balls to the wall

English

Etymology

It is possible this phrase was coined before or during World War Two by American aircraft pilots. The throttle levers (accelerators) in the aircraft had round tops that looked like balls. To put the "balls to the wall" (the wall being the firewall in the aircraft) was to advance the levers all the way forward, making the aircraft fly as fast as possible. It now means to carry out an action as quickly as possible.

Alternatively, the phrase may come from the days of stationary steam engines. The governor on these engines consisted of two iron balls mounted on a rotating pivot that was geared to the engine. This pivot was connected to the steam valve that acted as the throttle. As the engine's speed increased, centrifugal force caused the balls to move outward on the pivots causing the valve to close and slow the motor down. Conversely, if the engine slowed down, the balls dropped lower, which opened the throttle. If the engine was running at maximum speed, the balls would not be "to the wall" per se, but they would be at their maximum extension or "running balls out".

Noun

balls to the wall (plural only)

1. (US, idiomatic, slang) full throttle; maximum speed
2. (US, idiomatic) Maximum effort or commitment.
   • 2006, Michael D. Brown, Testimony before the US Senate Homeland Security Committee:

     I told the staff...the day before the hurricane struck that I expected them to cut every piece of red tape, do everything they could, that it was balls to the wall, that I didn't want to hear anybody say that we couldn't do anything—to do everything they humanly could to respond.