Usually, the English saying “balls to the walls” refers to approaching or handling a situation with a great level of attention, force, or urgency. The expression is thought to date to the United States military aviation involvement in the Vietnam War, though some people believe it can be traced back further to the Korean War. Regardless of origin, most sources do agree the expression is related to certain aviation terms and actions. Like many idiomatic expressions, this one can be translated into everyday life.
An airplane throttle, or power lever, is a type of stick with a ball-shaped topper positioned behind the cockpit’s firewall, similar to how a regular passenger vehicle’s gearshift is often positioned behind the vehicle’s dashboard. The throttle controls the airplane’s power level by controlling how much air or air/fuel mixture the cylinders receive. The closer to the firewall the pilot pushes the throttle, the more power the airplane has. When a pilot wants full power, he pushes the throttle all the way forward, toward the firewall. Therefore, when pilots push their throttles all the way forward to achieve full power, they are said to have pushed the balls to the walls.
Some experts claim the idiom originated during the Vietnam War, and was first recorded in 1969 by United States Air Force cadets. Some veterans have claimed to have used the saying during the Korean War, so it is possible the idiom dates to the 1950s. Since “balls out,” a similar saying with a similar meaning was used during World War II, it is likely “balls to the walls” did originate among military aviation personnel. Going further back, the variation “balls out” might have originated in the 18th or 19th century, when stationary steam engines were common. A stationary steam engine features a pivot with two iron balls, which acts as the throttle and is moved outward, or “balls out,” in order to increase the speed.
These days, when a person does something in a way described as being “balls to the walls,” it typically means he does it with great force or effort. Sometimes, it means he has approached the situation or chosen a course of action that is considered dangerous. Similar to many English sayings, this idiom can be applied to a variety of personal and professional life situations. For example, a team of paramedics might respond to an accident scene in a “balls to the walls” way, or an Olympic track runner might train in a manner considered “balls to the walls.” The saying can even apply to students who are pulling all-nighters to study for exams, write research papers, or prepare presentations.