Winged Wonders

Winglets have become part of the aviation landscape on everything from sports aircraft to the massive Airbus A380. They are by no means a new concept, but they are undoubtedly an increasingly critical one in an industry focussed on saving fuel and emissions.

The Problem with Lift.
Everything has its price and so is the case when it comes time for an aeroplane’s wing to produce lift. Gravity is not the only enemy of flight, for drag is another constant impediment resisting man’s efforts to fly. In fact ‘induced drag’, as the name would suggest, is a direct by-product of generating lift and aerodynamicists have long explored means to minimise this pestilence.

A significant manifestation of induced drag occurs when the higher pressure airflow beneath the wing moves outboard, or ‘spanwise’ in an effort to unite with the lower pressure airflow above the wing. Most of this interaction ultimately takes place at the wingtips as the two airflows combine in a turbulent mix that spirals away in the aeroplane’s wake. These turbulent flows are known as ‘wingtip vortices’ and not only create efficiency-draining drag but can provide a genuine safety hazard to following aircraft that encounter the disturbed wake.