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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 33 - Simultaneous Launches and Foam Flights
Setting up our first simultaneous triple launch.
Left to right:
OO, J4 II and Acceleron II
Pressurised and ready to go. This is the view from launch control.
1st Attempt -
Using food colouring makes launches more colourful.
They never collided but came close.
2nd Attempt -
Its a vertical drag race.
Although J4 II was quicker off the mark, Acceleron II soon overtook it.
J4 II being launched with blue foam.
The foam as it comes out is a lot paler blue, but still clearly visible.
J4 II descending. You can still see the remnants of the foam spray.
Standard J4 II foam take off.
A great looking foam trail. The rocket flew relatively straight but the cross breeze blew the trail around.
Another launch of J4 II soon after takeoff.
New launch location where we will start launching multi stage rockets. Abandoned air field.
Date: 21st April 2007      6:45am - 9:20 am
Denzil Joyce Oval. (launch site #4)
Clear skies and cooler temperatures. Light breeze
becoming moderate.
(click the name for rocket details)
Name Capacity Notes
Acceleron II 18.75 L This rocket remained in the same configuration as the last flight day.
J4 II 5 L This rocket remained in the same configuration as the last flight day.
OO 2.5 L This rocket remained in the same configuration since it last flew.

Team Members at Launch Event: PK, GK, John K and Paul K.
Number of launches:

It had been three weeks since we flew rockets, having spent the last two weekends doing static tests with foam. Since we have 3 launchers we decided to have a go at launching 3 rockets simultaneously. This was partly for fun, but also a practice run for launching multistage rockets, where a lot has to be done on the launch pad to get it all ready.

We also launched three jet foaming flights, again just for fun for the kids.... you know .... the big kids.

Flight Day Events

  • We arrived early again, because we knew that setting up three launchers was going to take a while. During the week we made a distribution manifold for the air supply so that three rockets could be pressurised simultaneously. The manifold has three hoses connected to it with quick release fittings.

    The setup time from arrival to launch was close to 50 minutes!
  • We wanted to use an in-flight camera, but it turns out the AAA battery had just died and we only had spare AAs. Need to bring spare AAAs for next time.
  • We knew that Acceleron II would be much slower than J4 II and OO on takeoff, so we put 7mm nozzles on the faster rockets to slow them down a little.
  • On our first simultaneous triple launch we forgot to put in the ballast water on the Acceleron II rocket. The OO rocket also did not fire at the same time, but just a little later. There is a lot that happens on the launch pad to remember everything, including operating two still cameras and two video cameras at the same time.

    The flights were good, but the parachute on J4 failed to open and it landed heavily. OO's parachute opened about 3 meters above ground so it landed well. It's good to see one of our oldest rockets still flying.
  • On the second attempt things went a lot better. Although OO was again a little late off the pad, but it was still pretty good. The parachutes opened on all three rockets. Since Acceleron had the ballast water in the payload section it was a lot more stable. It flew very straight and to its highest altitude to date. In excess of 100 meters.

    The only downside was that the single guy on the field putting up soccer nets had a close shave as Acceleron landed 2 meters from him. Murphy in action I think. He wasn't too happy, so we apologised but didn't have any further trouble. The only other people on the field were on our team.
  • We then flew J4 II by itself a number of times with foam because it is fun to see the column of foam and the noise it makes. In the first two launches with a 7mm straight through nozzle, the rocket had a very slow start and became quite unstable during flight starting to pitch over during the burn. This may have been due to the strengthening cross breeze, and also most likely the weight of the water/foam at the bottom of the rocket.

    On one of the flights the parachute opened while the rocket was still in the thrust phase but probably at an altitude of 60 meters. (see video)
  • On J4's last launch we used the 9mm CD nozzle that we tested last week. We wanted to characterise its performance in flight. The rocket flew and more or less confirmed our results from the CD nozzle static tests. The flight was pretty spectacular because the rocket looked like it had the guidance of a moth near a light. The nosecone deployed, but the parachute never opened and so it ended up landing rather heavily. With minor repairs, it will fly again.
  • We have been looking for a new launch site for the past couple of weeks because the oval where we are is too small for multistage rockets and the close shave with the guy only confirmed it today.

    In the afternoon we went to check out a potential launch site after scouring for sites on Google Earth around Sydney. On Google Earth we found an abandoned air field, about 40 minutes away from home, and it is very easy to get to. The one great thing with satellite photos is that you can see trees, and their absence.

    The site is a great location where we have a couple of hundred meters radius of flat terrain without any trees. I think we have found the spot for our higher altitude projects. (see photos at left)

Simultaneous Water Rocket Launches

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

Flight Record

Launch Rocket Pressure (PSI) Notes
1a J4 II 120 7mm nozzle, good flight, but parachute failed to open. Some nosecone damage, but flyable. Used 1.25L of water.
1b Acceleron II 120 Forgot to put ballast water in it, but it remained stable and had a good deploy and landing. Used 1.5L of water per segment.
1c OO 120 7mm nozzle, rocket flew well, with the parachute opening about 3 meters above ground. Used 700ml of water.
2a J4 II 120 Very good flight with a 7mm nozzle, good deploy although a little early.  Used 1.25L of water.
2b Acceleron II 120 Excellent flight. This was Acceleron II's best flight to date. It went straight up and very high. +100m. Parachute opened a little after apogee. Good landing.
2c OO 120 Very good flight with 7mm nozzle and 700ml of water. Good deploy and landed well.
3 J4 II 130 Used a 7mm straight through nozzle with Jet foaming. Beautiful slow take off with long foam trail. Parachute deployed too early. Rocket landed well. Used 1.25L of water.
4 J4 II 130 Used a 7mm straight through nozzle with Jet foaming. Beautiful slow take off again with long foam trail. Parachute deployed a little too early as well. Rocket landed well. Used 1.25L of water.
5 J4 II 130 Used a 9mm CD nozzle and jet foaming, with a very good slow take off. The rocket lost flight stability during the thrust phase. Nosecone fell off, but parachute failed to open. Rocket spiralled down, with a little TLC it will be up and lfying again.

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