Issue 54 Uncrewed Sytems Technology Feb/Mar 2024 uWare uOne UUV l Radio and telemetry l Rheinmetall Canada medevacs l UUVs insight DelltaHawk engine l IMU focus l Skygauge in operation l CES 2024 report l Blueflite l Hypersonic flight

110 UVD | Blueflite Patented and unique The overall design and architecture of the vehicles are Blueflite’s intellectual property, protected by a patent, Noppel says. US utility patent number 11492106 covers the entire design and functionality, including the independent tilt mechanics, staggered wings, integrated cargo bay and modularity. “We integrate third-party supplied components, such as propulsion systems and micro-electronics, which adhere to our standards and meet technical requirements. We carefully select the best to steadily raise the bar.” He emphasises that Blueflite provides a turnkey solution, encompassing the vehicle hardware, the onboard software stack and the operations software. “Only being in control of all three elements enables us to meet the stringent requirements to serve as a delivery drone platform provider,” he says. The vehicles have several patented features that Noppel describes as unique. These include vectored thrust for agile and precise flying characteristics, and energy-efficient, high-speed cruise, and a high degree of modularity. Another feature is an internal payload bay with a volume of about 0.1 cubic metres and multiple access points, including an automated belly door. Payloads can be dropped or winched down, and potentially loaded using an automated system. They can also be manually loaded and unloaded through a top hatch, which could be automated. Noppel emphasises that the vehicles’ support of autonomous loading and unloading limits their human interaction to professional and qualified people, minimising the risk from the open rotors. “We have also developed plug-and- play technology that enables the operator to assemble and disassemble the vehicles in the field in a short time, without much hassle,” he adds. A question of size Cobalt and Slate measure about 1.5 m x 1.5 m, with the propellers defining the extremities, but they are scalable. “Right now, we are keeping the all-up weight below 55 lb to stick to regulatory requirements, but larger and smaller versions are conceivable. This limit does not apply to military drones,” says Noppel. The fuselage has a 3D-printed loadbearing framework, to which stressed carbon-fibre panels are attached. Two grades of carbon fibre – 3K and 6K – in resin-impregnated “prepreg” cloth form are used. The K grades refer to the modulus, or stiffness, of the carbon strands, with the figure indicating the number of single carbon fibres twisted together to form each strand, with higher numbers denoting greater stiffness. With a payload of up to 5 kg, Cobalt is intended for relatively short-range operations, during which it will need to hover for an extended period of time and may lift objects off the ground. Its large-diameter propellers are spun at relatively low rpm by high-torque motors, achieving a top speed of about 45 mph and a range of 20-30 miles, depending on the payload. With about half of Cobalt’s payload capacity, Slate has different propellers, optimised for speed and range. As it has poor energy efficiency in the hover, it needs to transition to wing-borne flight to make the most of its battery charge. Slate’s motors are optimised to cover a different operating envelope, using higher rpm to achieve the required power and airspeed. Blueflight expects Slate to reach the 100 mph limit for civil UAVs, with a projected range of up to 90 miles. Modular propulsion Cobalt’s propulsion motors are in Vertiq 81-08 modules, where they are tightly integrated with a 60 A electronic speed controller (ESC), designed for use with lithium polymer (LiPo) batteries in 12S format, which have 12 cells connected in series. Each motor has an embedded position sensor, and the ESC runs advanced calibration and control algorithms. They are available with different voltage constants of 85 Kv, 150 Kv and 220 Kv. Maximum continuous torque is 2.3 Nm in flowing air. In general, motors with higher Kv values spin at higher speeds but provide less torque, while those with lower Kv values tend to produce more torque at lower speeds. Each pair of motors is supported on the end of a carbon-fibre arm by an aluminium mount. The arm is rotated in pitch by its actuator, while each tilt actuator is controlled independently, allowing for very precise and agile flying characteristics, Noppel says. “The drone can respond quickly and better operate in difficult weather conditions, such as high winds. It can also reduce time in the hover to save February/March 2024 | Uncrewed Systems Technology View down into the payload bay, revealing the 3D-printed load-bearing structure, along with payload bay-door actuators. Payloads can be lifted out or dropped or, as a later option, winched down