Investigation on continuously deflectable High-Lift Devices for a 3D High-Lift Configuration

Abstract

This work deals with the investigation of continuously deflectable high-lift devices. The aim of this work is to derive optimal high-lift settings for off-design conditions and to evaluate the benefits of this technology. Off-design is related in this context to airport, aircraft and atmospheric specific conditions. Within the work a fully automatized process chain (high-fidelity methods are used) is implemented to generate an aerodynamic database for various high-lift settings. This data base is used by a preliminary design tool to simulate the overall aircraft for take-off, approach and landing at off-design. The resulting data are fed in a response surface model (RSM) to obtain the overall behavior for the slat/flap deflection angle domain. The interpolated values are used to derive optimal high-lift settings. The results show consistent behavior. It is found that for take-off valuable benefits can be achieved. For landing the results indicate that a further flap deflection than the standard landing setting is beneficial. NomenclatureAoA Aircraft angle of attack,MAC Mean aerodynamic chord length, [m] M Mach-number, [-] Re Reynolds-number, [-] S Reference area, [m 2 ] t Temperature, [ • C] T /W Thrust to weight ratio, [N/kg] T rev Reverse thrust, [N] v Velocity, [m/s] v s1g 1-g stall speed, [m/s] W Weight, [kg] W/S Wing-loading, [kg/m 2 ] AEO All engines operative BFL Balanced field length CAD Computer aided design CFD Computational fluid dynamics FAA Federal aviation administration ISA International standard atmosphere LFL Landing field length LW Landing weight MLW Maximum landing weight MTOW Maximum take-off weight OEI One engine inoperative OEW Operating empty weight RSM Response surface model TOFL Take-off field length TOW Take-off weight Symbols δ Deflection angle, [ • ] γ Flight path angle, [ • ] µ rGround roll friction coefficient, [-]

Recent research topics in high-lift aerodynamics

“…19). In the scope of the national funded project MOVE.ON investigations were made how the high-lift setting of a given aircraft should be adapted based on an existing kinematics to improve the aircraft high-lift performance at off-design conditions [36]. Based on the generic FNG aircraft model, continuous and differential adaptions of the high-lift wing were analyzed in the full aircraft context with regard to achievable runway lengths depending on actual aircraft weight and environmental conditions (hot & high).…”

“…Optimal continuous high-lift system deflection path depending on aircraft weight and airport elevation; solid contour lines: weight ratio (TOW/MTOW) -dashed contour line: take-off-field length -red dashed line: path for optimal flap deflection for shortest TOFL at given weight (images from[36]). …”

Multi-fidelity Aerodynamic Design Process for Moveables at DLR Virtual Product House

“…Here the design of the new component, an adaptive dropped hinge flap (ADHF), is performed in regard to aerodynamics, kinematics and structure. Experiences from previously performed analyses on multifunctional high-lift devices from outside [2] and within the DLR [3], [4], [5], as well as experiences from aero-structural design optimization of the flexible wing in the DLR project Victoria [6] are taken into consideration for the design.…”