Date: 4th June 2006

Location: Backyard. (launch site #1)
Where exactly is that? Click the above link to see a Google Earth place mark. What is Google Earth?

Team Members: PK, GK and HK.

This was our first official launch day. In the space of about 3 hours we managed to build the first launcher prototype and fired the first bottles.

Events

• Very first launch on an improvised horizontal launch pad. We had to fire horizontally since the backyard is so small.
• The two rockets had no fins and no nosecones. It is really evident at how unstable rockets can be.
• One rocket managed to completely reverse course and headed back!
• We did learn that the launcher release mechanism works well and that the nozzles are easy to make.

Date: 11th June 2006

Location: David Thomas Reserve. (launch site #2)
Where exactly is that? Click the above link to see a Google Earth place mark. What is Google Earth?

Conditions: Cloudy and rainy day. A stiff breeze blowing northwards.

Team Members: PK, GK, Paul K, JK.

Other than the annoying rain this was a good day to be at the oval because there was no one else around.

Events

• Launched 2L and 1.25L rockets. This was the first time we launched vertically with enough decent pressure. We were amazed at how high the rockets went. probably 30-40 meters.
• The 1.25L rocket flew around 50 meters from the launch pad and into the bush. We recovered it successfully and it flew again.
• We used a SCUBA cylinder with a variable pressure regulator. Pressures ranged between 30 - 70psi.

Date:18th June 2006  11:30am – 1:00pm

Location: Curl Curl Beach , near the lagoon. (launch site #3)
Where exactly is that? Click the above link to see a Google Earth place mark. What is Google Earth?

Conditions: Nice sunny day with a moderate wind blowing north along the beach.

Rockets:

1 – 2L with ring fin. (Brotanek)

2 – 1.25L with ring fin and new foam nose cone. ring fin supported by IC containers. (Clobrda II.)

3 – unknown L – bottle from ??? with a single piece ring fin. and soft foam nose cone.

Team Members: GK,PK, IK, Paul K, JK, Jordan K.

Used a car foot pump to pump air instead of a scuba tank. This seems to work fine for pressures up to around 90psi, but it is a bit of work.

Most launches were between 40 – 70 psi.

Number of launches: ~ 10 to 12

Events

• Setup was straight forward, but had to move further up the beach as some people came near the lagoon.
• First was the 2L rocket, this one was the one from last week with a new tail as the old one was damaged on impact. The rocket flew into the water at the edge of the beach, Paul went to retrieve it, but the a wave managed to soak his pants completely. Note to self, bring a towel and change of clothes to next launch event.
• All three rockets went well and reached a decent height. Still do not have a way to measure the altitude, but something is in the works.
• The foot pump had to be operated by hand as the soft sand was quite unstable and kept tipping over, Note to self: must attach a bigger board for use on the beach.
• Angry Anderson and his friend were walking along the beach and came over for a chat. We let them have a couple of launches.
• On one launch Clobrda II  flew down range quite a ways and went into thick bushes it took quite a while to find it, but we did in the end. Perhaps some audio emitter should be added to make it easier to find … hmm either that or stay away from thick bushes.
• The launcher worked great except at one stage the release cord came undone. This was quickly fixed.
• All the rockets were quite stable in flight.
• Clobrda II’s fins were attached with a single wire at each strut attachment point. After a couple of impacts some of these broke. Even though the nose cone is quite soft and landing in sand, the impact shock is still quite high. Note to self: use stronger wire and also tape to help support the struts.
• We tested a 5mm restricted nozzle, which demonstrated a very slow take off, followed by good acceleration, but flying rockets horizontally is not very safe. The rocket started tipping over shortly after takeoff, due to the center of gravity being fairly low with all the water in it.

Notes to self

• Sand gets into everything at the beach.
• Children can keep themselves busy at the beach.
• Sand absorbs the impact better than grass.
• Have more clearance when testing smaller restricted nozzles.
• Take an accurate bearing when a rocket goes into bushes, and have someone guide you along the bearing.

Location: Curl Curl Beach , near the lagoon. (launch site #3)
Where exactly is that? Click the above link to see a Google Earth place mark. What is Google Earth?

Conditions: Overcast day with slight wind blowing north along the beach.

This week we had a collection of rockets. One was a 2L, two were 1.25L and a couple of detergent bottles.

Team Members: GK, PK, IK, Paul K, JK, Jordan K, RC, HK.

Number of launches: ~ 10 to 12

First couple of launches were powered by the foot pump, but the gauge was broken, I have no idea how the gauge needle got on the other side of the '0' stop. After that we switched to a battery powered compressor which made life a lot easier.

Events

• First rocket failed on the launch pad. The rocket was made of some detergent bottle, that burst at a very low pressure. It looks like it failed at the seam and burst. Only a tiny hole let all the air out.
• We tested an unfinished air brake system, with an improvised release mechanism, rocket went up fine, but the release did not happen and the rocket crashed into the ground. Upon hitting the ground the mechanism released. I believe there was too much wind resistance that kept the mechanism from releasing.
• One launch of the 2L rocket nearly hit Rod (within a meter) but he saw it coming and moved in time.
• Three launches were video taped, and later analysed for flight duration. Of the flights recorded they were 5.65 seconds for the gold rocket, and 6.86 and 7.08 seconds for the 2L. According to the simulations a flight time of 7.08 seconds is roughly 55 meters altitude.
• We fired the 2L rocket with a pressure of 95psi our highest pressure yet, flight time is unknown but it was pretty good. The impact managed to buckle the 2L bottle, so it did not fly again. We did not want to pressurise a damaged bottle. The nose cone on this rocket needs serious work and will be the focus before the next launch. The 2 strut ring fin with PVC moulding is holding up remarkably well.
• The gold rocket had 3 party whistles attached to it, but they did not work. I think there just wasn't enough air pressure to make them work.
• Everyone had a launch and the kids got soaked in the ocean again. I remembered to bring a towel and change of clothes so that wasn't a drama.
• We also used silicon grease to grease up the o-rings on the nozzles to make them easier to release.

Location: Curl Curl Beach , near the lagoon. (launch site #3)
Where exactly is that? Click the above link to see a Google Earth place mark. What is Google Earth?

Conditions: Nice weather.

Rockets: This week we had a collection of 5 rockets again.

Team Members: GK, PK.

Number of launches: ~ 12 to 15

This outing was only the two of us. We wanted to get lots of pictures and video, but that is a little difficult with kids running around.

Events

• We discovered on the very first launch that the compressor pressure gauge would only go up to 40psi and then not go any higher. Arrrggh. Air was still coming out so we would let it run for a bit more but without knowing the pressure we don't know how close we were to the safe pressure limit, and so we only filled conservatively. We ended up using a stopwatch to have some consistency in the air pressurising stage.
• We videotaped a lot of the launches and took plenty of photos.
• Most rockets performed well, with the exception of the 2L rocket which had a definite asymmetry in its aerodynamics and so would fly in an arc rather than straight up.
• A new rocket was tested that had as its nosecone the cut off half of a kids ball designed for throwing through the air. The ball had 3 aerodynamic whistles which made a nice sound on the way up and on the way down. Because the nosecone was so heavy I only made the ring fin struts very short. The CP was still way behind the CG. This rocket flew the straightest of them all, it really shot straight up and landed within a couple of meters of the launch pad. But because I used aluminium Venetian blinds to make the fin struts, they had deformed quite heavily on landing. They were used in order to reduce the weight to as little as possible (due to the heavy nose cone). The gold rocket uses thin flat pieces of stiff plastic reinforced with bamboo skewers, and that works just great. I will have to build the rocket again but using the bamboo skewers for reinforcement.
• We ended up using about 8 liters of water so that we know how much to bring next time.
• We also flew the air brake rocket tested on flight day 4, with a modified release mechanism. The old plastic ring was replaced with a metal loop with two fishing sinkers attached at either side with a short length of string. The idea here was that the sinkers would flap about on the way down and hence pull the ring off. On first launch nothing happened and the rocket went nose first into the sand. The rocket was designed for this so there was no damage. On the second attempt the ring came off about 20 meters above the ground and the air brakes opened. 2 of the airbrakes broke the string that was holding them open and the third worked just fine. This upset the attitude of the returning rocket enough that it came down sideways and hence slower. So in essence the air brake worked, but wasn't elegant. I think we will shelve this kind of airbrake principal.
• The gold rocket flew many missions, and survived them all really well.
• About half way through the launch day, the return valve in the launcher came loose and we found it in the sand next to the launcher. We put it back in but unsecured, and it was gone with the next launch.

Location: Curl Curl Beach , near the lagoon. (launch site #3)
Where exactly is that? Click the above link to see a Google Earth place mark. What is Google Earth?

Conditions: Nice weather.

Rockets: 6 with various configurations and 2 with parachutes.

Team Members: GK, PK, AK, Paul and John .

Number of launches: ~ 20 to 25

This was a long day with a total of 6 rockets tested. Today we were testing parachute designs and the parachute release mechanisms.

Events

• The first parachute tested did not deploy at apogee but rather on impact. A less than desirable result. The release mechanism was a simple loose fitting nosecone with the parachute tucked under it.  I guess that aerodynamic forces were too great even at apogee that the nose cone was kept on.
• On a later attempt of the same rocket, the nosecone came off about 2/3rds of the way down and the chute opened just in time. A more reliable system is needed.
• Another launch attempt resulted in very late chute deployment as the rocket was about to impact near a group of people walking along the beach, but luckily the chute saved the day and caused the rocket to drift over the ocean. Parachutes not only work well in the air but also well in water. Normally a rocket gets quickly washed up on shore, but with a parachute open under water the washing up progress is rather slow. Eventually a team member had to go wading to retrieve it. I did not attach the nose cone for fear that the attachment string would interfere with the parachute deployment, figuring it would be no problem to pick up the nose cone off the beach. But alas it was lost at sea. NOTE TO SELF: attach the nosecone!

• On a different rocket, the chute was just draped over the nosecone, and although this worked quite well, the rocket failed to reach a good altitude due to the additional drag I think.
• All other rockets performed well.
• Strengthening the Venetian-blind fin struts with bamboo skewers worked remarkably well, and there were no more buckled struts even with impacts from around 70 meters.
• Post video analysis of the amount of time the rockets were spending in the air, revealed with the help of a simulator that maximum altitudes of around 75 meters were achieved. (8.06 seconds flight time)
• The launcher base was modified and the heavy steel framework was replaced with a lighter aluminium frame. This makes it much more convenient when carrying it around.
• An unusual rocket was tested that had a separating nosecone, but was designed so that it acted as a parachute itself. In order for this to work to CG had to be moved way back, and this was achieved with a coil of wire around the ring fin. This coil hung loose and looked like a spring. This design was only partially successful but the nosecone deployed as intended. Due to the weight of the entire rocket, it did not achieve a very high altitude.
• The gold rocket performed very well again.
• We brought camp chairs to sit on and food to munch, the amount of stuff we bring to each launch is increasing.