Wing Sweep

Wing sweep, Л, is a function of aircraft speed to delay transonic effects. For aircraft flying at less than Mach 0.6, a wing sweep is not required. A tapered wing with a zero quarter-chord sweep has some LE sweep; the trailing-edge sweep depends on the taper ratio.

Wing Twist

It is an essential geometrical adjustment to ensure that wing-tip effects do not create adverse conditions. A major requirement is to make the wing root stall earlier to retain aileron effectiveness at a high angle of attack (low speed) – especially during landings. A wing twist with washout would favor such behavior (and is the prevailing practice).

Wing Dihedral/Anhedral

To ensure roll stability (see Section 12.3.3), wing dihedral and anehedral angles are used. Generally, the dihedral is associated with low-wing design and the anhedral with high-wing design; however, there are designs that are the reverse: a high wing can accommodate a dihedral. The type and extent are settled through stability analysis, which is not discussed in this book. All civil aircraft have some dihedral or anhedral angle between 1 and 5 deg. If a high wing and/or a high-wing sweep increases lateral stability more than what is required, the anhedral angle is required to reduce it to the desired level. Some low-wing Russian bombers have a high-wing sweep that necessitates an anhedral angle, when the undercarriage struts must be longer to provide the desired ground clearance.

Leave a reply

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>