Open AccessAN ALTERNATIVE APPROACH TO INDUCED DRAG REDUCTION
Author(s) -
Nikolaos Kehayas
Publication year - 2021
Publication title -
aviation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.239
H-Index - 13
eISSN - 1822-4180
pISSN - 1648-7788
DOI - 10.3846/aviation.2021.15663
Subject(s) - drag , lift induced drag , wing , lift to drag ratio , wingtip vortices , lift (data mining) , parasitic drag , wingspan , zero lift drag coefficient , wing loading , mechanics , wing twist , structural engineering , aerospace engineering , angle of attack , engineering , physics , aerodynamics , vortex , horseshoe vortex , computer science , vorticity , data mining
Induced drag constitutes approximately 40% of the total drag of subsonic civil transport aircraft at cruise conditions. Various types of winglets and several non-planar concepts, such as the C-wing, the joined wings, and the box plane, have been proposed for its reduction. Here, a new approach to induced drag reduction in the form of a combination of an elliptical and an astroid hypocycloid lift distribution is put forward. Lift is mainly generated from high circulation in the center part of the wing and fades away along the semi-span towards the wing tip. Using lifting line theory, the analysis shows that for fixed lift and wingspan the combined lift distribution results in an induced drag reduction of 50% with respect to the elliptical distribution. Due to its wing planform the combined lift distribution leads to a 51.5% higher aspect ratio. If structural constraints are placed, then the higher aspect ratio may affect wing weight. Although any substantial increase of wing weight is not envisaged, further study of the matter is required. Zero-lift drag and lift-dependent drag due to skin friction and viscosity-related pressure remain unaffected. The proposed lift distribution is particularly useful in a blended wing-body design.