Why does/did B&M use pre-drops?

Hey guys. I'm starting this topic to get some healthy discussion and possibly some answers regarding B&M's use of pre-drops. It seems that nobody has come up with a solid answer as to what they're for, and I think with as many knowledgeable people as there are on this site, an answer can be reached.

So what do you think? Why were pre-drops designed in most of B&M's rides?

GO.

So the train didn't tug the chain.

Because they were boss in the back.

Originally posted by RideWarriorNation

So the train didn't tug the chain.

But that raises the question why a new invert, most hypers, flyers, and Hydra DON'T have a pre-drop.

I know on Tatsu only the second and third cars actually have chain dogs. The end of the lift is placed so when those two cars get to the top, the weight of the cars pulls the rest of the train over. I would imagine that in earlier years there was a different design for the chain dogs or more cars were equipped with them, thus requiring the pre drop to reduce tension on the chain.

New train design = problem solved.

Originally posted by californiaroar

I know on Tatsu only the second and third cars actually have chain dogs. The end of the lift is placed so when those two cars get to the top, the weight of the cars pulls the rest of the train over. I would imagine that in earlier years there was a different design for the chain dogs or more cars were equipped with them, thus requiring the pre drop to reduce tension on the chain.

But chain dogs are essentially hinged hooks. It doesn't matter where they are because they should simply unhook when the train picks up more speed than the chain, or it reaches the end of the chain.


My hypothesis: Pre-drops were used so the first car could start the first drop with more speed due to the back cars that come off the lift pushing the front cars forward. It would give a less-varied experience of the first drop based on the row you sit in.

Originally posted by NoLimitzki




But chain dogs are essentially hinged hooks. It doesn't matter where they are because they should simply unhook when the train picks up more speed than the chain, or it reaches the end of the chain.


My hypothesis: Pre-drops were used so the first car could start the first drop with more speed due to the back cars that come off the lift pushing the front cars forward. It would give a less-varied experience of the first drop based on the row you sit in.

True, that could be why they did. From my own experience though, the chain dogs on Tatsu are not hinged. They are rigid and can't release the chain until they reach the end of it. If there were dogs on the last cars, they would push against the chain until those cars crested the lift, but since I don't work for B&M that's just my idea. I'm also not applying the dog design of Tatsu to all of their rides, it's just where I have my experience. I'm a certified operator for that ride, so I know it pretty well.

[gouldy]

Originally posted by NoLimitzki


My hypothesis: Pre-drops were used so the first car could start the first drop with more speed due to the back cars that come off the lift pushing the front cars forward. It would give a less-varied experience of the first drop based on the row you sit in.

I would think this statement is probably correct.


The idea that the cars would tug on the chain as the car speeds up over the top of the drop is ludicrous. The connection between the train and the chain is a simple mechanism which allows for the application of force in just one direction. As soon as the train begins to travel faster than the chain, the mechanism just rides over the top of the subsequent chain links.

Couldn't have said it better myself. I have the privilege of living near the New Texas Giant and that has the most noticeable sound (that I've heard) of the chain dogs sliding over the crest of the lift.

As seen at 0:18 and 3:26

That's also the anti-rollbacks, but yeah, same idea.
Every coaster does this, I really don't think B&M had some special system that couldn't disengage itself from the chain like every other ride does. The idea of getting a similar experience for the whole train is the most reasonable explanation I've heard so far on this topic.

On a side note, I was at Great Adventure this weekend and the whole way up the lift managed to completely forget that Nitro was one of their first rides without the pre-drop, which made for a pretty good surprise since we were in the back seat.

[gouldy]

The loud "clacking" sound you hear on the majority of coasters as they climb their lift hill is the Anti-rollback dogs constantly engaging and disengaging on the the Anti-rollback rack that runs the entire length of the lift hill. As the train crests the hill, I think the noise gets louder and faster. Obviously faster because the dogs are engaging and disengaging faster, louder for the same reason, but also I think that noise is a combination of both Anti-rollback and Chain catch dogs at that point.

Are the anti roll backs those things on the side of the chain life that look a little like this: /l/l/l/l/l/l

[GavG]

Yeah C Dude that is the anti-rollback rack.

I always thought the predrop was there to help with evacuating the train in the case of a last minute E-stop, but the train being at a constant speed sounds like the most obvious correct answer.

Yeah I'm aware that the anti-rollbacks do the same thing, but as it speeds over the lift, the chain dogs have a distinct "ping" that the rollbacks don't have.