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What makes a launch feel forceful?

Matt N

Well-Known Member
Hi guys. I was just looking at the top 10 fastest accelerating coasters in the world, and it occurred to me that Stealth at Thorpe Park (which I've ridden) is actually 3rd, launching from 0-80mph in 1.8 seconds! However, I found this strange, as I never hear Stealth get very high praise compared to the likes of Top Thrill Dragster, Formula Rossa and Red Force, all of which have less forceful launches. The world's most forceful launch is Do-Dodonpa at Fuji-Q Highland, launching from 0-111.8mph in 1.56 seconds, which actually holds the record by quite a significant margin and I hear quite a bit of praise for that, but I find it strange how people often seem to cite launches with a lower acceleration force as more forceful than coasters with a higher acceleration force. So my question is; what makes a launch feel forceful?

Take Top Thrill Dragster at Cedar Point as an example. I often hear that bounded around as the best of the "short and sweet launch coasters", and I often hear people say that its launch feels considerably more forceful than the likes of Stealth and Formula Rossa, even though the above rides have a more forceful launch in terms of acceleration force and in the case of Formula Rossa, is actually 30mph faster. Stealth is 3rd, Formula Rossa is 4th and Top Thrill Dragster doesn't even make the top 10, yet Top Thrill Dragster is always the one of these that gets the most praise and gets cited as the most forceful. In fact, Kingda Ka actually has a more forceful launch than TTD, and that thing is arguably one of the most criticised large coasters alongside the Big One at BPB! I'd also say that another example of a less forceful launch that is often cited as feeling really forceful is Red Force at Ferrari Land. That coaster often gets praised for its breathtakingly forceful launch, but it apparently has a lower acceleration force than Rita at Alton Towers and Blue Fire at Europa Park amongst other coasters that never seem to get much praise for their launches.

So before I ramble on for too long, my question is; what makes us perceive a launch as forceful? Is it the acceleration force? Is it the actual speed? Is it a combination of both? Or is it neither?
 

Jamesss

Member
Formula Rossa had one of the weakest launches I have done, despite supposedly having the fourth highest acceleration in the world.

I guess the reason some launches feel more forceful than others is because the rate of acceleration varies over the few seconds it takes to reach top speed, i.e. some start off quickly but then the rate of acceleration decreases as they creep up to their top speed; others start off relatively slowly but then they accelerate exponentially until they reach top speed.
 

Snoo

The Legend.
Staff member
Social Media Team
To me, always been the rate of acceleration. For instance, I could barely tell the difference between TTD and KK, even though KK supposedly goes MUCH faster. For LSMs as well, using two kinda like comparisons, Copperhead Strike vs Maverick.. you can noticably tell the difference between the sameish launch but the length and accel were wildly different.
 

Matt N

Well-Known Member
I was under the impression that Copperhead Strike went considerably slower than Maverick @Snoo (50mph compared with 70mph, I think?), so I'd be interested to know what you mean by "the sameish launch".
 

oriolat2

Member
I guess people rate TTD so highly because its one of the most ridden? I mean, if you have less people visit one particular coaster (Formular Rossa), not that many people are going to be able to compare it to anything, if that makes sense.

Do-Dodonpa was crazy intense. Borderline too much but I would love for a park to invest in such a beast of a launch, because this one has not been de-throned as the fastest accelerating coaster since it opened 18 years ago! 18 YEARS AGO!

I think something that helps enhance the feeling of a launch is the vehicle itself; the more exposed, the more "intense" it feels. Take Furius Baco, for example. It only accelerates from 0-84 mph in 3,5 seconds (although it has been reported to be launching at 75 mph for many seasons now) but having your feet dangling and riding on such a wide vehicle makes the experience much more thrilling than if you were riding in a regular Intamin train.
 

Snoo

The Legend.
Staff member
Social Media Team
I guess people rate TTD so highly because its one of the most ridden? I mean, if you have less people visit one particular coaster (Formular Rossa), not that many people are going to be able to compare it to anything, if that makes sense.

Do-Dodonpa was crazy intense. Borderline too much but I would love for a park to invest in such a beast of a launch, because this one has not been de-throned as the fastest accelerating coaster since it opened 18 years ago! 18 YEARS AGO!

I think something that helps enhance the feeling of a launch is the vehicle itself; the more exposed, the more "intense" it feels. Take Furius Baco, for example. It only accelerates from 0-84 mph in 3,5 seconds (although it has been reported to be launching at 75 mph for many seasons now) but having your feet dangling and riding on such a wide vehicle makes the experience much more thrilling than if you were riding in a regular Intamin train.
I'm REALLY waiting for MaxxForce this year for that exact reason. I haven't had that sort of force in regards to acceleration before and I'm excited to feel it finally on a launch. I am, hopefully barring issues, getting to get on Dodonpa next year so I can't wait to compare.

I was under the impression that Copperhead Strike went considerably slower than Maverick @Snoo (50mph compared with 70mph, I think?), so I'd be interested to know what you mean by "the sameish launch".
Sameish as in an LSM launch with the same length. I realize the speed difference is obvious but I've had more powerful launches from shorter/smaller LSMs in compare to others depending on acceleration, which as I said is the biggest factor.
 

Matt N

Well-Known Member
Sameish as in an LSM launch with the same length. I realize the speed difference is obvious but I've had more powerful launches from shorter/smaller LSMs in compare to others depending on acceleration, which as I said is the biggest factor.
Ah right. Thanks for the clarification @Snoo!
 

Hixee

Flojector
Staff member
Administrator
Moderator
Okay, few parts to this. Apologies if this ends up sounding like 'teaching one to suck eggs', but figure it's worth addressing the different aspects.

So firstly, to answer your question directly:
So before I ramble on for too long, my question is; what makes us perceive a launch as forceful? Is it the acceleration force? Is it the actual speed? Is it a combination of both? Or is it neither?
It's kinda a bit of some and neither of some. :p

Inherently, it's the rate of change of acceleration - called Jerk (https://en.wikipedia.org/wiki/Jerk_(physics)) - that gives us the greatest sense of intensity of a particular launch. In much the same was that velocity is the rate of change of distance over time and acceleration is the rate of change of velocity over time, jerk is the rate of change of acceleration over time. The non-linear nature of coaster launches, coupled with the concept of jerk, explains why some launches feel so much stronger than others.

Take Rita, for example. If you do the basic maths: 0-60mph in 2.5s is just over 1G. Now, that's not a small acceleration force, by any means, but think about how it feels. It's a hard punch that tails off. Compare this, for example, to a race car accelerating at roughly the same rate. It's going to have a much slower punch at the start (it can't get the grip) building to an enormous amount of acceleration. On average, both are going the same thing - about 1G - but in reality the Gs during the launch are changing as they go. The intensity you feel is linked to how those forces change over time down the track.

Another factor is air resistance and how you notice that on your body. Doesn't necessarily affect the launch forces, but will likely affect how you perceive the launch. Suddenly smashing through air with your face at 100mph feels pretty intense whatever the scenario. :p

The next part is - why do some launches feel different? Particularly those using different launch technology. It is (with a minor few caveats along the way) all down to their underlying technology.
  • Hydraulic/Air - These rely on compressing a fluid to a high pressure, suddenly releasing it using that explosion to launch the train. The most pressure available (and therefore the highest launch force, assuming that the train's weight is constant) is right at the instant they release the valve. That's why, generally speaking, hydraulic/air launches have a hard punch followed by a trailing off. Caveat - this can be modified by adjusting the compression, with special valves, pulleys, etc, so you can tune the launches. You might not want as hard of a punch (Formula Rossa), or you might want a really harsh punch (Do-Dodonpa), but fundamentally you get the biggest force right at the start.
  • Magnetic - These rely on using electric power to generate magnetic fields. If you want a more powerful launch, you've got to have a more powerful magnetic field, which means a more powerful electricity supply. In electromagnets it's all about electric current, and it's hellishly expensive to carry lots and lots of current (go read about Ohm's Law, transmission losses, high voltage power, all that sort of thing). Basically, you could do whatever launch profile you like with magnets, provided you've got the money for the power supply and copper. You can, however, keep whatever launch rate you like down the whole launch track, meaning you can achieve that much more continuous launch feeling. Advantage is, as battery and capacitor technology improves, we can expect to see more and more powerful magnetic launches out there - especially as they're far less complicated mechanically, and so are far less prone to downtime (Lightning Rod excluded).
That's all I've got time to write, at the moment, but hopefully it makes some sense and helps get your head round it a bit. It's a highly multi-factor question, and there's an awful lot that goes into it. :p
 

HeartlineCoaster

Active Member
Here's the mathematical formula:
Compressed air for the best 'Jerk' (I like that, gonna use it now) + not feeling like you're riding on glass (Dodo tyres) - roughness being the overbearing sensation (certain hydraulics).
= The other S&S launchers.
 

Kw6sTheater

Member
Going from a standstill to a higher speed and a high rate of acceleration generally contribute to the feeling of forceful launches. For example, FireChaser Express at Dollywood has launches that are surprisingly punchy and intense due to the quick rate of acceleration and acceleration from a standstill, while being very slow in actuality (0-16 mph in 1.1 seconds and 0-20 mph in 2 seconds). On the other hand, Copperhead Strike’s second launch takes riders from 35 to 50 mph in 2 seconds; while this is considerably faster than FireChaser Express’s two launches, you don’t really notice the acceleration or feel any force, as you are traveling at a relatively fast speed already.
 

spicy

Active Member
This reminds me of some interesting debate back when Rita first opened and this picture appeared online of the Rita hydraulic control computer.



It stated in the Max acceleration bar that it launches at 29.71 meters a second which would have made it the quickest acceleration on an Intamin launch coaster at the time at 1.5 seconds to 60mph.
 

Antinos

Slut for Spinners
Social Media Team
We can discuss math and physics all we want but that doesn't consider the psychological aspects of this question. There are so many factors that affect our senses - adrenaline, caffeine intake, a good night's sleep...what are all the things that happened leading up to you launching on whatever ride to put your brain in the state it's currently in?

For example, why is @Snoo comparing Copperhead's and Maverick's launches as such? He's been in Maverick dozens of times at all points of the day at many different times of the year in many different states of mind and physical status - he knows the ride inside and out. He's only ridden copperhead a few times, all towards the end of our first day at Carowinds and also during the second day when we were still feeling the affects of fatigue and probably dehydration as well. It was also a new, exciting experience that probably had our adrenaline pumping a bit. I thought Copperhead's launch wasn't as good as Maverick's - it starts out quite weak but picks up as the train approaches the end of the launch, but in a weakened physical state like we were in, I can see why it would feel more intense.
 

Hixee

Flojector
Staff member
Administrator
Moderator
We can discuss math and physics all we want but that doesn't consider the psychological aspects of this question. There are so many factors that affect our senses - adrenaline, caffeine intake, a good night's sleep...what are all the things that happened leading up to you launching on whatever ride to put your brain in the state it's currently in?
You're right, and it's good to note. I answered the question of why some launches ARE more intense than others (the maths and physics stuff), not why some FEEL more intense than others (the squishy psychological stuff). ;)
 

DelPiero

Well-Known Member
Jerk (https://en.wikipedia.org/wiki/Jerk - that gives us the greatest sense of jerk is the rate of change. Jerk explains why some
feels on your body. Doesn't necessarily affect how you perceive smashing your face at 100mph followed by really harsh punch. You can, however get your head round it a bit, there's an awful lot that goes into it. :p
I knew this post was coming from you.


I have nothing to add to this, I'm not that much of a goon.

Don't anyone dare post a cred shame pic.
 
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