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Blue Fire, a launched looping roller coaster at Europa-Park, Germany

A launch is a method of propelling a roller coaster train. This mode of acceleration powers many of the fastest roller coasters in the world. A launch uses one or a series of linear induction motors (LIM), linear synchronous motors (LSM), catapults, tires, chains, or other mechanisms employing hydraulic or pneumatic power.

Function

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A launch serves the same basic purpose as a lift hill - providing power to the train - but accomplishes it in an entirely different manner. A lift hill gives the train potential energy by raising it to the highest point in the track (and not significantly accelerating it). A launch gives the train kinetic energy by accelerating it to the maximum designed speed (while not significantly raising it). Launches feature improved speed and acceleration when compared to traditional chain or cable lifts. They also take up significantly less space than a lift hill, as well as providing an instant start to the ride without having to wait to be pulled up a lift.

The launch track - the stretch of track on which trains are accelerated - is always straight and is usually banked upwards slightly so that if the launch does not activate, a train would roll backwards to the beginning of the launch track. A launch track normally includes some form of brakes to slow the train down. Depending on the type of coaster, these brakes may be used in every run of the coaster (this is normally found on a shuttle roller coaster where the launch track also serves as the main brake run) or they may only come into play when a rollback occurs, normally on a complete-circuit coaster such as Red Force, Top Thrill Dragster and Kingda Ka. In either case, the brakes are retracted to allow trains to launch, and are engaged at all other times.

Electromagnetic

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LSM

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The LSM launch on Red Force

Linear synchronous motor (LSM) launches use electromagnets to propel trains forward. On the track are multiple electromagnetic fins. Electromagnets in front of the train attract the train until the train passes, at which point they quickly switch polarity to repel the train.[1]

LSM launches are the most common type of launch.[2] Additionally, they are easier to maintain than other launch mechanisms as they feature no moving parts. However, they utilize very large amounts of electricity.[1]

LIM

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The LIM launch on Wicked Twister

Linear induction motor (LIM) launches also use propulsion via electromagnets. LIM launches use sets of electromagnets which create a magnetic field. This magnetic field propels the trains using a metal fin on the bottom of each train.

The first LIM launched coaster was Flight of Fear in 1996.

LIMs are much less frequently used now - as of 2024, there has only been one LIM launched coaster built in the last decade.[3] However, LIMs can also be used for general transport, such as the Tomorrowland Transit Authority PeopleMover at Magic Kingdom or monorail and maglev trains.

Fluid pressure

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Hydraulic fluid

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The catch car for Rita's hydraulic launch

Hydraulic launches, pioneered by Swiss manufacturer Intamin, give the riders greater acceleration with improved smoothness over electromagnetic and catapult launch mechanisms.[4] The acceleration from a LIM/LSM launch is greatest at the beginning and dies off rapidly, while the acceleration from a hydraulic launch remains fairly constant throughout the duration of the launch.

The core of the system involves powerful hydraulic pumps, usually eight, that are each capable of producing approximately 500 horsepower (373 kW). In Kingda Ka's configuration, the system can produce a peak power of up to 20,800 hp (15.5 MW) for each launch. Hydraulic fluid is pumped into several different hydraulic accumulators – energy storing devices – containing two compartments that are separated by a piston. As the incompressible hydraulic fluid is pumped into one compartment, nitrogen in the other compartment is compressed. At launch, the fluid under pressure from the accumulators is used to drive a number of hydraulic motors (commonly 16 or 32), which spin a large winch drum that winds a cable attached to the lead car of the train, called the catch car, in a matter of seconds. The cable runs under the launch track, and the catch car moves along a groove in the track's center.

The motor is positioned at the opposite end of the catch car on the launch track. While the train inches forward into a ready position, the pusher mechanism moves back from the motor toward the train. Once the pusher connects, the anti-rollback braking system drops beneath the track, giving the train the green light to be launched.

The first hydraulic launch roller coaster was Xcelerator reaching 82 mph (132 km/h) in 2.3 seconds. This was the first of 14 Accelerator Coasters manufactured by Intamin. The key feature of this model was a hydraulic launch. The world's tallest roller coaster, Kingda Ka at Six Flags Great Adventure, is capable of reaching 128 mph (206 km/h) in 3.5 seconds. The fastest roller coaster in the world, Formula Rossa, reaches 149 mph (240 km/h) in 4 seconds using the hydraulic method.

Another manufacturer, Vekoma, began producing hydraulic-launched coasters in 2004 with the opening of Booster Bike at Toverland in the Netherlands, reaching speeds up to 47 mph (76 km/h).

Pneumatic (compressed air)

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Using the same type of system as a hydraulic launch, a pneumatic launch uses compressed air to launch the vehicle. The technology was developed by S&S as the Thrust Air 2000 model. The first coaster of this type was Hypersonic XLC, which opened at Kings Dominion in Doswell, Virginia, USA in 2001. This coaster closed in 2007. Another incarnation, Ring Racer, was open for only 4 days. Compressed air launches are able to provide more acceleration than traditional pneumatic launches, with Do-Dodonpa at Fuji-Q Highland in Japan having held the acceleration record from when it opened as Dodonpa in 2001 to its closure in 2024, launching riders from 0 to 112 mph (180 km/h) in 1.56 seconds (this record is now held by Stealth at Thorpe Park, UK). S&S has brought back pneumatic launches in China with OCT Thrust SSC1000 and Bullet Coaster at Happy Valley Wuhan and Happy Valley Shenzhen respectively. Maxx Force at Six Flags Great America marked the return of pneumatic launches in the United States.

Other styles

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Eddy current launcher (LEM)

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Magnets are placed under the cars and a series of flywheels coupled to aluminum discs is in the launch zone: there is no contact between the two. The system can be used also for speed up intermediate launchers, and for braking, with static aluminum blades, at the end of the ride. Due to the energy stored in the flywheels, the power demand for launching is flat. Two operating examples of this technique are the Drifter at Sochi Park in the Sochi Olimpic Park and at FunWorks, Abu Dhabi (manufacturer I.E.Park[5])

Weight drop

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In a weight drop launch, a dropped weight winds a cable to pull the train until it accelerates to its full speed. Dropped weights were used in early installations of Shuttle Loop.

These rides are often not very tall, and usually achieve speeds of 60 mph (96 km/h).

Flywheel

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Many shuttle loop roller coasters have a flywheel launch mechanism. Rotational energy is stored in the flywheel, which then catches on a cable attached to the train. The flywheel releases its energy to propel the train forward.[6]

Electric motor and spring tension

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Arrow Dynamics' Launched Loop coasters, which were popular in the 1970s and 1980s, use a powerful electric motor and tensioned springs to propel a launch car forward. The launch car pushes the train outward to a drop, and then returns to its position. After the train reaches the opposite platform, another catch car works the same way. An example of this is Irn Bru Revolution.

Friction wheels

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Another type of launch is by friction wheels. The launch track consists of a series of horizontal tires that pinch the brake fins on the underside of the train. One example of this is the Incredible Hulk Coaster at Universal's Islands of Adventure.

Examples

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References

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  1. ^ a b Weisenberger, Nick (2013). Coasters 101: an engineer's guide to roller coaster design (3rd ed.). Leipzig: Amazon Distribution. pp. 46–50. ISBN 9781468013559. Retrieved 17 June 2024.
  2. ^ Marden, Duane. "Element Search Result". rcdb. Retrieved 17 June 2024.
  3. ^ Marden, Duane. "Roller Coaster Search Results". rcdb. Retrieved 18 June 2024.
  4. ^ Pendrill, Anne-Marie (2008). "Acceleration in one two and three dimensions in launched roller coasters". Academia. 43 (5): 483. Bibcode:2008PhyEd..43..483P. doi:10.1088/0031-9120/43/5/003.
  5. ^ "I.E.Park in the roller coaster database". rcdb.com. Retrieved 2020-12-14.
  6. ^ "ESshuttlelooptyp2GF".
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