Selection of Wing Design and Configuration
An aircraft’s wings are some of the most important design considerations, with their shape and size affecting virtually every aspect of the aircraft’s performance. The wing configuration describes the arrangement and design of an aircraft’s lifting and lift-related surfaces. There are numerous terms and classifications used to describe configurations, with many different designs experimented with over the years. Most aircraft, however, come in one of several different common configurations.
The most common aircraft design is the monoplane, an aircraft with just one wing. Monoplane wings can be mounted on various points on the fuselage, such as a low-wing, which is attached near or below the bottom of the fuselage, a mid-wing which is halfway on the fuselage, and a high-wing that is mounted on the upper fuselage. There are even parasol wings, which are mounted above the top of the fuselage and attached via struts and pylons.
The first aircraft ever flown, the Wright Flyer, was a biplane, featuring two wings of similar size and shape stacked one above the other. Biplanes were originally used to compensate for unrefined airfoil designs, generating the lift that a single wing could not. Biplane wings can be equal or unequal in length, and can be staggered (one set slightly ahead of or behind the other) or unstaggered. There have also been aircraft with even more wings, such as triplanes, quadruplanes, and multiplanes, but they have never been as popular or widely used.
Another important consideration for wing configuration is the aspect ratio, the length and width of the wing itself. A low aspect ratio means that the wing is short and stubby, and is most commonly seen on high-speed aircraft like the Lockheed F-104 Starfighter and North American X-15. Moderate aspect ratios are used on general purpose aircraft such as airliners, and wings with very high aspect ratios are extremely aerodynamically efficient, and are used mostly on high-altitude subsonic aircraft such as the U-2 spy plane.
One common design consideration is if the wings are swept forward or back. Doing so alters their dynamic properties, with swept-back wings popular for faster aircraft mounting jet engines, especially those designed for supersonic flight. There are even aircraft that can change the sweep of their wings, such as the F-14 Tomcat, which lets them change their profile mid-flight.
There are divergent designs, of course. One of the most common of these is the delta wing, which features a wing in the shape of a large triangle that runs along the entire length of the aircraft, incorporating the aircraft’s control surfaces into them.