Search results
Results from the WOW.Com Content Network
Schemes have been devised to define airfoils – an example is the NACA system. Various airfoil generation systems are also used. An example of a general purpose airfoil that finds wide application, and pre–dates the NACA system, is the Clark-Y. Today, airfoils can be designed for specific functions by the use of computer programs.
English: Selected airfoils in nature and various vehicles, with their approximate chord length indicated. Sources for the shapes of the airfoils: Low-speed ULM wing: drawn over own photo of low-cost, low-speed ultralight; Propeller blade: drawn over own photo of a sliced WW2-era bomber propeller
The profile was designed in 1922 by Virginius E. Clark using thickness distribution of the German-developed Goettingen 398 airfoil. [1] The airfoil has a thickness of 11.7 percent and is flat on the lower surface aft of 30 percent of chord. The flat bottom simplifies angle measurements on propellers, and makes for easy construction of wings.
For example, the NACA 2412 airfoil has a maximum camber of 2% located 40% (0.4 chords) from the leading edge with a maximum thickness of 12% of the chord. The NACA 0015 airfoil is symmetrical, the 00 indicating that it has no camber. The 15 indicates that the airfoil has a 15% thickness to chord length ratio: it is 15% as thick as it is long.
The Kline–Fogleman airfoil or KF airfoil is a simple airfoil design with single or multiple steps along the length of the wing. The purpose of the step, it is claimed, is to allow some of the displaced air to fall into a pocket behind the step and become part of the airfoil shape as a trapped vortex or vortex attachment.
Supercritical airfoils feature four main benefits: they have a higher drag-divergence Mach number, [21] they develop shock waves farther aft than traditional airfoils, [22] they greatly reduce shock-induced boundary layer separation, and their geometry allows more efficient wing design (e.g., a thicker wing and/or reduced wing sweep, each of which may allow a lighter wing).
An airfoil affects the speed and direction of the flow over a wide area, producing a pattern called a velocity field. When an airfoil produces lift, the flow ahead of the airfoil is deflected upward, the flow above and below the airfoil is deflected downward leaving the air far behind the airfoil in the same state as the oncoming flow far ahead.
Mean aerodynamic chord (MAC) is defined as: [6] = (), where y is the coordinate along the wing span and c is the chord at the coordinate y.Other terms are as for SMC. The MAC is a two-dimensional representation of the whole wing. The pressure distribution over the entire wing can be reduced to a single lift force