Aerodynamic Performance as a Function of Local Twist in an Unmanned Airplane

Recently published works predict that any planform shape may be optimized with twist to reduce the induced drag to an optimum value. The objective of this paper is to observe how the distance between the wing root and the twist start line is linked to the maximum lift –drag ratio and to the maximum lift co efficient on an unmanned aerial vehicle designed for the early detection of oil leakages in the extraction areas. The aerodynamic analysis was performed using a panel code to compute the inviscid flowfield, a viscous drag built to estimate the viscous drag , and the pressure difference rule to calculate the maximum lift coefficient. The results show that the maximum lift –drag ratio increases and the maximum lift coefficient reduces as the distance between the wing root and the twist start line decreases. The lift –drag ratio increases 1.51%, and the maximum lift coefficient decreases 3.55% respect to the value for the untwisted airplane. The twist start line was placed at 0.815 m as the greatest lift –drag ratio augmentation is located at this station. The res ults demonstrate that the maximum lift –drag ratio and the maximum lift coefficient are linked to the distance between the wing root and the twist start line.

[1]  R. Crabbe Simple Numerical Method to Compute Viscous Lift Loss of Wings , 1998 .

[2]  Pedro J. Boschetti,et al.  Increasing the Lift-Drag Ratio of an Unmanned Aerial Vehicle Using Local Twist , 2008 .

[3]  Ludwig Prandtl,et al.  Applications of Modern Hydrodynamics to Aeronautics , 1923 .

[4]  Alfred E. Magnus,et al.  PAN AIR: A Computer Program for Predicting Subsonic or Supersonic Linear Potential Flows About Arbitrary Configurations Using a Higher Order Panel Method. Volume 1; Theory Document (Version 1.1) , 1981 .

[5]  Walter O. Valarezo,et al.  Method for the prediction of wing maximum lift , 1994 .

[6]  Pedro J. Boschetti,et al.  Design of an Unmanned Aerial Vehicle for Ecological Conservation , 2005 .

[7]  E. N. Tinoco,et al.  PAN AIR Applications to Weapons Carriage and Separation , 1981 .

[8]  Warren F. Phillips,et al.  Lifting-Line Analysis for Twisted Wings and Washout-Optimized Wings , 2004 .

[9]  Eastman N. Jacobs,et al.  Airfoil section characteristics as affected by variations of the Reynolds number , 1939 .

[10]  Robert E. Spall,et al.  Minimizing induced drag with wing twist, computational-fluid-dynamics validation , 2006 .

[11]  E. Tinoco,et al.  Application of a higher order panel method to realistic supersonic configurations , 1979 .

[12]  J. Iwan D. Alexander,et al.  Application of a higher order panel method to realistic supersonic configurations , 1980 .

[13]  G. F. Syms Low-Order Method for Predicting Aerodynamic Performance Degradation Due to Ground Icing , 2002 .

[14]  Warren F. Phillips,et al.  Lifting-Line Analysis of Roll Control and Variable Twist , 2003 .

[15]  T. Derbyshire,et al.  PAN AIR summary document (version 1.0) , 1982 .