As the cart is not motorized, the entire movement of a roller coaster is almost exclusively the result of the action of the force of gravity. Therefore, the path of this exciting toy always has a huge descent that gives the initial impulse for the cart to travel the rest of the way. “Using physical terms, we say that, at the top of the mountain, the vehicle accumulates the so-called potential energy that, during the fall, is transformed into kinetic energy – or movement energy – by the action of gravitational force”, says physicist Antônio of Padua, amusement park consultant. The detail is that part of this energy is lost in the form of heat, due to friction with the rail and the air, which gradually decreases the speed and maximum altitude that the cart can reach. While he is at full steam, the emotion is really due to the design of the route, whose objective is to throw the passenger into the most frightening situations possible. But some basic precautions must be taken.
The speed in the loop cannot decrease too much, otherwise the cart will fall. High-speed turns should be banked inwards to increase contact with the rail and prevent the vehicle from going off at a tangent. In spite of the ever more outlandish – and frightening – circuits, the basic principle of the toy remains the same since the first modern roller coasters, created in the late 19th century. But there are also some new features. One of the most important was the development of propulsion systems to launch the trolley from the boarding platform, eliminating the need for the large initial descent as a source of thrust. One of these systems, which uses electromagnetic attraction to move the carts, makes them reach 160 km/h in seven seconds, a record for this type of toy.
Acceleration obtained in the first descent is fundamental to define the rest of the path
accumulated energy
At the top of the first climb, the cart accumulates the energy it will need to travel the toy’s entire path. That energy turns into speed as he plummets downhill, causing that famous butterflies in his stomach.
controlled traffic
Many rides operate with up to five carts at the same time, so sensors are used to control the flow. “The trolley has no brakes, but it can be stopped at strategic locations using an external brake, to avoid collisions”, says administrator Hércules Vergari, maintenance supervisor of a park in São Paulo
initial push
The most common way to hoist the cart to the top of the mountain is using a rotating chain positioned in the middle of the track, right at the beginning of the path. Hooks attached to the underside of the cart catch onto the chain as the vehicle rolls over it. This is the only time the cart receives any kind of propulsion.
dispute of forces
In a looping, passengers are literally upside down. At that time, it is the movement of the cart that keeps it on the rails, preventing it from falling to the ground by the action of centripetal forces – which pulls the vehicle towards the center – and gravity
Miscalculation
The height of the loop is always proportional to the great descent covered by the cart before this exciting obstacle. The higher the previous slope, the higher the looping can be. If engineers do not take this into account when designing the roller coaster, the cart’s acceleration may not be enough to overcome the centripetal and gravity forces acting on the obstacle. Result: vehicle crashes
final stop
When the trolley approaches the end of the route, at the same point as the departure station, a sensor detects its arrival and activates the brake system. It works with clamps positioned on the rails and between which passes a blade attached to the bottom of the trolley. When the clamps close, they compress the blade and brake the vehicle.
Each rail format ensures different fun
TRADITIONAL VERSION
The first modern roller coasters, from the late 19th century, were made of wood, a material that still has its fans to this day. In this type of toy, the cart shakes a lot, ensuring an extra dose of emotion. On the other hand, as the wooden structure is quite heavy, the path cannot have complex obstacles, such as loopings.
METALLIC BOLD
Steel tubes started to be used in structures in the middle of the 20th century. As the mountains became lighter and more flexible, it was possible to create new maneuvers (such as screw and looping) and bigger and bigger toys. At Top Thrill Dragster, in the state of Ohio, in the United States, there is a drop of 130 meters and the carts reach up to 200 km/h.
FOOT OUT
The steel roller coaster allowed for the development of various types of rails and trolleys. One of the most exciting and fun is the inverted track, where the cart is under and not on top of the track. Because of this arrangement, people’s legs dangle in the air and you can visualize the chasms that appear on the path far below you.