Posts Tagged ‘launcher’


Barbed Gardena Style Fitting + Wire Cage Development

Barbed Gardena Style Fitting
The barbed Gardena style female quick connect  fitting we ordered arrived  today. This fitting has a  longer barbed connector that ensures the hose can be clamped tighter to the fitting so the hose doesnt  blow off under high pressure.  This one is made by Neta but is the same style as the Gardena ones and accepts a 9mm male nozzle. Thanks to the friendly staff at Dural Irrigation Supplies for going through the product brochures to find it and ordering it in specially :)

Barbed Tail Gardena style connector

You can see from this pic that the area available to clamp the hose to the fitting is much longer than a standard fitting.

Close up of barbed connector

We did a simple replacement of the existing fitting on the launcher and installed  this new female quick connect fitting  to the high pressure hose.

New connector attached to the launcher

Wire Cage Development
Members of the  Water Rocket Forum are currently in the process of writing a set of  rules for  speed and distance world records for water rocket cars. We are gladly taking part in this process to ensure people who participate do it in a safe and consistent manner. One of the items that will go into the rules is having a cage around the pressure bottles on the car to contain any fragments /  connectors in the case of a pressure vessel rupture and explosion.

The cage will need to ensure no piece bigger than 10mm x 10mm can get out of the cage. We have found a galvanised welded mesh product which is used for aviaries and chicken coops that has a mesh size of 6.5mm x 6.5mm. This will provide a sturdy cage which only requires 1 wrap of mesh. Typical chicken wire has a twisted hexagon  of 12.5mm mesh size which would require two wraps to meet the mesh size specifications in the rules.

Mouse and Snake Mesh - 6.5mm x 6.5mm

This closup pic shows the mesh size better – tape measure is in cm

Closeup of Mesh

We will make a couple of cages, one for the rocket car and one to do hydrostatic tests in. We will feel a bit safer doing burst tests now if the bottles are in the cage. We will just need to try to contain the noise of the explosion with a wrapping of carpet or something around the cage  :)

Once the rules are established and agreed we should be ready to  submit a record entry pretty soon there after with the current car :)

Posted by on November 5th, 2010 2 Comments

Updated Launcher – High Pressure Components

Next on the list was upgrading the launcher with metal connectors and high pressure hose.  We upgraded the following

– replaced the gardena quick release on the abort extension hose to a male Nitto connector
– replaced the  first gardena quick release on the launcher with a Nitto Female quick release
– replaced the poly hose on the launcher with high pressure hose (290 psi)
– replaced the poly  90 degree elbow with a metal 90 degree elbow with bards

The abort extension hose was the first to be updated and now all connections are Nitto air hose connectors, the male Nitto connector was added to the end. The barbed section goes into the hose.

Nitto Male Hi Cupla Std 30PH

Added Nitto male to end of abort hose (to connect to launcher)

The brass elbow was fitted into two sections of high pressure hose, one section has a Nitto female connector to connect to the abort extension hose, the other end has a gardena quick release to connect to the rocket nozzle.

90 Degree Brass Elbow with barbed connections

This section effectively converts from air hose connectors to gardena quick release.

High Pressure converter from Nitto Air hose to Gardena connector

We have managed to find a female gardena connector that has a barbed connection on the hose side. This barbed connection goes 30mm down into the hose and ensures there is  more space for the clamp to hold the hose to the  gardena connector.  At the moment there is only about 8mm-10mm of the gardena connector down inside the hose, so there is a chance it might  fly off under high pressure.  We  ordered the barbed one in from our local irrigation supply store, so we will probably replace the one we have on the launcher prior to the next launch with the new one once it comes in.

The high pressure hose and connectors were mounted back on the movable section of the launcher, strapped to the steel rod and screwed down.

High Pressure Hose mounted back on the launcher

All the sections  were connected up for a test and no leaks.  This configuration is upgraded to the high pressure hose and connectors from the pump to the launcher, here is a picture of all the sections connected

All sections of upgraded launch system

This current launch system lets us position the abort valve 5m from the launcher and the pump another 15m back from that if required for high pressure launches and tests. We will do a high pressure test of the hoses and connectors in this configuration without a bottle to ensure the system can hold without any leaks.

Posted by on October 28th, 2010 2 Comments

Horizontal & Vertical Launcher Upgrade

Since we have been concentrating on water rocket cars for the last 6 months, our vertical water rockets have been collecting dust in the garage. So this weekend we have upgraded to launcher so it can be used for horizontal as well as vertical water rockets. This way we can launch the water rocket car as well as our vertical water rockets on the same launch day.

To achieve this we have  added an extra splash guard on two hinges which are fixed in the horizontal position by 2 bolts. We will replace the nuts with wingnuts to allow easier removal.

Extra Splash Guard on hinges

The extra splash guard has a slot cut out for the launch string to feed through in horizontal launch mode.

Splash Guard slot

Here is the launcher in the horizontal launch mode with its height adjustable gardena quick connect.

Launcher in Horizontal launch Mode

A support rod was cut and bored through the centre to allow a bolt to fit in it. A correct sized nut was then countersunk and apoxied into the top of the support rod.

Support Rod with nut embeded

The support rod clips onto the launcher when not in use

Support Rod stored while not in use

When the two botls are undone from the bottom of the launcher and the splash guard is moved to the vertical position, the support rod fits into a 22mm countersunk hole in the underside of the splash guard. A screw then holds it solidly in place. Here is the launcher in vertical launch mode.

Launcher in Vertical Launch Mode

The launch string is moved to  accommodate the vertical launch through a 90 degree bend.

Launch string moved for vertical launch

It takes only a couple of minutes to swap from one launch mode to the other. The 20Litre water container is used in both modes and keeps the launcher firmly in place.

Posted by on July 19th, 2010 Comments Off

Updates – Variable Height Launcher

Due to the extra length of our new “Green Hornet” water rocket car, we need to do some updates to the launcher. The updates needed are

– Lengthen the distance between the quick release and the launcher
– Make the quick release height above the ground variable

We have different rear wheels on the Green Hornet which has changed the height of the nozzle above the ground. The old launcher was setup with the quick release at a specific height to match the rocket car. So as we try these wheels and experiment with other lighter wheels, we need to be able to quickly adjust the height of the quick release.  Its important the quick release mates well with the rocket nozzle otherwise it will leak under pressure

Launcher Mated to the Green Hornet

As can be seen from the pic above the length of the hose to the quick release has been increased by about 30%. There is plenty of space between the new rear wheels and the launcher. The hose is kept rigid by being cable tied to a steel rod under the pipe.

Launcher hose strapped to steel rod

The steel rod is bolted to the movable section of the launcher.  The heads of two hex bolts (ready for 4 when I find another 2 bolts) run in metal channels (old curtain rod) up the face of the splash guard. Wingnuts on the bolts enable the movable section to be positioned and tightened at the location required.

Closeup of movable section of launcher

A hole was drilled in the movable section and a channel cut out of the splash guard for the launch string to be fitted. The launch string will work freely at any height.

Launch string groove

Here are a few more pics of the launcher mated to the “Green Hornet”

Launcher mated to rocket car

Another pic

Close up of mated quick release connection

The launcher and the new rocket car are finally ready for a launch day. We also have three reinforced bottles almost ready to swap in if hydrostatic testing goes well.

Posted by on July 4th, 2010 Comments Off