The pusher-configuration UAV type (pictured below) has been under development for two years with the first pre-production prototype now in preparation. That aircraft will be shipped to the USA to support marketing demonstrations in conjunction with Florida-based Autonomous Unmanned Air Vehicles (AUAV).
Silvertone principal Bob Young says the design is initially being optimised for small civil users new to the sector, particularly in the agricultural industry, but with other variants in planning to meet the requirements of the existing UAV marketplace.
The 1930s retro design – which Young acknowledges “is the right way to describe it” – is based on modular principles with the system disassembling into forward fuselage, tail boom, wings and engine subsystem. “It will be a very elegant aeroplane”.
The forward fuselage incorporates an extended payload tray accessible by removing the nose cone, with the tray also removable allowing quick role changes of the UAV.
An ability to reconfigure the basic airframe to support either high speed or endurance missions using alternate wing kits is also in development, says Young, as is a twin-tail boom variant that would allow for the fitting of a larger engine and propeller module. The existing design has a 4m (13ft) span with twin hard points on the inboard wing sections. In the twin-tail configuration, the existing boom would be detached from the rear fuselage and connected directly to one of the hard points, with a second tail section fitted to the other.
The existing demonstrator has undergone three design iterations to reach the pre-production standard. The existing demonstrator has an all-composite fuselage and laminate wood-foam and composite wings and tail structure. Production standard moulds for all remaining structural components are now in preparation Young says, including the use of laser trimming.
The engine used in the December flights, carried out at Bathurst, west of Sydney, was a 25cc (1.6 cu. in.) glow plug system adopted from the model aircraft industry and demonstrated speeds of 70kt (130km/h). The production standard engine is likely to be sourced from Germany’s 3W-Modellmotoren, says Young, with dash speeds of more than 87kt anticipated.
Aircraft avionics are being developed around AUAV’s Ezi-Nav system and will support 1,500 waypoint inputs, Young says. The air vehicle datalink, a frequency-hopping system to provide redundancy in the event of channel loss, is also based on AUAV equipment.
Maximum take-off weight is forecast at around 20kg (44lb) for the production standard aircraft with an empty weight of 10kg. Fuel tank capacity is 5 litres and, with the new engine, is expected to allow for endurance operations of 10h in cruise mode.
The tricycle undercarriage is sprung to allow for rough field operations. For endurance profiles Silvertone is investigating the use of drop-off dolly carriages or a rail launch system. A monowheel landing system is being investigated for recovery as part of that alternate configuration.
Initial production phase plans are based on a first-phase build of five systems, and a second run of 10. Silvertone is anticipating being able to support construction of up to 20 systems a month if the UAV proves commercially successful.
A basic flight-ready system for small, first-time users will comprise the modular air vehicle with basic flight avionics, controller and engine. Payload selection would be up to the customer says Young, with Silvertone supporting integration.
This approach will help keep overall acquisition costs low for new users, Young argues, but he also expects the design to attract established UAV system houses looking for new configurations. “I would love to see this picked up by someone with real experience in autonomous systems and explore what they could really do with it,” he says.
Silvertone built its first UAV in the mid-1970s, selling a small number of systems, designated Weightlifter, to the then Australian Weapons Research Establishment in Adelaide. Those aircraft were used to support experiments in the use of UAVs equipped with bomblets to harass enemy forces, Young says.
The Flamingo emerged from initial approaches to Silvertone from within Australia for a UAV capable of flying surveillance grids over broad acre farmlands to locate herds of wild goats.
Source: FlightGlobal.com