Each flight log entry usually represents a launch or test day, and describes the events that took place.
Click on an image to view a larger image, and click the browser's BACK button to return back to the page.

Only 2 of the 3 boosters are shown.

The sustainer is an approximate size stand-in for the final design.

Reverse angle

Reverse angle

Reverse angle

Date:  25th September 2010
Location:Workshop and Doonside, NSW, Australia
Conditions:  Warm, Sunny 26 degrees C, very light breeze, high cloud.
Team Members at Event: GK, Paul K, John K.

Polaron G2

We have now begun work on a set of higher performance rockets based on the knowledge we have gained so far. We want to concentrate on optimizing the rocket as a whole rather than just the individual components. This means improving the aerodynamics and reducing weight, while increasing capacity as well as higher launch pressures. We are reviewing all systems to see where we can make improvements.

We are starting with the Polaron G2 rocket that will be developed in three separate phases. We are targeting initial launch pressures of 250psi (17 bar) and so most of the equipment will need to be retested/upgraded for these pressures. 

Phase 1

The first phase will consist of a 15.9L single stage rocket. This will use a bigger nozzle most likely 15 or 16mm. Phase 1 will test both the rocket systems and ground equipment to the higher pressures and loads.  

Phase 2

In the second phase we will add 3 x 10.6L drop away boosters and extend the main stage by another 3.15L for a total of ~19L. The nozzle will be reduced for the main stage to perhaps 9 or even 7mm for a long sustained burn. Jet foaming will be used to power the main stage while the boosters will use larger nozzles and water only.

This phase will include a set of static ground thrust tests to measure the thrust produced by the jet foaming main stage with different nozzles, to determine which one will be used in combination with the boosters.

Together the three boosters will have slightly more capacity than the Acceleron V booster.

Phase 3

Phase 3 will be broken into two sub-phases.

Phase 3a - A small streamlined sustainer will be developed and tested. The capacity and size of the sustainer is still yet to be determined.

Phase 3b - The sustainer will be fitted to the Polaron G2 main stage. The main stage will be reduced in length and capacity to accommodate the sustainer. The main stage nozzle will be increased again and the main stage will retain the 3 drop away boosters.

That's the overall plan over the coming months but actual time frame is open as it is dependent on development time available, launch windows, and resource allocation. The image below shows the overall size and design of the G2 rocket.

Click for a larger image

Spliced Quads

In order to get better efficiency in terms of volume per length of rocket, we are making longer sections of  pressure chambers by splicing together two spliced pairs of bottles, effectively giving us a 5.3L sections that are 110mm wide. We want to be able to retain the modular nature of our rockets as it makes it easier to develop and transport them. The sections are again connected by tornado couplings.

Fins

We are looking at using some 4mm plywood to make the fins out of for these rockets. Although a little heavier than the Corriflute material they are stiffer and can be made more aerodynamic. Hopefully they will survive the landing. We are initially going to paint them in epoxy, but if more strength is required, they can always be fiberglassed over.

We made a small fin bevelling jig so that we can make nice aerodynamic leading and trailing edges on the fins. It is based on this design: http://www.ausrocketry.com/forum/viewtopic.php?f=6&t=1782&start=13

The jig is made from a flat piece of wood with a Dremmel mounted at an angle. A couple of adjustable guides allow us to get nice clean edges.

Camera Sight

I've added a simple sight to the camera handle we've been using to film the rockets. At low altitudes it is possible to track the rocket on the camera screen but, when it gets too high, it is impossible to see. Now we can just look through the sight and know that both the DV as well as the high speed cameras are pointing at the right place.

We used it quite a bit on this NSWRA launch day, and it worked very well to keep the rocket mostly centered in the screen at higher altitudes. The better tracking accuracy should allow us to zoom in a little more during the flight.

Flight Day Report

• We went to the Doonside launch this week to do the final test flights of the Mk3. stager. We wanted to see how it held up to higher acceleration, and hence higher compression forces. The Baryon V booster was fitted with a 15mm nozzle. We also wanted to test the sustainer fin support arrangement for the higher accelerations.
• The first flight was at 120psi using 2L of water, which was closer to the optimum rather than the 800mL used during the Parraweena launches with smaller nozzles. The rocket took off visibly faster and the stager worked great at burnout again and the sustainer separated cleanly and vertically. We didn't have a camera or altimeter on either of the rockets, since we didn't know if they would survive the higher loads. Both the booster and sustainer landed well.  On the next set of flights we will need to include the altimeter and camera.
• The second 2-stage launch setup was identical to the first. We noticed that once the rocket was pressurised, the sustainer was leaning over slightly. This may be the result of bottle stretching, or it may have been that I put the rocket on the support braces the wrong way around. Each of the braces is individually adjustable for each fin. The flight went well, however, the rocket tipped over slightly in the direction the sustainer was leaning, but the short burn of the booster still kept it going mostly vertically.
• Staging was clean again and the rocket went fairly high. Both booster and sustainer landed without damage. The time from launch to staging was a mere 0.72 seconds. The large nozzle is very effective in getting all that water out quickly. :)
• With this launch, that makes 12 / 12 successful Mk3. staging flights since we fixed the initial issues with the stager.
• The last flight of the day was Axion VI because we had enough spare parts to put it together on the spot. We flew it in a Jet Foaming configuration, and used 2L of water for a longer sustained flight. Because of the added water, the takeoff was relatively slow, but because the rocket is fairly long, it remained stable.
• The boys also flew a number of small pyro rockets. We even entered one into the altitude competition, though we don't know the results yet.
• Overall it was a very good flight day, with quite a few people showing up for the launch. It's always good to see new faces.

Only a short video this week of the three water rocket flights from the day:

Flight Details