The project LDAinOp (Low Drag Aircraft in Operation) is promoted within the national funded aerospace research program V (LufoV-1) with a time span from January 2014 to March 2017.
The focus of the project is to investigate and develop key technologies for low drag transonic wings. The abbreviation LDAinOp is representative for Low Drag Aircraft in Operation –
a minimization of air drag as key goal of future airplane generations, characterized by laminar wing air flow. The following partners have a work share within the project:
A general problem of laminar wings is that in the climb phase to cruise altitude at low mach number a suction peak on the wing upper surface occurs. This is causing a complete loss of the laminar flow in the very important climb phase especially for short range aircraft. In order to prevent this, adaptive structure concepts for local adaptation of the wing profile and thus wave drag reduction shall be investigated.
Besides laminar approaches also variable camber (VC) flaps for adaptation of the wing to different operational conditions are used for control of the wave drag of a (full turbulent) wing in off-design. The VC function enables to optimize the the pressure distribution of the laminar wing.
A laminar wing with low sweep angle causes a high wave drag at higher mach number. At cruise on the wing appears a transonic area, which ends with a compression shock. In the context of the Project the position of the compression shock shall be fixed/localized by use of a VC flap and of shock control bumps (SCB) for control of the compression shock in the area of the spoiler elements. The work share of DLR within the project is depicted in the figure above.
The contributions of the department FT-SSY are a kinematics synthesis for optimal coordination of the trailing edge high lift device (flap) and the spoilers with Shock Control Bump, the integration of the trailing edge concepts regarding space allocation and detailed optimization of the kinematics and actuation design, as well as establishment of an holistic system architecture (for the primary and secondary flight control) and the corresponding safety analysis at system level.