Writing Homework Help

Just a short discussion

Do a little research and find an aircraft that ignores the area rule, or find one that you think has made extreme use of the area rule. Describe why you think that is so and explain the other relevant aerodynamics of the design.

Manuel Martinez

The Area Rule, which is also called the Whitcomb area rule (because of who discovered it), is a design technique used by aircraft to reduce the amount of drag caused by air flowing at transonic and supersonic speeds during transonic flights, which are speeds above 250mph and below 760mph. The area rule says that two aircraft have the same longitudinal, cross-sectional area distribution, have the same wave drag. It does not matter how the area is distributed laterally (for example, in the fuselage or the wing). Also, to prevent the formation of solid waves of shock, the total area of distribution must be smooth. As a result of this, planes have to be carefully designed so that, at the wing’s location, the fuselage is narrower so that the total area of the aircraft does not change as much. For example, the design of the Boeing 747’s upper deck “hump” was initially designed to be as small as possible because of the ordinary streamline principles. Later on, it was realized that the drag could be reduced even more by lengthening the hump part of the aircraft to minimize wave drag, offsetting the tail surface’s contribution. This new and improved design was introduced on the 747-300, which also improved the cruise speed while also lowering the drag, with the side effect of slightly increasing capacity on passenger flights. The aircraft AIRBUS-380-800 has several features that are related to the area rule. For example, the jet engines are in front of the wings and the shaping at the wing root.

Orlando Gonzalez

Hello Everyone! In the 1950s Richard Whitcomb found what was called the area rule (he is also credited with the invention of winglets). The area rule can be described as an aircraft approaches Mach 1, the air flowing around the fuselage and wings begins to exceed Mach 1 leading to the transonic speed range. Whitcomb found that to minimize the amount of wave drag created by an aircraft, its cross-sectional area needed to change smoothly. When the wings spread out from the fuselage, the total crosssectional area quickly increased – and so did the wave drag (Udris, 2015). The solution was to taper the fuselage in where the wings spread out. That balanced the total cross-sectional area and minimized wave drag. As I’m doing the research I came across the Boeing Sonic Cruiser, this project started in early 2001; however, it had to be canceled because of the effects of 9/11. The Sonic Cruiser was a Boeing concept, for a widebody that would cruise at very high subsonic speeds. Its wingspan was similar to the 767, but it had nearly twice the wing area. The engines were not on pylons, instead, they were buried in the wing. The Boeing Sonic Cruiser would follow the area rule to its max capability. This minimizes drag allowing for higher airspeeds. Boeing was trying to accomplish what the Concorde couldn’t, subsonic flight with higher payloads. The Sonic Cruiser concept ‘morphed’ into the 7E7 (E for efficient), which then became the 787 Dreamliner, complete with composite materials (Georgilidakis, 2021).