Airbus’s A340 laminar-flow test demonstrator took to the air for the first time Tuesday for the EU-sponsored Clean Sky “Blade” project. The four-engine jet, dubbed “Flight Lab,” took off from the Tarbes aerodrome in southern France at 11 a.m. local time and landed at Airbus facilities in Toulouse after a three-hour, 38-minute test mission.
Blade, an acronym for Breakthrough Laminar Aircraft Demonstrator in Europe, aims to achieve a 50 percent reduction in wing friction and up to 5 percent lower CO2 emissions.
The first test aircraft in the world to combine a transonic laminar wing profile with a true internal primary structure, the A340 Flight Lab incorporates two transonic laminar outer wings and a highly complex flight-test-instrumentation (FTI) station in the cabin. The extensive modifications to the A340-300 took place during the course of a 16-month working party in Tarbes, with the support of numerous industrial partners across Europe.
“We began by opening the flight envelope to check that the aircraft was handling correctly,” explained Philippe Seve, an Airbus flight-test engineer aboard the A340 for the first flight. “We achieved our objective to fly at the design Mach number, at a reasonable altitude and check everything was fine. We also checked that the FTI was working as expected, to identify further fine-tuning for the next flights.”
A team of 10 specially trained pilots, test engineers and flight-test engineers prepared for the first-flight milestone for several months, spending time in a simulator and familiarizing themselves with the FTI systems installed on the flight-test aircraft. Separtely, a working party of 70 people performed the FTI installation inside the aircraft, while teams from Bremen, Germany, and Broughton, UK, worked on the outer wings with a team from Stade, Germany, installing a pod containing infrared cameras on the fin.
On the wings, hundreds of measurement points gauge the waviness of the surface to help Airbus engineers ascertain its influence on so-called laminarity. It marked the first time Airbus has used such a testing method on an aircraft. Other firsts include the use of infrared cameras inside the pod to measure wing temperature and the acoustic generator that measures the influence of acoustics on laminarity. Finally, an innovative reflectometry system measures overall deformation in real-time during flight, based on the sunlight's reflection on the new wing panels.
A key goal of Blade centers on measuring tolerances and imperfections present while sustaining laminarity. To that end, Airbus plans to simulate every type of imperfection in a controlled manner, revealing by the end of the campaign the tolerances for building a laminar wing. Plans call for the Flight Lab to fly for some 150 hours in the next few months.