Strength in B&M track.

Why don't you just get a better wheel?

tonymtdew said:

That shimmy is transferred safely to the ride structure in TTD. What is safer? I would argue for TTD, as the track itself absorbs the shimmy better, where as the Train itself (with ultimately weaker construction than the track) on KK takes the load of the shimmy. That flexibility in a *rigid* structure is safer. My old Engineering Statics/Dynamics prof had this discussion with me before in 2004.

Are saying that, according to your professor, its better to transfer energy into a rigid (i.e. not designed to flex) structure as opposed to transferring said energy into an object which has several flexible joints and soft materials (such as the train)? If that is what you are saying, then where did you take this class? I just want to make sure that I don't send my kids there... when I have them, of course.

Transferring energy into a rigid structure is not a good thing. That rigid structure is designed to be stay rigid - that is, its not supposed to flex, vibrate or "shimmy". Of course, I'm sure there is engineering allowance and design strategies that account for, and are designed to effectively dissipate, track flex. Regardless of track design, there will be flex, and that is part of the design. However, energy in the form of vibration can be a complete mess, and is much more difficult to "design in" to a rigid structure. There are countless variable that can affect the magnitude and type (such as harmonic, etc) of vibration, including temperature, weight of the train, launch speed and so forth. When that vibration is transferred into a rigid structure, it has to dissipate somewhere, and usually its simply through mechanical (vibratory) and audible energy. That mechanical energy shakes the structure, which goes against the engineered design of the ride, and can cause a myriad of problems over time, including weakened joints, etc.

Now, I'd be willing to bet that there is allowance for vibration when it comes to coaster designs. I was simply trying to set the record straight regarding your professor's comments.

tonymtdew said:
At Kingda Ka, it is a tradeoff, that shimmy is then transferred to the train itself.

How do you figure? If the shimmy is caused by the wave coming off the track from the deceleration of the catch car, it's still going to travel through the track, only on Kingda Ka, it'll go through those supports.

tonymtdew said:As it is being launched down the track, the catch car simply decelerates as the train continues down the track at its top velocity without the train coming into any further contact with it.

Who said otherwise? I wouldn't call the deceleration "simply" anything though. The catch car has magnets that run over similar fins in the center of the track to very, very quickly decelerate from 120 mph to zero. That energy has to go somewhere. A lot of it is heat, but some of that forward energy will still be transmitted through the track.

Jim Hancock said:
Tony stated a "teeth shattering ride" and it reminded me of an problem B&M has with flat spots on their wheels, causing extreme roughness. I was trying to describe the technique B&M requires about lubricating their tubular track.

And I'm still calling B.S. because your statement is totally unqualified. You're suggesting that rolling wheels are going to get flat on one side because of a lack of track lubrication. That's completely illogical. Sure, wheels will get flat if they sit long enough in one place, but rolling over track? Please. B&M coasters are arguably the smoothest in the world, and I can say with a reasonable degree of certainty that no one is scaling the ride every three days to paint the track with goo.

I agree with Jeff, B&M has by far the smoothest ride. Take a look at Raptor it's been there for how long and it's still very smooth.

djDaemon said:
That mechanical energy shakes the structure, which goes against the engineered design of the ride, and can cause a myriad of problems over time, including weakened joints, etc.

You forgot to mention total collapse - ala VertiGo. Although, that was wind induced vibration, not ride induced. But still a possible issue with vibration.

Oh yeah, vibration can completely obliterate anything, provided its of the correct frequency and such. With the right conditions, really bad things can happen.

Galloping Gertie. Such a great feat of engineering. I can't believe it held together as well as it did, I would have thought the oscillations would blow it apart long before it finally did fall.

Jeff

Thats your opinion and I respect that. I would suggest the first chance you get and your around people in the know (Park/maintenance/ B&M types) you pose that question to them, exactly as I stated. Only I did not state they "scale" the track, they do the job with a long stick/pole with paint roller on the end, from the ground in the "low areas" only. My only request is that if you find this maintenance procedure is correct - please state so.

Screamomatic

The composition of the wheels really help dictate the "speed" the train reaches on the track. Some coasters have a combination of different types of poly wheels (hard/soft) and some have nylon/poly combination. Some have all nylon. This is dictated by the manufacturer during original test runs and accelerometer testing.

The burden of proof isn't on me. Again, I'm challenging you to respond to my comments. How does a wheel get flat on one side rolling over track?

All three Intamin coasters at Cedar Point use the same wheels. That's right out of the mouth of Monty Jasper, VP of Maintenance/Construction, during the Q&A of a construction tour in the winter prior to Dragster opening. There was a time when seemingly endless experimentation occurred with wheel composition, but those days are obviously over.

OK - I give up - uncle -

Here's is what I know - B&M stated that they discovered a phenomenon concerning the nylon road wheels because of a lack of lube on the track. What occurs is exactly 12 scuffs or flat spots around the circumference of the wheel occured. They said they had not figured out exactly what caused it - yet. They did say that the lube as described would resolve the problem. I can not give you an engineering study on exactly why this occurs.

Wheels - The Mantis has combination poly and nylon (poly on the rear car) and what you said is the same thing I said (in general). There was a time of endless experimentation per the manufacturer until a good mixture was found, mixture meaning different poly composition on the face of the wheel. I'm finished, done, uncle.

I believe you, Jim. Of course, I don't know everything and everyone in the industry, so I could be completely gullible and just buying your line of BS since you're obviously a 14-year old kid who's just posting to get attention.

I know, I know.... but your "brother's best friend's cousin" told you so. I guess with those kinds of references it must be true.

It's odd, though. You have better grammar than most of the 14-year old attention whores, use bigger words, and have taken up an educated, intelligent discussion about engineering type stuff and haven't insisted that Millennium Force could go 150mph if they increased the lift speed by 5mph.

I call shenanagins. You're actually an adult, aren't you!?

djDaemon said:

Are saying that, according to your professor, its better to transfer energy into a rigid (i.e. not designed to flex) structure as opposed to transferring said energy into an object which has several flexible joints and soft materials (such as the train)? If that is what you are saying, then where did you take this class? I just want to make sure that I don't send my kids there... when I have them, of course.

What I said is that it is designed to transfer the energy into the rigid track. A rigid structure is exactly that, something that, A rigid structure that by design is to stay still, such as the track, a skyscraper, etc. However both MUST absorb the energy, and if it does not, it will break. A building is designed to sway several meters in any direction (except vertical). But it is still a rigid structure? Understand? Of course, take some engineering courses before you try to make any qualitative arguement.

Jeff said:

How do you figure? If the shimmy is caused by the wave coming off the track from the deceleration of the catch car, it's still going to travel through the track, only on Kingda Ka, it'll go through those supports.

You don't understand engineering Jeff, stick to your bases first.

Those support structures do not allow for absorption of energy on KK, they simply keep the track from swaying, well something NEEDS to give, the energy is unloaded unto the train, which is extremely visible from behind the launch on KK.

Stick to your day job.

Don't be a dick. You won't win any argument that way. You're telling me that the supports on Kingda Ka aren't going to transfer any energy into the ground, that they don't move at all, and that's absurd. You're suggesting the energy of the decelerating catch car just disappears, and it's a generally accepted theory that energy is not created or destroyed, so it has to go somewhere.

That energy ain't going with the train, because the moment the catch car begins to decelerate, the train isn't touching it anymore.

Jeff said:
Don't be a dick. You won't win any argument that way.

Oh I guess I can't follow your footsteps?

Jeff said:
You're telling me that the supports on Kingda Ka aren't going to transfer any energy into the ground, that they don't move at all, and that's absurd. You're suggesting the energy of the decelerating catch car just disappears, and it's a generally accepted theory that energy is not created or destroyed, so it has to go somewhere.

The track will always accept some form of energy, however, the more support structures they would use to minimize lateral sway reflects the energy to the train more, as the stiffened structure will not absorb.

PS-the energy "theory", is not a theory. In fact, it is a law.

Jeff said:
That energy ain't going with the train, because the moment the catch car begins to decelerate, the train isn't touching it anymore.

Oh so you are in agreement with me from what I said in the beginning, that the deceleration of the dog will have no affect on the coaster?

Jeff said:
Someone here theorized that the shimmy in this case is caused by the energy transferred out of the catch car in its deceleration at the end of the launch run.

tonymtdew said:
As far as the catch car theory, I would doubt it. It would be more like, the train is in a controlled launch and cannot move freely until it is released from the launch car. As it is being launched down the track, the catch car simply decelerates as the train continues down the track at its top velocity without the train coming into any further contact with it.

Dude, you've been saying all along that the energy is going with the train! Now you say it's not?

Michael Darling said:
I believe you, Jim. Of course, I don't know everything and everyone in the industry, so I could be completely gullible and just buying your line of BS since you're obviously a 14-year old kid who's just posting to get attention.

I know, I know.... but your "brother's best friend's cousin" told you so. I guess with those kinds of references it must be true.

It's odd, though. You have better grammar than most of the 14-year old attention whores, use bigger words, and have taken up an educated, intelligent discussion about engineering type stuff and haven't insisted that Millennium Force could go 150mph if they increased the lift speed by 5mph.

I call shenanagins. You're actually an adult, aren't you!?

I have made occasional posts over the last few months concerning a number of technical issues in hopes it might clear up some misconceptions. For the most part I've enjoyed reading everyones theory and opinions on a varity of subjects.

I really don't need all these insults - my opinion is BS - I'm a young kid looking for attention - etc. I thought my long experience in the amusement industry might help out with some misconceptions and what ever else, but I guess no one wants to learn more about a number of issues that goes on behind the scenes. I invite anyone to "check out" what I've stated with someone of authority, in the industry, over the summer season - should the opportunity be right. Name dropping does not phase me as I knew Monty when he was a green horn engineer for Six Flags Engineering in Texas. This fall during the IAAPA show in Orlando, I will be having my annual lunch with Claude Mabillard and I refuse to tell him his lubricant is goo. I think it's in Orlando (at the convention center) this year, but you guys should know all that. As it was in Atlanta last year. Sorry to be a bother.

Oh yeah? Well... Well... *I* have lunch with Walter AND Claude. TWICE a year. TWICE!

That was just a joke English. I was just showing how dumb name dropping sounds. So long.

First of all, no one said you were a kid or anything else. Your credibility was being challenged. And Gilman was being sarcastic and trying to take a dig at me, not you. He doesn't post anything unless it's a dig at me.

I asked Monty about the lube, and he confirmed that it is indeed what they do. I don't care that you or anyone else here is right on any topic... I just need attribution. If you show up and start spreading the gospel with zero indication of who you are, where you've been or what you know, you're going to get get called on it. That's the Internet, the same place where people have insisted that B&M has a three-ride contract with Cedar Point. That one still hasn't panned out.

Now that said, how can you account for a lack of lubrication causing flat spots on the wheels? If you were to suggest that it could over time cause the kinds of "blow outs" that Magnum wheels get, where the friction and heat apparently causes the material to vaporize closer to the hub first, then I can see how that would be. But uneven wear I don't get.

By the way, Mantis and Raptor do indeed use the same wheels.

IAAPA is in Atlanta again this year. Which is a damn shame, because I don't think Atlanta helps the attendee count at all.

tonymtdew said:

Understand? Of course, take some engineering courses before you try to make any qualitative arguement.

Hmm... Maybe I should take some engineering courses. Oh, wait! I already did! Geez, I almost completely forgot! As it turns out, I have taken classes in engineering. Actually, I have one of those things that you get... umm... what are they called again? Oh yeah! Degrees! That's it - I have a degree in engineering, as it turns out.

For ease of reference:

tonymtdew said:

At Kingda Ka, it is a tradeoff, that shimmy is then transferred to the train itself. That shimmy is transferred safely to the ride structure in TTD. What is safer? I would argue for TTD, as the track itself absorbs the shimmy better, where as the Train itself (with ultimately weaker construction than the track) on KK takes the load of the shimmy. That flexibility in a *rigid* structure is safer. My old Engineering Statics/Dynamics prof had this discussion with me before in 2004.

In this post, you indicate that the preferable method of dissipating the vibrational energy, which is generated by the acceleration of the train, is to let the rigid tower structure absorb it. This is, in fact, not the preferable method.

Designing the tower to allow for sway (flexibility) is one thing. Its fairly straightforward, in that the mechanical properties of the materials used naturally bend and flex. This flexing is only favorable to a certain degree, hence the angular support structure contained within the perimeter of the tower. The angular supports simply stiffen the tower to a point where it will stand indefinitely, yet be just flexible enough to bend when external forces act on it. If the structure were too rigid, the weak points (joints) would attempt to separate, which would cause, for example, the assembly hardware to shear, or experience some other type of catastrophic failure.

Now, designing the tower to absorb the "shimmy" is a completely different engineering monster. Vibrational energy is quite different in that it is potentially much more intense and dynamically variable, and thus can potentially cause a lot of problems. Some of this vibration will be absorbed by the structure itself, in the same way that a cast-iron skillet will absorb heat energy on a stove. That is the nature of the physical world. However, every rigid object has a maximum capacity of energy it can absorb - the bigger the object, the more it can absorb, assuming the physical properties of the materials are comparable. When vibrational energy is absorbed into a rigid object, the energy will simply bounce around that object until it has been dissipated completely. An example of this would be a tuning fork. You bang it against something, and the forks will vibrate for quite a long time, which produces noise. This noise energy is how the vibrational energy is dissipated. A rigid structure is not suited to do this, because vibration rattles everything within the structure - the steel columns, the flanges, the footers, bolts, etc. Designing a structure to absorb vibrational energy would require extensive use of materials suitable for absorbing that type of energy - flexible, soft materials, such as rubber. This energy tries to shake things loose, and is generally more problematic than forces caused by wind, which are more static by comparison. For an example - which is more jarring: Someone waking you up by rocking you gently, or by shaking you violently?

In addition, vibrational energy has a whole bunch of other problems that come along with it. Every rigid structure has a natural frequency. This natural frequency is essentially the frequency at which vibration will cause some type of failure. This is exactly what happened to the Tacoma Narrows Bridge. The structure was designed to sway with the forces generated by the wind, which seemed like a good idea. The problem arose when the wind energy's frequency matched the natural frequency of the bridge itself, causing it to bend and sway in an exaggerated fashion, which eventually led to catastrophic failure.

Regardless of what you meant, you're prancing around here claiming vast knowledge of something you obviously know little about. Don't assume you're the smartest guy in the World, as it does nothing but make you look like the most idiotic - trust me, I know from experience. Also, don't question my education, or anyone else's for that matter. There are people here who know far, far more than you, I or even Jeff could ever imagine when it comes to coasters.