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50 Insight | UAVs vertical stabiliser, instead of keeping them in the winglets where the Integrator and previous ScanEagles (as well as many other aircraft designs) have them. “The Integrator and the ScanEagle also have winglets; the ScanEagle3 does not. And it’s designed to function without a winglet, although if a customer did want to stash an antenna in a winglet, the ScanEagle3 is compatible with antenna winglets. But for the standard configuration, the antennas are in the aft vertical stabiliser,” Decker says. The UAV is powered by the N20 engine co-developed with Orbital (see UST 8, June/July 2016) for Insitu’s UAVs, with the use of that engine being a key design requirement issued by the then CTO early on. Mounted in the aft of the fuselage in a configuration similar to that in the Integrator, the 49.89 cc two- stroke engine produces 2.4 kW to power the MTOW of 36.3 kg and a maximum payload capacity of 9.1 kg. This signifies a marked increase in weight between generations of the UAV, with an unloaded weight of roughly 27.2 kg for the ScanEagle3 compared with 18.96 kg for the ScanEagle2. It’s a reversal of the downscaling trend in unmanned technology that allows the aircraft to have two payloads. One payload sensor can be stored in the nose of the UAV, another in the belly near the aft. To account for shifts in the CoG occurring due to changes in the weight carried in either payload bay, the rear of the 2.5 m-long (4 m wingspan) ScanEagle3 has a moveable twin-boom tailplane, similar in shape to the fixed tailplane of the Integrator UAV. The wing and tailplane together are attached to the main fuselage by 12 fasteners, allowing the entire aero package to be detached and moved forwards or backwards along the top of the hull as the sensor complement shifts. Test flights are continuing at the company’s test range to ascertain the precise ranges of weight combinations that can be carried in either payload bay without throwing the CoG off too far. “There are certainly limits, but even if we didn’t have a moveable wing, we would still have a fairly generous range of CoG envelopes,” Decker said. “So now that we have a moveable wing, we have an even larger envelope to work with.” The tailplane features two elevators and two rudders for flight control, with each of the 2 m wings integrating an aileron and a slotted flap. “The slotted flap was not on the ScanEagle or Integrator; we needed this vehicle to have equivalent ‘capture energy’ to our previous ScanEagles – despite being larger – so that customers could re-use the same Skyhooks for recovery,” Decker explains “The slower capture speed also means end-users can carry more payload than on the ScanEagle2.” As trials continue for the ScanEagle3, Insitu is exploring potential new partnerships in Australia, or collaborating with existing partners in the oil and gas industries, in order to arrange test flights outside the USA’s relatively restrictive airspace regulations. Agriculture While unmanned vehicle designs for aerial crop-spraying are no longer a new concept, the Kray Protection UAV from Russian company Kray Technologies has been designed to improve productivity in agriculture beyond merely dispensing with human labour. “It’s hard to improve costs further in a well-established industry like crop-spraying, compared with newer industries like aerial mapping and Big Data,” says Dmytro Surdu, CEO of Kray Technologies. “The productivity and the application efficiency of manned spray operations are already quite high with current technologies.” To that end, Kray determined that the best way to increase productivity over manned crop spraying was to offer a high airspeed. The UAV therefore uses August/September 2018 | Unmanned Systems Technology The Kray Protection UAV uses a patented fuel pump design to ensure agricultural chemicals flow efficiently from the tank to the atomisers (Courtesy of Kray Technologies) There are limits, but even if we didn’t have a moveable wing, we would still have a generous range of CoG envelopes