Is it possible to control the movement of an aircraft without using a single moving plane? The solution to this problem promises a number of benefits, but on the way to the cherished goal, the designers have already filled a lot of bumps. But a new exotic British vehicle made, according to the definition of its creators, a "historic flight". Historical is not historical, but important - that's for sure.
On September 17, 2010, an unmanned turbojet DEMON took off from the airfield on Walney Island in Cumbria. This unique device is relieved by its creators from the need to use ailerons, flaps and rudders for maneuvers.
True, these movable plumage elements are still present on the Demon-Demonstrator, but they can be disabled. We left them in order to compare the behavior of the car when driving in the classical and new ways.
The latter is called fluidic flight control. To put it simply, it works like this: the air, which is intensively injected into separate sections of the external flow near the bearing surfaces, changes the pressure distribution around the apparatus and thereby turns it in the right direction.
A seemingly intricate scheme has a deep meaning and ultimately leads to a simplification of the aircraft design, to an increase in the reliability of the device.
Let us explain that traditional wing mechanization is used not only to control the aircraft by roll, but also to regulate the lift during takeoff and landing, moving at low speed, and on tailless vehicles it also performs the function of an elevator.
All of these flaps, flaperons, and ailerons have worked well since the Wright brothers, but obviously add to the complexity, weight, maintenance, and chance of breakage. Therefore, engineers are looking for alternative ways to change direction or altitude.
And here, for many years, experiments have been going on in the field of boundary layer control, which, in turn, starts from the Coanda effect. By pumping out or blowing in air at key points of the wing or fuselage, it is possible, with the help of relatively thin jets, to influence the running of large flows.
But usually this phenomenon was used by innovators to reduce the aerodynamic drag of an aircraft and a sharp increase in lift at low speeds, and sometimes even as the main method of creating lift (the last example of this kind is mini-UFOs).
And the British focused their development on the problem of management. It is not for nothing that DEMON was built within the framework of the program with the self-explanatory name "Integrated industrial research of an aircraft without control surfaces" (Flapless Air Vehicle Integrated Industrial Research - FLAVIIR).
DEMON weighs 90 kilograms, its wingspan is 2.5 meters, and its speed reaches 278 kilometers per hour.
This unusual device was born in the cooperation of the transnational aerospace and weapons giant BAE Systems, Cranfield University and nine other organizations in the UK. The FLAVIIR program is funded by BAE Systems and the British Engineering and Physical Research Council (EPSRC).
So, forcing air into a set of slots in the wing creates the desired pressure drops on its surfaces, which leads to turns, a decrease or an increase in altitude. The very first flight of the DEMON drone without turning on the classic ailerons and flaps showed that this idea is workable.
In order to apply the described effect to control the flight of the drone, the shape of the trailing edge of its wing was slightly changed (in comparison with traditional profiles). However, its overall thickness remained about the same as that of conventional aircraft, which is important in terms of the prospects for the spread of technology.
This is, in general, all that can be seen during a cursory examination of the plane from the outside, apart from the unusual appearance of the engine exhaust nozzle. The rest of the innovations (that is, a set of mechanisms that control all these additional air flows) are hidden inside.
In a BAE Systems press release, Richard Williams, director of the Future Capability innovation program, said of the flight to Cumbria: "I am confident that I have witnessed an important moment in the history of aviation."
"Getting the plane to fly and maneuver safely without using conventional rudders is an achievement in itself. At the same time, we applied a number of new construction methods and new control mechanisms to achieve it. This is a very ambitious goal. And we have achieved it," the professor added. from Cranfield, John Fielding, chief engineer and leader of the team that designed The Demon.
The British say that DEMON will not be mass-produced, but the principles worked out on it in the future are likely to be used on other aircraft. DEMON, as a matter of fact, is needed to fill new cones with exotic technology.
