Over the summer, the fair in my area opens to the public once a year for people to enjoy animals, food, events, and the most important, rides. One of my favorite rides at the fair and are at many fairs and amusement parks around the world is the Gravitron. The Gravitron was designed and created by Wisdom Industries in 1983 and quickly spread to amusement parks around the world. The ride is completely closed with the exception of some having an open roof. Each Gravitron ride has 48 angled padded panels which the riders lean against on their back. The Gravitron rotates making a centrifugal force by the riders to the pads, allowing the rider to be lifted up from the ground with the 33kW 3 phase motor that can reach 24 rpm's in less than 20 seconds. At this speed riders are experiencing 3 times the force of gravity hence the name "Gravitron". With the addition of music and lights this ride is something you will never forget.
Step 1: Design Part One
The first step when making the Gravitron is to of coarse sketch out your design on a piece of paper with a ruler for straight lines. Then you want to label the dimensions and angles for the frame of the Gravitron and then the actual Gravitron itself. Please refer to the photo's above for the dimensions and angles of both.
Step 2: Design Part Two
After you have designed the Gravitron frame and inner part of the ride on paper, you will need to make the ride come to life. I used the program Autodesk Inventor 2016 to copy the sketch over on the computer. I first made the basic design of the frame and entered in the dimensions of the lines into Inventor. We will be using a laser cutter to cut out the frame we designed in Inventor. I chose to make the frame out of a 1/4 in piece of ply wood and used another 1/4 in piece as a base to glue the from on to.
Step 3: Design Part Three
Now for the third part of constructing this project is to make the inner part of the ride where the passengers and operator sit inside of the ride. I used the frame of the ride and made the inner part of the ride inside of the frame in Inventor to insure that the inner part of the ride would have a good fit into the frame. This part is going to be spinning so I decided to use a 3D printer to print out the inner part of the ride to make sure that every piece was equal and they are going to be printed in 45 degree pieces which take about 2 hours each to 3D print with a makerbot 3D printer. After all 8 pieces were printed I glued them together and made sure that it was going to be able to hold together and not fall apart when spinning.
Step 4: Motor & Wiring
In order to make the Gravitron spin you will need a small ac motor. I decided to use a 1.5 - 3v motor. I wired the motor to two double a batteries which would give the motor exactly 3 volts to spin at the highest rpm. I then used a 1 inch lego axle with a pre-drilled hole inside of the axle and drilled a hole the diameter of the axle into the bottom and middle of the Gravitron using a drill press. I then mounted the motor to a small piece of wood on the bottom of the frame with a screw and attached the axle which is inside of the Gravitron to the motor which allows it to spin. To finish with the motor wiring I wired the motor to a normal switch which allows you to turn the Gravitron on and off and mounted the switch to the side of the rear frame that I created out of scrap wood to cover the wiring and battery terminals.
Step 5: Wiring Led's
The Gravitron wouldn't be complete if you don't have bright lights to get a spectators attention to make the ride look fun to ride and watch. So I have decided to wire one 12" led strip to the bottom of the base below the inner part of the ride and two 3" led strips to the top of the frame. Both strip have RGB and have the same constant flow. The top led strips go from right to left. The bottom led strip goes from left to right both at the same speed and pattern just different directions. I wired the led strips to a 9v battery and used a 100ohm resistor so that the led's won't burn out from too much current. I then wired the led strips to the same kind of switch used to turn the ride on and off. I mounted this switch to the top of the rear cover so that it would be a little more hidden.
Step 6: Sanding & Painting
Once you have the 3D printed Gravitron glued and assembled, it needs to be sanded with a palm sander using 180 grit. I used the palm sander to sand the top and bottom of the Gravitron and then used the same grit by hand to do the sides of the Gravitron. Note don't sand the 3D material too much or it will start to tear apart. After you have the Gravitron sanded, I decided to paint it black with a matte black spray paint and then paint fake led lights on the bottom half of the Gravitron.
Step 7: Assembly
Once you are satisfied with your wiring and laser cut frame as well as your 3D printed painted Gravitron. It's time to mount the axle to the motor, flip both switches for the motor and leds and you have a smaller model of the Gravitron carnival ride.