In order to revolutionize stealth military aircraft, the American army is working on an X-Plane devoid of movable control surfaces. Here’s how.
For several years now, the American army’s research and development agency, Darpa, has been developing an X-Plane as part of the Crane project (Revolutionary aircraft control with new effectors). The aircraft is designed to reduce air friction on its cabin as much as possible in order to increase performance, and also reduce its radar signature as much as possible.
The aircraft does not have elements mobilesmobiles, such as daggerboards or flaps. In their place, the technology relies on what Darpa calls an Active Flow Control (AFC) system. On the cabin there are small thrusters or vacuum cleanersvacuum cleaners air valves that activate to change the airflow around the aircraft and maneuver it.
Darpa announces the launch of phase two of its futuristic stealth aircraft program. © Darpa Twitter
A future three-ton demonstrator
This January 17, the American agency announced that the preliminary design phase of the program has been completed. This means that a prototype equipped with the AFC system has been successfully tested on a wind tunnel test bench. Phase two will now begin. It will consist of developing softwaresoftware and flight controls to be able to design a real demonstrator. In phase three, a full-scale prototype weighing more than three tons will incorporate the AFC for flight testing.
It is always AuroraAurora Flight Sciences, a subsidiary of Boeing, which will lead this program. For the moment, on its test bed, the plane is modular. This process allows the wings and AFC modules to be replaced. This modularity gives it a certain flexibility to carry out different tests and find the most efficient architecture.
The Pentagon is working on an X-Plane without rudders or fins
Optimizing the flow of air around the cabin of an aircraft to reduce friction to zero is what the Pentagon seeks to do with an aircraft project devoid of fin or ailerons.
Article by Sylvain Biget, published on November 23, 2020
The aircraft should look like an arrowhead. No fin, no rudder, an elongated and pointed profile. Here is the artist’s impression of the experimental aircraft project of Boeing subsidiary Aurora Flight Sciences. For this X-Plane, the principle consists in reducing as much as possible the friction of the air on the cabin of the aircraft in order to increase its performance. The research is part of the Crane project (Revolutionary Aircraft Control with New Effectors) of Darpa, the US Army Research and Development Agency.
This project would make it possible to obtain a powerful and stealthy military aircraft because it has a low radar signature with such a profile. More ailerons therefore, but also more flaps to modify the profile of the wing at low speed and avoid the stallstall close to the ground. Instead, the technology relies on active flow control (AFC).
Make the air slide without slowing it down
Instead of moving planes, these will be small thrusters or vacuum cleaners that activate as needed to add theenergyenergy necessary for movement, or alter the airflow around the aircraft. For the rest, the cabin of the aircraft will be perfectly smooth and devoid of anything that could alter the aerodynamics. In all cases, the idea is to reduce friction as much as possible to improve performance. In addition to Aurora, the University of Arizona in the United States will conduct research for a first phase that will last at least a year. It should be noted that in parallel, other work, with the key to a demonstratordemonstrator, are led by Lockheed Martin and the Georgia Tech Research Corp. under the authority of Darpa.
