Prof. Rolf Henke: Aeronautics and traffic research by DLR in Niedersachsen

The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt – DLR) not only focusses on basic research but also primarily on application-oriented aero­­­nautics research. The primary objective of DLR aeronautics research is to boost the competitiveness of the national and European aeronautics industry and aviation industry and to fulfill the demands set forth by government and society. DLR is addressing the challenges of making the rapidly growing air transport sector effi­cent, environmentally friendly and sustain­able. DLR’s technology portfolio is based on the objectives of the European strategy paper “Flightpath 2050”, which superseded “Vision 2020” in 2011. The strategy paper describes the challenge of meeting societal and market’s needs, maintain­ing and extend­ing European industrial leadership, pro­tecting the environment and energy supply, as well as ensuring the safety and security of air traffic. Addi­­­tionally, research prioritisation, testing capabilities and education are being addressed. Among other things, these objectives will result in the development of an air traffic man­­agement system suitable for 25 million flights per year in Europe, the reduction of carbon dioxide emissions per passenger kilometre by 75 per cent (90 per cent reduction in nitrogen oxide emissions), the lowering of the accident rate in European aviation to less than one per ten million commercial aircraft flights, as well as the possibility for 90 per cent of the Euro­­pean people to reach their favour­ed des­tination in merely four hours.

To achieve these European goals, the Advisory Council for Aviation Research and Innovation in Europe (ACARE) is devel­­­o­­ping a Strategic Research and Innova­­tion Agenda (SRIA), which will supersede the existing Strategic Research Agenda (SRA) in 2012. The SRIA will also influence DLR’s aviation strategy.

With its existing aeronautics institutions the major aeronautic sites are located in Braunschweig and Göttingen, participa­­tion in the German-Dutch Wind Tunnels (DNW) and in the European Transonic Wind­­tunnel (ETW) as well as a fleet of research aircraft and helicopters, DLR possesses the capability to monitor the entire air transport system. DLR’s research on this subject includes land-based and airborne operations at airports, the aircraft as a highly complex system and flight management activities. A large part of the aeronautics research conducted by DLR is done at Niedersachsen locations Göt­­tingen and Braunschweig. In Stade, one of two Research Centres for Lightweight Construc­­tion Production Technology (ZLP) is currently being established as an ad­­ditional DLR-location in Niedersachsen.

Wind tunnels are an important factor in research for quieter aircraft or automobil­­es because they can be used to measure the aerodynamic and aeroacoustic proper­­ties of the tested objects. This is im­­portant in identifying sources of noise or measuring aerodynamic lift and stability. In December 2010, at the Braunschweig site, the DLR opened the most powerful wind tunnel in the world together with the DNW, which can be used for aircraft as well as for automobiles. In modern commercial aircraft, primarily the dominant main sources of noise creation are the focus of research, for example the engines, in addition to the landing flaps or the ex­­tended landing gear. Until now, minor sources of noise, which are still sig­nificant in their sum, could not be identified due to the intrinsic noise of the wind tunnel. This is now possible thanks to the new wind tunnel in Braunschweig. Disruptive sources of noise can be directly identified and thus excluded.

Flights with the flight simulator can even provide information on the use of the air­­­­­craft later on from the ground. In addition, DLR is planning a new simulator centre in Braunschweig, in an important step into the future of aeronautics research. The joint project between DLR and the TU Braunschweig is being in­corp­orated into the existing infrastructure and will create unique possibilities in aeronautics research. This is where application research meets the universities’ academic approach to science. The centre’s core topic of research is the dynamic interaction between man and machine. Among other things, critical situ­­­ations are also to be simulated, ex­­peri­­mental campaigns prepared and studies on training efficiency conducted. Research on the effects of wakes, which are caused by aircraft flying ahead in air traffic, and the separation distances, which define air­­port capacity, is just one of many further important topics of research. Other re­­search topics include examinations of active control elements, such as the further development of the so-called sidestick, which was introduced to commercial avia­­tion by Airbus and which replaces the conventional control stick or the steer­­ing column of an aircraft. In addition, new cockpit display systems for helicopters are being tested to improve flight stabil­ity when transporting externally suspended loads as well as all-weather capabil­­ities and landing in poor visibility.

 DLR conducts many of its projects in cooperation with other research institutions such as NASA and industrial partners such as Rolls Royce or universities. For research into quieter landing, DLR has joined forces with Air Berlin, the German air traffic control centre Deutsche Flug­­sicherung (DFS) and the Frankfurt airport operator Fraport AG to research possibilities of reducing aircraft noise inter­fer­ence in communities in the greater Frankfurt area. The goals of the experiments were, on the one hand, to shift the noise away from the communities and, on the other hand, to prevent noise alto­­gether. Using state-of-the-art research in­­stru­­ments, the part­­ners tried various ap­­proach angles and approach paths. The satellite-supported Ground-Based Aug­mentation System (GBAS) was used during all approaches. GBAS is based on GPS, which makes it possible for satel­­lite signals to determine the exact location of a GPS receiver – in this case the air­­craft. A system on the ground improves the preci­­sion of GPS positioning to less than one metre when using GBAS. This means that pilots no longer need to ap­­proach the air­­port in a straight line from an early stage on; in­­stead they can deviate from the straight line thanks to highly precise 3D-waypoints. With GBAS, the pilot can choose from dif­­ferent approach angles and can fly parti­­cu­­larly steep or curved approach routes.

Also focussing on noise prevention, experiments were conducted with a helicopter, which DLR carried out together with re­­searchers from NASA in Göttingen. The greatest amount of noise created by a helicopter is generated by the rotor, which makes it possible to take off or land vertically. The rotor noise was the focus of the re­­search – helicopters need to be made quieter in the future.

Aside from aircraft, airports are also an additional focus of DLR’s research. Effect­ively managing airport processes is the equivalent of a logistical masterpiece: A growing number of passengers and freight want to be transported from one location to the next inexpensively and as quickly as possible. As a result, the hubs on the ground not only serve as hubs for air transport, but they are also the main gateway to other modes of transport. The airport as a system is being examined by DLR traffic researchers in Braun­­schweig together with partners from the German aerospace industry in an unprecedented approach. For the first time, a real-life and practice-oriented research project is being de­­signed to develop a multi-modal land and air-travel oriented airport management system. TAMS (Total Airport Mana­­ge­­ment Suite) aims at managing the activities of airport operators, airlines, air traffic control and other parties involved in the entire airport system more effectively in order to reduce process-related inef­­fici­­­encies such as waiting peri­­ods and environ­­­mental burdens. Investi­­ga­­­tion at numerous Euro­­­­­pean airports led to the con­­clusion that there is considerable room for improve­­ment when all parties involved in flight opera­­tions better coordinate their actions. This not only reduces costs, but fewer de­­lays and waiting periods can also signifi­­cantly reduce environ­­mental bur­­­dens. In addition, passen­­­gers have a better chance of making their connec­­ting flights. The project is supported by the German Federal Ministry of Eco­­nomics and Tech­­no­­logy as a light­­house project.

The author has a degree in aerospace technology from the Technical University of Berlin. He held various positions at Airbus for over 20 years, before assuming the position as a professor of aerospace engineering at the RWTH Aachen, where he headed the Institute of Aero­nautics and Astronau­tics. In 2010, Prof. Henke became a member of the executive board of DLR, where he is responsible for aeronautics research.