This blog covers the day to day progress of water rocket development by the Air Command Water Rockets team. It is also a facility for people to provide feedback and ask questions.

Monday, June 16, 2008

First trials of new staging mechanism

Over the last few months we have been slowly working on a new staging mechanism. On Sunday we spent some time completing it and running through some initial trials. We test fired it 3 times, at 60psi, 100psi and 120psi. We did the tests just in the back yard with only bottles connected rather than real rockets. We were pretty happy with the performance after a few adjustments.



Next we are going to build a very small second stage (~600mL), and a small booster - likely to be just a spliced pair of bottles. We want it fairly small so that it does not leave the local park. We want to see how it will go in flight before it is put on a bigger rocket with a bigger booster. This staging mechanism will eventually go on the Acceleron rocket, but could be used for a third stage on the Polaron rocket as well.

A full write-up with diagrams of the internal operation will be posted on our main site once we have done the test flights and had a chance to evaluate its performance. Weighing in at 94 grams it is a bit on the heavy side for small rockets, but for bigger rockets it won't make much difference. Acceleron's V's staging pod weighed in at over 400 grams, but also included the parachute bay.
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7 comments:

Søren said...

Euhm, I have been looking at your launch system, and I'm thinking of doing something like it. But I have a question. Those Gardena fittings, do they have some kind of 1-way vlve so that the water in the rocket does not flow into the air hose?

George Katz said...

Hi Soren,

Yes, the Gardena fittings do have a non-return valve in them for the exact reason you describe. We make our own non-return valves specifically for the Gardena mechanisms.

Søren said...

So they do have the non-return mechanism or you built it yourselves? What is the item-number of the fittings you use?

George Katz said...

Hi Soren,

Sorry my reply wasn't very clear. What I meant to say was that the Gardena fittings don't come with the non-return valve, but we put one in.

The fittings we use are just standard off-the-shelf ones you find in the hardware store. We try to pick good quality ones, as we have found some of the cheaper brands have varying tolerances.

We use plastic ones for staging mechanisms because of the weight, and brass ones for the launcher because of the durability.

Jeremy Lorion said...

Hi it's me Jeremy
I've got just a little question where do you find those gardena fittings because i have one but it's made from plastic i would like to build boosters but i can't do it with gardena fittings (plastic).Can we buy it on the internet?

Jeremy

George Katz said...

Hi Jeremy,

Do you mean the Gardena fitting on the staging mechanism or the one that releases the booster? The one used on the stager is an off-the-shelf plastic one modified so that it screws into an aluminium pipe we made. The Gardena fitting that launches the booster is made of brass and that was just bought at the local hardware store.

Jeremy Lorion said...

okay i think i will make later
the plastic gardena fitting work perfect for me

thanks