Archive for August, 2010


Triple Bottle Reinforced Stack – Hydrostatic Test

We have had our triple bottle stack of reinforced bottles ready for a while to hydrostatic test and finally got around to it this week.

Each bottle in the triple stack is reinforced using this method.  We had previously hydrostatic tested individual reinforced bottles to 180psi but not a stack of them. The 3 bottles in the stack are held together using robinson couplings.

Hydrostatic Test of reinforced stack

Our goal was to hydro test to 180psi. The bottles were filled with water, safety glasses were put on and being well back we pumped up to 180psi. This was a pic we took which says 177psi but we did put a few more psi in it to be sure we got to the 180psi. We left it for about 30 seconds before releasing the pressure with the abort valve.

177psi or 12bar

We didnt see any leaks which was good, so it was a successful test.

The triple stack has been fitted to the water rocket car ready for a test run. Based on the success of the last launch day we will probably need to fit a parachute to the car to slow it down, so we will turn our attention to that next.

Posted by on August 20th, 2010 Comments Off

Water Rocket Car – Demonstration Day

We were very fortunate this month to be invited along to Killara High School here in NSW to give a demonstration of our Water Rocket Car.

Murray Arnison contacted us through the HHWRSA website explaining he would  be  teaching his engineering class about water rocket cars this term and if we would be interested in coming along to do a demo. We were more than happy to oblige :) We organised for Mark to get the morning off school for this special science excursion.

We spent about an hour with the class showing the Green Hornet Water Rocket Car as well as the launcher and pump and how it all worked.

We used 100psi and 1L of water to ensure the car wasn’t travelling too fast across the quadrangle and several volunteers from the class waited on the other side of the quadrangle to stop the car plowing into surrounding  brick walls. Here is the short video of the launches.

A big thanks to Murray and the students, we had a great morning.  Good luck with your water rocket car designs and testing this term !!

Mark did a powerpoint presentation to his class the following week explaining about  water rocket cars and how we had developed it from a 1 bottle car to what it is now. He  even took the Green Hornet  in to show the class. Everyone including his science teacher was very impressed.

Posted by on August 18th, 2010 Comments Off

Water Rocket Car MkXI – Launch Day 2

This launch day was to test the mist rocket attachment in a horizontal configuration as well as try out the camera that was mounted to the water rocket car.

Here is the video

Both of the runs went well. The rubber tyres on the back have improved the stability again so this seems the way to go.

The mist attachment worked ok, but there was a lot of water left in the bottles, probably 500ml out of 1.5L. So we will need to improve this. Also filling the second bottle without getting water back in the first or filling the third bottle was difficult, so we will need to find a way to improve that.

The actual distances we achieved were very good. This is primarily due to this being the first successful full run we have done with the lighter chassis. The second run at 120psi could have gone at least another 20m if we had enough road. The 144.5m (458ft) will stand as our current record, for the moment anyway. We did have a bit of wind on the day which may have assisted a little but not significantly

The camera mounted on the car worked well, we did some test runs previously with the camera pointed backwards towards the nozzle but it just got covered in water from the launch which made for a pretty uneventful video.

We are off to do a water rocket  demo at one of the State High Schools tomorrow, so we are all ready for that. We are keen to share a bit of WRcar  knowledge with the students and see what they can come up with.

Posted by on August 2nd, 2010 Comments Off