When it debuted in 2005, Kingda Ka at New Jersey’s Six Flags Great Adventure claimed the twin titles of the tallest and fastest roller coaster in the world. The 50.6-second adrenaline rush of a ride takes roller coaster fans up a 456-foot top hat tower and reaches a top speed of 128 mph in 3.5 seconds. Oh!
What gives Kingda Ka her incredible record success? Hydraulics.
If that concise explanation makes you scratch your head, let’s dive into some of the details. Until the late 1970s, almost all modern roller coasters were pretty standard. Whether the tracks were made of wood or steel, a powerful lift chain driven by a click-clack-click motor clicked a mountain train slowly down a lift hill. At the top of the hill, the chain unhooked and gravity took over.
Most roller coasters built in the late 1970s still use the tried-and-true approach, but some travel designers have been replacing conventional lift hills with a series of launch systems. They can increase acceleration, speeds, heights, and (of course) excitement, as well as create different types of driving experiences. Screaming out of the charging station, roller coasters thrown like Kingda Ka take away the anticipation of the lift hill and provide non-stop action from start to finish.
To send mountain trains and their intrepid passengers screaming out of the box, travel designers have developed a variety of launch methods including magnetic propulsion, compressed air, and electric motors. But hydraulics offer a relatively simple and efficient way to get mountain cars moving fast, VERY fast.
A roller coaster on steroids
A hydraulic launch system is similar to a traditional roller coaster… on mega doses of steroids. Instead of a lifting chain, the roller coaster uses a cable that is wrapped around a giant winch. Attached to the cable is a capture car, a device that hooks onto trains and launches them down the launch track. To marry the two of them, a “dog” falls from the center of the train and hooks onto the carriage. About two-thirds of the way down the Kingda Ka horizontal launch pad, the train accelerates to full speed, the dog gets up and disconnects from the train, the magnetic brakes slow the capture car, and the train continues through the tower. vertical 456.
Gravity takes the train through the other side of the tower and returns to the station.
Unlike conventional roller coasters, which generally reach their highest speed after roaring in the first fall, Kingda Ka hits 128 mph on the approach to the tower. “In theory, we want to achieve the same speed on both sides of the tower,” says Michael Reitz, Six Flags corporate engineer and member of the development team who worked at Kingda Ka. “But wind, passenger weight, heat, humidity and other factors affect actual speeds.” He says Kingda Ka usually accelerates to about 120 mph at the bottom of the other side of the tower before he navigates his second hill and heads home.
That explains how the Kingda Ka trains start from the loading station. But how does the winch produce enough thrust to pull the cable down the launch pad? Hydraulics.
Reitz explains that the winch is connected to eight 500-hp hydraulic motors that sit on top of a huge reservoir of hydraulic fluid. Compressed nitrogen gas forces fluid through engines to generate power. The engineer points out that the motors send the energy they create to introduce giant accumulators and compares the process to exploding balloons.
“They store huge amounts of energy, then at the right moment, poof, they release it,” says Reitz. “They are capable of producing 20,800 peak horsepower.” For comparison, a car engine generally delivers around 175 hp. We are talking about serious power here.
Even faster and higher?
There are similar hydraulic coasters (albeit smaller and slower), including Top Thrill Dragster at Cedar Point and Xcelerator at Knott’s Berry Farm). With its blazing-fast and blazing-fast specs, Kingda Ka begs the question: how much higher and faster could designers make roller coasters? “The challenge is not ‘Can we do it?’ «Reitz says, alluding to the roller coaster. “The question is ‘At what cost?’ «
Parks can count on roller coaster fans lining up to test their mettle on bigger, faster thrill machines, but bragging rights only go so far when bean counters look at ROI. The sky, apparently, is the limit (as is the speedometer), but how many parks would be willing to shell out the tens of millions of dollars it would cost to build roller coasters across the sky?
Since Kingda Ka opened, another roller coaster, Formula Rossa at Ferrari World in Abu Dhabi, has surpassed the New Jersey attraction as the fastest roller coaster in the world. It also uses a hydraulic launch system. As of 2018, Kingda Ka still holds the height record. But not for long apparently. A “roller coaster” called the SkyScraper that is reportedly coming to Orlando (though its announced opening has been delayed multiple times) would rise above the current champion.
