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.
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.
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. https://www.youtube.com/watch?v=j2Xn84L3Kcs