Each flight log entry usually represents a launch or test day, and describes the events that took place.
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Date:  22nd January 2011
Location: Denzil Joyce Oval, NSW, Australia
Conditions: 26 Degrees C, wind 25km/h gusting to 30km/h mostly clear.
Team Members at Event: PK, John K and GK

It has been a while since the last update. My family and I had been visiting the US for the last three weeks for Christmas and new year. We closely investigated white solid rocket fuel lying all over the mountain slopes in Colorado. It was nice to have a break from building and launching rockets, but we are looking forward to more development and rocket launches this year. I now have a better appreciation for those who launch water rockets in freezing conditions.

We brought back a few tubes of PL premium from the US as we only had a couple left which are close to their expiry date. With the fiberglass reinforcements we find that we don't use it much for splicing anymore, and use it mainly for attaching things to the PET bottles like fins.

Polaron G2 - Progress

Since the last update we have decided to extend the Polaron G2 rocket by another spliced-quad to give us a total of just over 21L capacity. The nosecone has also been completed and tested.

The nosecone has to be attached differently to how we normally do it due to the tape not bonding well to fiberglass. We had to glue a section of a PET bottle to the top spliced quad and then tap a number of holes so that screws could hold down the nosecone mechanism. We use big blobs of PL premium on the inside of the PET section and drill smaller holes into those. The machine screws then tap their own thread when you screw them in.

The fins for this rocket were constructed from Coreflute and attached with PL premium to a removable brace. All up they weigh 155 grams. This let's us swap the fins easily if they are damaged, or the spliced quad that they are attached to is damaged. Normally we tape the fin can on to the rocket, but because tape won't hold to the fiberglass, we are using a few small PL premium blobs to hold it in place.

We are also adding Craig's flight computer to the rocket's payload bay to gather data on the first flights. It will also serve as a back-up altimeter. I am interested in seeing what kind of G loading the rocket undergoes during launch. This will help us design components for future versions of the rocket.

The rocket is mostly ready for flight now, but we still need to pressure test it whole to around 150psi to check for leaks in the tornado couplings.

Nosecone

The entire G2 deployment mechanism including the G2 parachute weighs in at 361 grams. This is somewhat on the heavier side, but compared to the rest of the G2, it isn't too bad. There are weight savings possible, but we won't bother with this version.

I borrowed the idea of attaching the nosecone to the main parachute line from my LOC/Precision weasel pyro rocket and how it attaches the shock cord to the inside the body tube using epoxy and nylon line. I didn't want to put another hole in the nosecone.

G2 Nosecone Test Flight Report

We went down to the local park today to test fly the G2 nosecone. The wind was blowing pretty hard at around 25km/h so we nearly cancelled the launch. We decided to move up wind at the oval away from our usual launch area. Because the wind was going away from the road and down the length of the oval we decided to launch. When we launch the G2 we are going to have to do it in steady conditions to stop it drifting too far.

The first flight flew @100psi and slightly into the wind which meant it wouldn't drift nearly as far, especially with the bigger parachute. The nosecone separated soon after apogee, but it took the parachute a little longer to fully deploy as it had a few wraps of the main line on it. The rocket landed well without damage.

We flew the rocket again with an identical setup, but this time it flew down range during the boost phase, but luckily it didn't drift far and again landed without damage. We stopped after two flights as we didn't want to take the risk of damaging or loosing it in a tree.

The tests showed that the mechanism works well and can survive landings. The mechanism will experience bigger loads during the G2 launch, but the actual launch will be as good a test as any. We will now attach the nosecone to the G2 rocket for it's first flight. Although the deploy delay was set for 3.1 seconds after launch, the parachute didn't fully inflate until 5.8 and 6.1 seconds.

Here is a highlights video showing the operational detail and the two test flights.

Day 99 - Highlights

Servo Timer II

I've also been spending quite a bit of time over the last few weeks working on the next iteration of the flight computer we use on our rockets. The new version is smaller and easier to use. It has all new firmware which was mostly written on the bus while commuting to and from work. Sometimes you just wish the bus took a little longer when you're in the middle of debugging. I'll be posting more progress details on this in the coming months. I have the prototype working on a breadboard currently, and have started ordering the components. I'll get a few test boards made up first and fly them before making a bigger run. I also still need to write the user manual for it.

Flight Details