What is aspect ratio?

guide
June 12, 2023
WINGFOIL

The aspect ratio is a coefficient that characterizes the elongation of a wing. It is the square of the wingspan divided by its projected area.

→ Aspect ratio = wingspan² ÷ projected area

On a square, one could take the length of the square compared to the other side of the square, but on a wing, there are variations in different chord lengths to take into account.

The aspect ratio of a wing.

A wing is characterized by its length (span), its chord (width), and its surface area. The aspect ratio is the ratio between these elements, which yields a coefficient that allows for the comparison of wings.

For example, between a Carver 1700 (AR=5.5) and a Flyer 1300 (AR=7), the latter has less chord length compared to its length, thus resulting in a higher aspect ratio. Therefore, the higher the aspect ratio, the greater the span!

The influence of elongation on navigation.

The higher the aspect ratio of a wing, the less drag it will generate compared to the same surface area. For example, if I have a Carver 1500 and a Flyer 1500, the latter having a higher aspect ratio, it will experience less drag and therefore be slightly more efficient in terms of speed. A wing with high elongation will also have what we call a better glide ratio. Once you stop giving it speed, it will take longer to descend. It’s like comparing a glider to a fighter jet: once you cut the engine, the glider takes much longer to descend. On the other hand, wings like the Carver with more moderate aspect ratios allow for greater maneuverability and turning compared to a wing like the Flyer, which has better glide and flight characteristics. In windfoiling, there is a search for lift in light winds. Therefore, working with higher aspect ratios is necessary to minimize drag and maximize lift. In slalom, we look for tolerance and maneuverability, so working with slightly lower aspect ratios is preferred. The same applies to wingfoiling. If you want to ride waves, a Carver wing will be perfect. You can take it in any direction, and it will never stall. However, on flatter water for pumping or slalom wing practice, a Flyer wing with a higher aspect ratio will be ideal. It offers less drag relative to lift, resulting in more speed and longer flights. If you want to know everything about wingfoiling, a dedicated guide to the practice has been written for you!