Datalogging the rides? "G forces" question.

[brdavis]

I've lurked the INTERCOT boards for a year or so now, draining off amazingly useful information, so first thank you. Now I've registered and de-lurked to ask a specific question: has anyone ever measured the actual accelerations involved in the various Disney attractions? I know Disney has - what about guests? Students?

My family & I just finished a 5-day stay at WDW (the new DVC suites at AMKL are really wonderful - quite big). Another passion of mine is LEGO robotics, and I've got a PhD as a physicist, so... I datalogged the accelerations on a bunch of rides. I figured I couldn't be the first guest to do this, but I've found precious little else on the subject on-line (a lot of speculation or quotes from literature, but not first-hand measurement).

So has anyone (else) done this? What were the results? I have profiles for Mission Space (2.1 G's max, during 1st stage & lunar flyby), Everest (max G's about 2.4 on four occasions, the first as you drop down the first big hill after the reversal), All three WDW MK Mountains (highest G's are at the bottom of Splash, actually, at 2.5, and the lowest total G's are between the 2nd & 3rd lifts in Big Thunder around 0.2 G's), Triceratops Spin (with my daughters in control) and Primeval Whirl (2.25 G's in the 2nd drop). Does anyone have any more information on this? Ideas? Questions?

Thanks again for a lot of great help you folks have provided over the years. I'm not sure if I have a lot to provide back, but if anyone wants acceleration data I'll try to help ;) .

PS- Regarding motion sickness: I'm the guy who does things like thrusts his head forward off the seat in MS, and then twists it from side to side. Yes, I realize I'm nowhere near "normal" in this, but my kids seem to have inherited the ability as well, so they appreciate it :) .

--
Brian Davis

[magicman]

Brian,

(1) Welcome to INTERCOT: De-Lurked Version
:welcome:

(2) I don't know this, but from the information you provided in your OP, I believe YOU are going to be the INTERCOT G-FORCE & ACCELERATION GURU.

(3) I was wondering if you have any data comparisons on Space Mt & Rock n Roll Rollercoaster???

Again, welcome.

[#1donaldfan]

I just wanted to say that the information you provdied was interesting...I have wondered from time to time what kinda force was behind particular rides....now I know......thanks again, and welcome to intercot...offically speaking.....:thumbsup:

[Figgyluv03]

Welcome!!!!

I think you are the first! When I was in high school, we did something similar at Six Flags. They had a day where all the science classes could come and do experiments and stuff, and it was a lot of fun. Never thought about doing it at Disney.

[laprana]

:jaw: WOW! What interesting info! It all kind of went wooshing past my head when I read it, but still cool! Don't have much to add, except

:welcome: to Intercot! :pixie:

[caryrae]

I wondered about RnR to and also ToT. I am guessing with ToT the highest would be when you are at the bottom of the drop heading back up.

[brdavis]

Thanks for the welcome all! As Figgyluv3 mentioned, I know that student groups sometimes do this in other parks, but the actual data seems hard to find. I'd really love to do RnR and ToT (as well as the green version of MS), but we "only" did MK, AK, & EPCOT this time around. My original intent was to absolutely get both MS and EE, and I got those (actually a few times each, once in the front seat on EE), but once you start, well... it's a lot of fun. I'm not sure when our next trip is, but the datalogger will certainly go for some rides again. If you want more details, I blogged about it in a (LEGO) blog entry:

http://thenxtstep.blogspot.com/2007/10/nxt-meets-mouse-datalogging-disney.html

That's also got to be one of the better on-the-ride pictures I've ever had snapped (the other three folks are family). And I've actually tossed the screenshots of all the graphics up in a Brickshelf account (free image hosting for folks addicted to LEGO... we usually stay at Saratoga, and with the LEGO store just a 5 minute walk away the damage can be... extensive). If you want images, feel free (and if you want hard fast numbers, I'll gladly send them - I just wasn't sure if folks were very interested) :) .

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=282834

One of the interesting things in the graphs is that you can see the "character" of the ride (MS is very very smooooth... SM is really as rough as it seems, from the data, and Primeval Whirl is very distinct from the other rides), as well as the accelerations in all three directions: up/down in your seat, forward/back in your seat, and laterally (side to side) as you go around the turns. I'm going to try to really study the EE data by correlating it with the YouTube ride-alongs of the attraction (I had no idea those were there. Huh).

--
Brian Davis

[tundramom]

How awesome!! I've wondered specifically about MS. The one and only time I rode it I would have sworn something in the 4G's- it was actually painful/crushing in my chest. I don't know what a datalogger/NXT even is (not a techno geek- no offense) but I'm glad you do. I think you just earned yourself a specialty niche here. :welcome::coaster::geek2:
P.S. Off topic but I bet you know the answer to this too: While watching the shuttle take off the other day they had an altimeter/speedometer thingy on the screen. At one point the shuttle was going over 6000 mph, how many G's is that? What's the max a human can take?

[brdavis]

The one and only time I rode (MS) I would have sworn something in the 4G's- it was actually painful/crushing in my chest.
I wish I would have had this technology before the ride was "tamed" - I'm sure there would have been some fascinating opportunities during test runs. Currently, the "1st stage" sequence climbs smoothly to 2.1 G's, holding steady for about 12 seconds before ramping down. That's it. Honest. When the 2nd stage sequence kicks in it climbs back to 1.5 G's for about 18 seconds before climbing again to 2.1 G's before dropping down for "hypersleep". During the Mars entry sequence it only reaches 1.8 G's for a brief instant. That actually means even on the orange ticket you actually spend only about 90 seconds spinning at any reasonable rate during the 220 second ride. When did you ride it (what year)?


I don't know what a datalogger/NXT even is (not a techno geek- no offense)
None taken. The NXT is just a small programmable computer made by LEGO, and a datalogger is just a self-contained device that can collect a bunch of information and store it for later.


At one point the shuttle was going over 6000 mph, how many G's is that? What's the max a human can take?
If the shuttle kept going at a constant 6000 mph, it wouldn't be accelerating at all... the same as if you were going in a straight line at 60 mph in your car. An acceleration is a change in the velocity: like when you are going down towards the ground at 60 mph, and the track slows that downward velocity and gives you an upward velocity. That's an acceleration - a change in velocity. As to the top speed a human can handle isn't limited (right now, you're traveling about 1000 mph as the Earth rotates, carrying you with it). As for acceleration, humans can tolerate sustained accelerations of 9-12 G's under certain conditions, but most of us would black out at lower limits. Curiously, the space shuttle doesn't have a huge acceleration - only about 3.0 or 3.5 G's during liftoff, if memory serves. Curiously enough, you can reach those acceleration levels fairly easily on a playground merry-go-round (I used to teach a class in "physics of the playground" for 14-year-olds), so the acceleration levels in MS aren't all that unreachable... but the combinations of motions, and visuals, really generates an impression that is extraordinary. There have been times just before close that I've just exited and run right back around, riding 5 or 6 times in succession.

--
Brian Davis

[Disdad13]

Interesting stuff, Brian! Thanks for all the cool info. And, Welcome to Intercot!:welcome:

[garymacd]

PS- Regarding motion sickness: I'm the guy who does things like thrusts his head forward off the seat in MS, and then twists it from side to side. Yes, I realize I'm nowhere near "normal" in this, but my kids seem to have inherited the ability as well, so they appreciate it :) .

--
Brian Davis

I thought I was the only one that did that! You know that ride where you get spun around and then it tips up and the floor drops out from under you? I love that ride.

[Mufasa]

has anyone ever measured the actual accelerations involved in the various Disney attractions? I know Disney has - what about guests? Students?

To answer the OP's question- students in grades 3-12 that participate in Disney's Youth Education Series (Y.E.S.) programs at WDW can participate in a program about the properties of motion where they use accelerometers to measure the g-forces on several attractions around the Magic Kingdom.

In October 2002, Dr. Douglas H. Smith and David F. Meaney of the University of Pennsylvania co-authored an article in the Journal of Neurotrauma titled "G-Forces, Roller Coasters, And Brain Trauma: On The Wrong Track?" where they took g-force measurements from Rock 'n Roller Coaster along with other coasters at parks around the country and did not find any correlation between the g-forces encountered on the rides they studied with and the known thresholds for various head injuries.

Generally, it's believed that the average person would experience g-LOC (g induced loss of consciousness or blacking out) somewhere between 4 and 6 g's sustained.

With that understanding there are some established industry limits (you can research the subject for more details under the ASTM F-24 standards) that describe maximum g-forces and time duration although it's also important to keep in mind that we have to look at g-forces as they act on the human body along different orientations (X, Y, Z or in simpler terms, head to toe along the spine, front to back and lateral forces) as there are different levels that humans can comfortably tolerate along each axis that designers take into consideration.

As far as human limits to g-forces, a lot of our understanding on the subject is owed to the research of Colonel John Stapp of the US Air Force. When he started his research back in 1947, the belief at the time was that exposure to 18 g's would be fatal but his own personal testing particularly in regards to studying the effects of deceleration proved otherwise (Colonel Stapp survived a sustained 46.2 g in one experiment).

There are other examples of extreme g-forces at work- in 1977, a Formula One racer David Purley survived an estimated 179.8 g crash when he hit a wall and his car slowed from 108 mph to a dead stop in a distance of 26 inches.

This past F1 season also saw a tremendous crash at the Canadian Grand Prix when Robert Kubica of BMW Sauber clipped a barrier at 186.49 mph after losing control on the track and was subjected to an average deceleration of 28 g. The onboard data recorder from his car revealed a peak of 75 g during the crash.

To really put g-forces in perspective though, a study published about a decade or more ago in the medical journal Spine looked at everyday g-forces on the human body. You'll experience as much as 10.4 g when you go to sit down in a chair. Hopping of a step is about 8.1 g. A cough can generate as much as 3.5 g while a sneeze averages 2.9 g's. So analyzing or looking at g-force numbers alone doesn't tell the whole story.

[TheRustyScupper]

. . . So analyzing or looking at g-force numbers alone doesn't tell the whole story . . .

1) As usual, MUFASA is right on the money.
2) I used to design coasters and rides in a younger life.
3) We could make you sick, queasy or light headed at very low G's.
4) It is a simple matter to trick the body and its senses.
5) That is the TRUE secret in design.
6) Make it seem more intense than it really is !
7) Anyone can point a coaster 89º down and get speed.
8) But, make it seem fast with less than a 48º angle.

NOTE: Time and duration play a huge factor in G's body reaction. Given the proper amount of applied time, you would pass out in a 2-g ride. We have parts of 7-out-of-10 of ACE's top coasters, and they still amaze me.

[magicofdisney]

Well, this thread is certainly an interesting read. I still can't get over the fact that Mission Space doesn't offer the highest G-forces at Disney. Fool the senses indeed!

[tundramom]

[ When did you ride it (what year)?

Brian Davis[/QUOTE]

We rode it within the first year of it's opening. I've refused ever since, DH still loves it but he says it's not as intense as it was.
Great thread BTW:thumbsup:

[disneydeb]

:DWelcome to Intercot!:D

[brdavis]

Re-checking a very old thread...

To answer the OP's question- students in grades 3-12 that participate in Disney's Youth Education Series (Y.E.S.) programs at WDW can participate in a program about the properties of motion where they use accelerometers to measure the g-forces on several attractions around the Magic Kingdom.
Do you know if this information is ever released or shown outside of WDW? I'd love something to compare to.

So analyzing or looking at g-force numbers alone doesn't tell the whole story.
Absolutely - which is why I put up the entire graphs, as they really tell much more about the rides than a simple listing of peak accelerations.

Now, the reason I bother resurrecting the thread... I'll be down to WDW a the end of Oct, and wondered if there was anything specific folks were curious about (yes, RnR and ToT are on the list already). And no, I don't think I can carry it down Summit Plummet (though the thought has occurred...).

--
Brian Davis

[handmaidenofprincesses]

:welcome: to intercot, Brian!

Between you and Mufasa, this post is beginning to feel like a science class! (an interesting one though.. I'm just not sure I follow it very well from start to finish)

[kdsjjb]

Thanks Brian and Mufasa, that really is some amazing info!

Brian I really enjoyed looking at the graphs, but I have to admit that I was a little scared of the "Morning Ritual in the Bathroom" page until I actually looked at the info!

I look forward to reading more posts from you.

[TheWizofDiz]

Thanks Brian for the info...I found it all quite facinating and love all the rides you recorded.

May the "G Force" be with you....sorry, I just had to say it!

[Imagineer1981]

:welcome:

Welcome to the boards...OFFICIALLY. And thanks for all the hard work. As stated before...may the "G" force be with you :yoda:

[MickeysEars]

:fworks::welcome:

great info, my husband will find it very interesting...thanks

[DVC_dad]

Speaking of G force on MIssion Space...

My wife rode this ride when there was only 1 line. You had either the full expereince or you didn't ride.

That in and of itself isn't a big deal, except that she was 3 months pregnant at the time.

That would be Samson, he is our 5th of 7 children. He is fine and healtly and honestly he is one of our best behaved and smartest children. Maybe we should have centrifuged the others down while in untero eh?

It wasn't until AFTER this experience that we heard of that first child that died shortly after riding. We figured risking it again was borrowing trouble so she hasn't ridden it again pregnant.

:secret:

That is some really interesting scientific information about rides. Great post if I may say so.

[brdavis]

Well, a follow-up. Several people, after seeing the logs of rides I made last year, asked me about RR and ToT, which I wasn't able to get that trip.

Well, I just got back from another trip :)

This time I had a sensor with a higher upper limit, so not only did I do some rides I'd not done previously, but I re-did some rides that I suspected might have been more than the previous accelerometer could handle. For those of you who want the pretty graphs, I tossed them onto Brickshelf again (all the images prefixed with "DLD" are from this trip):

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=282834

The upshot?

RR hits 4+ G's going into the first loop (in the front seat... the very front seat), with the launch pushing you forward at 1.25 G's - just 3.2 seconds after launch, you are 160' down the track moving at around 53 mph (no wonder it takes your breath away!)... or at least that's what the data I took implies (not too far off what WDW claims in various TV shows I've seen). Unlike many Disney 'coaster, it almost never drops towards "0 G's" - there's almost always a strong force pushing you into your seat, very different from BTMRR or EE.

ToT was wild... and I have to agree with Mustafa, that ride is awesomely engineered. At no time did the acceleration top 1.75 G's, rather mild even by Disney standards, but of course it doesn't feel that way. There are also times the ride accelerates you downward not in a free-fall but slightly slower than a free-fall (I hadn't noticed this before), and yes it clearly accelerates you down "faster than gravity" at times (holding the datalogger firmly to the seat with one hand while flying up out of the seat was a special experience :) ).

AK's EE itself I didn't do justice to last time: with the new accelerometer, I could see what the G-forces really peak out at. Previously, I'd reported it tops out at 2.5 G's "or more"... well, it's more. The first backwards run hits 2.9 G's (we were nearly in the front seat, other seats it's probably higher), and the "photo-drop" after the shadow puppet animation tops out at 3.8 G's, much higher than I had previously figured it (and again, this is likely slightly higher in the middle of the train, so treat these as lower limits).

EPCOT's TT was another big surprise: during the outside loop, just as you curve around the main building, you are pulling 2 G's, smashing you into your seat. I hadn't expected that (guess I'm distracted by the feeling of speed).

At MK, I measured Goofy's Barnstormer ("it's OK, honey, it only reaches 1.7 G's at the bottom of the hill"), where the last "flat" turn throws you into the person on your left at around 0.4 G's. SM I logged again, as well as BTMRR (5 times, actually, to compare runs), and the Spinning Teacups. These are always a favorite of mine: I've been known to develop and pop blisters in the course of a single ride, so you can picture how hard I'm trying to crank those teacups around. It turns out that within 12 seconds of starting, you end up pulling almost 1.6 G's (that's about 1.2 G's straight out) if you ride in a teacup with me... and I keep it spinning like that, at about 40 RPM, for nearly the entire ride. My DS loves going on the Teacups with me - with just the two of us, he ends up plastered to the seat and can't reach the wheel. The other adult in the ride with us this time was... somewhat less impressed :).

More technical (LEGO) details in a blog entry here:

http://thenxtstep.blogspot.com/2008/11/datalogging-disney-redux.html

--
Brian "want to go on the Teacups with me?" Davis