# Designed around the heartline?

Tuesday, October 14, 2003 8:41 PM
I always hear people saying that B&M coasters are designed around the heartline, but watching Medusa E. the other day, I noticed something.

(I think) When the train exectues the zero-g roll, the part of the train that actually does not get translated (and is thus the axis of rotation) is the bumper/nub thing which is in line with all the joints connecting the cars. This makes perfect sense, because any other axis of rotation would be prevented by said joints.

So does "designed around the heartline" not mean that the train rolls around an axis which is about chest level on riders (which is what I always thought it meant), but that some other calculations are done in reference to that point? I can't really think of any other degrees of movement that would be drastically affected by being through the train as opposed to through the heartline of the riders.

Is that phrase just a bunch of "I read it on the internet so it must be true"?

Edit: "executes" used to be "enters" which didn't make sense

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Be polite and ignore the idiots. - rollergator
"It's not a Toomer" - Arnold Schwartzenkoph
"Those who know don't talk and those who talk don't know." -Jeff

*** This post was edited by ApolloAndy 10/16/2003 12:16:50 AM ***

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Tuesday, October 14, 2003 9:10 PM
No it's not a bunch of bs.........it is true and has been discussed on here before. Basically the physical heartline in a zero-g roll follows the natural parabola of a floater hill, at least on an inverted coaster. On an inverted, the wheel assembly doesn't translate, meaning the heartline of the passengers follows the parabola that causes the zero-g sensation.

However, it might be another situation on the sitdowns. Looking at this pic of Scream! http://www.rcdb.com/installationgallery2169.htm?Picture=11
it seems it also follows the parabolic heartline as well.

Intamin sitdown loopers seem to do a straight line heartline though.
http://www.rcdb.com/installationgallery1412.htm?Picture=10

Hope that helps..........that's how I understand it anyways.

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Kyle
-Raptor Crew-
2000-01

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Tuesday, October 14, 2003 9:20 PM
Blaster you are most deffinately correct. If you watch, because of the parabolic shape of the inversion the car ends up remaining level throughout the actual inversion. If you look at that Scream! pic you can see quite obviously that the axis of rotation for the car occurs at the exact center of the person even with the heart. The axis of rotation cannot be at the axle joints because of the fact that they change position they do not remain perfectly level, and by definition the axis of rotation is around a fixed point

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"your mother was a hampster and your father smelt of elderberries now leave before I taunt you a second time!)

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Wednesday, October 15, 2003 12:09 AM
Intamin rides are designed around the heartline aswell. If you look at this picture, you'll see that the the heartline rolls are designed around the riders heartline. IMO the Intamin 0g is way more effective than the B&M version.

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Corey
"Afterward, services resumed for about 20 minutes until the congregation realized the church was on fire." - www.channel3000.com

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Wednesday, October 15, 2003 4:01 AM
I'll buy Corey's comment, but not the other two. What the heck is a parabolic heartline? The cars remain level? No they don't they spin around. Of course the inversion is parabolic, but the unique point that actually travels the parabola is the center of the nub. Every other point including the rider's heartlines get spun around.

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Be polite and ignore the idiots. - rollergator
"It's not a Toomer" - Arnold Schwartzenkoph
"Those who know don't talk and those who talk don't know." -Jeff

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Wednesday, October 15, 2003 5:28 AM
The best example I've always seen of this is the impulses and now TTD. If you look at the twists on these vertical rides, the track bends out and around at a funny angle. But, if you can find a picture (I can send you one later today that I have if you can't find one) looking directly up at the "spikes" on these rides, you can see the heartline effect.

Think of it as putting a string right where you want the rider's heart to go. Now, instead of designing the track perfectly along that string (a-la Arrow), you instead put a cardboard cutout of the cross-section of your train with a hole at the rider's typical heartline. Now, pull that cutout along the string, making the inversions you want (including camelback zero-Gs and vertical twists), but instead of putting the track on the string, put the track where the wheelbase of the car cross-section fits. It's the same design concept as is used to design roadways. B&M and Intamin and to a lesser extent, Vekoma seem to design this way (best example: the Intamin vertical inlines) but older Arrows are not designed this way, they're designed along the string itself.

Edit: still didn't completely answer your question - if you've ridden say Volcano and then compare the feeling in those twists to those on Medusa East, you'll notice a much snappier entrance and exit on Medusa and a much more ... violent? ... floating (zero-G) sensation. Volcano's twists are like floating on a cloud, or what I would imagine being in space to feel like, while Medusa's are "hey you're on a coaster there buddy!" snappy, violent and forceful. I would imagine that Intamin would design their rolls with a "straight, taught string" while B&M put a slight curve upwards in their "string" and maybe even ... uh ... how to put this ... wrap the string around a paper towel tube before applying the template ... am I making sense here?

Edit3: (can ya tell I like this subject?) another good example of Intamin's use of this is the final run of Millennium Force before the last overbank. If you're standing on the concrete ramp up to the station and you look back at the turn (not sure if there's a pic out there like that or not), you'll notice that coming out of the turn after the bunny hill, the track seems "misaligned" to the right with the subsequent straight track, and again, "misaligned" to the left before the overbank. But, if you think about it, when you're coming out of a turn, you'll want to overswing the turn to keep the rider's heartline along that turn, and going into the next one, you'll want to kick in the direction of the turn, so you can then rotate the car around the heatline to execute the overbank without pulling the rider's heartline along with you in a jerky (read: headbanging) motion. Make sense?

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Brett
Resident Launch Whore
2003: (new) SFMM, KBF, PGA, SFMW, PKD, SFGAdv, Dorney (old) CP [17], KP [5], SFWoA [7], Hershey [2] ... What a summer!
*** This post was edited by Impulse-ive 10/15/2003 9:30:52 AM ***
*** This post was edited by Impulse-ive 10/15/2003 9:34:53 AM ***
*** This post was edited by Impulse-ive 10/15/2003 9:36:39 AM ***

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Wednesday, October 15, 2003 6:54 AM
I understand the concept of designing around the heartline. I do it on all my k'nex coasters. That's not the issue. It's actually really easy to see if you look at the profile of Xcelerator because the top of the tower is jogged forwards a bit.

My issue with the first two responses wasn't that I didn't understand them, but that their language was not descriptive/made up.

The issue is that "the string" on *B&M* sit-down coasters doesn't seem to pass through the riders at all, but through the center of the train (which is pretty close to the riders' feet). I don't see how this is different from older Arrows. This is easily observed by watching Medusa through the zero-g and noticing that the point which doesn't move (i.e. has the string through it) is not the riders' heartline, but the bumper/nub on the train. (Why do I feel like I'm just repeating myself over and over when nobody bothers to read it?).

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Be polite and ignore the idiots. - rollergator
"It's not a Toomer" - Arnold Schwartzenkoph
"Those who know don't talk and those who talk don't know." -Jeff
*** This post was edited by ApolloAndy 10/15/2003 10:58:58 AM ***

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Wednesday, October 15, 2003 7:43 AM

The visual that you're describing on Medusa East is probably a result of the fact that B&M is not taking the rider's heartline straight through the roll on a floorless/sitdown coaster. Look at Batman's roll - ascend to the roll, execute, and drop. Medusa's is all inclusive - the leveling point of the hill containing the roll is the middle of the roll. That's why the two feel so different. On Batman, you're intended just to roll inline, and therefore if you look straight down the twist, the track is extended beyond and the "string" would run straight through the heartline. But, Medusa East's roll is intended to bring the heartline in a parabolic hill all the way to the crest which is mid-roll. The roll itself is not the only piece of the inversion, the hill is an integral part. Therefore rather than a straight line for the rider's heartline, you have a peaked one. The roll happens in just such a way that the dimensions of the car make it appear that the nub of the zero car is the focal point for the roll, but if that were true, then the roll on a floorless/sitdown would feel no different than that on inverts and the term "kumbathingy" would never have come to be (and I wouldn't favor Medusa E and Kumba over other loopers ...)

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Brett
Resident Launch Whore
2003: (new) SFMM, KBF, PGA, SFMW, PKD, SFGAdv, Dorney (old) CP [17], KP [5], SFWoA [7], Hershey [2] ... What a summer!
*** This post was edited by Impulse-ive 10/15/2003 11:45:30 AM ***

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Wednesday, October 15, 2003 7:55 AM
I think that what B&M actually does is a bit more sophisticated than simplu designing rolls around the heartline. When a coaster is going through an element such as a zero G roll, several things are happening at once. The coaster is rolling and it is following a parabolic arc. This describes the more or less steady state things that are happening. There are also transitions as accelerations change that must be designed such that the transitions don't occur to suddenly. These transitions are one of the major causes of head banging. B&M seems to deal with all of these through some pretty sophisticated design work. Obviously, their system works.
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Wednesday, October 15, 2003 7:56 AM
Exactly, its that arc that produces what he's describing. It's an optical illusion more than a design flaw, if you could call it that.

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Brett
Resident Launch Whore

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Wednesday, October 15, 2003 4:17 PM
I have a feeling I'm not getting credit for seeing what I saw.

It's not an optical illusion. When the train goes through the zero-g, it rotates around the bumper/nub. Said bumper/nub goes through the perfect parabolic arc all the way through the element. It does not spin around another point on the train (like the heartline of the riders as you're suggesting) which would cause it to leave the perfect parabolic arc, but other points on the train spin around it (thereby making it the axis of rotation). If you look at the zero-g from a profile, you will notice that all the bumper/nub/joints form a perfect parabola, but the riders' heartlines form a parabola + sinusoid.

Let me get straight to the point, because I'm not sure I understand where we disagree. Do you think the axis of rotation for a roll on a B&M floorless going through a zero-g roll is somewhere other than the bumper/nub?
If so where (my next post tries to address that) and if not, why do you say it's designed around the heartline?

On a completely unrelated note, I don't really buy the big difference between the types of zero-g rolls. Having ridden Medusa E. and W. (both being my home parks) more than my fair share of times, I haven't experienced a different sensation on either. YMMV.

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Be polite and ignore the idiots. - rollergator
"It's not a Toomer" - Arnold Schwartzenkoph
"Those who know don't talk and those who talk don't know." -Jeff

*** This post was edited by ApolloAndy 10/15/2003 8:41:05 PM ***

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Wednesday, October 15, 2003 4:27 PM
Look at this picture:
http://www.rcdb.com/installationgallery94.htm?Picture=5

and tell me that the axis of rotation is somewhere in the chest region of the riders. Especially look at the relative roll of the zero car and the one car and imagine where the axis of rotation would have to be in order to produce that position. (Hint: It's closer to the track than the fiberglass shell)

This one is a little harder to see:
http://www.rcdb.com/installationgallery605.htm?Picture=3

but it makes the point a lot clearer. The last two rows of the train clearly did not rotate with respect to each other around an axis going through the riders. Where the axis is, is not easily determined, but it sure ain't at chest level.

If you really want to see what I'm talking about, download the kumba video from Coasters2k.com and watch the nub in the very last clip of the video (which is really excellent, btw). It doesn't go anywhere. It just spins.

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Be polite and ignore the idiots. - rollergator
"It's not a Toomer" - Arnold Schwartzenkoph
"Those who know don't talk and those who talk don't know." -Jeff

*** This post was edited by ApolloAndy 10/15/2003 8:40:54 PM ***
*** This post was edited by ApolloAndy 10/15/2003 9:02:09 PM ***

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Wednesday, October 15, 2003 4:54 PM

Impulse-ive said:

The roll happens in just such a way that the dimensions of the car make it appear that the nub of the zero car is the focal point for the roll,

By focal point do you mean focal point of the parabola (which I assume you don't mean, because that wouldn't make any sense) or the axis of rotation?

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Be polite and ignore the idiots. - rollergator
"It's not a Toomer" - Arnold Schwartzenkoph
"Those who know don't talk and those who talk don't know." -Jeff
*** This post was edited by ApolloAndy 10/15/2003 8:56:56 PM ***
*** This post was edited by ApolloAndy 10/15/2003 9:02:55 PM ***

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Wednesday, October 15, 2003 4:58 PM

Impulse-ive said:

Look at Batman's roll - ascend to the roll, execute, and drop. Medusa's is all inclusive - the leveling point of the hill containing the roll is the middle of the roll. That's why the two feel so different. On Batman, you're intended just to roll inline, and therefore if you look straight down the twist, the track is extended beyond and the "string" would run straight through the heartline.

From what I understand, an inverted and floorless heartline roll are designed totally around the riders in the same way.

Look at it this way. If possible, try to imagine a train going through Kumba's camelback element (3rd inversion). Keep your eye on the riders and not the train or track. If you notice, the riders are going through the same exact motions as they do while going through a heartline spin on an inverted coaster.

The two elements look totally different because they are designed differently (track above or track below) Yes, they may feel different as well but the heatlines are usually smaller than the versions found on the larger floorless coasters. There are some larger heartlines (like on Montu) that feel just like those on the floorless or sit-down coasters, well, at least to me.

Sorry to confuse anyone on this. I just wanted to share my opinion.

-Sean

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Wednesday, October 15, 2003 5:33 PM
Andy, in the last two pics you posted are not centered. if you're looking for the axis of rotation, you'd need a pic looking straight at the proposed axis.

the Kumba pic is close and actually disproves your theory. take your mouse and follow the position of the nubs. you'll see that it arcs. now follow the heartline of the riders, it follows a much more straight line. if you have to, go into a photo editing program and use the draw tool.

the reason B&M's zero-g rolls appear to be designed around the nubs is because of the curved element. if you laid the element flat like Intamin does, you'd see it would follow Intamin's design. along the same lines, if you took Intamin's rolls and added an arch, they'd look like B&M's.

so B&M's are designed around the heartline, but they are curved as well. in addition, its kinda hard to look directly at the heart line on B&M's rolls considering they're usually 100 feet in the air. on the other hand, many Intamin rolls are closer to the ground and easier to photograph the heartline.

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-Bob (formerly Coaster Jedi)

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Wednesday, October 15, 2003 7:40 PM
The axis of rotation is going to be parabolic (arcing through the zero-g roll), not straight. More importantly, since the picture is taken at an angle, things that appear to be in a straight line (a line which isn't a ray from the viewer) are not neccesarily in a straight line. Imagine if you looked at a piece of paper from a "profile." All four corners appear to be in a straight line, but clearly they are not. I don't think linear geometry can rightly be applied to a picture.

Okay here's a pic that I found (although invert) that I think really proves that the axis of rotation is NOT the heartline of the riders: (yes, I should be doing work, not hunting for pics)

http://www.coasterimage.com/dp/dp013.htm

In this picture, you can see the heartlines of the riders move laterally with respect to the motion of the train (they spin around a bit) and hence cannot be the axis of rotation (If you really want my analysis of why this is so, keep reading). However, a point a bit closer to the rails, maybe somewhere around the nub, does not move laterally and thus, is the axis of rotation.

Let me clarify a few things that I already know so they can stop being restated:

a) the axis of rotation does not move laterally through a roll. Thus, it will form a straight line in the plane of the track from a birds eye view.
b) the axis of rotation should form a parabola when viewed from profile.
c) Intamins (as shown in Corey's pic) are designed around the heartline
d) If B&M zero-g's were flattened, the axis of rotation would not move as the train rolled.

I (think I) also understand the proposed counter argument: Because of the parabolic/curved shape of the entry and exit into the element, something that appears to not be moving may be doing so because of two simultaneous opposite motions cancelling each other out, and may therefore appear to be the axis of rotation and not be.

However, this is simply not true of lateral movement. When viewed from a bird's eye, every point on the train will trace out a sinusoid (okay, I'm discounting the speed change and the vertical movement, but you get the idea). The further (absolute distance) the point is from the axis of rotation, the greater the amplitude of the resulting sinusoid. One set of points, the axis itself, will form a degenerate sinusoid of 0 amplitude. i.e. a straight line in the plane of the track. Thus, any point that moves laterally at any time (i.e. is at any distance other than 0 from the plane of the track - which is what my pictures are trying to demonstrate for any point that isn't the nub) is not on the axis of rotation.

Anybody from 'round GAdv./Dorney want to go watch Medusa/Talon (I know it's invert but it demonstrates the point) with me?

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Be polite and ignore the idiots. - rollergator
"It's not a Toomer" - Arnold Schwartzenkoph
"Those who know don't talk and those who talk don't know." -Jeff

*** This post was edited by ApolloAndy 10/16/2003 12:12:26 AM ***

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Wednesday, October 15, 2003 8:13 PM
I can actually say that ApolloAndy is correct on this one with 100% confidence... I have worked with coaster blueprints and I know that the track does not rotate around the "heart" of the riders, or anywhere close. For instance, on Intamin Impulse coasters, the "heartline" is actually the center of mass of the train, which is located a little above the headrests. B&M coasters are the same way, the heartline is closer to the wheels of the train... I'm not sure exactly how one can be weightless in a B&M heartline with the cars rotating about an axis much lower come to think of it, I never really sat down and questioned it too much.... but I do know that some of them throw you to the side more....

Now Togo heartlines... those definitely feel like the heartline is literally through your heart, and those heartlines have a completely different feel to them, more like a carpet being pulled out from underneath you...

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Wednesday, October 15, 2003 8:33 PM

Sean Flaharty said:

Look at it this way. If possible, try to imagine a train going through Kumba's camelback element (3rd inversion). Keep your eye on the riders and not the train or track. If you notice, the riders are going through the same exact motions as they do while going through a heartline spin on an inverted coaster.

If what Keith says is true and both inversions are perfect parabolas, then (I think) the riders should not go through the same motion. On a sitdown, the riders start above the axis of rotation (which traces the parabola) and get rolled below it and then above it. On an invert, the riders start below and get rolled above and then come back down.

This actually leads me more to believe that neither element is a perfect parabola but are designed with that up and down rolling in mind to keep them more similar.

I know that I haven't found a significant difference on any B&M zero-g roll: invert, floorless, sit-down, or otherwise.
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Be polite and ignore the idiots. - rollergator
"It's not a Toomer" - Arnold Schwartzenkoph
"Those who know don't talk and those who talk don't know." -Jeff
*** This post was edited by ApolloAndy 10/16/2003 1:30:56 PM ***

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Wednesday, October 15, 2003 8:37 PM
Keith:

Any idea why this is so "revolutionary" compared to say, an old Arrow? Or where the "designed around the heartline" myth/phrase came from?
*** This post was edited by ApolloAndy 10/16/2003 1:01:07 AM ***

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Wednesday, October 15, 2003 8:45 PM
Andy - I have absolutely no idea, I don't really know all the technical details... :)

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