German researchers are studying how insect contamination on aircraft wings would decrease efficiency of future planes.
In a project by the German Aerospace Centre (DLR), scientists are using a research A320 aircraft to analyse how and where insect accumulates on the plane’s wings.
While not a problem for current aircraft, insect contamination may become an issue for future generation ultra-smooth high-tech wings, increasing fuel consumption and thus decreasing efficiency.
"Modernising future commercial aircraft by fitting them with laminar flow technology gives rise to particular challenges in terms of the surface quality of the wings, quite similar to those encountered with gliders," said DLR researcher Dominic Gloß. "Gliders are commonly fitted with 'bug scrapers'; in the same way, we have to avoid surface contamination as well."
Laminar flow wings, which are currently being developed by engineering teams around the world, have substantially smoother surface than current wings. This feature enables the laminar flow wings to produce less drag, thus improving fuel efficiency. However, insect contamination disturbing the laminar flow would eliminate the improvements.
The goal of the InCoVal (Insect Contamination Validation) project is to design a solution to the problem using a new flap system. The flaps fitted to the leading edges of the laminar flow wings are extended during take-off and landing. They must be of such a size that they shield the wing from insects without reducing the high-lift performance. The enhanced lift provided by the flap system is crucial for ensuring stable flight during the comparatively slow flight regime used for take-off and landing.
The insect protection flaps are retracted once the aircraft reaches faster speeds at greater altitudes, meaning that the air will then flow over the clean leading edges of the wings. The insect contamination is contained within the laminar flow wings, which are made of modern, ultra-lightweight composite materials.
In the upcoming phase of the study, the German researchers will measure where on the wings the insect accumulates the most, using a simple adhesive foil. The foil, attached to the wings of the research aircraft right behind the leading edge flaps, will be taken to laboratory at the end of each day for further analysis.
“Our flow models then help us design future flaps specifically to deal with insect contamination,” says Gloß.
The researchers had already gathered initial data on insect distribution across the wings during low altitude flights conducted in the summer of 2013. The current set of flight tests will be used to continue acquiring a full dataset on insect contamination.