How Much Does Wind Affect A Coaster?

[metalhead7]

The particular coaster in question is Desparado. On a travel channel documentary, owners of the casino made the claim that with the right wind speed, Desparado can reach speeds of up to 93mph (13mph faster that rcdb lists as its top speed). I know train weight, weather, wind and many other factors can change one's ride experience, but can speed be changed by that much? or is this show full of crap?

 

[Hixee]

The exact extent to which wind effects a specific coaster is pretty impossible to work out. Even the best computers in the world would still only be making approximations. However I'll just say a quick word on air resistance generally.

Air resistance (or the drag force from air resistance) is proportional to the relative velocity between the wind and object squared. That is to say: F=kv^2, where k is a constant dependent on all the factors of the wind and object (size, shape, density of air etc etc). This is the fundamental equation for drag, however often k is represented by a few more terms. Anyway, it's the v^2 that is the important factor.

This relationship means that if the windspeed doubles, the drag force increases by a factor of 4 (conversely if the windspeed halves then the drag force reduces by a factor of 4). As we're interested in the relative speed between the wind and air (100mph car in stationary wind is the same as stationary car in 100mph wind as far as the drag is concerned) it doesn't seem unlikely that a healthy tail wind would give the train that extra reduction in relative wind speed to cause the speed to increase by 13mph. Whether these figures for Desperado are actually accurate I wouldn't know, but it doesn't seem unrealistic to me - and we did a lot of drag calculations this year.

Rushed reply, but hope it makes a bit of sense.

 

[Luxornv]

Even accounting for wind speed, drag, or negative drag, I still don't think it's possible for the coaster to go that fast. Sure, if there's a tail wind, it makes sense that it will push the train. However, if there are winds high enough to push it an extra 13 mph over the advertised speed, then the ride may have to shut down due to severe weather. If the wind can affect it that much, then it will likely have the reverse affect when the train eventually turns into the wind and it may valley in the middle of the course. There are a few equations which can approximate the speed of a coaster. I just don't have them memorized off the top of my head anymore. I've tested it on a few coasters, and the advertised speeds are close to what these equations predict. If you've taken high school physics, then you know the equations I mean, the ones for position, velocity, and acceleration.

 

[Hixee]

^This is a factor I hadn't considered actually.

It's probably quite feasible that a tailwind would reduce the drag enough to cause a 13mph increase in speed, but as soon as the train was running sideways or into the wind you'd be in a bit of trouble.

With regards to the equations that predict the speed of the coaster you're going to need a slightly more complex model than high school physics. The basic F=kv^2 relationship might be covered, but they rarely take in account more complex (and realistic) air resistance, which is kinda what we're looking at. Unless high school physics now covers 2nd-year fluid dynamics... Assuming constant acceleration (freefall in a vacuum, so pretty much the perfect situation) the train should reach about 82mph, so saying that with a decent tailwind it could reach 93mph is verging close to **** for me.

So to summarize for metalhead7: Yes, a tailwind might 'add' an extra 13mph to the speed, given a range of other factors too (although I'm thinking that 93mph might be a bit too high), but the coaster probably wouldn't be operating in conditions like that. The headwind on the return trip would likely make the coaster stall. So make of that what you wish - I'd call it out to be dubious. Not wrong, but unlikely - like I said, we don't have access to the actual figures so...

 

[furie]

I found that with guts churning, a coaster can be most uncomfortable, but if you let rip down the lift hill, the release of pressure on your bowels and the knowledge those behind have just had a massive face full of guff can really improve the entire ride experience to a joy beyond compare.

 

[marc]

^I just knew it would be you or Ian that replied like that

 

[Hyde]

It depends.

Some parks are built in windy areas, others are not.

Cedar Point has experienced it own share of bad wind effect: Dragster has famously stalled on the top hat three times because the wind was able to slow down the train to just the right speed that it reached equilibrium. Raptor too stalled out on its turn headed in to the MCBR because of an extremely high head wind.

These are obviously negative effects of wind, but in turn it would be possible for wind to act as a tailwind, helping push the train faster.

 

[Mike]

Not sure about your question, but I REALLY wouldn't want to ride Desperado when it's windy...
Apart from having sand smacked in your face if it was windy, the ride can barely make it over the first hill anyway; and that's when it's not windy!