As you can probably imagine, the shape of the wing has a lot to do with what it’s good for.
Straight Wing: Sometimes called the Hershey Bar, this is the easiest wing to construct and is generally pretty good at low speed.
Tapered Wing: This is a step up from a straight wing and is what you find on most civil aircraft today, it combines the benefit of being easy to construct with a higher aspect ratio and reduced weight.
Elliptical Wing: The most efficient wing for subsonic flight, this takes the aspect ratio increase from the tapered wing a step further, however, they are harder to construct.
Swept Wing: This shape is designed for use at speeds approaching the sound barrier, the more intense the sweep, the faster the airplane is intended to go. This is to keep the structure inside of the shockwave generated by going supersonic. These wings perform best at moderate speeds.
Delta Wing: Delta wings are designed to give the aircraft a high wing area (to reduce wing loading and allow for better energy conservation) and keep the wing itself inside the shockwave generated by going supersonic. These wings do best at high speeds.
Want the best of both worlds? Engineers have cracked that:
The Tomcat can do Mach 2.5 and stalls at 110 knots.
There are other characteristics of wings that aid performance as well.
One of the first things a private pilot learns to do is stall. Not to get comfortable with stalling, but to know what a stall feels like.
This is great in trainers, but more advanced aircraft have different characteristics when on the edge of stall. What influences this? Wing shape, for one.
When a wing is designed with a twist in it, it’s said to have washout – this allows the outer portion of the wing (where the ailerons are) to stall AFTER the inner portion. Why? So that there’s still roll control on the edge of stall.
On earlier wings where there isn’t any washout – the wing becomes thicker toward the wingtips – this achieves the same effect, but also increases drag.
Tip Tanks & Winglets
In the Starfighter, mentioned earlier, there were a number of variants, some with wingtip fuel tanks, some without. The ones with tip tanks performed better at low speeds than the ones without. This is because the tip tanks act like winglets, a wingtip section that’s usually vertical, and shape the airflow around the end of the wing – this causes some interference drag at the aileron and allows for better control.
As an added benefit, winglets and tip tanks contour and reduce the wingtip vortices (which are basically like streamers of pure drag hanging off of each wingtip), improving efficiency.