Is Drop Zone unsafe?

---

Jim Fisher said:
Add almost any recent Intamin to the coasters with magnetic brakes, plus some of the Premiers. This is juist what comes to mind right now.

---

I was specifically wondering about wooden coasters with magnetic fins, though. There's only a few of them so far. Although I wouldn't be surprised to learn the new Intamin woodies use 'em.

------------------
--Greg, aka Oat Boy
My page
"I can't believe I just left a nuclear weapon in an elevator." -- Farscape

Actually, I believe the fin does indeed make contact with the caliper, which creates with wiz-ooshing noise heard on the ride.

---

Yeah, I was wondering what made that noise. It's a cool sound actually :-)

I knew the thing would have delayed braking, but MY GOD I wasn't expecting it to slow down that low to the ground. That is a bit freaky. I swear it looks like it's gonna crash.

Corey

---

ApolloAndy said:

Also, I remember seeing on the discovery channel segment about Acrophobia that the alloy in the brake fins changes as your travel up and down the tower. Is that also true of the PKD version or did they just use the different length fins to do the same thing?

AA, I really believe I read somewhere that the alloy composition varies as the fins get closer to the ground. I don't even remember the metals involved, LOL, but I'm pretty sure I saw that...

Assuming that's the case, it would make sense that the PKD version just employs the same principle, increasing the proprotion of the *effective* (read: magnetic) material at a faster rate than in the PKI version...
------------------
Acronymphomania (n): the socially unacceptable love of heights, and acronyms
Thanks for the memories #23...there is NO "next Jordan"

---

First of all, on magnetic braking theory, John Michael Darling has it pretty much exactly right. And as rollergator mentioned, the alloy does change from fin to fin on those drop towers. I remember reading the manual for the Moser drop tower and seeing the notation in there that particular fins have to be installed in particular places. Apparently in testing they started with a fin and magnet combination that took the descending car to a sudden stop and made it really hard to bring the car all the way to the ground!

Here's the thing...with friction brakes, the braking force generates tons of heat. Ever hear of "brake fade" in your car? As the brakes get hot, they become less effective. If the brakes are hydraulic, you have to worry about thermally isolating the cylinder from the brake pad, or you run the risk of boiling the fluid, making the brakes fail. Plus, you're talking about a mechanical system, with lots of moving parts to break down.

With magnetic brakes, they don't appear to do much, but the mechanical action is happening on the electrical level. You don't see any action, but it's really busy!

Over on Guide to the Point, I proposed a couple of ways to recover braking energy from Dragster to re-use for the launch. To recap one of my arguments...to try and capture electrical energy from the magnetic brakes would be simple enough; a current is induced in the brake fin, and that current could be dumped into the power grid. But there MUST be an enormous load there. Usually, those fins are 'wired' as a short-circuit to maximize the load. If the load goes away, so does the braking force, so if you try to capture the power and something goes wrong, you're running without brakes!

So to the best of my knowledge, nobody is trying to use magnetic brakes as regenerative power supplies, for this very reason.

--Dave Althoff, Jr.

The first time I saw Drop Zone, I saw the riders get on, I think they have different colors on each area of the gondola. This green thing locks into the gondola and slowly pulls it up the tower....... then at the top drops the freakin gondola! I mean the ride is as tall as the eiffel tower!

---

SFNE Freak said:
...I believe the fin does indeed make contact with the caliper, which creates with wiz-ooshing noise heard on the ride.

---

That would explain two things:

1.) The "wiz-ooshing" noise

2.) The slight wear marks found on the brake fins themselves.

---

Rideman said:

Usually, those fins are 'wired' as a short-circuit to maximize the load. If the load goes away, so does the braking force, so if you try to capture the power and something goes wrong, you're running without brakes!

---

You're right, Mr. Rideman. I never stopped to think about that before... That would be a good reason not to mess with trying to harness that current.

------------------
- John

The sound you hear is not as a result of any contact with the fins. The noise is created by the magnets - when it slows, the kinetic energy (motion) is converted to heat, electricity (as Dave was delving into above) and... sound energy.

I think the reason it looks like they've been rubbed on is a result of a grease that the gondolas and rails are coated in. It splashes off during the course of the day, and weather would make it smudge in, looking as though it's scuffed.

If you want to ride it fearlessly - take our baby for a spin. It's taken me a good number of years, but I can finally ride this thing fearlessly (and I guess any other in the world by definition). You've all left your lapbars a few clicks out on coasters before, well I don't think I need to explain (or will, in case Captain Safety Jr. comes along to preach about my wrongs)...

------------------
So what if the best coaster in Australia is a second hand Arrow?

-www.totalthrills.com-
Australia's Premier Source for Thrills!

I know what you mean Coreo81. The gondola stoped RIGHT at the bottom and created this HUGE wave of air that knocked everyone down.

Magnetic brakes actually produce just as much heat as mechanical brakes. Conservation of energy dictates that the energy has to go somewhere. Of course there is no wear on magnetic brakes.

If an eddy current brake is run constantly it is possible to get brake fade by heating the magnets to the point that their magnetic field is reduced. I don't know of any applications for an amusement ride though where the brakes are operated constantly.

If there is any physcal contact on a magnetic brake it's time to call the mechanic and shut down the ride.
*** This post was edited by Jim Fisher 4/19/2003 9:34:39 AM ***

I don't think those roto-drop rides like drop zone are safe. I'll just stay off 'em. Better off riding rough Arrows than dead on a tower.

Good point (duh...what was I thinking?). Big difference is that (at least according to Magnetar) with the magnetic brakes, the heat is generated in the fin, which can dissipate that heat rapidly. In friction brakes, the heat is in the fins and in the calipers, and while the fins can deal with the heat, the calipers are more massive and more apt to trap heat...

--Dave Althoff, Jr.

Wow, that magnetar site is really interesting. Thanks for posting it.

Thw "wiz-oosing" noise is no different then the sound an electric motor makes upon start up. There may be some slight misalignment of fins which can cause where but magnetic brakes should have no touching parts.

Now if we couls get the things to work on cars or trains we woudl be talking.

Trains already use a similar system in dynamic braking, their motors turn into generators which for all intense and purposes turn the energy into a giant toaster in the form of a grid much like a toaster, the energy is returned to the atmosphere as heat. Of course the sytem is only a suplement to the regular friction barakes but you get the idea. To go one step further dyanamic braking on electric locomotives is returned to the overhead wires as electric power that CAN be reused. Now that is pretty interesting.

------------------
Ah what the hell.....Magnum What?

S:ROS blew me away

*** This post was edited by MagnumForce 4/20/2003 8:12:32 AM ***

Does anyone have a picture of the "track" that the gondolas on drop towers run on? I have never been able to spot anything on Drop Zone at PKI even remotely resembling a track, other than a few hundred bolts at every connection point along the tower, and the cables, unless they have some job in holding the gondolas in place. *** Edited 6/23/2004 3:07:39 PM UTC by CoasterKrazy***

I worked at Drop Zone last year I was a part of the first crew that opened it up. Ive rode the ride plenty of times, it is a very safe ride. And It does not rotate either.

Also it seats 56 people, 14 in each row, not 50. :-p

---

CoasterKrazy said:
Does anyone have a picture of the "track" that the gondolas on drop towers run on? I have never been able to spot anything on Drop Zone at PKI even remotely resembling a track, other than a few hundred bolts at every connection point along the tower, and the cables, unless they have some job in holding the gondolas in place.

---

Some of my pics of PKD's Drop Zone (yet to be posted on the site even :) ) - here and here

You can see the "track" in those pics.

Also a video of PKI's Drop Zone showing a full ride cycle and all of the ideas, theories and explanations here in play.

Hope these help a bit :)

*** Edited 6/23/2004 4:52:37 PM UTC by Lord Gonchar***

In my understanding, another huge contributor to PKD's ride feeling scarier is the spoke design. Apparently wind resistance is drastically reduced so the ring falls quite a bit faster.

On the rotating models (Acro, PKI) is there anything preventing the ring from rotating while it falls?

The rotation is powered by an electric motor I'm assuming. Prior to dropping the gondola, these connections would be broken, and I'd like to think that this action would also lock the rotation gears.

These are the rails on a Giant Drop. I can't picture it being too much different from the Gyro system, maybe just not quite as big. I've never actually seen the the wheel system as its housing system is tightly enclosed, but given the I-beam design of the track, I've always assumed it's a fixed two wheel system where there's a wheel on each side of the I-beam, presumably bevelled for a tight lateral fit. Given the amount of lubrication they use, I don't think there'd be any surprises if it were a steel wheel.