How does hydraulic launching work?

With the new Knott's coaster coming out, I think it would be helpful to know how hydraulic launching works. Is it launched by air? Electricity? I really don't have any idea. Could somebody explain it to me? You don't have to get real technical, just the basics. And pics would help alot too. Is the system new or has it been around ahile? Thanks!

I think AIR

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Cuase Theres Nothing Like a Little R&R, The Riddlers Revenge

Hydraulic means Oil. Well, actually any fluid in a liquid state, but oil is almost always used. The advantage of air (which is pneumatic) is that it flows very fast. The advantage of hydraulic is it doesn't infringe on S&S patents. Errrr, I mean, you need less fluid to do the same work, because it takes less energy to pressurize it. The disadvantage of a hydraulic system is that liquids move MUCH more slowly than air, so they probably have a pretty interesting porting scheme in their cylinder. Also probably some interesting extremely low viscosity oil and a large accumulator.

GregLeg and I were chatting about this and the problem we have is that liquid systems would not likely move fast enough, or at least no existing things we could think of work this way.

I can't help but wonder if someone just didn't get the details wrong. It's not like a Cedar Fair park to build something unproven.

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Jeff - Webmaster/Admin - CoasterBuzz.com, Sillynonsense.com
"As far as I can tell it doesn't matter who you are. If you can believe, there's something worth fighting for..." - Garbage, "Parade"

Hence the reason it is a prototype.  Lets just wait until may (or at least until march for Solace) and let Intamin work their magic.
 
PS: Jeff, this is system is already fully tested.

*** This post was edited by PxPxPunKrAwKeR on 12/18/2001. ***

Intamin would have shown Cedar Fair, working scale models, using the technology and even full scale sections of tracks with trains that they would have used to perfect this technology.

It sounds like a very messy way to lauch a ride - I can't help but wonder what it will look like under the station in a few years when park mechanics have had a chance to play with things. If you've seen a Citroen at a repair place, you'll know what I mean.

I'd imagine this lauch system will be rather quiet too.

Well, Intamin know what they are doing, and Cedar Fair will have waited for the neccessary work to be completed before contracting Intamin to build such a ride.

The benefit with hydrolics is, they are incredibly strong, but usually slow. Intamin have obviously found a way to get hydrolics pumping quickly, without the danger of leaks or bursts.

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Greatest movie in the history of mankind -- ~Young Einstein~

I don't doubt Intamin, it's just not characteristic of the company, as a look at their history shows.

And if it is "already fully tested," I'd like you to give me an example.

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Jeff - Webmaster/Admin - CoasterBuzz.com, Sillynonsense.com
"As far as I can tell it doesn't matter who you are. If you can believe, there's something worth fighting for..." - Garbage, "Parade"

Actually, it wouldn't be impossible to make a zippy hydraulic system, just expensive.

Here's my best guess based on a limited experiance with hydraulics.

You'd have a bladder or piston accumulator. This is basically like a large hydraulic cylinder that is kept under pressure by gas on the other end. The advantage here is the compression of the gas is a large energy storage reservior, which conceptually is like a weight drop or a flywheel: you charge it with a reasonably sized pump motor slowly, then can extract all of the energy quickly.

We're probably talking largest accumulator ever seen by man, though, as usually they're used to to even out the pressure of a system, as hydraulics aren't usually used for burst power.

Next you'd have a cylinder and some method of attaching it to the car. There are many ways to do that (magnetic coupling, a little sticky-uppy-bit, friction, etc) but it really doesn't matter. The cylinder as I see it would have a VERY large inlet port in the back and also ports on the sides every few feet, which would open valves after the car passed by. This way you could get around the oil's viscosity simply by putting an obscenely large inlet area into the cylinder. This is similar to what S&S is doing with dadonpa, they have three separate tanks and three sets of valves. This would have more than three, I'd wager, but the same concept.

Now, WHY hydraulic is anyone's guess, except I'm willing to venture S&S has some pretty heavy patent coverage for air launches. Also it would be cheaper to operate than a ta2k. It couldn't overheat like the LIMs on impulses are wont to do, and you can get really heavy duty 100% duty cycle hydraulic components easily. Hydraulics and PLCs go together like... well damndable heat transfer classes and damndable partial differential equations.

 

I'll try my hand at ascii

_______|port|___|port|___|port|___|port|__|port__                . .   ||                                                                |      |  |-----
----------------------------------------------|piston|  port
----------------------------------------------|      |  |-----
__||___      ___       ___       ___       ___       |_ _|_|
           |port|     |port|     |port|     |port|     |port|

 

okay that's really ugly but kinda shows what i mean

Yep, hydraulics are very powerful. My guess would be that it is set up like a Shuttle Loop - cable drive, TA2K as well. Now as with the older weight-launched models, the counterweight falls slowly as it is, so pulleys & cables are used to double or even quadruple its speed to the drive cable. (I could be wrong about this.)

With Xcelerator, simply replace the counter weight with horizontally mounted hydraulic ram(s). It's all in the pulleys/cables set-up.

*** This post was edited by Taipan on 12/18/2001. ***

This is true -- hydraulics get you power, but not a lot of speed.  Through the magic of gears and pulleys, you can step low speed/high power up (or down depending on your perspective ;) ) to high speed/reduced power.  Hmmm...
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--Greg
"Beat the rush, sign up for your post-Mean Streak MRI now..."
My page  My other page  And my coaster page

Let me point something out...

YES, accumulators can be used for impulse power. Most of the big simulators do exactly that; that's how they can get those cylinders to move sixteen feet in less than a half-second (Star Tours). No way to get that kind of power out of a typical hydraulic pump without going way way way way way oversize, but it can be done with an accumulator.

Also, remember that you can use a reduction pulley system, which trades applied force for distance. In the case of a launch, you would want more distance in order to limit the force applied to the passengers, so an n:1 reduction system ought to be just about right. That also lets you use a shorter firing cylinder, and it lets you move more slowly. God help you if the cables get tangled. :)

Finally, it's not as though hydraulic "launches" have never been done before. Ever see a Chance Sling Shot? I forget how tall the tower is, but the standard 48' trailer sits behind the ride and features a big-*** hydraulic cylinder connected to a 4:1 pulley system to haul the carriage up and down the tower. The maximum stroke on that cylinder would be 24', so I guess the tower is just under 96' tall...

--Dave Althoff, Jr.

If youve ever seen show at Aircraft Carriers like the USS Carl Vinson then you will understand what im going to say. To land the plane a cable must latch on to the plane and a hydraulic motor slowly brakes the cable. In this new ride the opposite will be used the cable will be pulled and tightened such as on vertigo at Cedar Point, the cables are pulled and the riders are launched. The only difference between this ride and say Dodonpa is the way the cables are pulled.

 

http://www.coasterhut.com

I dont realy get what camatose was saying about the cars. So how are the cars attched to the pipe?

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What in the world is in that bag?Watch u got in that bag!?!?!?!?!?!?!

I think the hydraulic jacks will pull cables that attach to some type of pushing carraige (like Montezooma's). The cables will thread through some pulleys to increase the distance of the shot.
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"I'll bet that thing hits 5 Gs going through that loop.....faaar ooouut!"

You know Jeff, you really should think before you speak! Intamin prototyped the ride at its plant, and Jack saw it there first....

And the system is basically the same thing as a TA2k. Fill a chamber with hydrolic fluid, pressurize it, release into a chamber with a piston, and the piston drives the train foward. And if you doubt that it will work with a liquid, well the compressed air on a ta2k becomes a liquid too...

First of all, janfrederick appears to be obviously correct about the pusher. And there will almost have to be some kind of reduction/multiplication system to get sufficient stroke out of the launch system.

Second, PxPxPunKrAwKeR you should remember a critical point about hydraulics and why hydraulics are so useful: Liquids are non-compressible. Hydraulic accumulators usually work because one end is a permanently charged nitrogen cylinder. Fluid goes in under high pressure (but low volume) to compress the nitrogen cylinder. Then, on demand, the fluid is forced out at high pressure *and at high volume* by the compressed nitrogen gas.

Nitrogen is used, by the way, because it is mostly inert, unlike air which can cause a nasty explosion.

--Dave Althoff, Jr.