HYLTEC Laminar Flow Systems Flight Tests: Flight Testing of Anti-Icing and Anti-Contamination Systems on the DLR Do228 Test Vehicle

Hybrid laminar flow control (HLFC) promises a large potential for drag reduction. Much effort has been put into the development of this technology, but relatively little experience has been gained with the hardware and systems that will be required to protect the wing surface against ice accretion and insect contamination. In frame of the European program HYLTEC a new leading edge box has been developed for the wing of the DLR test aircraft Dornier Do 228. The box is equipped with a laser drilled suction surface in combination with different test panels for bleed air anti-icing, shield protection, fluidic anti-contamination, fluidic anti-icing and a reference area. Suction pressure is produced by a bleed air driven jet pump. The pressure distribution can be measured by one row of pressure taps. Transition location is observed by an infrared camera. A video camera near the wing tip records insect and ice accretion at the leading edge. The flight tests have been conducted in four test campaigns starting December 2001 and being completed in September 2002. First tests of the suction system showed that depending on flap deflection and suction velocity transition locations between 25% and 50% of chord length could be achieved. Without suction no laminar flow could be observed. In three test campaigns the different systems show their ability to keep the surface clean against insect contamination and ice accretion. The mechanical construction as well as the systems layout and the instrumentation is described in detail in [1] and [2]