Method for the Pre-design of a Smart Droop Nose Device using a Simplex Optimization Scheme

Abstract

The high lift systems of modern-day commercial airplanes are highly effective systems providing the required lift during take-off and approach at low flight velocities. State-of-the-art high lift systems consist of movable control surfaces which when deployed increase high lift performance. Typical devices are slats and fowler flaps which consist of rigid parts supported and driven by complex mechanical systems. To achieve the goals defined in the “Vision 2020”, technologies to consequently reduce drag and airframe noise will be necessary. In this context especially the high lift systems at the leading edge are of major interest. Most experts agree that laminarisation is the only technology which has the potential for step changes in drag reduction within a suitable ti-meframe. But this technology requires high quality surfaces and does not comply with conventional high lift devices like slats. Because of the gap which forms between the slat and the main wing the flow is disturbed and causes transition to turbulent flow immediately after the slat gap. Additionally, the construction space in the next generation high aspect ratio wings is limited due to the employ-ment of slim profiles. Furthermore in recent research programs the slat gap is identified to be one of the most dominant airframe noise sources in take-off and approach. Therefore smart seamless and gapless high lift devices especially at the wings leading edge are a mandatory enabler for futu-re wings of significantly increased aerodynamic efficiency. In the european project SADE and the national project SmartLED gap- and seamless high lift devices for next generation wings are de-signed. The work presented is based on the initial design of an adaptive leading edge device in these projects and focused on the optimization of such a system regarding issues of shape accura-cy in cruise flight as well as in approach and strength requirements.