Water Rocket Car Launch Cage + Guide Rail

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thampson
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Water Rocket Car Launch Cage + Guide Rail

Post by thampson »

We have just about finished our launch cage to use for our first record attempt in the dragster class. So we thought we would share how we built our cage and some of the lessons we learned doing it.

The cage should be finished tomorrow, there is still a little bit more mesh to go on. I am posting a detailed build on our website (link below) for those interested in more detail. It will need to be in three parts as its quite long. The first post of three is about the design stage and the building of the frame and connection of the launcher, its live now.

http://wrocket.hampson.net.au/?p=1319

I want to make sure there are some pics and content on the forum as well and not all on our website. So Ive attached some pics below. These are all from part 1 which is the build of the frame. We used 35mm x 18mm pine for the frame itself. I estimate approx 16m of it all up. The cage is 155cm long, 45cm high and 71cm wide. The cage is designed to fit over the launcher and recoil with the launcher when the car launches. Yes it still recoils, even with 20kg of water ballast on the launcher.

Due to our wing arrangement, we have to install a guiderail. It seemed pretty obvious that the wings would probably hit the side of the cage before the rear of the car emerged from the cage. We also needed to install a hinged access panel to gain access to connect the nozzle to the launcher, it was too far to reach in from the front of the cage and try to connect them.

Here are a couple of pictures from part 1.

Frame Assembly
Frame Assembly
water-rocket-car-cage 005.jpg (613.83 KiB) Viewed 77 times
Assembly of the frame
Test Fit of launcher
Test Fit of launcher
water-rocket-car-cage 010.jpg (685.21 KiB) Viewed 77 times
Test fit of launcher and Access Door
Launcher connected
Launcher connected
water-rocket-car-cage 016.jpg (346.15 KiB) Viewed 77 times
Launcher attached
Car on launcher in cage frame
Car on launcher in cage frame
water-rocket-car-cage 019.jpg (330.43 KiB) Viewed 77 times
Car in place on launcher inside the frame

I will document the second section and add some pics in the next few days - Launch Rail attachment, the lugs on water rocket car, painting.

The third section is adding the mesh itself which was an ordeal all of its own . I have the scrathes to prove it .. LOL :)

-todd-
HHWRSA
Hornsby Heights Water Rocket Space Agency
http://wrocket.hampson.net.au
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Re: Water Rocket Car Launch Cage + Guide Rail

Post by U.S. Water Rockets1 »

Hey Todd,

That launcher system is really looking like a winner. You have paid a lot of attention to detail and have really put some serious effort into the design. That's very impressive!
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thampson
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Re: Water Rocket Car Launch Cage + Guide Rail

Post by thampson »

Thanks for the kind comments US Waterrockets :)

-todd-
HHWRSA
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http://wrocket.hampson.net.au
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Re: Water Rocket Car Launch Cage + Guide Rail

Post by thampson »

Here is Part 2 of the launch cage construction. This part deals with the guiderail and the attachments to the car.
We have documented it on our website as well in a little more detail for those interested.

http://wrocket.hampson.net.au/?p=1337

The important bit here was getting the launch rail level. If its not level the car can bind up if its too low at the front or cause to much friction and slow the speed down significantly coming out of the cage. The other possibility is if its too high at the release end the car can get slightly airborne and unstable coming off the rail. The goal is to minimize the friction and get the car out of the cage in the middle with all 4 wheels on the ground.

To achieve this we used a spirit level to make sure we got the wooden section of the rail with the floor where the car would sit. We did this by clamping the suspension sections to the top of the cage and adjusting it until it was perfectly level. Then we marked the suspension sections, cut each one to the correct length and screwed them to the top of the cage.
Cage with suspended rail attachment
Cage with suspended rail attachment
water-rocket-car-cage 028.jpg (628.31 KiB) Viewed 65 times
Due to our split tail design, the best placement for us was with the rail right down the middle of the water rocket car.
Car test fitted under the rail attachment
Car test fitted under the rail attachment
water-rocket-car-cage 025.jpg (637.35 KiB) Viewed 65 times
Our rail is a curtail rod that is 1.5m long. This was a freebie from a local council cleanup, so always good to keep your eye out for freebies that may be useful in this hobby :)

Here is the car sitting under the rail
Test fit under the launch rail
Test fit under the launch rail
water-rocket-car-cage 005.jpg (647.05 KiB) Viewed 65 times
We made up some attachments to add to the car, and used screws with the right head size to slide down the rail. The benefit of using screws is that the height could be easily adjusted for the perfect fit down the guide rail. We used three lugs so that the car should still stay on the rail if 1 fails.
Launch lugs are visible down the centre of the car
Launch lugs are visible down the centre of the car
water-rocket-car-cage 004.jpg (654.97 KiB) Viewed 65 times
The cage was given a coat of paint to smarten it up a little, ready for the wire mesh to be added
Coat of paint :)
Coat of paint :)
water-rocket-car-cage 008.jpg (353.62 KiB) Viewed 65 times
The last post will cover the adding of the mesh ... will put this up shortly

-todd-
HHWRSA
Hornsby Heights Water Rocket Space Agency
http://wrocket.hampson.net.au
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Re: Water Rocket Car Launch Cage + Guide Rail

Post by WRA2 »

thampson wrote:Here is Part 2 of the launch cage construction. This part deals with the guiderail and the attachments to the car.
We have documented it on our website as well in a little more detail for those interested.

http://wrocket.hampson.net.au/?p=1337

The important bit here was getting the launch rail level. If its not level the car can bind up if its too low at the front or cause to much friction and slow the speed down significantly coming out of the cage. The other possibility is if its too high at the release end the car can get slightly airborne and unstable coming off the rail. The goal is to minimize the friction and get the car out of the cage in the middle with all 4 wheels on the ground.

To achieve this we used a spirit level to make sure we got the wooden section of the rail with the floor where the car would sit. We did this by clamping the suspension sections to the top of the cage and adjusting it until it was perfectly level. Then we marked the suspension sections, cut each one to the correct length and screwed them to the top of the cage.
water-rocket-car-cage 028.jpg
Due to our split tail design, the best placement for us was with the rail right down the middle of the water rocket car.
water-rocket-car-cage 025.jpg
Our rail is a curtail rod that is 1.5m long. This was a freebie from a local council cleanup, so always good to keep your eye out for freebies that may be useful in this hobby :)

Here is the car sitting under the rail
water-rocket-car-cage 005.jpg
We made up some attachments to add to the car, and used screws with the right head size to slide down the rail. The benefit of using screws is that the height could be easily adjusted for the perfect fit down the guide rail. We used three lugs so that the car should still stay on the rail if 1 fails.
water-rocket-car-cage 004.jpg
The cage was given a coat of paint to smarten it up a little, ready for the wire mesh to be added
water-rocket-car-cage 008.jpg
The last post will cover the adding of the mesh ... will put this up shortly

-todd-
Hi Todd,

Sorry to hear that you got scratches adding the mesh. (this was supposed to make it safer) DOH:

Thanks for sharing your trials and tribulations in building the cage. Your cage is much sturdier then I imagined one would make it.

I imagined a cage where the competitor would take the mesh and wrap it into a "U" shape, turn it upside down, and attach it to two wood "rails" protruding from the front of the launcher. A matching shape could be cut from wood for the back. TC:
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thampson
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Re: Water Rocket Car Launch Cage + Guide Rail

Post by thampson »

This is the last post for the cage construction. This covers putting the mesh on, air hose access and testing everything is working

The full detail is on our webite for those who want to read more detail.
http://wrocket.hampson.net.au/?p=1349

Firstly the mesh we used was a zinc coated welded steel mesh. It has a 6.5mm (1/4″) square aperture and a 0.6mm wire diameter. This mesh is usually used for snake and mouse protection on aviaries.

Putting it onto the cage we learnt a lot and have the following tips to share

TIP 1 : SAFETY SAFETY SAFETY – Anytime you are working with mesh or wire its very very important to wear wraparound eye protection and gloves while handling the wire and mesh. Wire strands can easily get into your eye and you dont get a second chance with your vision. Also the mesh is very sharp when cut so gloves are needed !!!!!!

TIP 2: USE AN ANGLE GRINDER TO CUT THE MESH – Use an angle grinder to cut the mesh. It cuts through it like butter and also trims off the sharp edges all in one go.

TIP 3: CUT THE MESH 10mm SHORT OF THE FRAME EDGE to prevent cutting your leg as you walk past it once its on.

TIP 4: USE TEK SCREWS TO ATTACH THE MESH TO THE FRAME

The Tek screw is definitely the safe and fast way to attach the mesh to the frame, we learnt this trick from aviary builders after first trying to wire wrap the mesh to the frame.
Tek Screws attaching mesh
Tek Screws attaching mesh
water-rocket-car-cage 011.jpg (419.44 KiB) Viewed 54 times
Here the Tek screws are used to attach the mesh, also the mesh is cut 10mm back from the edge

Here is what a Tek screw looks like. It has a self drilling bit on the end and the hex nut hold the mesh against the frame very securely
tek screw
tek screw
tekscrew.jpg (6.83 KiB) Viewed 54 times
We secured the access door with a sliding latch to lock it in place when the car is under pressure
Door Latch
Door Latch
water-rocket-car-cage 004.jpg (484.28 KiB) Viewed 54 times
We cut out a few of the squares to provide access for the airhose. Here is the airhose attached to the launcher
Air Hose connected
Air Hose connected
water-rocket-car-cage 007.jpg (988.83 KiB) Viewed 54 times
Here are some final pics of the cage and car ready for launch
Cage rear
Cage rear
water-rocket-car-cage 003.jpg (873.15 KiB) Viewed 54 times
Cage Side View
Cage Side View
water-rocket-car-cage 002.jpg (519.16 KiB) Viewed 54 times
Car + Launcher + cage
Car + Launcher + cage
water-rocket-car-cage 012.jpg (498.26 KiB) Viewed 54 times
We will put some grease on the guide rail and do some launch tests under pressure to make sure all is well before heading out to the test track to go for some longer distances :D

-todd-
HHWRSA
Hornsby Heights Water Rocket Space Agency
http://wrocket.hampson.net.au
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Re: Water Rocket Car Launch Cage + Guide Rail

Post by ninja_iga »

very impressive!
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Re: Water Rocket Car Launch Cage + Guide Rail

Post by WRA2 »

Very impressive Todd,

One question. Does it disassemble for easy transport?
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Re: Water Rocket Car Launch Cage + Guide Rail

Post by U.S. Water Rockets1 »

Wow Todd, that is coming along even more impressive than what you posted before. The details like the pain and the shiny silver mesh make the cage a real sight to behold. The whole car and cage setup is sure to draw in a lot of attention when you go out to launch. You're going to become a local celebrity!
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Re: Water Rocket Car Launch Cage + Guide Rail

Post by thampson »

Hi Lisa,

I think the U shape option for the cage should work, but I thought I would need a sturdier frame due to the rail that I decided to put in. I think short bodied cars with a U frame with plenty of space on the sides should be fine. The longer the car is the more chance the rear will clip the cage on the way out.

With the option to transport it, it doest really breakdown so I use the roofracks on my car to get it to the launch site. I use 4 long thick cable ties they are 10mm thick and 400mm long and it doesnt move. The rocket car and everything else fits in the back with the rear seats down and the cage on the roof.
Cage on the roofracks water rocket car and everything else in the back of the car
Cage on the roofracks water rocket car and everything else in the back of the car
img_0125.jpg (406.99 KiB) Viewed 31 times
This pic was from our test launch today. I will post some videos soon

-todd-
HHWRSA
Hornsby Heights Water Rocket Space Agency
http://wrocket.hampson.net.au
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Re: Water Rocket Car Launch Cage + Guide Rail

Post by thampson »

Ninja_iga, Lisa and USWaterRockets

Thanks for the kind words :).

Im not sure about local celebrity, but we sure did get some funny looks with the cage on the roof today :)

-todd-
HHWRSA
Hornsby Heights Water Rocket Space Agency
http://wrocket.hampson.net.au