last updated: 21st october 2023 - Day 226 to Day 230 - Various Experiments

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Construction - Basic


Ring Fins

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Construction - Advanced

Robinson Coupling

Splicing Bottles #1

Splicing Bottles AS#5

Reinforcing Bottles

Side Deploy #1

Side Deploy #2

Mk3 Staging Mechanism

Multi-stage Parachutes


Construction - Launchers

Gardena Launcher

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Medium Launcher

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Launch Abort Valve

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How It Works

Drop Away Boosters

Katz Stager Mk2.

Katz Stager Mk3.


Dark Shadow Deployment


Recovery Guide


How Much Water?

Flying Higher

Flying Straight

Building a Launcher

Using Scuba Tanks


Video Taping Tips

MD-80 clone

Making Panoramas


Burst Testing





Servo Timer II




V1.3, V1.3.1, V1.3.2


Deploy Timer 1.1

Project Builds

The Shadow

Shadow II


Polaron G2

Dark Shadow

L1ght Shadow

Flight Log Updates

#230 - Tajfun 2 L2

#229 - Mac Uni AON

#228 - Tajfun 2 Elec.

#227 - Zip Line

#226 - DIY Barometer

#225 - Air Pressure Exp.

#224 - Tajfun 2

#221 - Horizon Deploy

#215 - Deployable Boom

#205 - Tall Tripod

#204 - Horizon Deploy

#203 - Thunda 2

#202 - Horizon Launcher

#201 - Flour Rockets

#197 - Dark Shadow II

#196 - Coming Soon

#195 - 3D Printed Rocket

#194 - TP Roll Drop

#193 - Coming Soon

#192 - Stager Tests

#191 - Horizon

#190 - Polaron G3

#189 - Casual Flights

#188 - Skittles Part #2

#187 - Skittles Part #1

#186 - Level 1 HPR

#185 - Liquids in Zero-G

#184 - More Axion G6

#183 - Axion G6

#182 - Casual Flights

#181 - Acoustic Apogee 2

#180 - Light Shadow

#179 - Stratologger

#178 - Acoustic Apogee 1

#177 - Reefing Chutes

#176 - 10 Years

#175 - NSWRA Events

#174 - Mullaley Launch

#173 - Oobleck Rocket

#172 - Coming Soon

#171 - Measuring Altitude

#170 - How Much Water?

#169 - Windy

#168 - Casual Flights 2

#167 - Casual Flights

#166 - Dark Shadow II

#165 - Liquid Density 2

#164 - Liquid Density 1

#163 - Channel 7 News

#162 - Axion and Polaron

#161 - Fog and Boom

#1 to #160 (Updates)



Each flight log entry usually represents a launch or test day, and describes the events that took place.
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Day 62 - 15mm Nozzles with long launch tube and CATOs
Prepping Tachyon IV for first flight.
At ~170psi the coupling fails and the top section is ejected.
An old workhorse - J4 getting ready to fly.
Perfect weather conditions to launch in.
You need to keep your eyes peeled at all times.
Some of the Pyro rockets flown on the day by other members of NSWRA.
Axion launched with 15mm nozzle and a long launch tube.
Axion reached 480 feet. (146m)
Axion's second flight.
Too close to the rocket eating trees.
J4 Flight 1

(Photo:Andrew Eltobaji)

Water only flights are visibly faster than foam flights at the same pressure.

(Photo:Andrew Eltobaji)

A deployed parachute is always good to see.

(Photo:Andrew Eltobaji)

Katz stager Mk2.
Stager undergoing ground tests at various pressures.
Mk2 stager connected to the booster on the bottom with a dummy second stage on the top.

Date:  28th June 2008
Doonside, NSW
Cool, light westerly breeze, mostly sunny. Temp: 10-18 degrees C
Team Members at Event:
GK, AK, PaulK and JK

With dad in Europe this launch day, we didn't launch any of the bigger rockets as we need to bring both cars to fit all the equipment in. But there were a few new experiments we wanted to try with the smaller rockets. Photos of pyro rockets from the launch day are available: here.

Launch Day Events

  • First up we wanted to fly Tachyon IV a reinforced pair of bottles made at least 6 months earlier. This Robinson coupled pair of bottles has been hydrostatically tested to 200psi when it was made, and again to 180psi a few days before the launch. However, the coupling gave way on the pad at around 160-170psi. The bottom of the bottle failed and the upper bottle with payload flew off. The bottom bottle was forced downward  over the release head and I had to cut the nozzle out of the deformed bottle.

    We were testing 4 new things on this flight:
    a) Flight  testing V1.5 of the flight computer.
    b) Launch detect contacts connected to the flight computer. A plastic strip attached to the launcher  gets pulled out during launch triggering the flight computer. This is an alternative to using a G-switch.
    c) High pressure launch using Robinson coupled re-enforced bottles.
    d) A baffle connected to the Robinson coupling to prevent the blow-through effect on a high pressure launch.
  • We learned a couple of things from the failed launch. You should always expect the rocket to blow even though it has been tested. The flight computer survived the violent acceleration of the explosion. The baffle was ripped out of the bottom bottle, but because all the air was redirected in 4 directions sideways it prevented the top bottle from flying too high. The entire payload section survived without damage.
  • To get at least one good launch under our belt we launched the trusty J4 with water only. It was a good uneventful flight. We flew it again for the next launch but with foam this time. Again it was a good flight with a good landing.
  • Next we replaced the standard 9mm release head on the medium launcher with a 15mm release head. This release head has an 1120mm long integrated launch tube. The Axion rocket with its full bore Tornado couplings was chosen as the rocket for the test. This was our first long launch-tube launch. We filled the rocket with 1800mL of water.

    The launch was a lot faster than what we are normally used to and the launch tube and release mechanism worked well. We applied some silicone grease to the launch tube prior to launch to minimize the friction effects of the launch tube against the nozzle. The rocket was flown with a video camera and an altimeter. The camera got a nice steady shot on the way up. Altitude was 345 feet (105 m).

    This release head will be used for our first FTC trials.
  • As we were filling the rocket for the second attempt and approached 130psi, one of the middle Tornado couplings let go of the bottle thread and the top part of the rocket flew off. Surprisingly there was no damage done to any part of the rocket. The top section flew up quite a ways but being unstable simply tumbled back down and landed on the grass. The on board video camera filmed the entire episode. As I was the person pressurising the rocket I couldn't be filming the rocket at the same time and so we don't have any ground footage of the incident.
  • I unscrewed the coupling and tried it on another bottle. If tightened too much it jumped a thread. Perhaps the coupling was just over-tightened. The rocket had been sitting in the sun for a while as well and the coupling being black may have heated up and softened further. Not really sure what happened here.
  • I replaced the coupling just to make sure, and screwed in the Tachyon IV payload section as I wanted to test the V1.5 flight computer in flight. We filled it and launched it again without incident. This time the rocket flew to 480 feet (146 m) . Since the payload section wasn't setup to fly with a video camera no onboard footage was obtained.

 (If the video does not play, try the latest Flash player from Macromedia)


We are happy with how the 15mm launch tube and release head worked and we'll be using more of it in the future.

Katz Stager Mk2.

A number of ground tests were performed in the last couple of weeks of the Mk2 staging mechanism. The video below shows the ground tests. The first couple of tests are of an earlier prototype with the final two tests being with the actual flight hardware. The second stage in these videos is completely filled with water to prevent it from flying anywhere.
(If the video does not play, try the latest Flash player from Macromedia)
We are now building a small second stage rocket and booster to test it in flight.

Flight Details

Launch Details
Rocket   Tachyon IV
Pressure   160-170 psi
Nozzle   9 mm
Water   870 mL 
Flight Computer   V1.5 - 4.6seconds
Payload   Baffle
Altitude / Time    N/A
Notes   Rocket exploded on the launch pad. Bottom bottle was destroyed, but payload section, fins, nozzle survived well
Rocket   J4
Pressure   130 psi
Nozzle   9 mm
Water   1.25 L 
Flight Computer   V1.3.1 - "9"
Payload   None
Altitude / Time    N/A
Notes   Good flight, nice and stable. Good deployment and good landing.
Rocket   J4
Pressure   130 psi
Nozzle   9 mm
Water   1.25 L  + foam
Flight Computer   V1.3.1 - "9"
Payload   None
Altitude / Time   N/A
Notes   Very good flight with foam. Parachute deployed right around apogee, good landing.
Rocket   Axion
Pressure   120 psi
Nozzle   15 mm with 1120mm long launch tube.
Water   1.8 L 
Flight Computer   V1.3.1 - "9"
Payload   Altimeter, Camera
Altitude / Time   350 feet (105m)
Notes   First flight to use a 15mm nozzle with a long launch tube. Fast take off, good landing.
Rocket   Axion
Pressure   130 psi
Nozzle   15 mm with 1120mm long launch tube.
Water   1.8 L 
Flight Computer   V1.3.1 - "9"
Payload   Altimeter, Camera
Altitude / Time   95 feet (29m)
Notes   Middle coupling let go at 130psi. Just prior to launch. Top section landed well without damage.
Rocket   Axion
Pressure   130 psi
Nozzle   15 mm with 1120mm long launch tube
Water   1.8 L 
Flight Computer   V1.5 - 4.6seconds
Payload   Altimeter
Altitude / Time   480 feet (146m)
Notes   Very good launch, straight and fast. Good parachute deploy and good landing.


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