Articles for "Aeronautics"

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Aeronautics | 01. September 2021 | posted by Bernd Kärcher

Soot in aircraft exhaust and the climate impact of air traffic

Kondensstreifen am Himmel
Credit:DLR (CC BY-NC-ND 3.0)
Aircraft engines emit soot particles that act as 'condensation nuclei'. Small cold water droplets immediately condense and freeze into minute ice crystals, becoming visible as contrails in the sky.

Aircraft emissions are associated with all sorts of environmental problems. Researchers have long been studying the different kinds of emissions in order to understand how air transport is altering the composition of the atmosphere, cloud cover and the climate. Aircraft contrails are anthropogenic clouds of ice. My work in the 1990s showed that the physical properties of the white wispy trails aircraft trace across the sky are best explained by their soot emissions – black carbon particles and condensable substances like sulphuric acid produced during the combustion of fossil fuels such as kerosene. read more

Aeronautics | 08. June 2021 | posted by Florian Wozny

Climate-neutral flight through carbon dioxide offsets – an interim solution

Flugzeug am Himmel
Credit: DLR/Alejandro Morellon (CC-BY 3.0)
More environmentally friendly air transport of the future – interim goal of climate-neutral flight

Since 2021, airlines have had to offset emissions on international flights that exceed the average values for 2019. This is done with the help of carbon dioxide compensation projects that invest in renewable energy sources or the preservation of forests, for example – that is, reduce or store greenhouse gas emissions. Credits are then issued for these projects. However, the climate impact of the credits depends strongly on the underlying project types. In a new DLR discussion paper, my team and I show the limits of mandatory offsetting.

Rising fuel prices have already led to airlines investing in technological advancements, as fuel accounts for approximately one third of total operating costs. For example, engines and combustion processes have been improved over the years. Fuel consumption is falling by about two percent per year. However, the environmental benefits have been offset by the enormous increase in air traffic. Policy-makers are faced with a dilemma. read more

Aeronautics | 25. November 2019 | posted by Johann Dauer

ALAADy symposium: Face-to-face with a new transport drone

ALAADy Symposium in Braunschweig
Image: DLR

Can low-cost drones capable of carrying as much weight as a pickup truck be built and operated cost-effectively? An interactive event format brought representatives from industry and humanitarian aid organisations and DLR researchers together to discuss this topic. A new technology demonstrator and almost four years of research results were presented at the Symposium on Automated Low-Altitude Air Delivery in Braunschweig. read more

Aeronautics | 08. November 2019 | posted by Georg Dietz

From idea to take-off – preparing for a HALO measurement flight

Credit: DLR (CC-BY 3.0)

No matter how many measurement flights we have already conducted, just before take-off the entire team assembles in front of the hangar and watches HALO's departure together. However, it takes days of planning and preparation to get to this point. For the SOUTHTRAC mission, all activities are carried out according to a fixed schedule, which is designed to ensure that flight preparations go as smoothly and efficiently as possible. Preparations for each flight take four days. As a measurement flight usually takes place every other day, several flights are always being planned at the same time, which is a complex task for everyone involved. At this point, I would like to present a timeline of the processes that have to take place before a measurement flight. read more

Aeronautics | 11. July 2018 | posted by Johann Dauer

Unmanned helicopter superARTIS delivered humanitarian goods

Credit: DLR (CC-BY 3.0)
Preparation of the next flight

During the second week of the pilot operation in the Dominican Republic, the superARTIS team performed different humanitarian delivery missions together with Wings for Aid and the World Food Programme. The flights took place in an area called 'Bajo Yuna', which suffers from frequent flooding and related 'last mile' delivery problems. These flight tests are one of the founding stones to connect DLR's UAS projects with applications in humanitarian technology. read more

Aeronautics | 28. June 2018 | posted by Johann Dauer

Helicopter UAS superARTIS on a humanitarian mission in the Dominican Republic

Credit: © DLR
Discussions with local stakeholders such as the Red Cross and identifying possible missions for the simulation

Last weekend, a team from Wings for Aid and DLR travelled to the Dominican Republic (DR), to test Unmanned Aircraft Systems (UAS) for humanitarian aid. They planned to deliver disposable boxes carrying 20 kilograms of emergency goods and drop them safely at their destination using DLR’s helicopter UAS, superARTIS. read more

Aeronautics | 01. September 2016 | posted by Fabian Locher | 3 Comments

A day in the tropical sky

Flugplatz Togo
Credit: DLR (CC-BY 3.0)
The apron of the hangar – the Falcon is ready for more measurements

It is the middle of the night on the coast of West Africa. A team of sleepy aircraft technicians and atmospheric researchers exit the hotel lobby. The humidity hits them like a brick wall – it is already 25 degrees Celsius outside. Their departure for Gnassingbé Eyadéma Airport is scheduled at four AM sharp. The first motorcycles of the day thunder past the walls of the hotel complex. Today’s take-off is set for 09:30. But the chauffeurs are late – again.

At 04:30, two cars drive up along the beach promenade through the still quiet streets of Lomé, the capital city of Togo.

Credit: DLR (CC-BY 3.0)
En route to the hangar via Boulevard Du Mono.

Twenty minutes later, the group reaches their destination – a small hangar next to the international airport. Waiting for them, ready for use, is the Falcon 20E , a very reliable member of DLR’s fleet of research aircraft. read more

Aeronautics | 02. June 2015

ARCTIC15 - Airborne SAR acquisitions up and running

SAR-Daten
Credit: DLR / Martin Keller (CC-BY 3.0)
A first SAR data quicklook of the Kangerlussuaq calibration test site. The colours represent the intensity in different polarisations (Red: VV, Green: HV, Blue: HH). The airport is clearly visible in black. From the centre of the image, the fjord extents in a south-west direction, where skidoo-tracks to the next village can be seen.

Three calibration flights, 10 flights to test sites, and over 100 radar data sets resulting in 4.8 Terabyte of SAR data. These are the numbers behind the work our F-SAR team conducted within the last two weeks – including even the alteration from the X-C-S-L to the P-band antenna configuration and fortunately only one bad weather day.

DLR's Do-228 airplane, with the F-SAR system on board arrived on Friday, 24 May, in Kangerlussuaq. On the following Monday, the team consisting of two pilots, one flight engineer and two radar operators took off for the first calibration flight. In the first two weeks, the antenna configuration for the X-, C-, S- and L-band frequencies was installed on the plane. This range of different frequencies will allow us to compare radar acquisitions with different penetration depths into the snow and ice. The team acquired SAR data over all the test sites where we had installed corner reflectors. Additionally, the area around the airport and town of Kangerlussuaq is overflown for calibration purposes and is well equipped with seven reflectors. It seems like the locals got used to these strange metallic artefacts in their town pretty fast.

Credit: DLR / Ralf Horn (CC-BY 3.0)
DLR's Do-228 with the F-SAR radar system on board after refuelling at the airport of Ilulissat, Greenland. The X-C-S-L antenna mount is visible on the rear of the plane.

Eventually, during the first days after the calibration flight, we had to face exactly those smaller and bigger problems – those that one must always expect during a campaign, as mentioned in the previous post. But the F-SAR team proved their problem-solving skills and campaign experience. From non-matching connections of the local oxygen supply to unstable electronic parts, they were able to fix everything without causing any delay to the campaign plan. I have to admit that I was already worried about losing one test site due to the technical difficulties, but the team was able to acquire almost all the data we had planned for. For now, we can say that the X-C-S-L phase was successful, giving us plenty of scientific data.

Credit: DLR / Georg Fischer (CC-BY 3.0)
The F-SAR team preparing to remove the X-C-S-L antenna from the side of the Do-228 airplane.

The change to the P-band antenna configuration was completed successfully. The P-band wavelength is the longest we will use during this campaign and penetrates several tens of metres into the ice. We are already curious about what kind of subsurface features we will see in the data.

Today, while I'm writing, the F-SAR team is flying over the K-transect to conduct the first P-band acquisitions. Currently, we are all very optimistic about the upcoming part of the campaign.

Aeronautics | 29. May 2015

WindVal: Petta reddast

Betanken der Falcon vor dem Start
Credit: DLR (CC-BY 3.0)
Falcon ready for the jet stream flight, in the background is the NASA DC-8

In Iceland you hear one phrase very often: 'petta reddast', which can be translated as "it will all work out okay". With that in mind, we started planning the flight to have a closer look at strong changes in the horizontal and vertical gradients of the wind speeds in the atmosphere, which is one of the key objectives of the ADM-Aeolus WindVal campaign.

When operating from Iceland, the ideal target region for such an endeavour is in or near a jet stream (fast flowing current in the atmosphere with a meandering shape) over the North Atlantic that is within range of the aircraft. The situation on Friday 15 May 2015 offered a great opportunity to address this aim and coordinate with the NASA DC-8 to observe strong jet stream winds. We have total of four wind lidar systems on the two aircraft, the DC-8 and DLR’s Falcon. read more

Aeronautics | 21. May 2015

ARCTIC15 Field Campaign

Forschungskampagne in Grönland
Credit: Silvan Leinss
The other, more beautiful side of field work. -22 degrees Celsius without wind on a sunny day can feel quite warm and comfortable. Perfect working conditions!

ARCTIC15 is a campaign promoted by the Microwaves and Radar Institute of the German Aerospace Center (DLR), carried out in cooperation with ETH Zurich and with the support of the Alfred Wegener Institute (AWI). It takes place in Greenland from mid-April to the end of May 2015 with the objective of collecting polarimetric-interferometric SAR data at different frequencies (X-, C-, S-, L- and P-band) over different facies of the ice sheet. The measurements are performed using DLR's airborne F-SAR sensor. In total, the activities involve five test sites and include the collection of ground measurements, like ground penetrating radar (GPR) profiles and snow and firn stratigraphy, as well as the installation of GPS stations and corner reflectors for the calibration of the SAR acquisitions. read more