Research aims to eliminate drag from dead insects

The German Aerospace Center (DLR) and Airbus are investigating how the build up of dead insects disturbs the airflow over new wing designs.

The aim, say DLR, is to look at whether insect protection can be incorporated into future designs.

Extremely low-level flights by the DLR ATRA research aircraft over Magdeburg-Cochstedt Airport have shown flow pattern specialists how insects affect aircraft.

‘As part of our research work on laminar-flow technology, we are working with Airbus to pursue the aim of improving commercial aircraft in terms of environmental sustainability, noise emissions and cost-effectiveness,’ said Dominic Fabian Gloss from the DLR Institute of Aerodynamics and Flow Technology. ‘The numerous insects that encounter the front portions of the wings hinder the development of large laminar-flow, low-friction areas on the wing, rendering the effort to save fuel by using laminar flow ineffective.’

After the test flights, insect remains were also evident on the nose of the aircraft
After the test flights, insect remains were also evident on the nose of the aircraft

Modern wings made of carbon fibre are being investigated in the area of laminar-flow technology. The wings of the future will need to have particularly smooth surfaces for the laminar flow, so that significantly lower drag can be achieved.

‘In future, special front flaps that are extended during take-off and landing to increase lift are also expected to protect the wing from insect contamination,’ Gloss said in a statement.

Test flights

The DLR ATRA, an Airbus A320 converted into a research aircraft, has become the researchers’ flying laboratory for new technology.

‘We are using the ATRA for the tests in circling flights. Each test point involves some ten flights over the airport at low altitude,’ Gloss said. ‘Insects typically fly very low, which presents a particular challenge for in-flight research.’

‘From the DLR site in Braunschweig, we set a course for Magdeburg-Cochstedt Airport with the ATRA,’ said test pilot Stefan Seydel. ‘The individual fly-bys over the airport were exciting – we used them to simulate the take-offs and landings of a commercial aircraft. The aim was to fly at around 15 metres above the ground, so that, in as short a time as possible, we could induce the undesired negative effects of insects.’

The test pilots carried out up to 30 low-altitude flights and subsequent touch-and-go landings in a day. The test flights took place between 23 July and 6 August, days selected for the numbers of insects expected to be present.

Using a number of adhesive films, researchers have documented the frequency and distribution of insects on the wing. The insect patterns can now be loaded by the researchers into their computer models for the development of future wing models
Using a number of adhesive films, researchers have documented the frequency and distribution of insects on the wing. The insect patterns can now be loaded by the researchers into their computer models for the development of future wing models

‘The numerous low-level flights gave us a good picture of where the insects were sticking to the aircraft,’ said Gloss who, along with colleagues, captured the insects on a series of adhesive films and are now storing the insect patterns in their computer models. ‘We will use the computer results for future aerodynamic wing designs, for further developments in laminar-flow technology.’

The test flights at Magdeburg-Cochstedt Airport are an initial step in the ProWinGS (Performance Development for Wing Design, Ground Test and Simulations) project, funded by the German Federal Ministry for Economics and Technology under the 4th Aviation Research Programme.

Further test flights are planned for the end of August.