Adam Parr from Williams explains the hot-blown diffuser saga

“It’s a hugely complicated issue. Even if we know what it does to us, we don’t know what it does to everyone else. When people started to develop this hot-blowing technique, we sat down with Cosworth and asked if we could do it. They said yes and listed how many engines we’d need to develop it and how much it would cost. Then Patrick [Head] said, ‘hang on a minute, is this even legal?’”

“We discovered that there are three different rules under which it is probably illegal, two of which come under article 3.15. One is to do with parts that influence the aerodynamic performance of the car being rigidly secured to the chassis and the other is a new rule for this year, which says any system that relies upon driver movement to influence aerodynamic performance is illegal.”

“We asked for a clarification from Charlie [Whiting, FIA Race Director] and very rapidly we got the answer ‘No, this is absolutely not legal’. That has been his consistent view throughout all of this. Using the throttle in braking to gain aerodynamic performance is not legal; it’s using a thing that is moving rather fast and not rigidly secured to anything to help aerodynamic performance. That’s where we started and we were happy because it meant we didn’t have to spend a fortune developing a system.”