Arrow Corkscrew: Positive Gs or not?

Friday, December 5, 2003 7:01 PM
Hello - looking at coasters like Anaconda or general Arrow loopers with corkscrew element makes me wonder whether or not the riders would all "fall out" if it weren't for the OTSR during the corkscrew.
From outside the ride, it looks very much as if the centripetal force from the train rotation in the corkscrew wouldn't be enough to keep riders in the train-

I've been through quite a few of these elements on different occasions, and I think that my weight wasn't ALL on the harness, but on the other hand it also didn't have that "B&M" weightlessness feeling.

Am I right or wrong? *** Edited 12/6/2003 12:02:43 AM UTC by superman***

Friday, December 5, 2003 7:09 PM
I get a very distinct floating sensation going through the corkscrews at the end of SFMM's Viper, but they are admittedly taken rather slowly after all the brakes that are along that ride. I wouldn't be surprised if someone could come out if they didn't have any restraints.
Friday, December 5, 2003 7:11 PM
I don't know if I've ever felt like I was going to fall out of a corkscrew until I finally rode Vortex at PKI this year. I was completely out of my seat, and hanging onto the harness. Awesome.

It was my understanding, based on an old coaster article in Money magazine of all places (August, 1989), that the rider was supposed to feel 0 Gs at the apex of each corkscrew. The article included a reading from an accelerometer taken on CP's Corkscrew.

Friday, December 5, 2003 7:47 PM

Olsor said:...that the rider was supposed to feel 0 Gs at the apex of each corkscrew.

Wouldn't that defeat the purpose of the 0 G roll element? It was my understanding that some sort of +G's should always be present during an inversion.

Friday, December 5, 2003 8:13 PM
It's from like 15 years before B&M even existed with their ZeroG Rolls... and it's not even the same company. Arrow doesn't make inversions like that on their loopers.
Friday, December 5, 2003 10:53 PM
1989 was 15 years before B&M? Their first coaster was in 1992, and I believe their first coaster with a zero G roll was Kumba in 1994.

Or did you mean anaconda was made 15 years before?

Friday, December 5, 2003 11:01 PM
The Corkscrew is from 1975, Knott's Berry Farm (now residing at the home of America's number one Woodie, TREMORS).
Friday, December 5, 2003 11:17 PM
Kaldaim - I think when vertical loops reemerged in the 70's, in order to combat the failures of earlier circular loops, designers aimed to keep the Gs positive, but relatively low and constant throughout the loop.

But other than that issue, and in light of better-designed restraints, I don't think designers need to keep Gs at any specific level during inversions so long as the riders remain safe and comfortable. As you pointed out, B&M has the zero-G roll element. Their vertical loops are also designed with a much greater radius than the early Arrow vertical loops, and I have experienced some decent hang time on B&M vertical loops.

What surprises me, though, is that of the 6 coasters I've ridden with double corkscrews, I've only experienced serious hang time on Vortex's. Probably because they immediately follow the MCBR and are taken very slowly. But they were ridiculously fun, and I don't know why that design wasn't factored into all rides with double corkscrews. Even, as Tom Servo pointed out, if they need to put trims right before the element.

Friday, December 5, 2003 11:18 PM
Turbo - B&M's first ride was Iron Wolf in 1990. Kumba debuted in 1993, but B&M first used the zero-G roll on SFGAm's Batman in 1992. *** Edited 12/6/2003 4:20:18 AM UTC by Olsor***
Saturday, December 6, 2003 1:24 AM
The best Arrow corkscrews I've found are on PGA's Demon. Completely weightless at the apex and they are taken pretty quick. It isn't hangtime, it's a weightless airtime feeling. Completely awesome and pretty smooth.
Saturday, December 6, 2003 1:31 AM
What I was trying to say is that the generic Arrow corkscrew element came a while before B&M even existed...
Saturday, December 6, 2003 2:04 AM
I know that my shoulders pressed against the shoulder harness on Shockwave at SFGAm. If you sat in the last seat while entering the boomerang loop, you crawled through the first inversion of it.

Translation==== SLOW!!!!

Saturday, December 6, 2003 9:47 AM
Oh my bad, I mixed up the dates.
Saturday, December 6, 2003 9:50 AM
Chitown - I had completely forgotten about Shockwave's boomerang... as a younger and smaller lad, I remember once falling into the harness entering the boomerang, and returning to my seat in a much different position during the pullout. Somehow, though, that didn't seem as fun back then.
Saturday, December 6, 2003 9:51 AM
wait, isn't that a camelback twist on batman? or are camelback twist and zero g rolls the same?
Saturday, December 6, 2003 11:25 AM
I think "camelback twist" is the terminology used for sit-down rides, but it's the same thing as an inverted zero-G roll. The inverted zero-G roll just looks different because the track traces the inside of the element, instead of the outside. If you were to trace the line that the feet of the riders make during an inverted zero-G roll, it would more closely resemble a "camelback." "Heartline twist" is also another term used for the inverted zero-G roll.
Saturday, December 6, 2003 11:37 AM
They look very different to me. The "camelback zero-G roll" (or whateveer they call it now)is the element on the sit-down Beemers like Kumba. It's shaped like a camel back hill but twists at the apex.
The inverted coasters have a "heartline spin" (or heartline roll or whatever they call it now). This element is a flat (but twisted of course) section of track. It usually comes in the form of a hill with a flat section at the top, so it's shaped kind of like a trapezoid like this: /^^^\
The Kumba element is more like a triangle like this: /\
To make things even more confusing, I think B&M calls their corcscrews flat spins. To me, a flat spin sounds like a heartline roll.

I wish there were more of the camelback rolls and heartline rolls. They're way more interesting than cobra rolls and corcscrews in my opinion.

Saturday, December 6, 2003 12:28 PM
Matt - inverted zero-G rolls look different because of where the track is with respect to the train. If you trace a line where the feet of an individual row of riders on PGA's Top Gun travel during the roll, it will look very similar to the more angular path of the track during Kraken's roll.

Elements on inverted rides tend to be thinner, or narrower than the elements on sit-down rides, but the rider's heartline with respect to the element will be comparable. *** Edited 12/6/2003 5:35:35 PM UTC by Olsor***

Saturday, December 6, 2003 12:47 PM

Olsor said:
Elements on inverted rides tend to be thinner, or narrower than the elements on sit-down rides, but the rider's heartline with respect to the element will be comparable. *** Edited 12/6/2003 5:35:35 PM UTC by Olsor***

So... is it fair to say that with a similar heartline path, inverted coasters are cheaper? (less steel required)


Saturday, December 6, 2003 1:08 PM
The original corkscrew was designed so that you would feel positive Gs throughout (Source: Roller Coasters, Flumes, and Flying Saucers. Very good book about Arrow). Unfortunately either that design was changed or trims on rides have made them moments of airtime.

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