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LSM vs Hydraluic Launch?

Discussion in 'Q&A' started by C4Akbar, Jan 14, 2018.

  1. C4Akbar

    C4Akbar New Member

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    Title states the question.
    Some things that would be nice to cover:
    1. Cost Efficiency
    2. Acceleration & Top Speed
    3. Power Consumption
    4. Why do LSMs give diminishing returns during long periods of acceleration?
     
  2. Hixee

    Hixee Moderator Staff Member Moderator CF Award Winner 2016

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    Okay, let's see if I can help. I doubt anyone will be able to give any exact answers, unless they happen to have access to detailed specifications from two comparable coasters. Most of this is just an educated guess.
    In terms of "cost per launch", my feeling is that LSMs are cheaper. Once you factor in the higher wear and tear and maintenance of hydraulic launches, I think LSMs probably win out. In terms of total life cost, I think the LSMs probably pull ahead even further. I suspect that although the electrical and controls hardware for the LSMs are expensive (compared to the 'old school' technology in a hydraulic launch), the ever reducing cost of this stuff and the expensive maintenance costs of the hydraulic equipment mean that LSMs are always going to have the margin.
    There's absolutely nothing in the technology of LSMs that means they can't achieve the same acceleration and top speed as hydraulic launches. Hydraulic launches rely on storing the energy (in the form of hydraulic pressure) before the launch. LSMs can achieve similar energy storage (in the form of electrical capacitance) with capacitor banks. Provided the cabling can be designed to handle the very large currents during the launch, and provided the controls system is set up correctly, there's nothing stopping an LSM hitting any acceleration the designers want. This is of course, from an engineering perspective - you have to convince the finance team to pay for it too!
    As I've alluded to in the comment above, modern LSMs work in a similar way to hydraulic launches - they both store energy in between for launches for rapid release during the launch. Charging the hydraulic pressure or capacitor banks are probably reasonably similar in terms of inefficiencies, but there's a chance that the mechanical losses in the motors/pumps slightly outweigh the electrical losses in the capacitors and switchgear. Therefore, to launch the same train to the same speed in the same amount of time (in theory the same launch energy required), the LSM would consume slightly less power 'from the grid' than the hydraulic launch. That said, I could easily see this argued the other way... :p
    I'm not quite sure I understand this. As I've said in the comments above, LSMs can be configured to do any launch profile the designers wish. This is much harder to do with hydraulic launches, as it really comes down to the rate of release of mechanical pressure - something that drops off as the launch takes place.
    That being said, my experience is that generally LSMs don't push quite as hard at the start, but push pretty hard by the end. The opposite is often true of hydraulic launches, with the initial punch being strong, but them tailing off towards the end. The 'big' hydraulic launches that I've done (Top Thrill Dragster, Kingda Ka and Formula Rossa) all have multiple accumulators that are staged to keep the speed going - you can feel the "triple punch" quite notably on Dragster and Ka from what I can remember. It's a bit less apparent on Formula Rossa, but you can still feel it. Very different to Red Force where there's no let up the acceleration.

    Hopefully that helps a little?
     
  3. Coaster Hipster

    Coaster Hipster Well-Known Member

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    Sascha Czibulka of Intamin gave his elaborate insight into these issues during an interview I made a few months ago:


    (I linked the video straight to the relevant part. If moderators feel this is too much self-promotion, feel free to edit/remove this post ;) )

    Basically, the technology of LSM have improved enough (in terms of power needed and acceleration rate) so that according to Intamin, they're the preferred technology.
     
    Last edited: Jan 14, 2018
  4. Hixee

    Hixee Moderator Staff Member Moderator CF Award Winner 2016

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    Ah yes, what a fantastic insight!
     
  5. HeartlineCoaster

    HeartlineCoaster Well-Known Member

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    Neither. Air wins.
     

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