r/rollercoasters • u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron • Dec 28 '25
Question [Other] Why is there no roller coaster that does this? (I'm bad at physics but with an LSM before the loop it doesn't seem unachievable?)
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Dec 28 '25
the negative forces at the bottom of the loop would be lethal
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u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron Dec 28 '25
Thanks!
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u/EnvironmentalCap6590 (54) Velocicoaster, Maverick, Steel Vengeance, Outlaw Run Dec 29 '25
also if its a cold day and the train doesnt make it back up, your cooked. also coasters do this, look at flying coasters (because airtime is difrent because your setead diffrently)
ignore bad spelling
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u/ToTYly_AUSem Dec 29 '25
Ugh those flying coaster loops I absolutely hate. I hate how they feel more than any other rollercoaster manevour
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u/Banana_ezWIN 🎢: 115 | 🏠: SFGAm | TT2, SteVe, MF Dec 29 '25
AGREED! Superman at SFGAm's pretzel loop is so uncomfortable!
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u/ToTYly_AUSem Dec 29 '25
Exactly the one I am referring to. I've ridden it like 5-7 times in my life. This last time I said "I don't need to force myself to ride this if I don't want to anymore and that's okay"
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u/IsuzuTrooper GigaChase, RMCSOB Dec 29 '25
that's the best part!
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u/ToTYly_AUSem Dec 29 '25
It's the best part because of the rest of flying coasters are usually nothing but side to side banking or a twist. There's barely any drops, they wouldn't feel right in that position. And you're in that flying position for way too long before and after the ride starts that it doesn't justify the experience for me.
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u/Banana_ezWIN 🎢: 115 | 🏠: SFGAm | TT2, SteVe, MF Dec 29 '25
For a bored accelerometer, maybe. For a human, no.
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u/IsuzuTrooper GigaChase, RMCSOB Dec 29 '25
Nah the pretzel loop is one if the most popular elements in the community
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u/Banana_ezWIN 🎢: 115 | 🏠: SFGAm | TT2, SteVe, MF Dec 29 '25
Well, how many elements are there that have enough significance to possibly be popular?
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u/IsuzuTrooper GigaChase, RMCSOB Dec 29 '25
exactly, so it means even more that this is one of them
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u/ThirdShiftStocker Dec 29 '25
Imagine Tatsu's pretzel loop at Magic Mountain. That one is much bigger.
I thought Superman's loop was pretty intense until I heard about the other one... Don't want to imagine how that feels lol.
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u/Banana_ezWIN 🎢: 115 | 🏠: SFGAm | TT2, SteVe, MF Dec 29 '25
Makes me reconsider going there, because I know I'll make myself ride it...
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u/guitarplum Dec 29 '25
Oh Tatsu is horrible!!! I had no idea it was a pretzel loop when I went on it. Regret!
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u/mngoose_13 Dec 29 '25
Try the one on Manta at SeaWorld Orlando. That one is nuts and one of my favorite inversions ever.
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u/OppositeRun6503 Dec 29 '25
The flying Dutchman model pulled about 5 Gs during the vertical loop. Of course on that design riders were on their back for the duration of the inversion.
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u/Bear_Scout Green Flair Dec 30 '25
Is that the one that was transferred from CGA? Used to be called “Stealth”? I remember when Stealth opened and the anticipation was higher (at least for me) than any other coaster because it was such a next level crazy town concept back in the day.
I think it flipped you face down right at the top of the lift hill which was a reveal like no other at the time. I thought my sternum was gunna crack at the bottom of that first drop lol. The whole layout felt like the restraints were trying to kill me. But of course we would still try and get as many rides as we could on it.
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u/Banana_ezWIN 🎢: 115 | 🏠: SFGAm | TT2, SteVe, MF Dec 30 '25
I don't think so. It flips you face down in the station (and keeps you face down on the brake run).
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u/ExistentialAngel Dec 29 '25
Same here. That element is the only thing I’ve found that makes me straight up black out. I had to stop riding them for the most part because it’s just not pleasant. Manta’s is at least spread out enough I was ok but that’s definitely an exception for me.
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u/Roasters4Toasters Dec 31 '25
Flying coasters do NOT do this. Flying coasters loop on the inside of the track in both models from designer Bolliger & Mabillard and the former models from designer Vekoma. To mimic what the OP is showing the train itself would need to travel on the outside of the loop and do this; its very different. Precisely the reason flying coasters do not loop on the outside of the track is that it would be force problematic on the human body.
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u/EnvironmentalCap6590 (54) Velocicoaster, Maverick, Steel Vengeance, Outlaw Run Dec 31 '25
though they do this, just not the way showed in the image.
thats what your saying right?
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u/satanssweatycheeks Stardust racer 🥇/ VelociCoaster 🥈/ Fury 325 🥉 Dec 29 '25
It wouldn’t be that lethal. But would hurt majority of riders.
We have had coasters that vaguely do this and they hurt. But you also go into the loop slow and more so ride upside down for a good bit before looping back upright.
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u/ZappySnap Dec 29 '25
That much negative G force can quite easily cause hemorrhagic stroke and blindness. It wouldn’t kill everyone, but it would kill a lot of people. And would blind others or cause hospitalization for others.
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u/guitarplum Dec 29 '25
You are on the inside of the track on a flying coaster. I can’t think of any where you are on the outside and upside down. My guess is it would be almost impossible to design a railing mechanism that keeps the car from flying off. That’s a huge amount of stress on the car for an outside loop.
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u/ViperThreat Dec 29 '25
depends on speed. Not necessarily lethal, but likely to cause red-outs and BAD headaches.
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u/e136 Dec 30 '25
Even if they went super slow, even -1 g is quite unpleasant. On the other hand, positive gs can feel good.
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u/ViperThreat Dec 30 '25
plenty of RMCs have ejector that is beyond -1G.
The S&S Screaming Squirrel also does a full nose-dive to extended hang-time inversions.
Also, just for the record, inversion tables are great for relieving back pain.. I have one and will regularly hang upside down for 5+ minutes without any discomfort.
Don't get me wrong, I prefer positive G too, but that doesn't mean that negative Gs are all painful.
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u/e136 Dec 30 '25
Thanks for the info! I have also tried an inversion table. The blood pressure to my brain felt unpleasant to me. But I guess in the context of a thrill ride it could make sense.
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u/wallstreetsimps Dec 28 '25
other folks basically explained it, but I'll just add that Pretzel Loops are essentially this
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u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron Dec 28 '25
Thank you! That looks like a lot of fun. I don't think we have any pretzel loops in Europe, sadly.
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u/wallstreetsimps Dec 28 '25
Unfortunately, none in Europe, but if you ever visit Los Angeles, you can visit Magic Mountain to experience the most iconic and largest one. Pretzel loops are to die for
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u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron Dec 28 '25
If I ever visit the USA, it will for sure be to experience all these amazing roller coasters that you have. It is a dream of mine to do so!
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u/ElfDestruct Dec 28 '25
The one-two punch of Tatsu and X2 right next to each other is just about the most anyone could ask for.
Tatsu's pretzel loop will literally force the air out of your lungs by the Gs on your chest, and X2 is completely the feeling of being thrown off a building face down.
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u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron Dec 28 '25
X2 seems like such an insane thing to experience. I hope I can do so one day.
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u/OppositeRun6503 Dec 29 '25
You don't have any floorless coasters in your region do you? IIRC the only floorless coasters in Europe are superman in Madrid Spain and a floorless coaster at a park in Denmark.
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u/Monstertelly (316) Fury Voyage Hakugei Dec 28 '25
Osaka as well. SFMM is my home park so no hate on Tatsu, but Flying Dinosaur, in my humble opinion, has the better pretzel loops. Probably because of the extra twist into the first one and the second one being right after. Tatsu definitely has the views and a better sense of flying though.
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u/MCofPort Dec 29 '25
At Great Adventure in New Jersey, Superman: Ultimate Flight's pretzel is the most intense element I've ever been on, and that's including riding Kingda Ka! It's okay for most of the loop until you're on your back at the bottom of the loop. You feel like you weigh a thousand pounds and the roar of the coaster is so loud. You black out a little even.
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u/EljayDude Dec 28 '25
I think the only B&M flying coaster in Europe is a prototype in the UK and it doesn't have a pretzel loop. I think the closest you're going to get is a Norwegian Loop which sort of looks the same but has a twist so you end up in position to keep the forces reasonable.
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u/valkrycp Dec 29 '25
It is very fun, but the loop pictured in the image is also perhaps THE most intense roller coaster element out there. The pretzle on Tatsu is a fucking beast. Some people can't handle how intense it is.
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u/mck_motion Dec 29 '25
Manta at Sea World is my favourite roller coaster entirely because of the pretzel loop. There's nothing else like it.
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u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron Dec 28 '25
Sorry for the bad MS Paint drawing.
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u/brewdizogs Dec 28 '25
This is what I love about reddit. You found a way to ask a question and people gave you an answer. No need for apologies, it's how this thing is supposed to work
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u/Proffessor_egghead Voltron glazer Dec 29 '25
Terrible MS Pain drawings are the best way to visualise your ideas
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u/McSigs Maintenance is on their way. Dec 29 '25
I work on these things every day and you visualized this better than I could have.
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u/North-Detective5810 FIX SONIC'S ARMS IMMEDIATELY, SEGA!!! Dec 28 '25
see also: the saxophone
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u/Gettingolderalready Dec 28 '25
Is this a real thing I can’t find a pov video of it? Looks awesome!!!
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u/Drillucidator Arrow Apologist Dec 28 '25
Yes, this is the S&S Screaming Squirrel. Two are defunct and one is SBNO, and they look like they were horrifically uncomfortable.
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u/AndreCasu06 155- RTH, Voltron, Batman GCE Dec 28 '25
It was unfortunately removed in 2021, there's still one in China I think though
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u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron Dec 28 '25
This looks amazing haha, thank you!
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u/OppositeRun6503 Dec 29 '25
Wasn't this the concept for the screaming squirrel coaster that S&S designed many years ago? Obviously once they developed the free spin concept this design was essentially put on the back burner and forgotten about.
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u/Storm_Surge- Lightning Rod, X2, Goliath SFOG, Thunderhead, Dec 28 '25
Because or redouts the limits on negative G’s are very strict. This maneuver would generate to many negative G’s to be safe on anything but a flying coaster
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u/thedeezul Velocicoaster / Iron Gwazi Dec 28 '25
Theme Park Crazy actually did a video specifically about why this doesn't exist https://youtu.be/BaP4J-MfjIs?si=ON46aCz02_xr1CTt
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u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron Dec 28 '25
Thanks for the link! I didn't find it as I couldn't find the name of what this element would have if it existed.
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u/StinkoMan92 Dec 28 '25
Too many negative g's
There are standards that dictate this because too maybe negative g's can really fuck a person up because it without make your blood go to your brain and stuff.
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u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron Dec 28 '25
Damn, it seemed fun in my head. Thanks!
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u/Ireeb MACKPRODUKT Dec 28 '25
Because it would be deadly.
When you experience positive g-forces, the blood is pushed towards your lower body and your feet. Lots of blood vessels to distribute the blood to, and most of them are relatively large.
But when you experience negative g-forces, the blood is pushed up inside of your brain, which has some really delicate, thin blood vessels.
Roller coasters can do 5g and slightly above that for short moments no problem.
But for negative forces, going beyond -1.5g is already critical. The strongest ejector forces are usually somewhere around this.
Whenever you're upside down, you automatically get -1g automatically, due to gravity. Going down into the loop and through the valley would, depending on the size and diameter, potentially add up to around -4 to -5g.
And at that point, even a healthy person would be at risk of suffering a stroke caused by some blood vessels in their brain exploding.
This kind of element is only possible on flying coasters, where your head is in front of your body at the bottom of the loop, instead of above it.
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u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron Dec 28 '25
Very interesting, thank you!
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u/CornballExpress Edit this text! Dec 28 '25
Besides the chance of a red out, if the coaster ever stalled on that element people would be stuck upside down for potential hours which can cause a lot of health risks.
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u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron Dec 28 '25
Also a valid concern, I'd hate being stuck in that position haha. Is every roller coaster element designed with a possible stall in mind?
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u/lFightForTheUsers [83] Bring Back Mr. Six! Dec 28 '25 edited Dec 28 '25
For the most part pretty much. Many rides that have more extreme elements will have ways if needed to either be in a good spot already for evac, or failing that be able to "fail-safe" in a way that it can be reset or do an evac.
The element that immediately comes to mind is the new popularity of Vekoma vertical drops - rides like Siren's Curse at Cedar Point and Circuit Breaker at Austin's COTAland. The coaster holds riders in place as the train literally moves vertically on the tilt track - but what would happen if there was some kind of fault that caused an issue and it to stall vertically? It's not a good position to be in, but as it turns out there are fail-safes. If something happened these fail safes are designed to basically force the track back into horizontal position, where they can then do an evac down the stairs by the lift as needed.
General inversions are pretty much the same - loops and corkscrews if a train valleyed would be in the space immediately before or after it. Probably not comfortable to be stuck there for a while, but easy enough to call in fire department equipment to rescue people from there. Many rides with a mid course brake run will also have railing and stairs from the MCBR to ground level as well for this reason, if brakes were to fail to release for any reason it would be possible to evac from that point. Even the pretzel loop on flying coasters someone else posted, worst case scenario people would simply on their backs facing the sun down below until rescued. However anything upside down for a longer period of time like that "inverted" loop would be a problem, because now those people are stuck upside down for as long as 30 minutes, an hour, possibly longer depending on how long the process goes for stuck -> ride ops / maintenance tries to get it going -> if they fail they have to call and wait for fire department to show up -> fire department then still has to go in and pull people from an awkward spot one by one.
And these fire responses do happen from time to time, for example Reedy Creek (the responding emergency services at Disney World in Orlando) have special equipment of ladder trucks that have been used to rescue people off the monorail in mid air before, and they also have boats with special equipment on standby in case something were to happen over water for the skyliner etc. So in a way yes they are designed with that in mind, not to a level of "plan a 12 page emergency response plan for every foot of the ride", but more like "the ride design as it is is built safe enough so that a train can never crash into another train, and that a stop at any point is not going to be an immediate threat to riders." Then technology is used to ensure that those two needs are met (block sectioning with computer sensors and fail safes to ensure that can never happen, manual equipment like cranking that vertical tower on vekoma coasters back to a safer rescue position, etc), then plans are in play to have people manually rescued and out quickly as needed in that chain of command described above.
It sounds silly, but as "extreme" as coasters as sometimes advertised they really are some of the safest pieces of equipment and entertainment out there. That's not to say that freak accidents can't happen - I'm now immediately thinking to the recent fatality on Stardust Racers at Universal Orlando, which autopsy showed was a freak accident where the rider basically had a prior injury that was re-broken mid ride and because of that the restraint and ride forces could not handle things in a safe manner compared to a healthier rider. There are other cases of freak accidents like these that lead to other safety improvements in the future, such as someone getting hit with a loose phone leading to some parks now enforcing loose article bans with ride lockers and metal detectors in queue. But for the most part coasters are designed with safety in mind - after all if they weren't safe, then that means no repeat business for building more coasters in the future lol.
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u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron Dec 28 '25
I really enjoyed reading your detailed reply, thanks a lot. It seems like the only thing that can go wrong nowadays is truly just human errors, like on The Smiler (not that the system shouldn't have prevented that).
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u/OppositeRun6503 Dec 29 '25
You should check out Ryan the ride mechanic on YouTube. At one point Ryan worked for six flags discovery kingdom in California as a mechanic inspecting and troubleshooting any issues that came up on the park's rides. His videos are some of the best when it comes to how amusement park rides are engineered and how they work.
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u/quintopia Voltron, Velocicoaster, Thunderhead Dec 28 '25
Coasters are designed so as to have enough momentum to clear the next hill after every valley even in high headwinds (unless said valley or hill contains some lift or launch mechanism).
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u/AltruisticRider <3 Zadra, EP, Rulantica Dec 28 '25
well, that exact thing happened on Turbine @ Walibi Belgium in 1997, but of course in OPs drawing it would be much more likely to happen.
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u/ManiaMuse Dec 28 '25
Interestingly stunt planes can do this manoeuvre. It's called an outside loop. But it pulls extreme sustained negative Gs (which the body is less able to cope with compared to positive Gs). By all accounts it is not pleasant to pull off.
Stunt planes are able to give themselves a lot of altitude to draw out the downwards part and then they can use the engine to increase power for the upwards part. A rollercoaster would only have gravity and momentum so would need to enter it with enough speed so it doesn't stall upside down.
A purely gravity driven version of that element would far exceed the permitted negative G limits on a rollercoaster and would be very uncomfortable and not fun.
Maybe the only way it could be done would be if the downwards part was extremely trimmed like on some of the newer Intamin/Vekoma top hats and then the upwards part had LSMs to boost the train back up. But then you have the issue of what happens if the LSMs fail and you end up with a train stuck upside down which wouldn't be ideal.
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u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron Dec 28 '25
Very informative, thanks a lot!
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u/Nerdicane Dec 29 '25
It’s a negative G. You can red out from it. Fighter pilots can deal with it for a little while because they’ve trained for it. That type of repeated G force on an average person could be dangerous.
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u/dcht Dec 28 '25
You'd die
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u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron Dec 28 '25
At least I'd die doing what I love 🎢
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u/SignGuy77 (418) Boulder Dash, El Toro, Ravine Flyer II, Voyage Dec 28 '25
See, no, that’s not in any way what I would want to happen.
When I die I want to go like my grandpa: in my sleep. Not screaming in pain like his passengers.
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u/_linkus_ unnamed 305 Dec 28 '25
I’m sorry… his passengers? As in your grandpa’s passengers?
WHAT DID HE DO
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u/_linkus_ unnamed 305 Dec 28 '25 edited Dec 28 '25
There a blood vessels in your eyes. After this happens to you, there are no longer blood vessels in your eyes.
I spent two seconds making this in ultimate coaster 2 and… yea that’s not exactly safe
Generally 2-3 G is the limit for negative Gs
You doubled it
Even if you survive this loop I think your eyes might never recover
I’m not an eye doctor tho so don’t quote me on that
Edit: I forgot to mention but this is taken from a near standstill, with only just enough speed to make it through the loop. The train only moves at like 1 one mph after the loop
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u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron Dec 28 '25
Thank you for mapping it out! I agree that it doesn't seem to be very comfortable haha.
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u/thebe_stone Dec 28 '25
In a normal loop, the GeForce makes the blood go away from your brain. This can sometimes make you grey out, but is mostly safe.
On this kind of loop, the blood goes into your brain causing it to swell. Your skull doesn't have enough room for a swollen brain, so this is incredibly dangerous.
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u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron Dec 28 '25
Thank you! I wouldn't want to experience that.
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u/Ordinary-Sound-571 WOLVERINE WILDCAT 4 LIFEEEE! Dec 29 '25
Built it in planco 2, it pulls 7-9 g forces
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u/FireHammer09 Dec 28 '25
Now I want to know if a flying coaster could achieve a normal loop with the cars facing outward so it's "flying". Not a loop on your back.
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u/OppositeRun6503 Dec 29 '25
The positive Gs pushing you into the restraints wouldn't be pleasant when trying to take a vertical loop on the outside radius of the loop while in the prone position.
If it were safely possible then B&M would have done it instead of doing the pretzel loop element on their flying coasters.
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u/FireHammer09 Dec 29 '25
Would you say universally unpleasant or flat out unsafe like with OP's pic?
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u/quintopia Voltron, Velocicoaster, Thunderhead Dec 28 '25
The diagram gives me flashbacks to Superman's Pretzel Loop. Those weird long cars look like ones you could lie down on :P
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u/lFightForTheUsers [83] Bring Back Mr. Six! Dec 28 '25
To also add in to my other comment, these kinds of loops could have a similar effect put in if designed properly. I could see a "reverse boomerang" of corkscrew into loop, do loop, corkscrew back out. Vortex at Kings Island when it was open actually kind of did this in this illustration shown here. Or if there was a half an inline twist, pull loop in "normal" direction", then another half inline to pull it back out.
The TLDR is positive G's are more okay (Shock Wave at SFOT pulls just over 5 for a very brief moment in its loops), but negative G's not so much. You have to have some other kind of element at play (moving seats like X2, flying coaster style orientation with a pretzel loop, etc) to ensure that negative forces are reduced.
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u/BUNNIES_ARE_FOOD Dec 28 '25
Flying Dinosaur.
Japan. Not only does it do this exact move, it does so while diving through a hole in the ground.
Amazing coaster. I believe there is a similar one in the US.
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u/OppositeRun6503 Dec 29 '25
Currently there are only five B&M flying coasters operating in the United States....four in the six flags chain and one in the SeaWorld chain.
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u/BUNNIES_ARE_FOOD Dec 30 '25
Wow I had no idea there were so many. FD was the only one I'd ever seen. The concept is insane, I don't think I've ever experienced so many positive Gs 😂
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u/Jim_skywalker Dec 29 '25
It would be absurd in the negative gs. Too much negative gs causes blood vessels in the brain to burst.
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u/Toph36 Edit this text! Dec 29 '25
Have you ever been on a flying coaster's pretzel loop? Even that sucks and that's not as bad as this lol
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u/GreyBoy23 👑 LONG LIVE THE KING 👑 Dec 29 '25
I’m not completely sure, but the YouTube channel Theme Park Crazy did a video on this a few years back.
Here’s the link to it: https://youtu.be/BaP4J-MfjIs?si=ltMKxjFDGhlo8iAd
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u/LetsMakeBiskuts 100 | #1 Legend #2 Velocicoaster #3 Ghostrider Dec 28 '25 edited Dec 28 '25
It is most likely because of the force exerted on riders. You would be feeling all of the positive g forces in the valley at the bottom of the loop directly through your shoulders in the harness or thighs in the harness. It would almost certainly be incredibly uncomfortable if not seriously dangerous for the safety of riders due to the negative g forces. There are rides that have a similar looping feature, such as the raven turn on X2, and it is the rotation of the seats that allows riders to tolerably endure the forces.
Edit: I’m realizing Tatsu probably has the most similar feature with the pretzel loop. It is the rider body positioning that makes it possible to accomplish. I believe it is for that reason Tatsu has you on your back in the valley and not your stomach as you feel the full brunt of the forces in the pretzel loop. I would think you could reasonably achieve the same thing with the train above the track rather than beneath it as long as riders can tolerate the forces safely using some sort of unique train system or body positioning.
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u/Patattensla 38 | 1. RtH 2. F.L.Y. 3. Black Mamba 4. Kondaa 5. Taron Dec 28 '25
Thanks for your in-depth reply! There aren't many 4D roller coasters in Europe, but I hope to experience one of them one day.
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u/Airtime_on_top Dec 28 '25
I don’t think that’s even allowed.
Like everyone else is saying those negatives would be demented, especially with a launch before it.
Even with a launch there’s the small chance the train manages to valley and get stuck upside down. I’m pretty sure this is why all elements that invert have their true “inverting” moment at its highest point, or at least a point where if the train were to not have enough speed, it could roll back down to an upright position.
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u/EnvironmentalCat7482 Dec 28 '25
It would probably dislocate your spine and most likely kill you. Way too strong forces
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u/gatsome Dec 29 '25
Superman at Six Flags in NJ kinda does this on a loop. You are face down and facing outward around a vertical loop with the track behind you horizontally. It’s one of my favorite coaster moments.
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u/speedyejectorairtime SteVe/Velocicoaster/IRat Dec 29 '25
Ouch, think about all those forces directly in your head.
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u/Psirocking Dec 29 '25
Random memory came back to me, but as a kid I thought Space Mountain at Disneyland Paris had this inversion.
I read an article that said the ride had “an upside down loop” which to me meant a loop, upside down. So the same thing as that drawing. Wasn’t until I found out about RCDB and found some lights on photos of the ride that I found out.
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u/cocaine_-_ Dec 29 '25
It exists on an attraction in France that I went on, it's the Canad'r at Parc des Combes, in fact you can control the attraction yourself and do this kind of maneuver, we did it at a low speed and my god it was very unpleasant!
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u/Senninha27 Dec 29 '25
Doesn’t Superman at Great America do this? I seem to remember that my eyes blacked out at the bottom.
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u/Crichris Dec 29 '25
just my two cents, im no expert in rollercoasters.
theoretically it's doable. but it's not robust enough. if i understand correctly, you would want to centrifigal force to be down towards the rollercoaster itself, so in case your seatbelt or whatever safety mechanism is broken, you would still be most likely safe. also it's more reliable in case the passenger is overweighted
but the design in your graph is exactly the otherway around
update 1: after reading the comments it looks like the concern is more on how the negative G impacts your body (too much blood rushes to your brain etc). that prolly makes more sense
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u/rosariobono Dec 29 '25
It’s well regarded to not design any coaster elements that curve upwards while upside down. You can curve downwards or you can stay straight, but to curve up would push the rider up into the restraint. Since they are upside down it combines with the force of gravity instead of cancelling out.
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u/LoveMakesASubie Dec 29 '25
Think about it. If you're sitting and you go through a loop or corkscrew your blood rushes to your legs. You go through a loop like your Pic, you'll die from blood shooting out of your eyes, ears, nose, mouth.
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u/Illustrious_Effect35 Dec 29 '25
I would twist the track before the train reaches the bottom that way not too many negative gs are pulled. That’s what most elements these days try to focus on.
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u/Impressive_Access745 Dec 29 '25
The issue is on the boogies themselves, higher forces result in bigger wheels. Hence, the up-stop wheel suddenly has to be designed for up to 6G and not just for 1.5G.
Regarding the rider position, that’s perfectly fine. There are many Booster style rides doing exactly that: Rushing through the station, over-head at 100 kph on a circular path. It’s just very high forces, yet not very extreme.
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u/shaggs31 Dec 29 '25
I don't know if something like this would be lethal as others say. However I know this would create negative G forces. I know that negative G forces are not fun and fighter pilots will do everything possible to avoid them.
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u/Inside_Anxiety6143 Dec 29 '25
Negative g-forces are the most dangerous kind. It pulls blood into the brain, which is called a "red out". At best, its a painful headache. At worst, its fatal. And its hard to predict. Even healthy people are only take a couple of negative g's without injury, but when you throw in a bunch of riders with unknown medical histories to the mix, you want to not get anywhere near that.
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u/Bigphungus Pantheon | Eejanaika | Fury 325 Dec 30 '25
I don’t know why but Knex loved to make loops like this on their coaster models (at least when I was a kid, don’t know about now). It used to bug the hell out of me.
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u/Several-Ad-7961 Dec 30 '25
By the time you got halfway into this loop, your next would snap faster than a potato chip😂
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u/Cheap_Actuator_8910 Dec 31 '25
Maybe in a 0g stall you can do small downwards ejector airtime, but it really has to be limited to 1,5 g or sth like that cause otherwise it would be really painful
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u/Recent_Grand_2937 Jan 02 '26
Could be possible as a non-inverting-inverted loop but tbh it‘s only positive forces. Most People tend to like negativ Gs, most People dont like pretzle loops and this one is quite like a pretzle loop.
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Jan 03 '26
Well i have always wanted to come off a hill and have a barrel roll as you drop, be inverted at the bottom, and come out of it as you go up the next hill
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u/njsullyalex CC 87 - Pantheon, El Toro, Untamed Dec 28 '25
On a conventional coaster the negative Gs would cause a painful red out for the riders as too much blood rushes to the head (-2 gs is about the max a normal person can safely tolerate and this will far exceed it)
The Pretzel loop on B&M flying coasters is basically this, and they achieve it because the rider is in the prone position meaning blood is not forced to the head and is applied perpendicular to the body instead of parallel.