Diamondback - Rattling Sound On First Drop?

Went to Kings Island yesterday and got quite a few awesome rides in on Diamondback. Producing some serious floating air, last night. Anywho, during our rides, and while standing under the first drop, I noticed the train always makes a really loud rattling sound just as the train begins to enter the pullout of the first drop (maybe it happens at the support where the pullout takes place?). Any idea why it makes this noise? It almost sounds as if it were a wooden coaster hitting the anti-roll backs as it crests the top of a bunny hill. Which is odd, since it’s going down hill.

It caused some interesting debates yesterday, and I’d like to know if anyone actually knows what causes this sound.

Here is a video I found of it on Youtube were it makes the noise (you can hear it really good at 0:34).

http://www.youtube.com/watch?v=6KnRKwHW7bA

It's probably just a loose body panel or something.

Yeah, probably just some loose track and some loose bolts too, but nothing to be alarmed about...

Nothing to see here... move along.

I concluded early on (as it has been making this sound since last Spring) that it is the chain clutches. Diamondback generates real honest-to-goodness airtime and even as it lifts you out of your seat, it also lifts the chain clutches and anti-rollback dogs which, as you know, are pivotally mounted under the floor of the train, and are not spring loaded. At the top of the drop you can hear the clutches hit the floor of the train. As the train pulls out of the drop, gravity returns and pulls the chain clutches down against their lower stops. So you get a rattle at the top, then another rattle at the bottom.

I'm about 95% certain that's what it is.

--Dave Althoff, Jr.

95%? I would have thought you were 95.7% sure ;)

That's the most logical explanation I've heard yet. Thanks, RideMan! :)

I concluded that sound is the wheels leaving the track on about a 40 ft segment of that first drop and then chattering when they make contact again at a higher speed.

Whatever it is, There is some Harmonic Vibration that causes the paint to chip off the main supports. They go out there about twice a month and paint it with a roller and a long extention.

^That sounds logical...until you remember that B&M's wheel assemblies are spring-loaded and that wheels never leave the track.

You might be right but there is definitely a second or so where there is no noise.

First HWN I've seen you miss dude??

Wait.. Diamondback made a rattling sound?

I would call that thematic :)

My reply would have been the second post in the topic, about how it's a thematic special effect that they didn't get working until this year, and how the ride would sport a new high-tech daytime hologram of a snakes mouth at the bottom of the hill that the train runs through, but I didn't go though with posting it... because it was all baloney. :)

BTMR has rattling thematic sounds too, no? Pretty cool effect.

'Moosh, I beg to differ with you.

I rode Diamondback in Rows #13 and #3 (among others) which are front rows of cars. It's the oddest thing...when Diamondback goes all floaty, the road wheel, which you can see from the seat, goes all jiggly. It actually comes loose from the rail, coming up just enough that the wheel can wobble a bit. I don't think that's making the noise that we're hearing on the drop; in fact the wobble isn't in time with the rattling described here.

When you think about it, though, it makes perfect sense. The guide wheels are indeed spring loaded. I don't think it's a literal spring; I think it's a little plastic bumper that slips in between the guide wheels (GravityKraft uses something similar, actually, on their guide wheel sets). But there does not seem to be any such spring loading between the road- and up-stop wheels. I think the up-stops are mounted on a similar pivot to the guide wheels, but instead of a spring, it seems to be the weight of the car that is used to squeeze the up-stop tight against the rail. So when the train goes weightless and stats to lift from the rail, the tension that holds the up-stops against the bottom of the rail goes away, which allows them to pull back just enough to allow the road wheel to go loose. It didn't seem to get loose enough for the edge of the wheel to get clear of the rail.

In short, I am not so sure that B&M's wheel sets are designed around actual honest-to-goodness airtime! Lucky for us, Diamondback delivers, in spite of what B&M might have planned for.

--Dave Althoff, Jr.

Goliath at SFOG also rattles, but seems pretty much throughout the whole ride. Seems like it has since it opened.

Last time I was on Hulk it rattled though the course. But that actually sounded (and felt) more like a bad wheel bogey.

That ride is a mess when it comes to its wheels and springs.

I have never met a Beemer that didn't have a goofy rattle/shake at some point in it's course.

Hulk is like that the whole way through though. I want to believe that it's a maintenance issue, but the same park seems to take care of the Dragons pretty well.