Air traffic increases in volume by up to six percent every year. To make air travel more environment-friendly and quieter, researchers at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR), together with partners Airbus, EADS Innovation Works and Cassidian Air Systems, have been carrying out research to reduce the aerodynamic drag of aircraft and have developed an alternative to the traditional leading-edge slat. A morphing leading edge is expected to replace slats to create an innovative high-lift system. This construction significantly reduces air resistance and noise during landing.
Credit: DLR (CC-BY 3.0).
Normally, the flaps and slats are lowered during take-off and landing to provide the necessary lift at low speeds. This creates a gap between the wings and slats, which can be seen on the right on the front edge of the wing. Air can flow through the gap from the underside of the wing to the top – generating noise. With the development of the smart droop nose (morphing wing leading edge), the researchers have solved this problem. The smart droop nose morphs in such a way during take-off and landing that the leading-edge slat is no longer needed. The leading edge can be lowered by up to 20 degrees with virtually no loss of lift.
The PowerWall display allows designers and researchers to see future systems and components in unprecedented detail, and from all directions. With special glasses, the projections are seen in three dimensions on the screen. The projectors are located inside the PowerWall.
The rotor test facility at the Institute of Flight Systems.
The world's largest research autoclave is located at the DLR site in Stade.
C²A²S²E-Cluster: Europe's fastest computer for aeronautics research
Credit: DLR/Thomas Ernsting.
Since they are ideal for displaying the two separate vortices of wake turbulence, good visibility of the condensation trails at cruising altitudes above 10,000 metres was essential for carrying out the tests. Experts at the DLR Institute of Atmospheric Physics used the Schmidt-Appleman criterion to predict the formation of condensation trails.
After arrival at the DLR Center for Lightweight Production Technology (Zentrum für Leichtbauproduktionstechnologie; ZLP) in Stade, the 16-ton lid was mounted on the research autoclave.
What looks like a wind tunnel is actually an air intake chamber. Engine researchers use the 16-metre-long, eight metre- diameter enclosure to remove turbulence from air before it reaches the compressor of an engine during testing. This allows them to achieve optimal and repeatable conditions for their experiments.Fans and compressors are important research topics at the DLR Institute of Propulsion Technology by reason of the great influence they exert on the performance of engines and their noise emissions. The researchers are working on new designs for axial and radial compressors, and verifying their multidisciplinary development techniques using prototypes. The multi-shaft compressor test facility, shown in this image being prepared for a test, is essential for this process.
Credit: DAAD / Lannert.
Reduced pressure on the top of the blade draws air upwards; this produces a vortex – the blade tip vortex – that is then directed downwards. When other rotor blades subsequently come into contact with these vortices, the 'chopping' or throbbing noise characteristic of helicopters is produced.
The GRoFi, or Large Scale Parts in Fiber Placement Technology, is based on independent robotic units for automated production of components made of composite materials.
Karen Mulleners from DLR Göttingen adjusts the model of a helicopter rotor in preparation for taking measurements.
Air flows around a rectangular wing in the 50-metre-long transonic wind tunnel at Göttingen. The wing is then caused to oscillate, as can happen during flight. This leads to turbulence in the airflow, which impacts another, smaller aerofoil that also begins to oscillate.
Computer simulation of the turbulence around models of a wing and horizontal stabiliser, as would occur during a gust of wind. The red areas show strong vortices, the blue shows areas with opposite rotation.
GroFi - Large-Scale Parts in Fiber Placement Technology is based on independent robotic units for automated production of components made of composite materials
In the Turbine Department of the DLR Institute of Propulsion Technology, the flow over the Rolls Royce rotor is made visible through the injection of dye.
Credit: Rolls-Royce Deutschland/DLR.
These investigations are being conducted in the one-metre wind tunnel at DLR Göttingen. "DLR and LaVision have a leading position in optical metrology, and we are bringing some extraordinary investigation subjects with us," explains Richard Bomphrey from the Zoology Department at the University of Oxford as he describes this Anglo-German collaboration. Oxford is one of the leading research centres for the study of insects. The insects are fixed to small rods with a drop of glue, which can be removed upon completion of the tests without harming them.
The key to understanding the flying characteristics of insects lies in precise calculation of the airflow velocities behind their wings. To establish this, these creatures are placed in a wind tunnel to enable them to exhibit the most natural flying characteristics possible. To do this, researchers exploit a reflex action; as soon as locusts cease to feel ground under their feet and find themselves facing a headwind, they begin to fly. The locusts and the moths are fixed to small rods with a drop of glue and are then blown at 11 and seven kilometres per hour respectively. This glue is removed from the insects after completion of the tests, without harming them.
A test candidate from the Germany Armed Forces during the first trial of the new helmet mounted display in the generic cockpit simulator at the DLR Institute of Flight Guidance.
Together with its partners Airbus and Lufthansa Technik, DLR has developed an electrically driven nose wheel powered by a fuel cell. This enables aircraft to move to the runway – or to taxi to their stand – without using their engines. This development can help to significantly reduce pollutant and noise emission. Studies have shown that about 20 percent of the emission of pollutants such as nitrogen oxides and carbon dioxide produced during ground operations at an airport can be avoided. In an initial test conducted in 2011 using the DLR A320 ATRA research aircraft, this nose wheel proved that the electric drive is capable of moving transport aircraft of this size.
The DLR Falcon on a measurement flight. The nose boom is fitted with a five-hole sensor to measure such things as the static and dynamic pressures in the atmosphere. Through intakes on the fuselage exterior of the Falcon, scientists collected data relating to atmospheric trace gases during the SHIVA flights, which enabled them to demonstrate that biogenic halogen compounds can be transported into the higher layers of the atmosphere by tropical storms.
The laser sensor of ALLFlight (Assisted Low Level Flight and Landing on Unprepared Landing Sites) is integrated into the small box below the helicopter. In the framework of DLR's ALLFlight research project, scientists are developing a system to generate a digital map for the cockpit and assist the pilots in difficult situations - up to a fully automated landing.
DLR researchers Gerrit Lauenroth (front) and Felix Werner adjust the laser. This makes the airflow visible.
Seldom do you find a group of travellers as quiet as these 63 mannequins.
At DLR Göttingen, the air flow in the aircraft cabin is made visible with laser and fog particles. The main obejctive of these studies are to increase passenger comfort.
DLR's FHS research helicopter during a test flight in wind conditions. Helicopters can rescue people in danger as well as transport particularly bulky and heavy loads. For this reason, it is important that the helicopter and its external load remain stable and under control during flight. DLR has developed a pilot assistance system (project HALAS - helicopter external load assist system), to stabilise and precisely position the external loads on the helicopter automatically, without intervention of the pilot. This is the purpose of DLR's research helicopter FHS (Flying Helicopter Simulator), a converted Eurocopter EC 135, equipped with the necessary hardware.
What will the aircraft of the future look like? Researchers at the German Aerospace Center are trying to answer this question. One possible option is known as a Blended Wing Body (BWB), an aircraft whose fuselage merges with the aerofoil section of its wings. These aircraft will be lighter, use less fuel and provide more space for passengers. For the first time, DLR researchers have generated computer-based designs for both the fuselage and cabin, establishing a theoretical basis for an enhanced and integrated aircraft design.
Visitors to DLR's German Aerospace Day will be able to take a look at the HBK-1 high-pressure combustor test bench. Scientists here are researching low-emission combustion chambers for aircraft engines.
The DLR Falcon 20E research aircraft was selected as the most appropriate aircraft for measurement flights. The Falcon has a full range of instruments to record flight dynamics and a nose boom that records the local incidence angle at the front of the aircraft in an undisturbed airflow.
Claus Wahl, a DLR scientist in the Chemical Analysis Department, working on a mobile measuring device to analyse exhaust emissions and measure particulates generated by 'Gas to Liquid' (GtL) fuels. In modern combustion research, chemical and instrument analyses are indispensible in analysing the emissions from combustion processes and deriving measurements to reduce pollutants.
On 18 September 2011, the German Aerospace Center (DLR) is holding its Aerospace Day in Cologne-Porz. On this date, DLR and the European Space Agency (ESA) – alongside other partners, will be showcasing their research projects from the aerospace, energy and transport sectors.
Tests have already been carried out on models of the Airbus A380 in the Cologne Cryo-Tunnel (Kryo-Kanal-Köln) – and on German Aerospace Day visitors will get to see an Alpha Jet model. Here, complete models, half models or wing profiles are exposed to wind speeds of up to Mach 0.42 (over 500 kilometres per hour).
DLR researcher Martin Frassl controls a DLR unmanned vehicle to assess the situation at the power plant. People were unable to access the site du eto a risk of collapse. In July 2011, 98 ammunition containers exploded in a Cypriot marine base, severely damaging a power station nearby. 13 people were killed. A nearby 793 megawatt power plant, providing 50 percent of Cyprus’ energy supply, was badly damaged. As part of a European relief campaign, on 22 July 2011, three members of the DLR Institute of Communication and Navigation flew to the site of the disaster.
The flight of birds is still largely unexplored; in particular, the movements performed during the beat of a wing and the airflow around the wing remain a puzzle to scientists. The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR), in collaboration with RWTH Aachen University (Rheinisch-Westfälische Technische Hochschule Aachen) and the German Armed Forces University in Munich (Universität der Bundeswehr München) is addressing this question. Starting on 26 April 2011, the scientists will be photographing the wings of an owl while in flight inside a closed room at RTWH Aachen University to obtain information about the how the shape of the bird’s wing changes during flight. This calls for basic research. Since the launch of the project in 2008, the team of scientists has succeeded in studying owl wings during gliding flight; the forthcoming measurements will be focussing on the wing beat phase.
The flight of birds is still largely unexplored; in particular, the movements performed during the beat of a wing and the airflow around the wing remain a puzzle to scientists. The German Aerospace Center (Deutsches Zentrum fuer Luft- und Raumfahrt; DLR), in collaboration with RWTH Aachen University (Rheinisch-Westfaelische Technische Hochschule Aachen) and the German Armed Forces University in Munich (Universitaet der Bundeswehr Muenchen) is addressing this question. Starting on 26 April 2011, the scientists will be photographing the wings of an owl while in flight inside a closed room at RTWH Aachen University to obtain information about the how the shape of the bird's wing changes during flight. This calls for basic research. Since the launch of the project in 2008, the team of scientists has succeeded in studying owl wings during gliding flight; the forthcoming measurements will be focussing on the wing beat phase.
On 1 May 2010, the Falcon took off at 13:00 CEST for another measurement flight over Iceland and its plume of volcanic ash. Despite light cloud cover, measurement conditions were almost perfect. The flight took the Falcon directly over the Eyjafjallajökull volcano. At a distance of approximately 200 kilometres from the volcano, the Falcon flew several times over the volcanic ash cloud at an altitude of six kilometres.
Contrails are formed from water vapor together with the soot particles ejected from aircraft. After a short time, ice crystals form in the cold atmosphere. Cirrus clouds can later develop from these contrails.
A fuel cell system delivers electrical energy capable of powering the nose wheel of a 70-ton aircraft.
The nose wheel drive system has already undergone successful tests in the laboratory, and comprises two highly efficient electric motors that are built into the rims of the aircraft's nose wheel.
On 2 December 2010, the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) opened the world's most powerful aero-acoustic wind tunnel in collaboration with German-Dutch Wind Tunnels (Deutsch-Niederländische Windkanäle; DNW). Scientists use wind tunnels to investigate the aero-acoustic properties of objects such as aircraft engines and wings. Not only is the Braunschweig wind tunnel one of the most powerful of its kind, but also it is so versatile that it can be used for cars as well as planes. This presents new possibilities in which to record and reduce sources of noise pollution.
Credit: DNW.
Thanks to its optical and electronic control system, the FHS can simulate the flight behaviour of other helicopters.
Numerical simulation: Simulated pressure distribution for an airliner in landing approach.