Background

Traditional aircraft wing designs, though widespread, have some considerable aerodynamic drawbacks. The use of discrete control surfaces (Elevators, Rudder, Ailerons) to control airflow around the aircraft is known to cause flow separation, especially at the limit of control surface deflections. To meet the ever increasing demand for more efficient, robust, and cost effective designs, there is an argument that conventional control surface methodologies need to be re-examined, in favour of “morphing” technologies and techniques.

Morphing technologies typically revolve around adaptive geometry structures and mechanisms and are very attractive to aircraft designers as they can provide substantial benefits to aircraft performance. However, even with the substantial research efforts over the last few decades morphing concepts still suffer significant challenges. These include added weight, insufficient structural integrity, excessive actuation loads, and inadequate surface continuity or rigidity under aerodynamic load.

A critical component of any compliant morphing structure is the morphing skin or surface. The skin must be flexible for actuation, but also rigid enough to resist airflow pressures which could otherwise reduce aerodynamic performance. Compounding these requirements is the need for the surface to remain smooth with minimal wrinkling around the underlying movable mechanisms.

Technology Overview

In response to these challenges, Brunel University has developed a viable, realistic solution in the form of an active wing/blade twist technology with an adaptive skin for seamless and adjustable changes in wing/blade twist angle.

Further technical details can be found in the following research paper:

https://bit.ly/2m985Ht

The following video is a demonstration of a test model aircraft built with the twisting technology in action:

The following video is a demonstration of a test flight of a model aircraft built with the twisting technology:

This technology also provides a novel alternative to existing mechanisms for winglets to enhance the performance and controllability of the aircraft, as shown in the video below:

Benefits

The important benefit of this technology is the ability to maintain a rigid skin with a low drag (smooth surface finish) despite high twist deformation during operation. Moreover, the structure is lightweight, and strong enough to carry aerodynamic loads. Compared with other mechanisms in the literature, this new design meets most, if not all, of the lingering challenges to morphing wing technologies and has been demonstrated in flight.

In experimental tests, Brunel’s morphing system was found to have achieved the highest ratio of Lift/Drag compared to aileron wing cases. The design also achieved the highest ratio of Roll Moment/Drag compared to aileron wings. Overall Preliminary flight tests show similar performance to traditional wing performance.

The concept has also demonstrated and met the following three main requirements:

• Adequate resistance to aerodynamic bending
• Sufficient compliance in twist for adequate roll performance
• Maintain a rigid, smooth, and continuous surface

Applications

• Aircraft wings
• Aircraft winglets
• Unmanned Aerial vehicles (from small drones to large UAVs)
• Helicopter blade optimisation
• Wind turbine blade optimisation

Opportunity

Brunel University are actively searching for a partner to further develop this technology with a view to commercialisation.

Brunel University researchers have also developed the related technology: “Reduction of Aerofoil Noise through Design Optimisation of the Trailing Edge“