CFD Study of the Impact of Variable Cant Angle Winglets on Total Drag Reduction

Abstract

Winglets are commonly used drag-reduction and fuel-saving technologies in today’s aviation. The primary purpose of the winglets is to reduce the lift-induced drag, therefore improving fuel efficiency and aircraft performance. Traditional winglets are designed as fixed devices attached at the tips of the wings. However, because they are fixed surfaces, they give their best lift-induced drag reduction at a single design point. In this work, we propose the use of variable cant angle winglets which could potentially allow aircraft to get the best all-around performance (in terms of lift-induced drag reduction), at different angle-of-attack values. By using computational fluid dynamics, we study the influence of the winglet cant angle and sweep angle in the performance of a benchmark wing at a Mach number of 0.8395. The results obtained demonstrate that by carefully adjusting the cant angle, the aerodynamic performance can be improved at different angles of attack.

Conceptual Design and Performance Optimization of a Tip Device for a Regional Turboprop Aircraft

“…Their proposed winglet design is considered a fair compromise between classic, low cant angle Whitcomb winglets and 'lifting' large cant angle winglets. Eliminating the constraints set by the cant angle paves the way to the exploration of 'variable cant angle' winglet concepts which, according to Guerrero et al [46], can potentially enable aircraft designs to achieve optimal performance at a wide range of angle of attack values. Promising results have been also demonstrated by the 'Shark' wing-tip family [47].…”

Variable cant angle winglets for improvement of aircraft flight performance

“…Therefore, the winglet can be adjusted at different flight conditions to get the best lift-induced drag reduction for the given flight phase; or it can be kept in the vertical position while in ground so that it reduces wingspan while meeting gate and runaway clearance; or it can act as a load alleviation mechanism where in the case of gusts or strong sideslip velocities, the winglet can adjust itself, so it reduces the bending moment on the wing and the device itself. This study is an extension of a previous work conducted by the authors [26]; however, hereafter it is extended to cover Mach numbers values of 0.3 and 0.8395. In addition, a more detailed wave drag quantitative and qualitative analysis is presented, together with a discussion of the effect of compressibility on the aerodynamic performance.…”

Using the Winglet Toe and Twist Angle to Improve Wing Aerodynamics Performance

“…Like the wingtip feathers of birds in ight, they can also bend effortlessly. [5] During winglet design, a variety of winglet design parameters such as span, sweep, cant, toe, twist and aspect ratio should be taken into account. [6] In this project we will study the effect of two parameter, Toe and Twist angle.…”