The handling characteristics of foils depend largely on the front wing. In addition to different sizes, almost every manufacturer also offers different types of wings, which are sold under the terms "high-aspect foils" and "low-aspect foils" across all brands. We will show you which type of foil is suitable for you below. If you have general questions about foil terms or are looking for tips on the right size of front wing, you can find them here here.
What does the "Aspect Ratio" reveal about the foil type?
The English term "aspect ratio" basically describes nothing more than the ratio of span to surface area. Tiesda You, Foil Designer at Starboard, explains the correlation: "Wings with a large span and less surface area have a "high aspect ratio". Conversely, wings with a large surface area in relation to the wingspan have a "low-aspect ratio" - these are wider wings with a smaller wingspan and thicker profiles".
The question of which type of foil you should choose has been on our minds for a long time. Over the years, we have compared countless foils of different types as part of many tests - and have gained the following insights, which are also based on GPS recordings. So what are the differences on the water when comparing low- and high-aspect foils of the same size?
Take-off & Speed
Due to the thinner profile, high-aspect wings require a slightly higher take-off speed on average. If you take off too early, these foils can also sink again, as thinly profiled high-aspect foils are only stable at higher speeds. With the usually thicker-profiled low-aspect foils, the resistance when starting off is somewhat greater, but the take-off is usually more controlled and reliable. The bottom line is that if you pump with feeling and technique, you can take off with a high-aspect foil at comparable wind speeds. But: Foil beginners benefit from thicker wings, as they take off more forgivingly and are more stable in the airflow.
Foil beginners benefit from the more stable airflow of the low-aspect foils when taking off
The differences in behaviour in wind holes are also striking - here the thicker ("low aspect") stays up noticeably longer and only drops at perceived walking speed, while the similarly sized but thinner-profiled high-aspect foil runs out of breath earlier. The differences in speed are also indisputable - although in many cases they are smaller than expected: If you compare front wings of identical size, you are on average a tad quicker with high-aspect wings. However, the speed advantages are often within the range of 2-3 km/h. The size of the front wing has a much greater influence on the speed potential of a foil - the smaller, the faster! For this reason, racers and freestylers usually use front wings with a surface area of well under 1000 cm2. However, these also require a very active riding style in order to get onto the foil at all - a no-go for foil novices!
The size of the foil is more important for the spee potential than whether it is a high or low aspect foil
Control - thick profiles have an advantage
The differences in control are also noticeable for everyone. Thinner profiled high-aspect wings react much more sensitively on average to incorrect loads. So if you unintentionally give the foil some fresh air in the wave trough, on the straight or during a manoeuvre, you will have to contend with a stall more quickly than with a more stable low-aspect foil, which often catches itself again and keeps the surfer up. Due to their good-naturedness, low-aspect foils are therefore also used for training beginners. The stabiliser (backwing) and the length of the fuselage also have a major influence on control. The longer the fuselage, the more stable the board flies around the lateral axis. Larger stabilisers also support this riding characteristic, but also reduce the speed potential somewhat.
High-aspect foils offer significantly more glide on swell waves
Glide - the domain of high-aspect wings
The situation is different when it comes to gliding on swell waves, Glide called: High aspect foils with their stretched wing shape have a clear advantage here. Even round and powerless swell waves can be ridden in a relaxed manner. If you enjoy flying endlessly on knee- to chest-high swells with a neutral wing position, there's no getting round a high-aspect foil. So are wings with a large wingspan generally better on the wave? When it comes to the aforementioned glide, then yes, because high-aspect wings simply glide longer on powerless waves. However, due to their larger span, the radii are limited. If you want to make real turns in breaking waves and are looking for a manoeuvrable ride, you will get more out of a low- or mid-aspect foil - ideally with a short fuselage.
Which foil type fits? The conclusion
Every type of foil has its justification. When it comes to pure take-off, the differences are marginal, but if you want to tack on gusty inland areas and are looking for a foil that stays in the air as long as possible in wind holes and manoeuvres and is particularly good-natured, you should look towards a thicker profiled wing with a low or mid-aspect ratio.
The thinner profile and slimmer wing shapes of typical high-aspect foils, on the other hand, have advantages especially when it comes to gliding, i.e. relaxed flying on round swell waves - ideal for downwinders on the Baltic Sea or large inland lakes, for example. Those aiming for jumps and freestyle tricks will also tend to favour slim high- to mid-aspect foils. However, when it comes to top speed (= jump height), the size of the front wing is more important than the question of high or low aspect ratio.
Manuel Vogel
Editor surf
