Brakes on B&M Inverts

[sclisso]

I've been wondering what the brakes after the lifts on B&M Inverts(and some other B&M coasters like Apollo's Chariot) are for? I thought maybe it was to relieve tension on the lift chain.

[TPDave]

Hi there,

 

They're not actually brakes, but a pre drop. The idea is that the track is at such an angle that the train moves at the same speed as the chain lift, reducing wear on the dogs etc.

 

More recently they've just been speeding up the chain at the end of the lift to achieve the same effect. Hence no pre-drops on some more recent B&M's.

 

Hope that answers your question

 

Dave

[sclisso]

Yeah, I know what you mean by the pre-drop. I'm talking about on like Alpengeist, for example, if you look at a video of Alpengeist going up the lift and once you're at the top there's the pre-drop and something hanging down from the track. I assumed they were brakes. You can even hear a sound when going down that sounds like brakes.Here's a video

 

http://www.youtube.com/watch?v=QdFXFhsfSnU

At seven seconds into the video pause and look at the track. Then play and listen for the sound. And i might've made a mistake, I'm not sure these brakes are on all B&M inverts.

[RCoasterny]

You're right, sclisso, there is indeed a brake right off the lift hill. This is the first time I've seen one on a B&M Inverted.

[coolhandluke]

Yeah, they're brakes. And no, they're not on all inverts. I know Afterburn has one too.

 

They're probably just trim brakes to help keep the speed consistent over the top.

[sclisso]

They're also on Apollo's Chariot on the little flat area before th drop if you watch a video of it. I think Coolhandluke may be right. It could be use to regulate the speed at the top to reduce wear.

[gisco]

My guess it is there for safety.

 

I don't know the mechanics but I would guess that the train engages the lift chain with some sort of hook system . When the train hits the top of the hill the hook disengages and there is enough weight over the top of the hill that the train is pulled over continues on its journey.

 

Now what if the power fails when the train is coming over the top but hasn't disengaged from the chain yet. They start to do an evac of the train from the back. All of a sudden more weight is on the front of the train pulling it over the hill. Could be very dangerous for someone who is in the middle of being evaced.

 

A brake up there would hold the train in place.

[jason10]

^

That did happen once. There is a video on youtube however, it was a Vekoma Sit-down if I remember correctly. Surely, logic tells you to evac from the front, brake or no brake!

[jjune4991]

here's that video jason10.

apparently a guy accidentally hit the button letting it go, with people still in it!

http://www.youtube.com/watch?v=rA5XmpL6VCk

[Crazy_Behemoth_Lady_Jess]

Lift chains can probably break because of the stress/tension that they're under. The B&M signature "pre drop" is used to relieve some of that tension in the chain. Just like how people can "break" from stress too!

 

I'm not exactly sure how often lift chains get replaced either.

 

But how come Behemoth doesn't have a pre drop? It's one of B&M's newer coasters.

 

As for that video, isin't CENTRIPETAL force enough to keep people in through the loops?

 

~ Jess "Behemoth is number 1" Chan

[jjune4991]

yes, but the drops and turns are where you want to watch out.

[sclisso]

The reason Behemoth doesn't have a pre drop is because after the lift, the train keeps going straight as opposed to the B&M inverts that typically cut back in a curve in the opposite direction thus, the pre-drop is needed to relieve stress on the chain.

[Carnage]

^ From what I understand that's not the reason the newer B&Ms lack the pre-drop. It's because the chain speeds up at the top of the hill reducing stress on the chain.

[sclisso]

Yeah, for the other coasters except Dive machines and Inverts and maybe stand-up. All B&M Inverted Coasters have pre-drops to reduce stress because of the extreme angle of the drops.They have curved drops or a curve before a drop, so to reduce the horizontal Stresses, before the train curves downward(the drop) there's a pre-drop. Now if an invert were to drop straight without any curve after the lift, I would say it wouldn't need a pre-drop unless its something B&M Inverts need for some reason.

[Carnage]

All B&M Inverted Coasters have pre-drops to reduce stress because of the extreme angle of the drops.They have curved drops or a curve before a drop so to reduce the stress from the horizontal Stresses as that heavy train curves downward there's a pre-drop.

 

Inverted drops tend to be much less steep then standard sit downs.

 

The curve and drop have more to do with the smaller clearance between cars then they do stress on the track.

[sclisso]

By extreme angle i didn't mean the drop itself, I meant the angle of the curve of the drop. I said the pre-drop had to do with easing stress not the drop itself.lol,I need to fix that last post to make it more clear.I murdered it,haha.But whatever, this is off topic, we're supposed to be talking about the brakes at the top, not the pre-drop and drop,lol.

[Crazy_Behemoth_Lady_Jess]

I think I know which brakes you mean. Most likely for emergency evacuation I'd say or something like that.

 

~Jess "Give me a brake" Chan

[snowboard83]

Well, on Alpengeist these predrop breaks are used frequently...unfortunately. They began being used around 1999 or so. They seem to be used to keep the forces in the cobra roll down on Alp. I remember the good old days sitting in the back seat of Alpengeist and getting unbelievable sensations going thru the cobra roll cuz of the G forces. Rarely is that "holding break" off anymore unfortunately, so Alpengeist has been MUCH tamer ever since, but still a great ride. If anyone remembers reading about Alpengeist breaking BOTH of someones legs with a preexisting condition "weak bones" you may understand one of the reasons they actually use this break on Alpengeist. It is possible, I will say, that it is used for evac purposes, but i tend not to think so. That break was on so hard for so much of this year, and it would ALMOST stop, and on empty trains it briefly would stop. I think it is maily used to "castrate" the ride. Maybe Alpengeist goes faster than designed, as has been the rumored case since it opened around the Williamsburg-Norfolk area. If you look at it, this holding break takes 10-15 feet or maybe even more off the total "freefall" drop when you watch the ride from the carousel area. It probably also reduces wear and tear and is probably a cost cutting method. Kinda like the way Alpengeist used to rip thru the 2nd half, and is now slowed much more by the mid course breaks.

[chrguy606]

I kinda remember that. I first rode alpengeist in may of 97, as my first big, multi inversion coaster, on my own accord, and it was mega awesome, and very intense. However, the next time I was able to ride it was jully of 06, and it wasn;t the same as i remembered it. It had been 9 nine years in between, so maybe my memory wasn;t all to sharp, but i remembered it being a lot more wild, especially in the last half.

[TPDave]

Yeah, for the other coasters except Dive machines and Inverts and maybe stand-up. All B&M Inverted Coasters have pre-drops to reduce stress because of the extreme angle of the drops.They have curved drops or a curve before a drop, so to reduce the horizontal Stresses, before the train curves downward(the drop) there's a pre-drop. Now if an invert were to drop straight without any curve after the lift, I would say it wouldn't need a pre-drop unless its something B&M Inverts need for some reason.

 

Erm, that doesn't stack up.

 

It doesn't matter what the train does after the pre drop, the track is straight where it leaves the train so there can't be a horizontal component of stress. In the picture below, you can see the front of the train is on the drop but the back is just leaving the pre drop, it's perfectly straight and not experiencing horizontal force.