No abstract

New configurations and technologies like adaptive morphing trailing edges offer the potential to improve the fuel efficiency of commercial transport aircraft. Using modern computational tools, it has become possible to effectively analyze the extent to which this technology improves aircraft performance. Parametrizing high fidelity structural models coupled to RANS-based aerodynamics with hundreds of variables provides the accuracy necessary to complete a meaningful comparison of aircraft with an without morphing wing technology. Using this computational approach, we perform multipoint aerostructural optimization, to provide an objective function which can leverage the adaptability provided by wing morphing. We show that for a seven point mulitpoint, the addition of a morphing trailing edge device along the aft 40% of the wing can reduce cruise fuel burn by more than 5%. A large portion of the savings produced by morphing trailing edges result from a significant reduction in structural weight, enabled by adaptive maneuver load alleviation. We also show that a smaller morphing device along the aft 30% of the wing produces nearly as much fuel burn reduction as the larger morphing device, and that morphing technology is particularly effective for high aspect ratio wings.

Non-morphing, conventional aircraft wings are designed for a compromise of good performance at a variety of flight conditions. Accordingly, such wings perform sub-optimally when considered at a single flight condition. Morphing trailing edge devices offer an opportunity to change this wing design paradigm by allowing wings to adapt to varying flight conditions. This adaptability weakens the correlation between performance at various flight conditions and increases the robustness of the wing's performance, providing closer-to-optimal performance at each flight condition. To study the isolated aerodynamic effects of this increased robustness, we performed a number of aerodynamic shape optimizations of a small morphing trailing edge device at a variety of flight conditions on the Common Research Model aircraft configuration. Comparing the performance of the aircraft with a morphing region spanning the aft 10% of the wing and an aircraft without morphing demonstrated a 1.02% fuel burn reduction with the addition of the morphing for a 7,730 nmi mission. We repeated this process with the inclusion of coupled structural deformations and found a fuel burn reduction of 1.72%. This value provides a baseline for the performance improvement potential of this technology, independent of any restrictions or safety factors limiting the use of morphing trailing edge devices for maneuver or gust load alleviation.

Adaptive morphing trailing edge technology offers the potential to decrease the fuel burn of transonic transport aircraft by allowing wings to dynamically adjust to changing flight conditions. Current aircraft use flap and aileron droop to adjust the wing during flight. However, this approach offers only a limited number of degrees of freedom, and the gaps in the wing created when using these devices introduce unnecessary drag. Morphing trailing edge technology offers more degrees of freedom, with a seamless interface between the wing and control surfaces. In this paper we seek to quantify the extent to which this technology can improve the fuel burn of transonic commercial transport sized aircraft. Starting from the undeformed Common Research Model (uCRM) geometry, we perform fixed-planform aerostructural optimizations of a standard wing, a wing retrofitted with a morphing trailing edge, and a clean sheet wing designed with the morphing trailing edge. The wing retrofitted with the morphing trailing edge improved the fuel burn as effectively as the full wing redesign without morphing. Additional fuel burn reductions were observed for the clean sheet design. The morphing trailing edge decreased the fuel burn by performing load alleviation at the maneuver condition, weakening the trade-off between cruise performance and maneuver structural constraints, resulting in lighter wingboxes and more aerodynamically efficient cruise configurations.

No abstract