Pirate+Ship


 * The Pirate Ship**

This ride is a big swinging ship that swings in a pendulum motion giving the riders a feeling of weightlessness. This feeling is obtained because the velocity at its maximum height is zero so the inertia from the motion matches the force of gravity allowing the rider to be suspended in mid-air for a brief moment in time.

It's a level 3 thrill ride. Here's the level 1 version for the squirmish.

Members '09: Tierra, Regan, Lauren and Vicky Members '08: Matt, Scott, Jesse and Jeff

Ride Givens:
 * Mass of Boat || 2.54e4 kilograms ||
 * Maximum height of center of Boat || 8.1 meters ||
 * Length of Boat || 13.1 meters ||
 * Radius of Pendulum || 9.7 meters ||
 * Width of Boat Arc || 26.2 meters ||
 * Riders per Ship || 54 people ||



(2008) For the accelerometer data analyzed at the bottom of this page, we were sitting at the far end, two seats behind our spot on this ride. During this ride, Scott filmed the accelerometer shown below. (you can barely tell, even in the picture)

//Note: This video has been lost in the world of Macs.//

The video above shows an accelerometer on the Pirate. The first red line is one g (9.8m/s^2) and the second red line is two g's. The acceleration that is shown in the video coincides with the y-acceleration in the graph.

2009:
 * Ride Overview

This is the x distance versus time graph. It is relative the center of the mast. If you look at it closely, you can see that the max and mins of the graph get bigger and bigger with every revolution. This is because as the ride starts up and swinging it gets farther and farther away from the point of relativity which is the center of the mast. It makes for a PHUN ride. LJ ** This is the Y velocity of the pirate ship. Each time the line hits the x axis, it represents when the ride hits equilibrium. At each each peak, you can tell that that is the spot where the pirate ship swung to its apex and began its descent. Follow along with the first period of motion, at first it has a positive y velocity, swinging to it's max, then it comes back down where it hits equilibrium and then back up on the other side to its apex and back to its equilibrium. That completes one period. In the next period, the peaks will be higher because the ship gets higher and higher over time. LJ **
 * This is the y distance versus time graph. The distance traveled is relative to the center of the mast of the ship. So it starts a little above ten meters. If you look closely at the graph you can tell the peak gets higher and higher every time. This is because the ship swung higher every time. Naturally, the ship wouldn't do this because of gravity. But because the machine is forcing it that way it will swing higher every time.** Again, It makes for a PHUNer ride. : ) LJ
 * [[image:Picture_6.png width="495" height="475" caption="Graph of Y-Velocity"]]
 * This is the X velocity versus time graph. When looking at this graph, you need to break it down into sections of four for each period. Logger Pro started graphing when we were up in the air, where velocity is zero, when we came down to the equilibrium point, the velocity was fastest. When we went back up, it hit zero again. We came back down to the equilibrium point and the velocity was faster still. Look at the graph, you can see each peak gets greater with the increasing velocity. This is why you feel you're going faster at the bottom of the curve of the ride.** LJ


 * Y-Velocity and X-Velocity have slopes to show what the accelerations were - there are linear fitted lines for both directions on the velocity graphs.....

2008:** x = side to side y = vertical z = front and back Note that all directions are relative to Scott sitting on the ride. This matters because the vest picks up gravity and during certain parts of the ride, only a component of such may have been affecting the accelerometer. This graph gives a good depiction of how the acceleration increased as the max altitude increased, which can also be seen in the video because of the much greater velocities requiring greater acceleration to change them. The amateur video filmed by Scott showed a similar maximum vertical acceleration, almost 2g's, as the vest did, so that simply shows that the little accelerometer is calibrated correctly (the video is not the best ever, but hopefully you can still see the max acceleration). Also, please note that because the data was taken from an end seat, we went much higher on one of the two sides of the swing than the other; that is what caused the "bumps" in between the larger ones in the altitude, and the unequal period in the others as well.

1) Y curve: First, it must be said that because gravity is included, the "zero" value for vertical acceleration is 9.8m/s, or 1g. Therefore, although these are the least values, they are actually the greatest positive difference from that "zero" position. At the highest altitude was our lowest velocity, so centripetal acceleration, which would add to gravity, was actually zero at the point that we were stopped (v/r^2 = 0/13.6^2 = 0) and therefore the only acceleration recorded is the component of gravity. Z curve: This really makes the least sense of all necessary explanations. With that, although in a simple pendulum the greatest acceleration occurs at the greatest angles (altitudes as well), such is apparently not the case here. I really cannot explain this one. Perhaps it has to do with that darned component of gravity affecting us again as we increased angle. However, as gravity is in the same direction as tangential acceleration (in a classical pendulum problem, the only tangential acceleration is the component of gravity) this absurdity is most likely a cause of the accelerating wheels discussed in (3). 2) Y curve: This is easy. Using the equation given above for centripetal acceleration, it makes perfect sense that the greatest acceleration will occur when both the component of gravity and the velocity are the greatest, which happen to occur at the same time: when we were at our lowest altitude, moving fastest, and sitting straight up. Z curve: again, this graph is odd, but the maximums can be explained through the wheels at the bottom of the ride 3) There were two wheels underneath the ship, which accelerated the ship into motion, as well as out of motion, whenever the ship was at the bottom of the swing. Therefore, although "pendulic" motion would say this should be the minimum, it was actually the max. the bumps are just caused by actually hitting the wheels. 4) As stated above, this should be zero, but if the accelerometer was at all crooked, it would have picked up components of the other two, which likely caused the pattern seen in the top graph.
 * Ride Details**