One of the FIFA World Cup’s most curious matters is the design of the ball that will be used. Players, coaches, viewers and commentators are interested to know the aerodynamic behavior of the new ball ‘Telstar 18’ as FIFA 2010 ball (Jabulani) and 2014 ball (Brazuca) drew some concerns and criticisms.
Will ‘Telstar 18’ behave better than Brazuca? Can player predict its anticipated flight trajectory? To answer these questions, the Sports Aerodynamics Research Centre at RMIT University, Melbourne, Australia headed by Professor Dr Firoz Alam has undertaken an aerodynamic study of ‘Telstar 18’ ball using RMIT Industrial Wind Tunnel.
The findings from these tests are amazing. For the greater interest of the viewers and commentators, RMIT thought it wise to make public the findings.
Does ‘Telstar 18’ Ball differ from its predecessors?
The ball of the World’s most popular game has undergone through incredible changes since 2002. The advancement of technology, popularity and economic interest have made possible to introduce new changes on the ball design. An epoch-making design change of Adidas made FIFA World Cup football is illustrated in Figure 1 since 2002.
All FIFA World Cup balls were made of 32 panels (20 panels-hexagonal & 12 panels-pentagonal) from 1970 to 2002. A significant deviation from the traditional leather made panel to the synthetic panel was introduced by Adidas for the FIFA 2002 World Cup ball. However, Adidas introduced more radical design change in its 14-panels Teamgeist ball in FIFA 2006 World Cup. The smooth synthetic panels were bonded instead of stitching.
The 8-panels ‘Jabulani’ ball along with its asymmetrical orientation and pattern of grooves was introduced in 2010 FIFA World Cup by Adidas. The Jabulani ball drew huge criticisms and comments from players and experts alike for its erratic flight behaviour. In FIFA 2014 World Cup, Adidas has unveiled a 6-panels Brazuca (meaning Brazilian way of life) ball which aerodynamically behaved much better than Jabulani ball. A newly designed ‘Telstar 18’ has been introduced for FIFA 2018 World Cup by Adidas once again. The outer skeleton of Telstar 18 ball is made of 6 synthetic panels as Brazuca ball but with different panel shape.
Will Telstar 18 behave better than Brazuca? Can player predict its anticipated flight trajectory? To answer these questions, the Sports Aerodynamics Research Centre at RMIT University, Melbourne, Australia headed by Professor Dr Firoz Alam has undertaken an aerodynamic study of Telstar 18 ball using RMIT Industrial Wind Tunnel. The study has discovered some interesting findings about the Telstar 18 ball.
The variation of drag coefficient (an indicator of aerodynamic efficiency, lower the coefficient, better the aerodynamic efficiency) between the two sides of Telstar 18 ball is less than 2% compared to Brazuca (3%), Jabulani (9%), Teamgeist (5%) and Fevernova (2%).
The Telstar 18’s sideway aerodynamic behaviour is very close to Fevernova ball used in FIFA 2002 World Cup in Korea and Japan. Therefore, Telstar 18 is expected to have more predictable flight in calm wind and non-spinning conditions than its predecessors Brazuca, Jabulani and Teamgeist balls.
For short pass, the Telstar 18 needs harder kick as its aerodynamic drag is higher at low speeds (below 60 km/h) than Brazuca ball. For mid-range distance, the Telstar 18 needs to be kicked softer (60 to 90 km/h range) due to its lower drag. However, for long distance, the ball requires slightly greater force-kick than Brazuca ball.
For goalkeeper, Telstar 18 will be slightly hard to grip compared to Brazuca ball due to its orderly square flat pimples in contrast to Brazuca’s prominent wavy patterned rectangular pimples. Telstar 18 has longer seam length (~4.2 m) and shorter seam depth and width than Brazuca ball.
Will altitude affect Telstar 18 flight trajectory in Russia?
The average altitude of 11 stadiums in Russia is around 88 m from the sea level and the average air temperature in June is approximately 18ºC. Hence, no notable altitude effect on aerodynamic behaviour of Telstar 18 ball is expected compared to 2014 and 2010 World Cup host countries Brazil and South Africa.
BDST: 1244 HRS, JUN 13, 2018