment, which had been awarded a contract in December 2006, has recently received an order for 30 systems through the programme's indefinite delivery/ indefinite quantity contract, which provides for purchases of up to $ 45 million over a period of five years. The system's aircraft is the onepound (450 grams) Wasp III. This has has a wingspan of 73.5 cm and carries integrated forward- and side-looking electro-optical colour cameras as well as a modular forward-or side-looking electro-optical or infrared payload. The system is capable of operating for up to 45 minutes at up to five kilometres from the transceiver.
Strix Data Wingspan: 3 metre Length: 1.17 metre Height: 0.30 metre Max payload weight: 1.0 kg Datalink range: 12.5 km Operational speed: 40 kt Altitude: 10,500 ft Max rate of climb: 4 m/sec Endurance: >1.5 hr Asio Data Span: 1.5 metre Length: 0.9 metre Height: 0.30 metre Max payload weight: 1.0 kg Datalink range: 10 km Operational speed: 15 to 45 kt Max rate of climb: 4 m/sec Endurance: >1 hr Otus Data Wingspan: 1.5 metre Length: 0.9 metre Height: 0.30 metre Max payload weight: 1.0 kg Datalink range: 10 km Operational speed: 15 to 45 kt Max rate of climb: 4 m/sec Endurance: >1 hour