Launch track
From Wikipedia, the free encyclopedia
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 launch track 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 track gives the train kinetic energy by accelerating it to the maximum designed speed (while not significantly raising it).
A launch track normally includes some form of brakes. 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 Top Thrill Dragster. In either case, the brakes are retracted to allow trains to launch, and are engaged at all other times.
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[edit] Types of launch tracks
[edit] LIM/LSM
LIM/LSM launch tracks have many (often more than 200) linear motors on both sides of the launch track. the train on this type of coaster has metal fins mounted to its sides to facilitate launching.
[edit] Hydraulic
A hydraulic launch track has a trough running along its center, a "catch car" that connects to the train for launching travels through this trough. The catch car is connected to a cable loop that runs along the entire length of the launch track, anchored by a pulley wheel at the near end of the track and by the launch motor itself at the far end. The launch motor is located in a small building under the end of the launch track. Only about 2/3 of the length of this type of launch track can be used for launching the train, as the catch car must be stopped after it disengages from the train.
[edit] Friction Wheel
A friction wheel launch consists of a series of high speed drive tires used in succession to propel the train forward. An example of a friction wheel launch is the Incredible Hulk Coaster at Universal's Islands of Adventure. The train begins to climb the lift hill at a normal speed, and begins to accelerate half-way up the hill.
[edit] Flywheel
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. [1]
[edit] Counterweight
Counterweight launch mechanisms are used on some shuttle loops. The trains are launched by dropping a large counterweight attached to a cable. The cable then drives the train forward. [2]
