https://cyberleninka.org/article/n/1075905.pdf

Robust design of NLF airfoils

As a substitute to the NASA GA(W)-2 airfoil, that is envisaged for a Light Transport Aircraft (LTA), a new airfoil NAL-MSNLF-136 is designed at NAL. It is shown according to model calculations that the thicker NAL airfoil shows better aerodynamic efficiency than the GA(W)-2 profile in the operatingC

 L
 range.

Design of a natural laminar flow airfoil for the light transport aircraft

An Aerodynamic Design Method of Propeller Airfoils with Geometric Compatibility as Constraints

SUMMARY The axial singularity inverse method for designing bodies of revolution has been improved by using higher-order doublet elements. The performance of the method for various element orders and other solution parameters is presented in detail. The results indicate that the method is generally more robust, less sensitive to insets and has a better-conditioned coefficient matrix compared with the source method of the same order. The condition number of the matrix is shown to increase with the thickness of the body, the order of the method, the number of elements and the degree of stretching of the node distribution. In general, good performance is attained for most bodies even with f, as low as 2 by using 10-12 second-order doublet elements with insets greater than 0-02L from rounded ends. Increasing the insets to 0.06L appears to improve the accuracy of the method for most bodies but slows its convergence.

Solution of the axisymmetric inverse problem by higher‐order line doublets

Design of a natural laminar flow airfoil for light aircraft

A new natural laminar flow (NLF) airfoil, the NALNLF-13; 208, has been designed for a light aircraft. It has been shown that the NAL-NLF-208 airfoil performs better than the Wortmann FX-60-177 airfoil because it is thicker and is estimated to give better aerodynamic performance larger L/ D) in the operating CL range. To take account of the difficulties in fabrication, the NALNLF-208 airfoil has been modified to incorporate appropriate bluntness at the trailing edge. A surface waviness (amplitude of 0.025070and wavelength of 4.1 %, each of the local chord) superimposed on the blunted airfoil is shown to have no significant 13; effect. It is concluded that the NAL-NLF-208 is robust with respect to performance and fabrication and could replace the Wortmann airfoil as a candidate for light aircraft after13; testing.

GS Dwarakanath

Papers

Design of a natural laminar flow airfoil for light aircraft

Design of a natural laminar flow airfoil for NAL's light Aircraft

Design of a natural laminar flow airfoil for the light transport aircraft