Accelerator Coaster
Encyclopedia
The Accelerator Coaster is Intamin AG
Intamin AG
Intamin Worldwide is a designing and manufacturing company in Wollerau, Switzerland. It is best known for creating thrill rides and roller coasters worldwide. The U.S. division of the company is located in Glen Burnie, Maryland, and is headed by Sandor Kernacs. The Intamin brand name is an...

's term for their hydraulically
Hydraulics
Hydraulics is a topic in applied science and engineering dealing with the mechanical properties of liquids. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the engineering uses of fluid properties. In fluid power, hydraulics is used for the generation, control,...

-launched
Launched roller coaster
The launched roller coaster is a modern form of roller coaster which has increased in use in the last decade. In place of a traditional chain lift, the launched coaster initiates a ride with high amounts of acceleration via one or series of Linear Induction Motors , Linear Synchronous Motors ,...

 roller coaster
Roller coaster
The roller coaster is a popular amusement ride developed for amusement parks and modern theme parks. LaMarcus Adna Thompson patented the first coasters on January 20, 1885...

 model. These models are the tradename for some of the fastest rides on earth.

An accelerator coaster is named because of its long, straight launch track
Launch track
The launch track is the section of a launched roller coaster in which the train is accelerated to its full speed in a matter of seconds. A launch track is always straight and is usually banked upwards slightly, so that a train would roll backwards to the station in the event of a loss of power.A...

, its tower, known as a "top hat", and its magnetic brakes that smoothly stop the train without touching it. After the top hat, the layout varies widely, ranging from a flat brake run
Brake run
A brake run on a roller coaster is any section of track meant to slow or stop a roller coaster train. Brake runs may be located anywhere along the circuit of a coaster and may be designed to bring the train to a complete halt or to simply adjust the train's speed...

 to several inversions.

If this type of coaster is not launched fast enough to clear the top hat (which can happen for several reasons), it will roll backwards
Rollback (roller coaster)
A rollback occurs on a launched roller coaster when the train is not launched fast enough to reach the top of the tower. It will roll backwards down the tower, and will be stopped by brakes on the launch track. Any roller coaster on which it is possible for a rollback to occur will have these brakes...

 down the tower and along the launch track. For this reason, the launch track is fitted with retractable brakes that are retracted for the launch and extended at all other times. The main brake run uses the same type of brakes, which are fixed in place.

An Accelerator Coaster's hydraulic launch is much smoother than other launch technologies such as linear motor
Linear motor
A linear motor is an electric motor that has had its stator and rotor "unrolled" so that instead of producing a torque it produces a linear force along its length...

s. While a linear motor-launched train's acceleration is greatest at the beginning of the launch and decreases throughout the launch, a hydraulic launch produces nearly constant acceleration throughout the launch.

Most accelerator coasters are launched from the station, but there are some that advance the train to a separate launch area, either for theming reasons (Superman Escape
Superman Escape
Superman Escape is an Intamin Accelerator Coaster at Warner Bros. Movie World in Gold Coast, Queensland, Australia. The ride opened on Boxing Day , 2005. It is the fourth roller coaster in the theme park...

) or to allow multiple trains to be loaded simultaneously (Top Thrill Dragster
Top Thrill Dragster
Top Thrill Dragster is a steel, Hydraulic-launched roller coaster located at Cedar Point in Sandusky, Ohio. It was the first "Strata Coaster", loosely defined as a complete circuit coaster that is over tall. It was built by Intamin and debuted to the public on May 4, 2003...

, Kingda Ka
Kingda Ka
Kingda Ka is a roller coaster located at Six Flags Great Adventure in Jackson, New Jersey, USA. It is the world's tallest roller coaster, and was the world's fastest until Formula Rossa opened in November 2010. The train is launched by a hydraulic launch mechanism to in 3.5 seconds. At the end of...

).

Restraints

Accelerator coasters are noted for their unique over-the-shoulder restraints, which are used on all accelerator coasters except the first two, Xcelerator
Xcelerator
Xcelerator is a steel launched roller coaster at Knott's Berry Farm in Buena Park, California. Xcelerator was Intamin's first hydraulically-launched coaster. Xcelerator is the fourth Intamin installation at Knott's...

 and Top Thrill Dragster, which use lapbars. These restraints feel like lapbar restraints while still providing the safety of traditional over-the-shoulder restraints. They consist of two major parts: a thick padded metal bar that swings down into one's lap, and two thin, flexible shoulder straps. For all but the largest riders, the shoulder straps won't even be noticeable.

These restraints are also notable for their locking system, which uses two hydraulic cylinders (for redundancy, in case one fails) rather than a ratchet. While a ratchet-based restraint only locks at each notch and will often be too loose or uncomfortably tight, the hydraulic system allows the restraints to be pulled down to any position, where they will stay. In the extremely unlikely case that both locking cylinders fail, the restraints are also held down by a seatbelt, as are most over-the-shoulder restraints.

These over-the-shoulder restraints also allow trains to be checked faster than with lapbars. The lapbars use a seat belt as a backup restraint. It must be checked by the ride attendants before the lapbar is lowered, as it cannot be checked properly with the lapbar down. This means that the guests must not pull down their own lapbars, but instead should buckle their own seatbelts, after which the attendants will check the seatbelts and lower the lapbars.

In contrast, the over-the-shoulder restraints are simply held down with a seatbelt. This means that the guests can pull down their own restraints and buckle their own belts, and all the ride attendants need to do is push down on the restraints and pull the seatbelts tight, saving significant time over the lapbar and seatbelt system.

How it works

An Accelerator Coaster's launch system operates on the same basic principle as a Super Soaker
Super Soaker
Super Soaker is a brand of recreational water gun, first sold in 1990 by Larami and now produced by Hasbro under the Nerf brand. Invented by Lonnie Johnson on November 13, 1989, the first Super Soaker, the Super Soaker 50, was originally called the Power Drencher...

, but on a much larger scale. The coaster's power source is several hydraulic pumps, each capable of producing 500 horsepower
Horsepower
Horsepower is the name of several units of measurement of power. The most common definitions equal between 735.5 and 750 watts.Horsepower was originally defined to compare the output of steam engines with the power of draft horses in continuous operation. The unit was widely adopted to measure the...

 (373 KW). These pumps push hydraulic fluid
Hydraulic fluid
Hydraulic fluids, also called hydraulic liquids, are the medium by which power is transferred in hydraulic machinery. Common hydraulic fluids are based on mineral oil or water...

 into several accumulator
Hydraulic accumulator
A 'hydraulic accumulator' is an energy storage device. It is a pressure storage reservoir in which a non-compressible hydraulic fluid is held under pressure by an external source. That external source can be a spring, a raised weight, or a compressed gas...

s. These accumulators are divided into two compartments by a movable piston
Piston
A piston is a component of reciprocating engines, reciprocating pumps, gas compressors and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from...

, one side filled with hydraulic fluid and the other with nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

 gas. The nitrogen is held in large tanks directly beneath the actual accumulator. As the hydraulic fluid fills the accumulators, it pushes on the pistons, compressing the nitrogen. It takes approximately 45 seconds to pressurize the accumulators with all pumps operating. All of this pressure is released during each launch, which typically lasts between 2 and 4 seconds.

The heart of the launch system is a large winch
Winch
A winch is a mechanical device that is used to pull in or let out or otherwise adjust the "tension" of a rope or wire rope . In its simplest form it consists of a spool and attached hand crank. In larger forms, winches stand at the heart of machines as diverse as tow trucks, steam shovels and...

, around which the launch cables are wound. This winch is driven by hydraulic turbine
Turbine
A turbine is a rotary engine that extracts energy from a fluid flow and converts it into useful work.The simplest turbines have one moving part, a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they move and...

s. The two launch cables are attached to the winch on its ends, and run through two grooves on top of the launch track. The cables are attached to the sides of the catch-car, which runs in a trough between the grooves. A third, single retractor cable is attached to the rear of the catch-car, it runs around a pulley wheel at the rear end of the launch track and returns to the hydraulic building along the bottom of the launch track, where it is wound in the opposing direction on the winch's drum.

The train connects to the catch-car with a solid piece of metal known as a "launch dog" that drops down from the center car. The launch dog is normally retracted and is held in place by a small magnet
Magnet
A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, and attracts or repels other magnets.A permanent magnet is an object...

, but the launch area has electrical contacts that demagnetize the magnet and cause the launch dog to drop down. The launch dog drops down at an angle, similar to the chain dog that a lifted coaster uses to connect to the lift chain.

Once the train and catch-car are in position and all is clear, the operator presses the "Launch" button and the launch sequence begins:
  1. The train's launch dog is released.
  2. The drive tires that advance the train to the launch track retract. Because the launch track is sloped slightly upwards, the train rolls backwards a few inches, until it is stopped by the launch dog engaging the catch-car.
  3. The anti-rollback magnetic brakes on the launch track retract.
  4. Approximately five seconds later, the launch valves in the hydraulic room open. The compressed nitrogen in the accumulators forces the hydraulic fluid into the turbines that drive the winch. As the winch winds in the launch cables, the retractor cable is unwound from the winch. After the train moves off the electrical contacts in the launch area, its launch dog is held down only by the force of the accelerating catch-car.
  5. Each section of brakes on the launch track pops back up immediately after the train passes a proximity switch.
  6. When the train reaches full speed and all the pressure in the accumulators has been released, the catch-car, still connected to the train, enters its braking zone. The catch-car uses the same braking configuration as the train, but is much lighter, so it slows down very quickly. As the catch-car begins to slow down, the train's launch dog retracts - the shape where it drops into is a "v" shape, so the dog is forced back into position as it runs over the catch-car and is held in place by the magnet, as the train continues on its way.
  7. Once the catch-car has stopped, the launch system resets - the winch reverses direction, returning the catch-car to the launch area using the third retractor cable, and the pumps begin recharging the accumulators. This normally takes about 45 seconds, after which the next train can be launched.


If the train rolls back, it will be brought to a near stop (magnetic brakes cannot completely stop a train) well before the beginning of the launch track. Regardless of the position of the catch-car when the train passes it going backwards, there will be no interference as the train's launch dog will be retracted. After the train slows to a near stop, the brakes will be cycled up and down to control the train's speed until it is back in launch position. On the larger coasters, this "launch reset" process can take more than a minute as the train must be moved very slowly. Once the train is back in launch position, it can be launched again or can be returned to the station.

The basic launch sequence is often accompanied by various theme elements. The most common is "starting lights" that cycle down from yellow to green, the green light coming on just as the train begins to accelerate.

The number of pumps, accumulators, and turbines varies with the speed the coaster is designed to achieve. Kanonen
Kanonen
Kanonen is a steel roller coaster located at Liseberg in Sweden. The ride, built by Intamin, features a hydraulic launch and opened in 2005. The tightly packed layout is a result of the lack of space available to build upon at Liseberg....

 (the world's slowest Accelerator Coaster) has a design speed of 47 mi/h, one pump, one accumulator, and eight turbines. Kingda Ka (the world's second fastest roller coaster) has a design speed of 128 mi/h, seven pumps, four accumulators, and 32 turbines. The system as a whole is capable of producing up to 20,800 horsepower (15.5 MW) for each launch, although a typical launch uses less than 10000 hp.

The catch-car is stopped by magnetic brakes identical to those used to stop the train. In order to give the catch-car room to slow down, only about three quarters of the launch track can actually be used to launch the train, the catch-car needs 64 feet(20m) on a 100 km/h accelerator coaster (and significantly more on a faster coaster like Kingda Ka) to slow to a full stop.

One major advantage of this launch system compared to others is its low power consumption, the hydraulic pumps run constantly and actually use less energy than most chain lift drive motors.

List of Accelerator Coasters

Name Height Speed Park, Location Year Opened rcdb.com page
Xcelerator
Xcelerator
Xcelerator is a steel launched roller coaster at Knott's Berry Farm in Buena Park, California. Xcelerator was Intamin's first hydraulically-launched coaster. Xcelerator is the fourth Intamin installation at Knott's...

 
205 ft (62.5 m) 82 mi/h Knott's Berry Farm
Knott's Berry Farm
Knott's Berry Farm is a theme park in Buena Park, California, now owned by Cedar Fair Entertainment Company, and a line of jams, jellies, preserves, and other specialty food, now part of The J. M. Smucker Company based in Placentia, California....

, California
2002 http://www.rcdb.com/1574.htm
Top Thrill Dragster
Top Thrill Dragster
Top Thrill Dragster is a steel, Hydraulic-launched roller coaster located at Cedar Point in Sandusky, Ohio. It was the first "Strata Coaster", loosely defined as a complete circuit coaster that is over tall. It was built by Intamin and debuted to the public on May 4, 2003...

 
420 ft (128 m) 120 mi/h Cedar Point
Cedar Point
Cedar Point is a 364 acre amusement park located in Sandusky, Ohio, United States on a narrow peninsula jutting into Lake Erie. Cedar Point is the only amusement park with four roller coasters that are taller than...

, Ohio
Ohio
Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...

 
2003 http://www.rcdb.com/1896.htm
Storm Runner
Storm Runner
Storm Runner is an Intamin steel launched roller coaster at Hersheypark. It was constructed in 2004 and was the third Intamin Accelerator Coaster. It reaches a height of 150 ft and catapults riders from 0 to 72 mph in 2 seconds. It features a top hat and three inversions, a dual...

 
150 ft (45.7 m) 75 mi/h Hersheypark
Hersheypark
Hersheypark is an amusement park located in Hershey, Pennsylvania, near the Hershey Chocolate Factory.Hersheypark was opened on April 24, 1907 as a leisure park for the employees of the Hershey Chocolate Company, an American confectionery company. Later, the company decided to open the park to the...

, Pennsylvania
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...

 
2004 http://www.rcdb.com/2498.htm
Rita  69 ft (21 m) 61 mi/h Alton Towers
Alton Towers
Alton Towers is a theme park and resort located in Staffordshire, England. It attracts around 2.7 million visitors per year making it the most visited theme park in the United Kingdom. Alton Towers is also the 9th most visited theme park in Europe...

, England
2005 http://www.rcdb.com/2787.htm
Kanonen
Kanonen
Kanonen is a steel roller coaster located at Liseberg in Sweden. The ride, built by Intamin, features a hydraulic launch and opened in 2005. The tightly packed layout is a result of the lack of space available to build upon at Liseberg....

 
79 ft (24.1 m) 47 mi/h Liseberg
Liseberg
Liseberg is an amusement park located in Gothenburg, Sweden, the park opened in 1923. Liseberg is one of the most visited amusement parks in Scandinavia, attracting around 3 million visitors annually. Among the noteworthy attractions is the wooden roller coaster Balder, voted twice as the Best...

, Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

 
2005 http://www.rcdb.com/2905.htm
Kingda Ka
Kingda Ka
Kingda Ka is a roller coaster located at Six Flags Great Adventure in Jackson, New Jersey, USA. It is the world's tallest roller coaster, and was the world's fastest until Formula Rossa opened in November 2010. The train is launched by a hydraulic launch mechanism to in 3.5 seconds. At the end of...

 
456 ft (139 m) 128 mi/h Six Flags Great Adventure
Six Flags Great Adventure
Six Flags Great Adventure is a theme park in Jackson Township, New Jersey, owned by Six Flags Entertainment Corp., the world's largest amusement park corporation...

, New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...

 
2005 http://www.rcdb.com/2832.htm
Skycar  112 ft (34.1 m) 57 mi/h Mysterious Island, China 2005 http://www.rcdb.com/3466.htm
Superman Escape
Superman Escape
Superman Escape is an Intamin Accelerator Coaster at Warner Bros. Movie World in Gold Coast, Queensland, Australia. The ride opened on Boxing Day , 2005. It is the fourth roller coaster in the theme park...

 
131 ft (39.9 m) 62 mi/h Warner Bros. Movie World
Warner Bros. Movie World
Warner Bros. Movie World is a popular movie related theme park on the Gold Coast in Australia. It is owned and operated by Village Roadshow since the take over from Time Warner and is the only movie related park in Australia...

, Australia
2005 http://www.rcdb.com/2999.htm
Stealth
Stealth (roller coaster)
Stealth is a steel roller coaster built by Intamin of Switzerland. The coaster is located in the Amity Cove area of Thorpe Park in Surrey, England, UK and opened in 2006. The ride reaches a maximum height of 62.5 m...

 
205 ft (62.5 m) 84 mi/h Thorpe Park
Thorpe Park
Thorpe Park is a theme park located in Chertsey, Surrey, England, UK. It was built in 1979 on the site of a gravel pit which was partially flooded, the intention of creating a water based theme for the park. The park's first large roller coaster, Colossus, was added in 2002...

, England
2006 http://www.rcdb.com/3081.htm
Speed Monster
Speed Monster
Speed Monster is a launched roller coaster located at the Norwegian theme park, TusenFryd. Built by Swiss manufacturer Intamin, the ride opened in 2006 and features a unique element known as a "Norwegian Loop".-History:...

 
131 ft (39.9 m) 56 mi/h TusenFryd
Tusenfryd
Tusenfryd is an amusement park at Vinterbro, Norway. The park is located 20 kilometers south of Oslo. Two of the longest motorway corridors in Norway, E6 and E18, meet nearby Tusenfryd and the park is located on the west side near where they meet. SpeedMonster, SuperSplash, ThunderCoaster and...

, Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

 
2006 http://www.rcdb.com/3245.htm
Zaturn  213 ft (64.9 m) 81 mi/h Space World, Japan 2006 http://www.rcdb.com/3454.htm
Desert Race  62 in 7 in (19.08 m) 62.1 mi/h Heide Park
Heide Park
The Heide Park Resort is a theme park in Soltau, Lower Saxony. With an overall area of over 850,000 m², it is one of the biggest German amusement parks and the biggest in Northern Germany....

, Germany
2007 http://www.rcdb.com/3617.htm
Furius Baco
Furius Baco
Furius Baco is a hydraulically-launched steel Wing Rider roller coaster located at PortAventura in Salou, Catalonia. Manufactured by Intamin, the ride opened on June 5, 2007 as the 2nd fastest roller coaster in Europe at 83.9 mph, which the ride reaches in 3.5 seconds...

 
46 ft (14 m) 83.9 mi/h PortAventura
PortAventura
PortAventura is a theme park and a resort in Salou, Catalonia, Spain; on the Costa Daurada , approximately an hour drive south of Barcelona. It attracts around 3 million visitors per year making it the most visited theme park in Spain. PortAventura Park is also the 6th most visited theme park in...

, Spain
2007 http://www.rcdb.com/3430.htm
Formula Rossa
Formula Rossa
Formula Rossa is a launched roller coaster located at Ferrari World in Abu Dhabi, United Arab Emirates. Manufactured by Intamin, Formula Rossa is the world's fastest roller coaster with a top speed of...

 
171 ft (52.1 m) 149.1 mi/h Ferrari World Abu Dhabi, UAE 2010 http://www.rcdb.com/4485.htm
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK