Unmanned Systems Technology 002 | Scion SA-400 | Commercial UAV Show report | Vision sensors | Danielson Trident I Security and safety systems | MIRA MACE | Additive manufacturing | Marine UUVs

31 Scion UAS SA-400 optionally piloted helicopter | Dossier sideways when still on the ground would be a disaster! “Then the autopilot has to react to any gust of wind as soon as it takes off. Then think about the added complication of the ground being the deck of a ship that is moving at sea. As a pilot you just do what you need to do, but we have to get a computer to do it.” The NRL needed the SA-400 to be able to fly sideways alongside a ship travelling at 30 knots into a 16 knot headwind. In other words, effectively it had to be able to fly sideways at 46 knots (53 mph/85 kph). “That is not normal and not easy – a tall order,” reflects Mogensen. “Jim [Sampson] can do it using manual control, having a lot of experience, but there are some very strange dynamics involved. It is hard to teach an autopilot to do that safely. “A helicopter doesn’t really want to fly sideways; it is like a weathervane trying to go against the wind. The main rotor doesn’t care – it is all about having the rest of the structure pushing against the wind. The balance between the wind resistance and your tail rotor’s ability to overcome that is a factor. Then there are some very strange helicopter dynamics, which has to do with which way the tail and main rotors are turning and the interactions between them; when you then add another force onto that, it will be different according to which side it affects. “And that all gets into some very complex dynamics. If we have Jim in the seat, he can feel that the helicopter doesn’t really want to do something any more, and he knows what to do to get out of it. But how do you explain that to a computer? You have to tell the flight controller when to say ‘no’, and then when it says ‘no’, what should happen. That all amounts to an enormous amount of programming.” Potential uses of the SA-400 Interestingly, the SA-400’s autonomous control system is sophisticated enough to allow a payload to command the autopilot. If, for example, the payload were a military one in the form of an early detection system, identification of a threat could lead to a given response. The strategy might be that the SA-400 acts as a sacrificial decoy to protect a convoy against an incoming missile, in which case the payload would call for the appropriate response of the autopilot. “The SA-400 control system can even be integrated with those of sister craft,” Mogensen says. “In the case of our missile scenario, there might be a number of SA-400s acting in convoy. The first to detect the threat might not be in as good a position as another to respond, so the integrated control system would ensure that the one in the best position takes the decoy action.” However, Mogensen emphasises that such military scenarios are no more than an example of the sort of capability that the SA-400 has, and that the long-term strategy is to also develop its potential in the civilian world. For example, it could be used in agriculture, not only to inspect crops but, by using the side tanks, to spray them as required. Without the fuel in the side tanks the flight time is still about 45 minutes to one hour. Many and varied are the potential uses of the very clever SA-400 Jackal. Unmanned Systems Technology | Spring 2015 The SA-400 can leave its pilot behind The pilot can see, sense, smell and so on, and once you take him out of the equation you actually lose about a million sensors and a data processor