Archive for November, 2010


Potential Launch Sites in Sydney >200m

For any future record attempts we make with the water rocket car, we will really need flat, clean asphalt that is at least 200m or greater in distance. Our current longest launch site is 170m long before hitting the concrete gutters at each end.

We decided to use Google Earth to scan the industrial areas of  Sydney and the Central Coast (100km North of Sydney) to see if we could find suitable launch sites. We  then used Google Street View to see if the sites were somewhat level. After an hour of searching we identified 11 sites that seemed suitable.  All of these wonderful tools are free from Google.

Here is a link to the 11 potential sites shown in Google Maps

We have started to visit each of the sites to have a look ourselves to see if they are good candidate sites for the water rocket car launches

Potential 1 – Road is very flat along the course,  a tiny bit down hill at the southern end.  There are some parked truck trailers which may be a hazard, road is 15 m wide. Not a dead end, the road to the west at the end was fairly empty – Length 315m  – Good Candidate

Potential Site 1 - Huntingwood, NSW- 315m usable

Potential 2 -The road sloped downhill to the north down towards the main road. Road is clean, no rocks  and mostly flat. Linfox Distribution Warehouse is at the end  (southern)  may be busy on Sundays as these guys tend to run around the clock with large trucks. Not a dead end, no bubble at the end road is  15 m wide – 272m long – Poor Candidate

Potential 3 – Large slope on this road from the middle to the northern end , not suitable for water rocket car  – Poor Candidate

Potential 4 – Site is generally uphill to the south and lots of rocks and potholes, cracks in asphalt – Poor Candidate

Potential 5 – This is the Western Sydney International Dragway staging area. There is no public access unless events are on in which case there are too many people there  – Poor Candidate

Potential 6 – all uphill no good – Poor Candidate

Potential 7 – Nice flat asphalt road along the course, new asphalt, clean no rocks or potholes, 16 m wide – 230m usable,  might be busy as there are many warehouses,  all of the road is usable, big bubble at one end, dead end road – Good Candidate

Potential 7 - Horsley Park, NSW- 230m usable

Potential 8 – The southern end of this road is not usable due to a slope down to a roundabout, the middle and northern section are usable, road is  fairly clean, is a dead end on the northern end –  16 m wide with 440m usable – Good Candidate

Potential 8 - Prestons, NSW- 440m usable

Potential 9 – 14m wide, 310m usable with  a few small bumps and slightly uphill away from the bubble . Dead end road, Bubble is quite large, road is smooth and clean. – Good Candidate

Potential 9 - Liverpool, NSW - 310m usable

Potential 10 –
Not visited yet 500m long, looks uphill a little from Google Street View

Potential 11 – This site uses pavers or paver type etching in the concrete road,  either way the lines in the concrete between them make it an unusable road. – Poor Candidate

That gives us 4 out of the 9 sites we have visited as good candidate sites. WE would probably have to launch early sunday mornings at these sites, but it does give us backup options if one or more are not suitable that day.

Posted by on November 18th, 2010 Comments Off

Predict Armadillo’s Burst Pressure

Armadillo Aerospace are a US company that develops reusable rocket powered vehicles. They are currently working on a Vertical Takeoff and Vertical Landing (VTVL) vehicle for suborbital research and passenger flights.  They are a very exciting company and part of the new era of commercial space enterprises. Here is a picture of one of their vehicles (pixel) that they flew in the 2006 Lunar Lander Challenge

Armadillo Aerospace Pixel Hover

They also flew a vehicle in 2007, 2008 (won Level 1 prize) and 2009 ( Second in Level 2 prize). Here is a pic the 2009 vehicle.

Armadillo Aerospace Technicians inspect their rocket

This week Armadillo were burst testing their first 48″ sphere tank and they decided to hold an informal contest to see who could guess the pressure the tank would burst, the prize an Armadillo Tshirt and patch.  I couldnt help myself and entered a guess at 585psi.

Turned out our guess  was the closest. The  tank actually burst at 609 (sensor1) / 617 (sensor 2) psi. The Armadillo employees guesses were closer than mine though :)

We also got a mention on the Hobbyspace Blog ,  with the results of the competition , thanks to Clark who runs the website for the mention :)

I will be wearing the Armadillo Tshirt with pride when it arrives :)

Posted by on November 14th, 2010 1 Comment

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