Effects Of Flap Deflection Research Articles

Safety Analysis for Icing Aircraft during Landing Phase Based on Reachability Analysis

Icing is one of the leading causes of fatal aircraft accidents worldwide. Encountering icing conditions, dynamic characteristics of the aircraft will be damaged, thereby greatly affecting flight safety. Research on real-time estimations of the safety envelope under icing conditions is critical to improve flight safety. In order to determine the safety envelope, the reachability analysis based on the level set method is presented. The reachable set is obtained via computing the Hamilton-Jacobi partial differential equation (HJPDE), which is based on optimal control and is used in the landing phase of an aircraft. The results show that icing will shrink the safety envelope. Particularly under severe icing conditions, the stall speed of the aircraft will increase, and dynamic behavior will be more sensitive. A slight change of command by the pilot may contribute to the flight state moving outside the safety envelope. Furthermore, the effect of flap deflection was considered, which positively impacts the expanding safety envelope during the landing phase. Finally, a maneuvering coping strategy based on safety envelope is proposed. Examples are provided using the NASA’s generic transport model (GTM), and the results can be applied to flight safety risk assessment, providing theoretical guidance for the design of envelope protection systems.

Computational study on wind turbine airfoils based on active control for deformable flaps

This study numerically investigates the aerodynamic performance of Deformable trailing edge flaps (DTEFs) to reduce the fatigue and ultimate loads of wind turbine blades. A parametric design is adopted to ensure the flexible deformation of the DTEFs. Based on experimental data, a simulation of a baseline airfoil is performed with two methods: A fully coupled viscous/inviscid method employed by the XFOIL program and a Reynolds-averaged Navier–Stokes solver with a Transition SST (T-SST) turbulence model. The static and dynamic performances of DTEFs are then investigated under different flow conditions by using T-SST and maximizing its numerous advantages. Results indicate that under steady conditions, the effects of flap deflection on the integral forces and flow field structures of airfoils vary from attached flow conditions to separated conditions. The gaps between unsteady aerodynamic responses and static values are greater in attached flow and light stall conditions than in deep stall conditions. The ability of DTEFs to control the fatigue loads on wind turbine blades is verified. Specifically, DTEFs effectively alleviate the force fluctuations on blades under gust-induced swinging when wind speed measurements are considered.

Computational Study on Effect of Flap Deflection on NACA 2412 Airfoil in Subsonic Flow

This computational study is aimed at studying the effects of flap deflection angle on aerodynamic coefficients of NACA 2412 airfoil and thus predicting the suitability of using the airfoil with flap at various phases of flight. The change in airflow over the airfoil at different angles of attack (0, 4, 8 and 12 degrees) and at different flap deflections give a clear understanding for the use of right combination of these two parameters. A full package of pictorial description for visualizing the changes in flow with and without the flap is provided through pressure and velocity contours.

Thin flat balances for testing thin delta wings at hypersonicspeeds

This paper concerns the design anddevelopment of two special novel thin internal strain gaugebalances for testing thin slab delta wings at hypersonicspeeds. Of the two balances, one is a thin three-componentbalance and the other is a thin six-component balance. Unlikethe conventional balances, which are circular in cross section,the balances discussed here are flat and have rectangular crosssections. Here, the design philosophy and the metallic architectureof these balances are discussed in detail. This paper is dividedinto three parts wherein the first part deals with the thinthree-component balance the second part addresses the thinsix-component balance and, in the third part, typical resultsobtained using these two balances are presented.The thin three-component balance has a thickness of 2.5 mm andcan be housed inside a wing as thin as 6 mm. Because of itsthinness, the axial output exhibited non-linear interaction from the normalforce loading. Hence, combined loading is performed. In order todeduce the second-order coefficients, a new methodhas been proposed and a comparison with the existing method showsthat this is better than the previous method. This balance has beenused to generate aerodynamic data on thin slab delta wings withand without lee-side balance housing bodies. In this way, it is demonstratedthat the lee-side bodies do interfere even when they come into theaerodynamic shadow of the wing.The thin six-component balance has a thickness of 4 mm and can be housedinside an 8 mm thick wing. Although this balance is also thin, it exhibitedexcellent linearity in all the bridges. In spite of this, it is subjected toseveral possible combinations of combined loading and the `work back' loadsare calculated using the linear coefficients. The work back loads agree verywell with the applied loads. Hence, linear coefficients have been used for thepurpose of data reduction. The effects of flap deflection on the aerodynamiccharacteristics of thin slab delta wings have been studied using this balance.All the experiments were conducted at Mach 8.2 and a Reynolds number of2.13×106.

Flight Development of the Avro CF-100 Mark 5 Aircraft

SummaryImprovements made to the aerodynamic characteristics of the wing of the Avro CF-100 Mark 5 aircraft are discussed. Modifications to the wing included increase in aspect ratio, addition of vortex generators, and deflection of trailing edge plain flaps. The effect of flap deflection and addition of vortex generators on the aerodynamic characteristics of the wing are shown to be closely associated with interaction of the upper surface shock wave with the boundary layer. Performance gains were demonstrated at high subsonic speeds at high altitudes. Vortex generators improved the buffet boundary, whereas flap deflection both increased aircraft ceiling and improved buffet boundary.

A Consideration of Calculated Versus Flight Test Take-Off Performance

Theoretic methods for calculating the ground run, transition, and steady climb distances during the take-off of an airplane are derived. The velocity for minimum take-off distance over a 50ft. obstacle is clearly indicated. . A series of approximately 40 take-off tests were made on a C-46 airplane. The technique for measuring and recording the test results and the presentation of the final data are described. The test data are compared with the theoretic calculations. I t is shown that not only the actual minimum take-off distances but also the effect of flap deflection and velocity on the total take-off distance can be accurately predicted by the theoretic methods. The relative effects of CL> CD, thrust, ground proximity, ground friction, and other variables on take-off distance are discussed, and the pilot technique derived for minimum take-off is stated. Finally, it is shown that the complete take-off characteristics of an airplane may be obtained from a short, well-planned test program, with the emphasis placed on determining the maximum accelerations acting on the airplane rather than on testing for minimum distances.