NewsDerby Announces New Change To The Masters Car06.15.2016 Beginning August 1, 2016 the rear airfoil on the front and back axle is no longer allowed. ALL Masters cars racing in sanctioned Soap Box Derby events beginning August 1, 2016 must meet this requirement. The airfoil MUST be the Soap Box Derby issued wood airfoil. A new set of Masters Car build plans will be released soon and the Masters Car kit will be updated to reflect the change. If you have any questions, please contact us at 330.733.8723 or firstname.lastname@example.org.