News New Gondola Transportation - Disney Skyliner -

[Missing20K]

You have literally no idea what you're talking about. The friction of the cable rolling through its various touchpoints would be far hotter than anything any ambient temperature is going to throw at it, regardless of where the system is. Friction don't care if its in Florida or Colorado. The hottest ambient temperature is going to be is what, 110? BFD.

delta_T=(7800*mu*Wab*v)/(J*(k1+k2))
delta_T = rise in temperature
mu = coefficient of friction
Wab = surface energy of adhesion
v = sliding speed
J = mechanical equivalent of heat
k1, k2 = heat conductivity of the two materials

In other words: If the cable can handle it in any other location, it doesn't matter that this is in Florida.

 

[Missing20K]

Everyone discussing AC and alligators.

@Obobru "Hold my beer"

 

[GeneralKnowledge]

You have literally no idea what you're talking about. The friction of the cable rolling through its various touchpoints would be far hotter than anything any ambient temperature is going to throw at it, regardless of where the system is. Friction don't care if its in Florida or Colorado. The hottest ambient temperature is going to be is what, 110? BFD.

delta_T=(7800*mu*Wab*v)/(J*(k1+k2))
delta_T = rise in temperature
mu = coefficient of friction
Wab = surface energy of adhesion
v = sliding speed
J = mechanical equivalent of heat
k1, k2 = heat conductivity of the two materials

In other words: If the cable can handle it in any other location, it doesn't matter that this is in Florida.

I’m not seriously challenging you but more just playing devils advocate....wouldn’t the sliding friction in a system like this be relatively minimal? The cable interfaces with all of its touch points in a rolling manner so I would think that the sliding speed from your equation would approach 0 in an idealized scenario. I wouldn’t expect the cable to heat up much due to friction.

That said I am 100% certain the hundreds of licensed PE’s involved in the development of this project and all of the components involved have covered this infinitely more thoroughly than @Obobru is giving them credit for.

 

[flynnibus]

You have literally no idea what you're talking about. The friction of the cable rolling through its various touchpoints would be far hotter than anything any ambient temperature is going to throw at it, regardless of where the system is. Friction don't care if its in Florida or Colorado. The hottest ambient temperature is going to be is what, 110? BFD.

delta_T=(7800*mu*Wab*v)/(J*(k1+k2))
delta_T = rise in temperature
mu = coefficient of friction
Wab = surface energy of adhesion
v = sliding speed
J = mechanical equivalent of heat
k1, k2 = heat conductivity of the two materials

In other words: If the cable can handle it in any other location, it doesn't matter that this is in Florida.

Ambient temp isn’t the concern... it’s sitting under that heat lamp known as the sun... which can raise surface temps significantly higher. A galvanized roof can hit 160deg just sitting in the FL sun. (http://www.fsec.ucf.edu/en/publications/html/fsec-cr-964-97/). Car guys measure even more on paint (https://meguiarsonline.com/forums/s...-in-the-sun-How-HOT-does-your-car-s-paint-get)

Two... you probably should not be throwing stones about knowing anything when you quote an equation that would result in 0 - because you googled friction and copied a formula about temperature from kinetic friction.... for a system that operates with static friction. Aka, the rope doesn’t slide through the system - the rollers and bullwheel maintain static friction to pull the rope and the sheaves roll with the static contact of the rope.

That said... I’m still not concerned because there would be numerous levels where such operating parameters would have already been considered by the peeps that wouldn’t just rely on napkin math.

 

[flynnibus]

I’m not seriously challenging you but more just playing devils advocate....wouldn’t the sliding friction in a system like this be relatively minimal?

Yes - he was accredited by google.com

 

[Missing20K]

Ambient temp isn’t the concern... it’s sitting under that heat lamp known as the sun... which can raise surface temps significantly higher. A galvanized roof can hit 160deg just sitting in the FL sun. (http://www.fsec.ucf.edu/en/publications/html/fsec-cr-964-97/). Car guys measure even more on paint (https://meguiarsonline.com/forums/s...-in-the-sun-How-HOT-does-your-car-s-paint-get)

Two... you probably should not be throwing stones about knowing anything when you quote an equation that would result in 0 - because you googled friction and copied a formula about temperature from kinetic friction.... for a system that operates with static friction. Aka, the rope doesn’t slide through the system - the rollers and bullwheel maintain static friction to pull the rope and the sheaves roll with the static contact of the rope.

That said... I’m still not concerned because there would be numerous levels where such operating parameters would have already been considered by the peeps that wouldn’t just rely on napkin math.

 

[Missing20K]

Who would have thought the most burn victims would be not in the gondolas but in this very thread?

 

[GoofGoof]

Try temperature combined with constant use year round and for very long days compared to a ski slope

If I’m reading your responses correctly your concern is that the hot temperatures in Florida combined with year round extended use could be a problem. Your logic is that it’s colder at a ski slope and also not year round operation. I know it was brought up already but there are gondolas built worldwide (including warm environments) and in urban settings or tourist spots that run year round. This is no different than those environments. It’s not a completely unique setup.

To your specific point on the type of rope used, I don’t think anyone knows of a specific example using that rope in a warm environment. That doesn’t mean it hasn’t been used in that environment just that people here don’t have knowledge of it. Outside of @Lift Blog most of us learned more about gondolas here than anywhere in the real world. We are hardly experts. I don't think you need to be an expert to say it’s safe to assume that both the imagineers on the Disney side and the engineers on the seller’s side would be way more informed than us and would know if the hot weather would be an issue for that particular rope. If it was they could easily have gone with another option, easy fix. I find it very hard to believe nobody thought of this and it will be a problem, but u never know.

Edit: when looking at the site lift blog posted for the cable, under technical specs one of the example systems listed is Montjuic in Barcelona. This is an urban, non-ski gondola used for tourism and runs year round. Barcelona is not quite as hot/humid as FL, but it can get into the mid 90s in August and it is humid there too in the summer (not Aug humid in FL, but still pretty unpleasant). It’s a pretty good example of a similar use.

 

[Kamikaze]

I’m not seriously challenging you but more just playing devils advocate....wouldn’t the sliding friction in a system like this be relatively minimal? The cable interfaces with all of its touch points in a rolling manner so I would think that the sliding speed from your equation would approach 0 in an idealized scenario. I wouldn’t expect the cable to heat up much due to friction.

That said I am 100% certain the hundreds of licensed PE’s involved in the development of this project and all of the components involved have covered this infinitely more thoroughly than @Obobru is giving them credit for.

The friction IS minimal, but its still going to be higher than anything the sun can throw at it (the cable). The guys reasoning is because FL is so much hotter than a ski resort, this cable is going to fail. All that needs to be proven is that the FL temperature is not a factor.

 

[JeffAndKaren]

Try temperature combined with constant use year round and for very long days compared to a ski slope

I think the performance of steel rope is well understood. As to ambient conditions, steel rope is used in the same environment as WDW in many critical applications: suspension bridges, cranes, guy wires, etc.

 

[MisterPenguin]

Ambient temp isn’t the concern... it’s sitting under that heat lamp known as the sun... which can raise surface temps significantly higher. A galvanized roof can hit 160deg just sitting in the FL sun. (http://www.fsec.ucf.edu/en/publications/html/fsec-cr-964-97/). Car guys measure even more on paint (https://meguiarsonline.com/forums/s...-in-the-sun-How-HOT-does-your-car-s-paint-get)

But roofs and cars have a side in which heat is captured and stored and then put back into the roof/container walls. Also, their topology is wide and thin which allows more of the material to be exposed to the sun and capture more EM. The metal rope, OTOH, is compact and has free flowing ventilation on all sides. This may allow it to emit more IR than EM it absorbs at a much lower dynamical equilibrium of temperature than a metal roof or car siding.

 

[Kamikaze]

Ambient temp isn’t the concern... it’s sitting under that heat lamp known as the sun... which can raise surface temps significantly higher. A galvanized roof can hit 160deg just sitting in the FL sun. (http://www.fsec.ucf.edu/en/publications/html/fsec-cr-964-97/). Car guys measure even more on paint (https://meguiarsonline.com/forums/s...-in-the-sun-How-HOT-does-your-car-s-paint-get)

Two... you probably should not be throwing stones about knowing anything when you quote an equation that would result in 0 - because you googled friction and copied a formula about temperature from kinetic friction.... for a system that operates with static friction. Aka, the rope doesn’t slide through the system - the rollers and bullwheel maintain static friction to pull the rope and the sheaves roll with the static contact of the rope.

That said... I’m still not concerned because there would be numerous levels where such operating parameters would have already been considered by the peeps that wouldn’t just rely on napkin math.

Even at 200 degrees its not a concern. Not the point.

It isn't static friction because the points don't spin at the same speed as the rope moves. They do reduce the friction, but it doesn't matter. Sure I googled the equation. I'm not going to write one based on some guy who thinks the cable is going to melt because Florida is hot.

Here's what it comes down to: Which will be hotter the touch points in the system, or the cable out in the sun? Since the answer is obviously the touch points (equation or not, its common sense) then the temperature in Florida is not a factor.

 

[Nubs70]

The friction IS minimal, but its still going to be higher than anything the sun can throw at it (the cable). The guys reasoning is because FL is so much hotter than a ski resort, this cable is going to fail. All that needs to be proven is that the FL temperature is not a factor.

If there was even a minute chance of failure due to environmental factors, neither any Professional Engineer nor Insurance company would sign off and the project would not be built.

 

[King Panda 77]

Even at 200 degrees its not a concern. Not the point.

It isn't static friction because the points don't spin at the same speed as the rope moves. They do reduce the friction, but it doesn't matter. Sure I googled the equation. I'm not going to write one based on some guy who thinks the cable is going to melt because Florida is hot.

Here's what it comes down to: Which will be hotter the touch points in the system, or the cable out in the sun? Since the answer is obviously the touch points (equation or not, its common sense) then the temperature in Florida is not a factor.

Have you factored in the extra heat from the burning bodies in the cabins ?

 

[Nubs70]

Even at 200 degrees its not a concern. Not the point.

It isn't static friction because the points don't spin at the same speed as the rope moves. They do reduce the friction, but it doesn't matter. Sure I googled the equation. I'm not going to write one based on some guy who thinks the cable is going to melt because Florida is hot.

Here's what it comes down to: Which will be hotter the touch points in the system, or the cable out in the sun? Since the answer is obviously the touch points (equation or not, its common sense) then the temperature in Florida is not a factor.

How do we know the idler wheels do not spin at the same linear velocity?

 

[Kamikaze]

If there was even a minute chance of failure due to environmental factors, neither any Professional Engineer nor Insurance company would sign off and the project would not be built.

Well thats not 100% the case, but the insurance risk would be to a point where it would be minimized before they'd sign off. The system is safe, it will be safe, and the craziness that people come up with is absolutely mind boggling. But then I'm reminded that people thought that if a train went over 50 mph, women's uteruses would fly out of their bodies, or that your entire body would melt.

 

[Incomudro]

Gondolas built by this company are utilized worldwide - many in tropical environments that are far more harsh than Florida's.
Additionally, this Disney application is one of the most pedestrian deployments.
Low to the ground largely over paved and readily accessible areas.
In other areas, Gondolas traverse radical mountainous regions in extremes of heat and cold.

 

[flynnibus]

But roofs and cars have a side in which heat is captured and stored and then put back into the roof/container walls. Also, their topology is wide and thin which allows more of the material to be exposed to the sun and capture more EM. The metal rope, OTOH, is compact and has free flowing ventilation on all sides. This may allow it to emit more IR than EM it absorbs at a much lower dynamical equilibrium of temperature than a metal roof or car siding.

Those materials heat up in the sun more than ambient temperature because metal is a better conductor of the energy than air. The difference is not due to the structure — it’s basic chemistry. The point of the example was to simply illustrate that ambient temperature as a threshold is irrelevant because air doesn’t hold heat like metal does. The direct exposure to the sun is far more powerful than simple ambient air temp.

Metal gets hot in the sun because it will conduct faster than it transfers to the adjacent air. And ambient temp is more relative to the discussion if you want to talk about how efficient the ambient cooling can get. But it’s still going to be hotter than ambient air temp.... so back to my point. Ambient air don’t mean #&&$#* here

 

[Kamikaze]

How do we know the idler wheels do not spin at the same linear velocity?

On the towers they don't really 'spin' at all, the cable just moves through them. They do move, but they're just rotating because of the cable. In the stations they are slower because they have to downgear the cabins so they are moving slower in the station so you can board.

 

[flynnibus]

Even at 200 degrees its not a concern. Not the point.

It isn't static friction because the points don't spin at the same speed as the rope moves. They do reduce the friction, but it doesn't matter. Sure I googled the equation. I'm not going to write one based on some guy who thinks the cable is going to melt because Florida is hot.

Here's what it comes down to: Which will be hotter the touch points in the system, or the cable out in the sun? Since the answer is obviously the touch points (equation or not, its common sense) then the temperature in Florida is not a factor.

You get zero points for partial credit.

The points do spin at the same speed.... that’s why it actually pulls the rope and not just slips.

You have the right conclusion, but completely wrong on all your justifications. You don’t have the fundamentals right at all.