Using a wind tunnel, Goff has researched the flight properties of the Telstar 18, drawing its drag curve to discover where the ball might dip and swerve in the air, similar to the knuckleball free kicks favored by Cristiano Ronaldo “Even if aerodynamically the Telstar 18 isn’t that different from the Brazuca, it’s still going to wobble a little bit differently because the panel shapes are different,” Goff says.
A: Butyl bladders are an excellent choice for the interior of soccer balls because they create an airtight seal in the inner compartment. This helps greatly with air retention. Even better, you will not have to keep inflating soccer balls that contain a butyl bladder for the fact that they hold air much longer than soccer balls that don’t have a bladder made from butyl rubber.
The secret to the authentic movements on a rebound with this ball is the inclusion of an SBR foam layer underneath the PU cover. This allows the power of a pass or shot to be transferred with more accuracy. It keeps the ball somewhat soft to the touch, but creates a realistic movement which allows players to develop an ability to start reading the game with accuracy without the need to purchase an expensive premium match soccer ball. It comes in all of the standard sizes and offers 4 unique design options, allowing players of any age or ability to begin working on their soccer skills.
At the World Cup level, these tiny changes in a ball’s aerodynamics can legitimately impact a team’s performance, so the intense scrutiny of the World Cup ball is perhaps to be expected. “You could argue that it’s the most important piece of equipment in the most popular sport in the world,” says John Eric Goff, Professor of Physics at University of Lynchburg.
“I kind of feel sympathy for the players and especially the goalkeepers that have to get used to a new ball,” Goff says. So far the Telstar 18 has received criticism from a few goalkeepers that played with it starting in November, unhappy with how it moves in the air and the way the surface feels. Goalkeepers, unlike every other player on the pitch, have to predict where the ball will go in order to block it, while also not having the freedom to run around the field to adjust as the ball flies. That means goalies often have the most complaints about a new design. “Every time there’s a World Cup and a new ball the goalkeepers complain, because they’ve been given a new ball,” says Goff.
On the other hand, replicas (sometimes called training balls or gliders) are designed to be just like the official match balls but are much cheaper. Their panels are often stitched rather than thermally-bonded and are made of a different material. However, they’re not necessarily less durable than official match balls. So, they’re the recommended option for most players.