Unmanned Systems Technology 017 | AAC HAMR UAV | Autopilots | Airborne surveillance | Primoco 500 two-stroke | Faro ScanBot UGV | Transponders | Intergeo, CUAV Expo and CUAV Show reports

Fairings enclose the booms and have reflexed trailing edges to trim to a positive angle of attack. The structure is selectively laser sintered nylon, the skin a vinyl sticker (Courtesy of AAC) 32 Dossier | Advanced Aircraft Company HAMR UAV will be a very small percentage of the electric power needed to fly the aircraft,” he says. For that reason, he doesn’t anticipate the need to use separate batteries or other power supplies for payloads, although customers will be free to do so if they want to. He emphasises that it is easy to generate enough electricity to power any sort of payload the customer wants, and that the control loop can also take such loads in its stride. “We plug in the power distribution to a payload downstream of the current sensor, so the sensor is just looking at what comes in and out of the battery, and it doesn’t matter whether the electricity is going to the payload or to spin props,” he says. Currently there are no data interfaces, but AAC can integrate radio downlinks as a component in the payload package, he adds. Flight testing The HAMR programme has logged around 60 hours in total in more than 330 flights with the four complete prototypes. Key test points achieved include fully automated flights, airspeeds of up to 20 knots and vertical speeds of 200 ft/ minute, both in climbing and descending flight. The longest non-stop flight to date lasted 2 hours and 16 minutes. Envelope expansion continues, with the next test points in the plan being increases in airspeed up to 40 knots, power polar testing to find the power required to achieve a given speed with and without the, vertical speeds of ±400 ft/minute and extending the endurance to 3.5 hours. While AAC made some (undisclosed) design changes in light of the flight test results, the most important lessons have related to improving the reliability of the propulsion system, Fredericks says. The focus of the flight test programme is to complete the expansion of the envelope, incorporate the final changes, finalise the design and establish a low- rate production line. Development so far has been financed in three rounds by Fredericks himself, friends and family and a seed round. Most recently, AAC has secured an investment from the Center for Innovative Technology’s GAP Funds and the Charlottesville Angel Network. Preparing for manufacture AAC does very little fabrication in-house, subcontracting most of that out – the fuselage, for example, is built by the Moore Brothers Company – but it carries out final assembly and integration work at its facilities in the Peninsula Technology Incubator in Hampton, Virginia. Challenges in finding suitable suppliers centre on striking the right balance between price and quality, Fredericks December/January 2018 | Unmanned Systems Technology Payload and endurance curves for HAMR with one fuel tank and two compared with a large battery-powered competitor (Courtesy of AAC) HAMR w/1 Fuel Tank HAMR w/2 Fuel Tank Large Battery Powered Competitor