NRA - statement of work (SOW) task title: advanced high-lift leading-edge system for laminar flow wings 1.0 introduction/background: the national aeronautics and space administration (NASA) is seeking…

NRA - statement of work (SOW) task title: advanced high-lift leading-edge system for laminar flow wings 1.0 introduction/background: the national aeronautics and space administration (NASA) is seeking laminar flow wings in cruise as part of its goals for the subsonic fixed wing (SFW) and environmentally responsible aviation (ERA) projects of reducing aircraft fuel burn as well as noise and NOX emissions. One major challenge to enabling laminar flow on wings is that all modern commercial transport aircraft require a high-lift system during take-off and landing. Although todays high-lift systems are very effective in generating the required lift at low speeds, the current mechanized leading-edge devices (i.e., slats), when stowed for cruise, result in unavoidable steps and gaps that are incompatible with maintaining laminar flow on the wing. Typically, a surface step height near the wings leading edge as small as around 0.01 inches could trip the boundary-layer, forcing transition from laminar to turbulent flow, which would result in a significant increase in skin-friction drag. In addition to commercial aircraft, military transport wing designs have similar aerodynamic concerns that are often exacerbated by short take-off and landing (stol), range, and seamless control surface requirements. Studies have been conducted in the past several years exploring novel wing designs that included concepts for seamless camber change for enhanced high-lift and cruise efficiency. Thus, IT is highly desirable to develop advanced high-lift leading-edge (ahlle) concepts that are compatible with laminar flow at cruise conditions while being able to meet or exceed the existing requirements during take-off and landing. Leveraging on the knowledge gained from past NASA and air force research laboratory (afrl) programs, promising methods of achieving high lift in the absence of a conventional leading-edge slat will be identified and tested in this investigation. 2.0 scope / objective(s): the scope of this effort is to provide wind tunnel testing of ahlle concepts for laminar flow wings in support of NASA SFW and ERA projects. The objective of this effort is to develop, examine, assess, and validate (through ground testing) realistic ahlle concepts best suited for reconciling aerodynamics requirements for high-lift during take-off and landing, and for enabling laminar flow during cruise for a typical modern transport. 3.0 description of the work/tasks to be performed: the contractor shall perform the following tasks: 3.1 high-lift leading edge ground test the contractor shall explore and test high-lift leading edge concepts designed for compatibility with laminar flow wings. 3.1.1 conceptual design: ahlle and baseline high-lift configurations the contractor shall develop a conceptual level design for three candidate ahlle concepts applied to an existing laminar flow airfoil. The conceptual designs shall include preliminary aerodynamics design, structural design, and activation mechanism design, all with a common trailing edge flap. The ahlle concepts explored shall include, but not be limited to, innovative passive, adaptive, or active flow-control devices. The goal is to achieve an equivalent lift required for a conventional leading edge slat system without producing surface excrescence (i.e., steps) that would cause the transition of boundary-layer flows from laminar to turbulent. The ahlle concepts shall be scalable to a large twin-engine commercial transport. The contractor shall describe the characteristics of the baseline laminar cruise airfoil and its high-lift system to be used for comparisons in this study. The baseline cruise airfoil and high-lift configurations shall be of a type that would be used for a family of modern commercial transports the contractor shall prepare and deliver a conceptual design: ahlle and baseline high-lift configurations report. (deliverable 4.