Adaptive wing

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An adaptive aircraft wing has at the trailing edge of the flaps , movable narrow additional flaps, by which the blade camber is changed so that, for each flight condition the optimal buoyancy is achieved. The purpose of this adaptive wing: It improves the aerodynamics of the aircraft , which reduces aircraft noise and fuel consumption. In addition, the aircraft can take off or land on shorter runways and also take off and take off more steeply. This lowers the noise pollution in the vicinity of the airport. The new flaps are already being used in a test version of the Airbus A340-300 . In the medium term, all Airbus aircraft could be equipped with it and make the aircraft more economical and environmentally friendly.

development

Developers took a step in the direction of an adaptive wing several decades ago: They installed extendable landing flaps on the trailing edge of the wing, which represented a good compromise between the higher lift required for take-offs and landings and a much smaller wing area sufficient for cruising flight . In the mid-1990s, researchers began to work intensively with the adaptive wing. The “high lift concept” project funded by the German Federal Ministry of Economics and Technology developed a first variant of multifunctional trailing edge flaps called “Mini-TEDs” (TED = Trailing Edge Devices). As part of a technology program, “Mini TEDs” were developed in cooperation between Airbus and EADS Innovation Works and subjected to a structural analysis on a first test bench. Since then, research in this area has been in full swing.

Mini TEDs

In principle, the “Mini-TEDs” function like a “ Gurney Flap ” in a racing car. Such a flap, which is positioned 90 degrees into the wind at the rear of the car, provides downforce , i.e. contact pressure on the rear axle , at higher speeds . The engineers made use of a similar effect with the adaptive wing - just the other way around: They installed the mini TEDs - 9 to 15 centimeters wide flaps made of carbon fiber composite material - on the underside of the landing flaps. If you fold out the “Mini-TEDs” by up to 90 degrees, they generate additional lift.

aerodynamics

If the "Mini-TEDs" on the wing's trailing edge are extended, a wake flow is created by two opposing air vortices . The airflow flowing past is deflected downwards so much that additional lift is created on the wings, which of course improves the flight characteristics of the aircraft. The flow path on the wing surface remains unaffected by the "Mini-TEDs", but the air resistance of the flaps is rather low. In some situations, such as the landing approach, this resistance is definitely desirable: Because the additional lift of the “mini TEDs”, the aircraft takes off earlier during take-off and pilots can approach the runway at a steeper angle. In both cases, the aircraft spends less time at low altitudes and the noise footprint , defined as a reference with a noise level of 80 decibels (roughly equivalent to the noise of a passing car) , becomes smaller.

But the “mini-TEDs” could also develop their effect during normal cruising. In this case, however, no noise footprint is reduced, but the flight is made noticeably more pleasant for the passengers. If the "Mini-TEDs" are linked to a turbulence sensor via the flight control, they can change the lift distribution over almost the entire span of the wings at lightning speed. Turbulence therefore has a much smaller effect on the aircraft. With the help of the "Mini-TEDs" they are practically counteracted. Such a flexible distribution of lift also has an impact on the construction of the wings. Because their strength requirements are essentially determined by the forces that cause gusts during flight. If gusts are generally lower through the use of “mini-TEDs”, developers could already take this into account when designing new wings. In the future, wings could be constructed with even less weight, which saves fuel and increases the range of aircraft.

However, this would require the use of absolutely fail-safe flight control electronics, since their failure would directly endanger the structural integrity. In the case of military aircraft with mini-TEDs, the use of the ejection seat would remain to rescue the occupants, which, however, could only be achieved with disproportionate effort in commercial aircraft, at least if all aircraft occupants were to be rescued.

AWIATOR

All current European research on the "Mini-TEDs" is being carried out within the framework of AWIATOR (Aircraft Wing with Advanced Technology Operation), a research project of the European Union . Under the direction of the EADS subsidiary Airbus, the Munich and Berlin Technical Universities and more than 20 partners from the EU and Israel are developing the most modern wing technologies for the next generation of commercial aircraft . The aim of the project is an overall wing design that combines promising technologies for active load control, gust load reduction, noise reduction and the reduction of wake vortices . In various individual projects - one of which is the “mini TEDs” - the different methods and components are first analyzed and then tested in flight tests.

See also

swell