4 replies to this topic

[gatekeeper45]

Hello all,

For my science project I decided to make a knex launch coaster. I have seen many people on youtube do it so i thought it would be easy. I didn't realize that they were using regular knex and I only have micro knex. My launch system was going to be based of a hydraulic launch system as seen in this video. https://www.youtube....index=6&list=WL. Could anybody please help me.

Thanks

[Beethoven]

Do you still need help with this? I designed that launch system so I can try to help you out.

[gatekeeper45]

Yes I am still looking for a solution. Could you please help.

[Rollerfreak987]

First, what do you need help with? Could you post pictures?

[Beethoven]

Well, you would need to be more specific. But what I can tell you about my mock hydraulic launch that's important is:

Speed is determined on the size of the winch you use. I used a regular power drill that had forward and reverse to run my winch drum.
You need to tie two pieces of string to the winch drums, one towards the right side, one towards the left side. Each of the strings connects to one side of the catch car. This allows the catch car to move in either direction depending on which way the drill spins the winch.

I used the chain dog on the bottom of the knex train to engage the catch car. Much like the real hydraulic launch systems, the dog disengages the catch car simply by the catch car slowing down and stopping as the train continues.

I used a set of drive tires that constantly ran to place the train into the correct spot on the catch car. The chain dog fell into a hole in one of the pieces on the catch car, and at that point it was ready to launch, which was done simply by blasting the drill at full power, then to bring the catch car back, I'd switch the direction of the drill and place the catch car at the right spot on the launch track which I had marked.

That had to be done manually, but I'm sure someone here with the right know-how could modify a drill and program something to automate all this.

Also important was the tension wheel system found at the beginning of the launch track, the launch cable ran around this which kept the right amount of tension on the system.