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.

Thursday, January 31, 2008

Launcher Pressure Test

In the last few days we've pressure tested the Polaron IV launcher to make sure there are no leaks. There are a lot of connections and we were not sure how well the seals would seal around the plastic compression seals around some of the copper manifold pipes.

All was good and we took the pressure up to 215 psi ( ~15 bar ) for both the main stage line and the booster manifold.

When pressurising, we really have to think about what valves get open or closed and in what order.

For the first launch the pressures will be in the order 110 - 130psi.

We made dummy plugs for the booster nozzle seats for the test. This allowed us to test that side of things without having to put the boosters on the launcher. We fitted a strapping tape reinforced small 300ml coke bottle to the main stage release head and used the 7mm aluminium nozzle that the main stage will use. All held up well, and we tested the bleed valves
for both the main stage and the boosters with success.

We are now working on the booster retention mechanisms and getting those attached to the boosters and main stage.

The update from last Saturday's launch event is also now available on the main site:


Sunday, January 27, 2008

NSWRA and Polaron IV Main Stage

Yesterday was a fantastic day for rockets. We are now members of the newly re-grouped NSW Rocketry Association (NSWRA) and went to one of their launch events at Doonside. There were many rockets flown on the day and we got a chance to fly three of ours.

We ended up finishing the Polaron IV main stage rocket at about midnight the night before and so we got a chance to test it. We flew it twice with the full payload (new camera, altimeter and flight computer). Both flights were very good and the new parachute also worked well.

The Polaron IV rocket is now pretty much ready to be fitted with the boosters and ready to go. We will probably run some tests first on the boosters being launched from the new launcher with a dummy main stage.

Full details of the flight day will be published shortly with pictures and videos.


Friday, January 25, 2008

Black Tape and Sun

As I was inspecting a couple of our rockets last night and getting them ready for tomorrow's launch day, I noticed that the bottles were warped in a couple of places. It appears that the warping was most severe where the wide black tape was. This also occurred on the unpressurised sections of the rocket.

This was likely to have been caused during the last launch day when we left the rockets sitting out in the sun for a couple of hours. The heat absorbed by the tape was enough to shrink the bottles a little under the tape.

This is likely to occur to other rockets that are painted in dark colours. I think we will be storing our rockets in the shade from now on, and perhaps switch to lighter coloured tape when the black stuff runs out.

I spent most of the last couple of nights trying to get the Polaron IV main stage ready for flight on Saturday. The payload section now has the new FlyCamOne camera built in, the Z-log altimeter, servo motor, batteries and a newly built version of our flight computer (V1.3.2). I just have to attach the door and latch mechanism to the payload bay and then attach the whole thing to the rocket body.

We want to test fly it by itself to make sure all the systems and recovery works before we attach the boosters to it.

If we do get to fly it this weekend, I will post pictures soon after that.

Tuesday, January 22, 2008

Booster Tests and Launcher Details

We've updated the main site with the latest details of the Polaron IV launcher and the new Gluon boosters.
The name Gluon was chosen because it continues with the sub-atomic particle naming convention we have been using for our rockets and also because it is our first operational spliced rocket using PL Premium glue.

The update can be found here:

The update also includes a video of the booster tests. It's not overly exciting but included for those who are interested.


Monday, January 21, 2008

Launcher and Booster Tests

We've had a very productive weekend this week. We completed the majority of the new Polaron IV launcher, spending about 8 hours in the workshop on Saturday.

The image below shows the state of the launcher currently. I will do a full update this week and post it on our main website that shows all the details and discuss some of the design issues.

On Sunday it was too windy to launch regular rockets and so we opted to do a number of booster test launches. We fitted a booster with a regular nozzle and launched it from our medium launcher. The main aim of the test was to see how the booster behaved in flight and how its recovery system would work. Full details of the booster will also be posted with the next web update.

The larger parachute is now finished for the Polaron IV rocket and the payload section is also well under way. With the altimeter, flight computer, and video camera, the payload section alone is worth around $300. Hmmm... I think I will add a padded nosecone extension for protection in the trial flights. This padded nosecone will be removed for the higher performance flights once the design is proven.

Friday, January 18, 2008

Holidays over

Having been OS for the last 3 weeks the holidays are over, and we are back in full time production of the Polaron IV launcher and rocket. We are concentrating our efforts on this in order to get it done as soon as possible. During the holidays dad machined up a lot of the necessary components for the launcher, and now we are pretty much ready to start assembling it all together. Dad also did a bit of work around the workshop putting up some new shelves and fixing a few things making it easier to do development.

The Polaron IV rocket will also be fitted with one of the new FlyCamOne cameras as well as the altimeter. I am weighing up whether to build the next version of the flight computer for this rocket or just use one of the existing ones. I may use V1.3.1 in the first few trials and then upgrade when the next version is finished.

This weekend looks like weather is not going to play ball so workshop time is in order. Hopefully we can get most of the launcher done.

This launcher is intended to take us up to the next level in rocket pressure and size. We eventually intend to be launching reinforced rockets from this launcher and hence it is being designed to handle 35bar (500psi) operational pressure. It will support both single nozzle rockets as well as rockets with 3 boosters. The booster nozzles can slide in and out allowing us to used different sized boosters and main stage.

I'll take some pictures over the weekend of the launcher and post them here or on the main site.

PL Premium Glue

We still have a number of tubes of 10oz (300ml) PL Premium glue available so if anyone in Australia is interested please let us know. Just email me: at
The tubes are AUD$8 each + shipping from Sydney. Standard postage rates apply. You can check the Australian Post office website for shipping charges.


Monday, January 07, 2008

Katz Stager and new cameras

Katz Stager

While developing our regular rockets we have been working on a new staging mechanism in the background - the Katz stager. We normally don't release details of concepts until we test fly them, but since it's been a while that we've done an update I thought I'd include it. We have built a prototype and test fired it a number of times by hand, but it is still to fly and at full pressure.

The full details of the stager and photos of the prototype can be found here:

New video cameras

We have also bought a pair of FlyCamOne V2 video cameras this week. So far we are very happy with the functionality and performance of these cameras, and are looking forward to mounting them inside rockets and flying them. They can record video at 640 x 480 resolution @ 25fps with sound, which is not bad for a 37 gram package. Recording onto an SD card allows you to get up to 30 minutes of video. Compare that to our existing cameras that record 320 x 240 @ 15fps and can only capture 30 seconds of video.

The other nice feature is the optional external power supply, the swiveling lens+sensor for minimal drag in the air stream and external shutter contacts to allow a flight computer to trigger recording or take 1280 x 1024 pictures.