![]() ![]() This means that the height at the thickest section is equal to 12% of the total chord. The airfoil plotted above has a thickness-to-chord ratio of 12%. The thickness of the airfoil is a very important design parameter and as always expressed as a percentage of the total chord. This is a convenient way to display an airfoil, as different chords can be normalized and compared directly to one another. In the example shown above, the chord has been normalized such that the leading edge is located at a chord location 0 and the trailing edge at 1. This often varies down the span of the wing as the wing tapers from the root to the tip. The length of the airfoil from leading to trailing edge is known as the airfoil chord. ![]() The airfoil upper and lower surfaces meet at the leading and trailing edges. This is easy to remember if you think of the front of the airfoil as leading its movement through the air. The front of the airfoil is named the leading edge and the rear the trailing edge. Before we do this we'll start by presenting a few fundamental definitions in order to understand how and why an airfoil is shaped as it is. We are now going to move from looking at the wing in planform and concentrate on the section profile of the airfoil that is used on the wing. We also discussed the aspect ratio and how a longer, thinner wing will reduce the total drag of the wing up to a particular speed whereafter transonic speed effects begin to dominate the total drag produced which necessitating a sweeping of the wing to combat the transonic drag rise. Now we'll move on and look more closely at the shape of the wing airfoil: why this differs from aircraft to aircraft, and how a careful airfoil selection will help to produce the flying characteristics you desire for your airplane.Īfter reading the post on wing area and aspect ratio, you should appreciate that there exists a very clear relationship between the size (weight) of the aircraft and the size of the wing (wing area) required to operate the aircraft as intended. ![]() Specifically we looked at wing area and aspect ratio. In a previous post we looked at the importance of the shape and plan-form of the wing, and how this has a great impact on the flying characteristics of the aircraft. Two distinct types of hysteresis in reattachment were observed.This is part 5 in a series of fundamental aircraft design articles that aims to give you an introduction to aircraft design principles. Once the flow was separated, the separation point moved upstream and the suction peak decreased in magnitude with increasing Reynolds number. The stall angle and the maximum lift coefficient increased with Reynolds number. As the Reynolds number was increased beyond this value, the stall type gradually shifted from trailing-edge stall to leading-edge stall. A fundamental change in the flow behaviour was observed around Re_c= 2.0 × 10^6. As such, attached and separated conditions, as well as the static stall and reattachment processes were studied. The angle of attack was incrementally increased and decreased over a range of 0° ≤ alpha ≤ 40°, spanning both the attached and stalled regime at all Reynolds numbers. The use of a high-pressure wind tunnel allowed for variation of the chord Reynolds number over a range of 5.0 × 10^5 ≤ Re_c ≤ 7.9 × 10^6. Reynolds number effects on the aerodynamics of the moderately thick NACA 0021 airfoil were experimentally studied by means of surface-pressure measurements. National Defense Science and Engineering Graduate Fellowship National Science Foundation grant CBET 1652583 Static measurements of a NACA 0021 airfoil at high Reynolds numbers Please use this identifier to cite or link to this item: Princeton University Undergraduate Senior Theses, 1924-2023 Princeton University Masters Theses, 2022-2023 Princeton University Doctoral Dissertations, 2011-2023 Princeton School of Public and International Affairs Liechtenstein Institute on Self-Determination Lewis-Sigler Institute for Integrative Genomics Department of Slavic Languages and Literatures
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