Launch mechanisms

[andrus]

Hey there!

In the "Busch Gardens 2011 coaster" topic there has been a lot of debate of wheter the new coaster will use electromagnets or hydraulics for it's launch. I wonder whats the difference between the two models, ie why a park choose to install a LIM/LSM coaster or one with a hydraulic launch?

These are the differences of the technologys as far as I know:
- Energy consumption: LIM/LSM require a lot of electricity while a hydraulics is a fairly cheap way of launching a coaster.

- Thrill factor: hydraulics has the far more powerful lunch of the two.

- Reliability: hydraulic launches are known to be unreliable, but from what I've read eg iSpeed (LSM) break down a lot too. And of the four hydraulics I've been on only one has broke down for a short period of time..

So why do parks still use LIM/LSM? They sure do have to have som advantage??

 

[MouseAT]

LIM/LSM launches don't use a catch car, so they don't require the train to be stopped before the launch. This enables them to be used for rolling and/or booster launches during the course of a ride circuit.

The LIM/LSM launches also have no moving parts (just electromagnets) so from a mechanical point of view they're a lot simpler. There's less that can go wrong with them than with complex, high pressure hydraulic systems.

 

[andrus]

Well ok, I see why it's good when you want to use a rolling launch. But is reliability the only reason that eg iSpeed uses LSM although it's launched from stand still out of the station?

 

[Snoo]

Reliability is key. The type of launch (rolling or stand still) has almost nothing to do with it. Maverick, for instance, can launch from a standstill or rolling (in the launch tunnel). LSM's are just twice as reliable along with providing the same type of thrill (going to 70mph with LSM's feels no different then 72mph on an Accelerator tbh).

 

[Gazza]

Energy consumption: LIM/LSM require a lot of electricity while a hydraulics is a fairly cheap way of launching a coaster.

To launch a train to x speed is going to take the same amount of energy no matter what system you use, so a theme park wouldn't get a lower power bill from using a hydraulic launch.

But the key is how the power is drawn. LSM/LIM only uses power when the train is launching, so for most of the day no power is being drawn, but for a few seconds every couple of minutes a huge amount of energy is being drawn during the launching process. The drawback with this is that the infrastructure has to be built to deal with this sudden spike in demand, and it also means the operation of the ride can be disruptive to other energy users around the park.

Hydraulic launches however are drawing power all day long, but at a lower rate in order to pressurize the accumulators. The act of launching a train does not impact on other energy users, and the infrastructure only needs to be built to deal with the lower average constant draw of energy.
Because of this, we have been able to see these faster accelerating launches that would've been too disruptive to achieve with LSM/LIM.

But, between the two, Hydraulic is more energy inefficient, because of all the moving parts, friction, fluids that need to be pumped etc.

LSMs are actually quite efficient in converting most of the energy used into launching power.

In fact, a park with a hydraulic launcher would be using more Joules of energy per day than a park with an equivalent LSM powered launcher.

These days however, power storage systems are getting around the issue of sudden spikes in energy usage with LSMs, so you are getting the best of both worlds.
Personally, I think we'll begin to see a shift back to LSM because of this.