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Dave Ware's Gilbert Erector Automated Roller Coaster

Dave writes: "I have redesigned my roller coaster model for the second time. This time I was able to make it fully automatic. Originally I planned to use the car to flip switches to reverse a P55 lifting motor at the right times to control the lifting mechanism. It did not turn out to be practical due to the light weight of the car and other considerations. I finally hit on a solution that was fairly simple, reliable and used only Erector parts. It required 2 motors. One to lift the car and a second one to pull the lift motor into gear. The description below focuses mainly on this new mechanism.

An insulated frame made of 2 I strips separated by 2 BY fiber strips sits at the end of the track and serves as part of a switch for the second motor. When the car rolls off the end of the track, its Z wheels land on the 2 I strips (with A girders to widen them slightly) which are connected to the motor circuit. Either set of wheels completes the circuit between the I strips through their axle. This starts the second motor which winds a string on an axle. The string pulls on the first motor’s gear shift lever and engages the gears. This starts two reels turning which wind up strings that go over pulleys at the top of the coaster and down to the bottom. These strings are attached to a cradle that sits over the frame and has strips that sit just below the flanges of the car’s Z wheels. As the cradle begins to lift, it catches the car by its flanges and lifts it up off the frame. This opens the circuit powering the second motor. The cradle continues lifting the car to the top of the coaster. At the top, the front of the cradle catches on two sort of hooks made from CH angles and tips up. This causes the car to roll out of the cradle and on to the track. The cradle continues tipping, and a bracket on it pushes on a lever attached to a string. This string goes over pulleys and down to the bottom where it pulls the motor’s gear shift lever in the opposite direction and out of gear. The reels are now free to turn and thus the cradle returns to the bottom by gravity and lands over the top of the insulated frame and waits for the car to complete its ride on the tracks. The cradle also serves to catch the car and stop it as it rides onto the frame.

The requirements for the second motor were low voltage for safety and the ability for it to turn freely when unpowered so the first motor could pull itself back out of gear. A P55 which is worm driven wouldn’t work. A P58 was the perfect choice. In order to lessen the load on the lever that pulls the first motor out of gear, a mechanism was needed to pull back on the string that pulls the motor into gear. When the first motor is in gear, it drives a right angle shaft which drives an eccentric that pulls back on the string and turns the unpowered second motor backward to take the tension off the string

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The cradle had to be carefully designed to fit over the frame without shorting it out. Guides attached to the insulated strips on the frame align the cradle as it falls in place. The cradle also had to have extra weights added to it so it would come back down on its own. The weights consisting of 4 Z’s had to be set out of the way of the frame and car and low enough so the cradle wouldn’t be top heavy and flip upside down on its way down. The "I" strips used on the frame had to be ones which had electrically conductive plating.

Other than that, the roller coaster is similar to the last one. I cut down on the height somewhat so that the car would not go so fast. The car now drops 5 inches instead of 6 on each track. The theory being that if it doesn’t slam into the flipovers so fast, it won’t derail as often. I also redesigned the flipovers and now seldom have derailments.

Not counting some screws and nuts, the only non erector part used was a piece of foam on the back end of the frame to cushion the car as it rams into the cradle and settles on the frame."