NASA engineers have successfully tested a fundamentally new unit on flying models - a wing-folding actuator based on a shape-memory alloy activation technology. There are no usual pneumatic, electromechanical or hydraulic devices here, there are not many parts. The wing bends because it has been programmed to take the desired shape when a certain stimulus is applied.
To achieve what they wanted, scientists had to develop a new alloy based on hafnium, nickel and titanium. It is distinguished not only by the fact of shape memory, but also by the effort with which a metal product takes it. The torque reaches 564 Nm, which is enough to bend the 136 kg section of the wing of the aircraft 90 degrees relative to the main body. Directly in flight, with high precision to maintain the stability of the aircraft in the air.
The key achievement here is that the alloy takes on a "memorized" shape not by itself, but in a controlled manner. And the control system has the ability to stop the process by moving the section to the specified distance. True, it is not clear what exactly serves as the initiator of the process, how reliable is all this in comparison with traditional mechanisms, and how to initially bring the wing into a shape that differs from the memorized one - by the press?
The authors of the technology cite two obvious advantages. The wing drive is 80% lighter after removing the old mechanisms. Plus, the innovation is great for carrier-based aircraft, which is stored with folded wings. A more powerful version of the drive is currently being developed, with a torque of up to 2260 Nm, which will be tested already on a real laboratory aircraft in a few months.