Decambering

About: Decambering is a research topic. Over the lifetime, 38 publications have been published within this topic receiving 359 citations.

Aerodynamic/mechanism optimization of a variable camber Fowler flap for general aviation aircraft

Abstract: A conventional Fowler flap is designed to improve the take-off and landing performances of an aircraft. Because the flight states of general aviation aircraft vary significantly. A Fowler flap with a double-sliding track has been designed, which is capable of changing airfoil camber while cruising and climbing as well as meeting low-speed performance requirements. The aerodynamic characteristics of the variable camber Fowler flap were studied by computational simulation, and cambering was found to be beneficial for improving the lift-to-drag ratio when the lift coefficient was larger than the critical value, below which decambering was more effective; this critical value differed somewhat under different conditions. Taking the mechanism into account, the take-off and landing configurations were optimized on the basis of the GA (W)-1 airfoil with a 30% chord Fowler flap. Compared with reference configuration, the maximum lift coefficient of optimized take-off configuration was increased by 6.6% as well as the stalling angle and the lift-to-drag ratio were increased by 1.3° and 7.58%, respectively. Moreover, the maximum lift coefficient of the optimized landing configuration was increased by 6.3%, and the stalling angle was increased by 1.1°; however, the nose-down pitching moment of both configurations increased. Similar results were attained on a general aviation aircraft wing/body combination. A 3D model of the variable-camber Fowler flap driving mechanism was established in a computer-aided design system, and the results showed that all design configurations could be achieved by the double-sliding track.

Geometry Based Quick Aircraft Modeling Method for Upset Recovery Applications

Abstract: A complete tool chain is developed for generating extended and enhanced flight models for low speed flights for applications of upset recovery research. Starting from geometry based automatic generation of the baseline model, additional algorithms are introduced to supplement the model for simulation of aircraft dynamics near stall and post-stall regions using decambering corrections, dynamic stall calculation and spin dynamics modelings. Together with additional functions for 3D lift corrections, drag estimations and weight distributions, significant enhancement has been made to the model generation capability of the vortex lattice method program. The generated Fokker 100 aircraft model is validated with direct comparisons to wind-tunnel measurements, manufacturer’s reports, academic publications as well as the flight data recordings of different accidents involving aircraft upsets.

Post-stall prediction of multiple-lifting-surface configurations using a decambering approach

Abstract: RINKU MUKHERJEE. Post-Stall Prediction of Multiple-Lifting-Surface Configurations Using a Decambering Approach. (Under the direction of Dr. Ashok Gopalarathnam.) A novel scheme is presented for an iterative decambering approach to predict the post-stall characteristics of wings using known section data as inputs. The new scheme differs from earlier ones in the details of how the residual in the Newton iteration is computed. With earlier schemes, multiple solutions are obtained for wings at high angles of attack as the final converged solution depends on the initial conditions used for the iteration. With this scheme, multiple solutions at high angles of attack are brought to light right during the computation of the residuals for the Newton iteration. In general, the new scheme is found to be more robust at achieving convergence. Experimental validation is provided using experimental airfoil lift curves from Naik and Ostowari for three different aspect ratios of rectangular wings. Results are presented from a study of the stall characteristics of wings of different planform shapes and two configurations of a wing-tail and a wing-canard configuration. Results are also presented from a study to investigate possible asymmetric lift distributions when the iterations were started with an initial asymmetric distribution of the decambering. Post-Stall Prediction of Multiple-Lifting-Surface Configurations Using a Decambering Approach

Airfoil for micro air vehicle

Abstract: An airfoil for a micro air vehicle that includes components enabling the airfoil to adjust the angle of attack (AOA) of the airfoil in response to wind gusts, thereby enabling the airfoil to provide smooth flight. The airfoil may include a first compliant region positioned between an inboard section and a first outboard section and may include a second compliant region between a second outboard section and the inboard section. The compliant regions enable the first and second outboard sections to bend about a leading edge section and move relative to an inboard section. This action creates smoother flight due to numerous aerodynamic advantages such as a change in the angle of attack and improved wind gust rejection due to adaptive washout as a result of the airfoil flexing, twisting and decambering.