Reduction of Induced Drag in Con guration Flight using Wing Twist at Post-Stall Angles of Attack

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.

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

A vortex-lattice numerical scheme that uses a novel decambering technique to predict post-stall aerodynamic characteristics is used to study the aerodynamics of tandem Cessna 172 aircrafts flying in echelon formation. Results like CL − α from the current method are compared with experiment. Additional results like section Cl distributions over wing spans, CM − α and CLW − αtw (i.e. CL of the leading aircraft for different angles of attack of the trailing aircraft) and analysis for (-)ve y-offset, which are available only from the current numerical method are reported that supplement the experimental results. Detailed post-stall numerical analysis and the effect of chord-wise, span-wise and vertical offsets on the aerodynamics of the formation are also reported.

Reduction of Induced Drag in Con guration Flight using Wing Twist at Post-Stall Angles of Attack

References

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

A Numerical Study of the Aerodynamics of Cessna 172 Aircrafts in Echelon formation

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