Unmanned Systems Technology 003 | UAV Solutions Talon 120 | Cable harnesses | Austro Engine AE50R and AE300 | Autonomous mining | AUVSI 2015 show report | Transponders | Space systems

10 Platform one Summer 2015 | Unmanned Systems Technology To meet the growing sophistication of UAVs, and as the demand for shared airspace leads to the need for systems that echo those of manned aircraft, Volz has introduced a fully redundant version of its DA26 servo actuator. The DA26 has been proven since 2008 and this new version, the DA26-D, in effect doubles it up, so that if one side should fail for any reason then the other can continue to operate the craft. Volz’s Mark Juhrig explained that the DA26-D is fitted with two actuation motors, two control circuit boards, two bus and power interfaces and so on, albeit with a single output. He also said some aspects of the control code have been simplified, to minimise potential sources of error. Some additional diagnostic code has been added as well, to detect and flag up any failing components. Of course, the redundancy has inevitably increased the weight of the unit. Juhrig also acknowledged that if one of the motors fails then there will be a 55% power loss as the remaining motor drives the output against the magnetic resistance of that motor. Juhrig gave the example of an unmanned helicopter as a key use of the DA26-D – if the servo operating its swash plate fails, the entire craft goes into emergency mode. While the use of the DA26-D still implies a single output shaft, Juhrig noted that since 2008, more than 1000 units of the DA26, which has the same geartrain and shaft, have been shipped, without any problem of that nature. Also new from Volz is the DA30, which features a ruggedised geartrain that reduces backlash and gear wear. The key to this is in the use of patented sinusoidal gears, reducing points of contact. “A traditional geartrain needs backlash to work,” Juhrig said, “and that is a compromise in the servo application such as this. We are working with the patent holder to exploit this new technology.” Actuator’s safety in numbers UAV hardware The Volz DA26-D actuator comes with full redundancy The Groupe Danielson Trident 100TD2 1.1 litre I3 turbodiesel profiled in depth in our previous issue ( UST Spring 2015) has been fitted to this light aircraft for flight testing. Danielson Aircraft Systems (DAS) reported that it has “replaced a Rotax 912S engine without significantly altering the weight”. We are also told that the 100TD2 has completed more than 4500 hours running on a test rig complete with propeller. DAS adds that a new propeller shaft and gearbox design is being tested, enabling the use of off-the-shelf hydraulic variable pitch propellers. This system is currently being tested with a Hartzell graphite variable pitch propeller. The 100TD2 is currently “in evaluation with several customers in the US and in Europe”. Meanwhile, Groupe Danielson is establishing a new foundry and a new machine shop, “to be able to cope with the increasing demand for the 100TD2”.