Introduction: PVC Water Rocket Modular Launch Pad With Gardena Connector
I have entered the PVC contest, if you like this project, please vote!
https://www.instructables.com/contest/pvc2017/
WARNING!!! SAFETY FIRST!!!
Always follow all these guidelines about the use of water rockets...
https://spaceflightsystems.grc.nasa.gov/education/...
There are a lot of tutorials that teach you how to build the perfect water rocket launch pad, and I believe I watched all of those. The most of the launchers uses the Clark cable-tie system which can be quite frustrating (because this system doesn't make the launcher perfectly water/air tight).
Another thing is, that most of the launcher tutorials requires to use PVC solvent, which is not a very "friendly" thing to handle, because it has a lot of hazards (very dangerous for the eyes, inhalation, fire, etc., etc.).
Last, but not least the portability. When I built the previous model, it was so bulky that I've had to carry the launcher by hand. Now, I can fit it in my Ikea bag.
So I thought how can I resolve these 3 problems?
Anyway, let's get started!
For this Instructable you need:
6x T shape PVC connectors 22mm
1x 2 meter PVC pipe 22mm
1x hose clip 35/45mm
2x 20mm zinc plated die cast pulley
http://www.ebay.co.uk/itm/20mm-Zinc-Plated-Die-Cas...
2 meter marine cord (5mm diameter)
1x Gardena/Hose connector
http://www.ebay.co.uk/itm/New-ABS-Garden-Water-Hos...
2 meter Clear Reinforced PVC Braided Hose 12mm internal diameter (rated 7 bar / 101 psi)
http://www.ebay.co.uk/itm/Clear-Reinforced-PVC-Bra...
a lot of zip ties 20cm
6x plastic topped corks
http://www.wilko.com/homebrew-accessories-equipmen...
a short piece of replacement floor pumps hose
http://www.ebay.co.uk/itm/Replacement-Floor-Pumps-...
1x innertube valve (I prefer the Presta, rather than the Schrader)
Some electrical tape
Loctite Powerflex
4 O-rings 1/2 inch
2mm screws
camping pegs (4 at least), to fix safely the launcher to the ground
Step 1: Gardena Connector and Clear PVC Hose... Rated With the Right Pressure!!!
First thing first, instead of using the Clark cable tie system, I used a Gardena Connector.
Connect the clear PVC hose to the Gardena connector. It should be a tight fit.
Cut 4 pieces (12 cm each) out of the long 2 meter pvc pipe.
Cut other 2 pieces (10 cm each).
Cut another piece 15 cm long.
Slide the pvc clear pipe inside the PVC white pipe, leaving the Gardena connector out the last piece of pipe you have just cut.
Slide inside the other part of the clear pipe, the piece of floor pump hose.
Slide the Presta valve inside the floor pump hose.
Now the fit is tight, but it's better to add some Loctite Powerflex inside every joint, and also it's necessary to add the zip ties to make the connection more reliable.
To make the frame of the launcher stronger, I used 3mm screws (the ones generally used for the servos horns).
Although the screws will keep together just the pipe and the connector, be extremely careful when you add those to the side where you have just slid the pvc clear hose.
If you poke/pinch it, you have to start from the beginning.
Step 2: Tape the Gardena Connector & Attach the Pulleys and the Marine Cord
*"Using the electrical tape, tape very tightly the Gardena connector to the top of the pvc pipe...
Literally, let the connector resting at the top of the pipe; it will not move."
*Please check the upgrade at the end of this tutorial, using Sugru glue is much better to complete the task above.
Attach the pulleys using 3 zip ties each.
Attach 2 pieces of marine cord (45cm each) to the Gardena Connector, using the metal hose clip
and slide those inside the pulley, tying the other side together making a knot at the end of it.
Close every pipe using the plastic topped corks, drilling one of this, in order to slide into it the clear pvc hose.
Step 3: Build the Base for the Rail
This is a very important part of the launcher, because to reach a good altitude, the water rocket has to be straight as much as possible during the launching phase.
To build the base you should cut 2x 3cm PVC white pipe and 2x 8cm.
Using the other 3T shape connectors, you'll create another base for the rail.
Slide 2 o-rings per side at the base of the launcher and use the zip ties to secure the base of the rail.
Attach that base using some zip ties.
Don't tie too much the zip ties!!! In this way you can adjust the distance of the rail, according to the size of the water rocket.
You need to connect what remains out the 2 meter PVC pipe (you've started to cut at the beginning of this tutorial), to the base you have just created.
Close the pvc pipes using 2 plastic topped corks.
Using the zip ties, create 2 "sort" of eyelets that will help to keep straight the water rocket during the launch.
WARNING!!! Use duct tape to protect the plastic of the water rocket, close to the part where you'll decide to put the zip ties/launch lug.
WARNING!!! Do not tie too much the zip ties around the water rocket, otherwise you'll create a dent in it, that can even cause the explosion of it.
Step 4: Nozzle for the Water Rocket
The trickiest part of this project is making the nozzle for the water rocket.
Regrettably, the male of the Gardena connector has a tread which in incompatible with the one normally used in the soda bottle. The good news is there are plenty of tutorials on Youtube how to make a good one.
The best ones, in my humble opinion are: USWR (UsWaterRocket) and AirCommandRockets.
USWaterRocket has a .stl file you can download for free, in order to 3D print your customised nozzle.
Step 5: The Sky Is the Limit!
Enjoy it, always following these guidelines...
https://spaceflightsystems.grc.nasa.gov/education/...
If you want to build a cheap launch pad made of metal, take a look at my other "ible".
Step 6: Upgrade Using Sugru Mouldable Glue
I wasn't very happy about the solution of using the electrical tape, to attach the Gardena connector to the PVC pipe, plus, this summer, with the hot temperature we have had, the electrical tape has melt down.
Doing a bit of research, I've found this phenomenal mouldable glue (Sugru), which can withstand temperatures between -50 / +180 Celsius degrees, plus this special glue is waterproof.
You just need to wait 24 hours to let the glue to settle down.