Unmanned Systems Technology 008 | Alti Transition UAS | Ground control systems | Xponential 2016 report | Insitu Orbital N20 | UAVs | Solar power | Oceanology International 2016 report

30 Dossier | Alti Transition focus here is on the aircraft platform, not payloads and data so much. We want to create an open platform that can be used for different missions by different clients and operators who can take the base system, add what they require and operate as needed.” One client who took an early interest in the Alti Transition project wants a link with a range of 50 km. “So we have been working with a couple of different suppliers of the hardware, along with Horus, to provide at least a 50 km encrypted data link and video link as well,” de Villiers says. “For longer ranges well beyond 50 km we are looking at 3G/4G options, but for now, for initial development and launch, we want to keep things fairly simple,” he adds. “Right now we are just keeping a straight direct line-of-sight link with GCSs and antenna trackers. Again, the client always has the option to add whatever they want on top of that.” Flight test progress The flight test programme is in its mid- to-final stages and is inevitably more complicated than those for either pure rotorcraft or fixed-wing designs as it has to cover rotor- and wing-borne regimes and the transitional areas between. Tests of the full-sized aircraft have focused on hovering, with wing-borne flight initially investigated with the sub-scale prototype. De Villiers says, “We’ve done quite a lot of hover testing, fine-tuning the PIDs. Obviously it’s a fairly large aircraft in a multi-copter format and it has a lot of momentum so it’s very important for us to get the PIDs and algorithms for hover mode stabilisation spot-on so that when we transition to fixed-wing flight, if the centre of gravity is off in a fixed-wing sense we know the multi-copter side can handle anything it throws at it.” When we spoke to de Villiers, the team was about to move on to fixed- wing flights with the full-scale prototype, following a successful campaign with the smaller one. The software code has been through several beta versions and the airframe has been cleared for testing. While it is too soon to say whether any changes will be made as a result of the June/July 2016 | Unmanned Systems Technology Airframe: in-house Airframe design consultancy: Carbonix Composite materials: SGL Group and Lavender Composites Petrol engine: Saito Electric motors: T-Motor Rotors: T-Motor Autopilot: ETH Zurich Ground control system hardware: Horus Ground control system software: ETH Zurich Key suppliers to the Alti Transition The fuselage with (from right to left) battery tray, sensor gimbal, avionics, rear bulkhead with carburettor and ignition assembly. Underneath is the integral fuel tank This CAD rendering shows the custom carburettor assembly with ignition module, throttle servo and connections. Details are likely to change in the production aircraft