In the world of aviation, it is known that as the cumulative surface area decreases, the speed increases along with streamlining the whole aircraft. NASA has been working on a design wherein the flight in question can fold its wings and NASA says there are advantages and will make it happen.
The key here is not to create controlled dives — like a hawk does when it folds its wings to plummet down at a high speed — but to increase the efficiencies and capabilities of the aircraft. The space agency calls this Spanwise Adaptive Wing (SAW). As of now, articulating wings have been used mostly for parking purposes, to allow planes to take up less space on an aircraft carrier’s decks or fit into smaller hangars. A few very large aircraft have folding wings to help them taxi between infrastructure at an airport. NASA says they have a very different idea from all of this.
Supersonic aircraft and very heavy aircraft both require vertical stabilizers for yaw control during flight. NASA says that smaller, more precise wing articulation and control is now possible thanks to advancements in the actuators required to move the wings. Most wing articulation is currently accomplished with heavy, bulky actuators that are usually hydraulic rather than electric. This has been because the hydraulic ones are the most time tested physical movement option on aircrafts today.
One example for use of articulating wings would be for supersonic aircraft. When flying at very high speeds, aircrafts create a lot of lift, but have less yaw control as a result. Thus folding the ends of wings of the aircraft will add more stability by creating more vertical surface to augment the rear tailfin. However, the plane would not lose critical lift during the difficult takeoff and landing stages because the wings could be straightened to add the lift surface to flight.
NASA has intended to test these ideas on the scale model PTERA (Prototype-Technology Evaluation and Research Aircraft) in the spring of 2017. That will coincide with ground-based tests of full-sized actuators capable of scale wing articulation. The objectives of this testing will be validation of tools and extensive testing of the system’s theoretical vehicle control evaluation. A full comprehensive analysis of airworthiness and potential fuel savings will also be done.
