Today we have another series of posts talking about wing aerodynamics, this time we will address the elliptical, it was a type that was widely used in the past, today it is very well regarded by aviation enthusiasts, mainly due to its great use in the second world war with the Spitfire, an English fighter manufactured on a laaaaarga scale, impressive in fact even today as they manufactured so many aircraft in such a short time. So let's start the description on how this type of wing works.
As it is noticeable by the name of the wing (elliptical right?), it is almost a rounded wing as it could be said, but not because it has a ball shape, or maybe a rectangle shape with balls, not quite that. An elliptical wing is a type in which it has a leading and trailing edge without being straight as in a trapezoidal or straight line, it is always in the form of a curve, that is, if I take a point of it and compare it with another next to that point the angle of inclination will be different, as exemplified in the image below.
This variable angle of the elliptical wing provided better aerodynamics in relation to the drag created, as well as the trapezoidal, so much so that creating a direct relationship between the straight and the trapezoidal, the elliptical performs better, both at low speeds and at high speeds. The lift on the elliptical wing is distributed equally, that is, every piece of area receives the same lift, but this creates a basic problem, when there is a stall it does not start at the tip or at the root as in other types of wing, it it goes all over the wing (just imagine, you start to fall all at once without warning), despite being quite efficient at low speeds you have to be careful with the Stall limit. Its rounded wing tip collaborated to reduce the vortex formed by the wind, further increasing its aerodynamic qualities, in fact, everyone knows that in of an airplane, all drag is harmful.
One of its characteristics is to high speed flight, a diving Spitfire in World War II could reach Mach 0.92, or it could slowly close to the ground dropping bombs, which makes the design for the aircraft very versatile in general. At cruising speed, it maintained numbers close to 600km/h, something that is still quite a lot for a propeller aircraft, even more driven by a single V12 engine that poured power into the various types of designed blades, both the tripods with pitch and geometry. variable as the 5 blades with the same configuration, which together with the wing allowed this dive to almost Mach 1.
Its construction in general is very difficult, both in the project that involves a more complicated calculation in relation to its area and its volume as well. The fairing that covers the structural surfaces of the wing and distributes the weight between them also had to be done with extreme care, especially for the era in which it was created. Each rib had a different size and different angles, but it was responsible for the same weight, its spars are different in size, all because of the leading and trailing edges not being completely straight.
At Enzo Donatti's request, the next part will deal with some types of flaps that are a bit unusual.
