32 all serial-numbered components to be stocked on shelves, retrieved and laid out in preparation for the assembly of a new UAV. These are largely pieces of aluminium for the body panels and bulkheads, which are made via a combination of laser and waterjet cutting, with ACC currently evaluating both processes for the best application in series production (laser cutting is potentially 20 times faster, but does require more rigorous programming, as well as significant stock of nitrogen for cooling to prevent thermal expansion in the metal). Four smaller, isolated rooms run in sequence along the length of the manufacturing floor, each one dedicated to a different stage of aircraft manufacturing. In the first room, rotor pylons are assembled; a process facilitated by a 1 t iron jig. Before riveting any aluminium sheets, ACC’s production staff will affix them to this jig, preventing any unintended bends being allowed into the body geometry, which would mean unwanted tension in the pylons. Claes demonstrated the risk of this problem by hand-lifting a large, 0.4 mm aluminium sheet for us, with it visibly flexing and wobbling under its own inertia when not held by rivets or tabs, as it is in the Thunder Wasp. For comparison, he then hand-lifted an assembled rotor pylon, which exhibited no flexing. The complete fuselages (including the central bridge section) are put together in the second room, also on a jig, before being moved to room four, where the complete UAV will be assembled. In the third room, the fuel tank is put together on another jig. The fourth room exists for the rotor systems and powertrains themselves to be installed in the pylons, and, as of writing, the engines are stocked here accordingly. Claes and Max showed us one unit of the engine, a TS100 from Czechia’s PBS Group, environmentally sealed in a vacuum bag in one of six identical crates. “Those six engines are our total stock of them at the moment,” Claes says. “It’s one of our most costly subsystems, but the power output and performance consistency are both very good for our purposes.” Once a UAV has passed through all four rooms, it is rolled out to the open area for systems integration and electrical installations. In a separate prototype workshop, the aircraft are allowed to be test-run at full power. They can be weighed down with concrete blocks for simulating real-world payload masses, with gas conduits for pumping exhaust safely out of the building and away from ACC’s people (and the aforementioned rotor test rig also sits in this room). “We will also test surplus rotor pylons here, running them on a test UAV to validate them. If the pylon passes those performance checks, we can remove it and put it in stock until it is needed for assembly into a sold unit,” Claes says. To remove a pylon for stock, maintenance checks and repairs, or when collapsing a Thunder Wasp for transport, an electrical connector running to the servos is first disconnected, roughly where the bridge and pylon meet. Then, 12 bolts around the pylon’s mid-section can be removed, after which the pylon slides off the bridge end. It can then be carried by one person to a specified room or fitted in a standard road van. Heavy fuel turbo As mentioned, the engine at the heart of the Thunder Wasp GT is PBS Group’s TS100, which has a peak power output of 241 bhp (180 kW) and a maximum continuous output of 214 bhp (160 kW) at which it has an SFC of 0.863 lb/hp/hr (524.94 g/kWh), with a typical operating fuel consumption of 67 kg/h, and a top output shaft speed of 2158 rpm for driving the transmission to the rotors, which run at roughly 1650 rpm. The 61.2 kg turbine engine measures 39.8 cm tall, 33 cm wide and 82.8 cm long, and it comes with an integral power turbine, gearbox and a 1 kW electric generator, of which 720 W may be used by the aircraft itself. “PBS is known for good engine design and expertise, plus this engine had exactly the performance we needed and proved very simple to control via its integrated ECU,” Max says. “We integrated its CANaerospace protocol into our autopilot, and that gives an interface with all the dials and December/January 2025 | Uncrewed Systems Technology Within the halls of Industrigallerian, ACC Innovation’s series manufacturing of Thunder Wasp GTs (and Dragonflies) is taking shape
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