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

20 Dossier | Scion UAS SA-400 optionally piloted helicopter time. Moreover, it had to be capable of taking off from and landing on a seaborne platform in conditions up to sea state three, which implies wave heights up to 1.25 m (49 in). “That means landing on a pitching, rolling, heaving platform,” notes Mogensen. “In addition, we had to make it fly sideways alongside the ship in a headwind and be controlled by the payload. Being able to do all of that is part of the trick!” The brief from the NRL imposed a very tight timescale for delivery of the first vehicle. Mogensen says that ruled out a clean-sheet-of-paper design. Instead, to win the bid it was necessary to re-engineer an existing and proven rotorcraft. Having studied the market, Scion UAS identified Eagle R&D’s Helicycle model as being ideal as a base for the SA-400. This is a one-man helicopter with a single main rotor, powered by a turbine engine. Sold as a kit for assembly by the customer, it was designed to be as affordable as an SUV. With its 90 bhp power unit, as standard it cruises at 95 mph and has an 11,000 ft operational ceiling. Designed by Buford John (‘BJ’) Schramm, the Helicycle has been for sale since 1997, and more than 70 examples have been completed and flown. Since 1997, more than 5000 flying hours have been logged by Helicycle owners, and when it came to analysing the Scion UAS bid, the NRL was impressed with the integrity of the Helicycle as the platform for the SA-400 Jackal. Having won the contract in September 2012, Scion UAS quickly took delivery of a Helicycle kit and built it up essentially as a standard product to establish a baseline for development. It also added an autopilot and servomotor-based controls in parallel with the standard controls so it could evaluate its potential as an unmanned craft, and it heavily instrumented the craft for the purpose of data gathering. In this form it made its maiden flight on December 23, 2012. While Mogensen notes that most of the SA-400’s components are upgrades from the Helicycle base, he adds that the re- engineering of it has involved “changing 90% of the parts. Looking back, it might seem that it would have been better for us to have started with a clean sheet of paper, but that wouldn’t have been possible within the timescale, especially as we needed a proven base to win the bid.” Mogensen remarks that Scion UAS has developed a good working relationship with Eagle R&D, from which it directly buys Helicycle kits. As an example, Eagle R&D didn’t have a complete CAD model of the craft and Scion UAS needed one for its development of the SA-400, so with agreement from Eagle R&D, Scion UAS reverse-engineered the missing components of the Helicycle in SolidWorks and has now shared that data with Eagle R&D in an ongoing spirit of cooperation between the two companies. Scion UAS chairman Jim Sampson adds, “We were taking an aircraft that typically flies at 850-900 lb gross weight and making it fly at 1200 lb. To do that, everything had to be analysed for strength, robustness and durability. We strengthened the frame, and in the moving parts we upgraded the bearings: we got rid of as many grease bearings as we could and went to self-lubricated versions such as Teflon-lined stainless steel – bearings that work in a wet or gritty environment. “That process of upgrading went on throughout the aircraft, so there are some fairly significant changes to the basic mechanisms. Then of course we had to allow for the servo motor integration into the hardware components, so that we can actuate them from our control system. Also, there is an entirely new carbon chassis, with the cabin and the fuel tanks.” Spring 2015 | Unmanned Systems Technology The SA-400 undergoing flight trials We had to make it fly sideways alongside the ship in a headwind and be controlled by the payload. Being able to do all of that was part of the trick!