Howto build a Launch Cage with Guide-rail – Part 2

Guide Rail
As we realized in the design stage a guide-rail is necessary to ensure the water rocket car clears the cage without hitting the sides on launch. We use a split tail design on our water rocket car, so for us the best spot to attach the guide-rail to the car is down the centre.

The guide-rail itself is  a metal curtain rod which we have used previously as a vertical launch rail for our vertical water rockets. It also happened to be about 1.5m in length which was a perfect length.

To attach the guide-rail to the cage we suspended a section of timber from the top of the cage along the centre. It was important to make sure this piece was perfectly horizontally  level, otherwise the car may bind up in the rail on launch.

Guide-rail attachment suspended from the top of the launch cage

there is a bit of clearance between the car  to attach the rail itself as can be seen from this test fit picture.

Test fit and clearance of rocket car to rail

The rail was then attached to the suspension section with some blocks to get the rail closer to the car.

Guide-rail attached to suspension section

Here is the car in place under the rail. The alignment looks pretty straight.

Car in place under the rail

Car Rail Lug Attachments
Next the lugs needed to be made up and attached to the car. As the bottles need to be able to be removed from the car, we made up some U shaped attachments. One is placed over the nozzle and the other over the first and second bottle gap. These are spaced to allow the bottles to expand without pressing too hard against either of  them and possibly rupturing or bending the lug attachment.

Guide-rail lugs and attachments

Large screw heads were the right shape and size to use as lugs to slide down the guide- rail, so appropriate sized screws were secured into the attachments. The attachments are secured into the chassis from underneath. Using screws as lugs allows for the height to be  adjusted by turning the screw in or out to fit in the rail correctly.

The U shaped attachments were painted green to match the rest of the car.

The cage was given a coat (or 2 ) of paint to smarten it up a bit. The launch rail attachment was painted green to keep with the Green Hornet theme :)

A coat of paint :)

The last part of this 3 part posting will cover the attachment of the wire mesh, test fitting the attachment lugs and adding the access to the launchers airhose.

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This entry was posted on Monday, January 24th, 2011 at 10:59 pm and is filed under Development. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.


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