TTD Anti-Rollback wheels

I hate weak seams, especially as a larger guy.

Jeff said:The length of the track has nothing to do with it. The only thing that really matters is the speed that the motor can achieve before the end of the launch.

Then by your own words, the track length does matter.:) If you're aiming for an 80mph launch, you're not going to have an 80ft launch track length without the intention of using more horsepower than necessary to achieve the top speed. It's obvious the "amount of energy" involved with the launch is different for each hydraulic launch coaster. But the same goes for the launch track length which is designed to fit where the park wants it and the speed that's required to complete the circuit.

I know the Hypersonic launch track was extremely short, and it blasted off to 80 mph in less than 2 seconds. Easily the most intense launch I've ever felt. Also the most painful on the arms if you hold them up. Can you say shoulder dislocation?

Well don't forget that it uses pneumatics for it's launch. They produce a MUCH more powerful launch.

Jugga if you are driving around in a circle even at a "constant linear acceleration" your acceleration is changing direction the whole time so that doesnt count. (without breaking the speed limit) go out onto a straight section of a highway and floor it. You will stop noticing the accelration after a few seconds.

TTD 120mph said:
It's obvious the "amount of energy" involved with the launch is different for each hydraulic launch coaster. But the same goes for the launch track length which is designed to fit where the park wants it and the speed that's required to complete the circuit.

No, now you're talking about efficiency. Again, ignoring other variables, it takes the same amount of energy to move an object a certain distance, in this case straight up. Different technologies may use different amounts of energy depending on their efficiency, sure, but the actual kinetic energy transferred to the train will always be the same. And with the conservation of energy, it's converted into potential energy as it rises to the top, then that energy is converted back to kinetic energy as it comes back down. That energy is in turn converted to heat when it hits the brakes.

Again, assuming uniform efficiency of the hydraulic motor, it would require the same energy to launch in 100 feet as it would 1,000 feet. My guess is that the faster the motor has to go in a short duration, the more energy is wasted as heat, but I'm not exactly up on my knowledge of the thermodynamics of hydraulic systems. :)

TTD 120mph said:
Well don't forget that it uses pneumatics for it's launch. They produce a MUCH more powerful launch.

Well yeah I know. I'm just saying, ridiculous launch. A little too ridiculous. It certainly didn't need any anti-rollback wheels.

Funny thing about the new Ring Racer coaster opening in Nürburg. They had to tone down the launch because the local whoever deemed there would be too many "allowed g forces" for their initial estimates and forced them to lengthen the launch time to 134mph in 2.5 sec instead of 1.8 sec. It's still ridiculously fast.:)

^^Ok, fine, I see what you're getting at in terms of the transfer of kinetic and potential energy, but that's not what we're disputing here...even though it is a variable that I've already acknowledged. I may not be as smart as you (seeing you have seniority and everything) but I know enough to know that the length of launch track DOES play a part in the launching aspect of a launch coaster like Dragster. I know you may be thinking I'm not thinking this through, but I'm sorry to say I am. I don't think it takes a lot of knowledge to see the relevance to the launch track length and launch speed.

Oh and another variable to think about is the catch car brakes and the amount of room they require to stop a catch car moving at high speeds. I know there's also the stopping of the engine that plays a part but you can't ignore the fact that the cc brakes are another major part involving the launch track length.

And if I'm really making no sense, just let me know and I'll go beat my face with a hammer or something for being stupid.:)

TTD120, I totally get where you're coming from. In fact, earlier today I almost made a comparison using an F/A-18, an aircraft carrier, and a full length runway. The takeoff from the carrier will feel much more forceful as the plane has to reach its takeoff speed in approximately 250 ft. (I think its between 200-300 ft., I think it may be closer to 220) as opposed to taking a couple thousand feet on a conventional runway to reach takeoff speed. The force is applied over a longer amount of time, making it not seem as intense as a carrier takeoff. I would think its the same with TTD/KK and their lengths of launch track. I have also heard many people say that the launch on Ka isn't nearly as intense and has a pulse to it. I know it has quite a bit longer of a launch track (not sure on specifics, but I do remember that it is surprisingly long), which is why I think of it as more of a carrier vs. runway comparison.

Touchdown said:
Jugga if you are driving around in a circle even at a "constant linear acceleration" your acceleration is changing direction the whole time so that doesnt count.

So, if an example proves you wrong, it doesn't count? W, is that you?

(without breaking the speed limit) go out onto a straight section of a highway and floor it. You will stop noticing the accelration after a few seconds.

No, your car's engine/powertrain will simply move into its power band (where you'll feel it's force more emphatically), and then out of it, where the acceleration will decrease, and you'll feel it less. You're not magically changing the laws of physics in your sedan, I'm sorry to say.

That said, a vehicle is a terrible example altogether. Several college-level physics classes would help clear this up for you, I'd imagine.

Jeff said:

No, now you're talking about efficiency. Again, ignoring other variables, it takes the same amount of energy to move an object a certain distance, in this case straight up. Different technologies may use different amounts of energy depending on their efficiency, sure, but the actual kinetic energy transferred to the train will always be the same. And with the conservation of energy, it's converted into potential energy as it rises to the top, then that energy is converted back to kinetic energy as it comes back down. That energy is in turn converted to heat when it hits the brakes.

Again, assuming uniform efficiency of the hydraulic motor, it would require the same energy to launch in 100 feet as it would 1,000 feet. My guess is that the faster the motor has to go in a short duration, the more energy is wasted as heat, but I'm not exactly up on my knowledge of the thermodynamics of hydraulic systems. :)

What are you even arguing about? We all know and understand that the same amount of energy is required to get the train over the top of the hill every time. The difference is in how long it takes to build up that energy. If the launch track is shorter, the acceleration must be higher in order to get enough velocity to get over the hill. I'm guessing you understand this and theres some misunderstanding as to what everyone is actually arguing about.

Touchdown said:
Jugga if you are driving around in a circle even at a "constant linear acceleration" your acceleration is changing direction the whole time so that doesnt count. (without breaking the speed limit) go out onto a straight section of a highway and floor it. You will stop noticing the accelration after a few seconds.

Accelleration is a change in velocity. Velocity has both a speed and a direction. Change one or the other and you have accelleration (a change in velocity).

Drive in a straight line with the cruise set at 5mph. Your body won't feel anything because you aren't accellerating. Now, take the steering wheel and turn it to the right 90 degrees so you turn. Your speed stays the same, but because your direction is changing you are accellerating. It is a constant accelleration of the same rate, and I guarantee your body feels it. You can spend 5 minutes going in a circle, and your body will feel every second of it, it won't suddenly stop because the accelleration is constant.

DJ - it wouldn't take a couple, this is high school intro to physics stuff. At least the concepts are, unfortunately its been too long since I've used the equations to actually break out the math.

You'd think, eh?

Obviously NCLB is, despite its "effective" name, leaving some of them behind. ;)

The way your body senses acceleration is via your internal ear. Depending on the direction, it is either sensed by hair cells located in ring cavity filled with fluid that senses when that fluid moves or by hair cells whose ends are suspended in a gellatinous material with stones dispersed within, when that moves the hair cells bend and send a signal. At zero accelration they dont sense anything.

However, if you are accelerating at a constant rate (say 5m/s/s) your sensory system will be sending the same signal to the brain. Your brain is designed to start ignoring sensations that do not change. Thats why you do not sense the accelration as strongly towards the end of TTD's launch.

I understand physics, but this isnt physics, its biology.

No, its still physics. You're just trying to muddy the waters with incorrect biology.

The reason you don't feel it towards the end of TTDs launch is that you have stopped accellerating and are being pulled at a constant rate (~120mph). No accelleration means nothing for the brain to detect. At least until you hit the turn upwards at which point you again accellerate and your body feels it.

^It's def noticeable when riding. If you are sitting in the front row on Ka and you crest the top hat and you look around you can see Philly! Part of me doesn't like those breaks at the top and I think thats why I like TTD so much more then Ka. I love how you glide over the top where as ka you lag.

Another reason why Ka has the breaks at the top is because the towers are different. If you look at Kingda Ka's tower, it is slimmer then TTD's. Top Thrill Dragster has a wider tower allowing for more rollbacks and for the train to get stuck up at the top. In the last couple of years I have seen less and less roll backs on Kingda Ka where TTD the last time we were there rolled back six times once every train!

Its not incorrect biology that is how you function. The question intially asked why you "feel" the acceleration more at the start.