Unmanned Systems Technology 001 | UAV Factory Penguin C | Real-time operating systems | Hirth S1218 two-stroke twin | Base stations | ASV C-Enduro | Composites | Datacomms

25 UAV Factory Penguin C | Dossier off’ servos, as is the airbag cover and the impeller that inflates it. The operator selects a landing point, and the autopilot calculates how to arrive there, taking into account speed, wind direction and so on. The autopilot is programmed to operate the ‘landing’ servos accordingly. A servo controlled by the ECU operates the engine cooling flap to keep cylinder temperature under control. The Penguin C has engine data logging via its ECU, with monitoring software that sends the data in real time back to the ground station. There the operator can look at displays of critical engine parameters such as fuel consumption (there is a capacitive sensor that monitors the level of fuel in the tank, while there is also real- time flow rate data from the ECU based on injector pulse width). UAV Factory designs and manufactures all the Penguin control circuit boards in- house, aside from that for the autopilot. The data link and autopilot boards are each encased by a dedicated aluminium box, whereas the others are enclosed by the fuselage. At the front of the Penguin is a pitot tube used to measure speed and altitude, so its data is a key input to the autopilot. An electric heating system guards against icing. Penguin C performance UAV Factory’s injected engine is designed to run for more than 500 hours between rebuilds. At its headquarters in Jelgava, Latvia, the company has a sophisticated engine testing cell, in which a power module can be run with a propeller attached to load the engine – propellers of different sizes provide different levels of loading. Data acquisition for development work includes the use of a pressure sensor in the tiny combustion chamber. The cell’s control system allows for flight simulation with unattended operation, so that engines can be run for hundreds of hours at a time for durability testing; engines are routinely tested for 60 hours at a time. The Penguin C is designed to operate routinely from -10 C to +40 C, so next to the cell is a fridge that is used to cool a power module to -30 C, to ensure it will then restart and run properly from that temperature; there is also an oven for a high-temperature test. The Penguin C is environmentally sealed with, for example, neoprene seals around all covers and with electronic components silicone-coated for protection; this keeps it flying through rain. Thanks to its sophisticated silencer, the engine has a low acoustic signature: measured from 30 m it registers only 59 dB, and at 5000 rpm it is claimed to be undetectable beyond about 700 m. The engine runs from 1600 to 8500 rpm and produces maximum power of 2.1 kW at 8,500 rpm (with 2.5 Nm maximum torque at circa 7,000 rpm). The development of fuel injection in-house is claimed to have improved fuel efficiency by 30% over an earlier, carburettor version of the engine, and with a significant improvement in reliability. Fuel consumption is quoted as 400 g/kW/h in cruise mode. In terms of fuel consumption, and hence the maximum possible length of mission, the most efficient speed is close to stalling, but for safety reasons the autopilot will be programmed to set a higher speed. There is also a compromise to be struck between the safe speed that provides the longest time in the air and the higher speed that covers the most miles on a given amount of fuel; this compromise depends on the mission. The Penguin C is designed for up to 20 hours of continuous mission time. Normal cruise speed is in the 37-43 kn range, and maximum level flight speed in still air is 70 kn. Maximum operational height is 4500 m. As such, it is clearly a powerful tool, one set to continue the Penguin success story for many years to come, flying high across many parts of the globe. Close-up of a Penguin C showing the gimbal and with the front cover removed The company has a testing cell in which a power module can be run with different propellers to load the engine Unmanned Systems Technology | November 2014