This is a record of the days we launched rockets and the
events that took place.
 

Date:  13th July 2008  (3:00pm - 4:30pm)
Location: Denzil Joyce Oval, NSW
Conditions: Cool, light breeze, over cast. Temp: 15 degrees C
Team Members at Event: PK and GK

Only a short update this week. Less than 48 hours after dad got back from Europe we went down to the local park to fly just one rocket in order to test the Mk2. staging mechanism in flight. We didn't get to the park until late Sunday afternoon due to other commitments. Overall it was a successful flight day.

The rockets specifically made for this test were the Baryon and Neutrino rockets.

Baryon booster

The booster consists of a spliced pair of 1.25 L bottles giving a total of 2.1 L capacity. The tail section was taken from the Tachyon sustainer. The stager was fitted to the top of the rocket.

Deployment System

A small collar was made from another PET bottle to hold the parachute against the top of the booster. The deployment mechanism is simply a piano hinge arrangement on a flap with the hinge pin being a piece of solid core electrical wire tied to the sustainer. As the sustainer is released it pulls the wire and releases the parachute on the booster.

This approach has two problems, firstly the parachute starts deploying at peak velocity which could rip off the parachute and secondly if the staging mechanism fails to release the sustainer, it will also fail to release the parachute. The advantages are that it is simple and lightweight. We will unlikely use this technique on larger boosters as too much damage would occur if a parachute wasn't opened properly.

The staging mechanism details are here.

Neutrino sustainer

The sustainer was designed to be small and lightweight so that: we wouldn't need extra supports on the booster; it was going to have ballistic recovery; and that it would not leave the local park. The pressure chamber was made from a 600mL Coke bottle, with another half a Coke bottle used to create a crumple zone above the pressure chamber and a soft foam nosecone to absorb the landing impact.

The sustainer also has a new fin arrangement that we haven't used before although the water rocket community has been using for eons. We made the fins from 3mm plywood and coated it with 5 minute epoxy to water proof it and smooth it out. We then sanded it to a smooth finish. The fins were just glued with PL premium to the pressure vessel.

Launch Day Events

• The booster was setup on the medium launch pad and the sustainer was simply placed on top. Once the sustainer was in the stager we raised the Gardena collar and put a support pin under it to keep it locked. Once we started filling it and got to about 30psi the stager locking pin came out and we removed the support pin. After that we continued to fill up to the full launch pressure.
  
  For the first launch we filled it to 100psi, to make sure that not too much stress was placed on the components. We really couldn't use much less as the rocket is quite heavy at lift off. (Sustainer is carrying water) The first launch went great and the staging happened right on cue. The sustainer took off very fast and flew to around 90-100m. The crumple zone was a little... well crumpled, but the rest of the rocket survived well.
• We set it up again and this time launched it at 110psi. But the staging mechanism failed to release and the rocket went up about 30meters before slowly turning over and crashing. It was a funny looking crash because as the rocket hit the ground the nozzle cap broke on the sustainer and all the pressure came out so the booster was bounced back up by the blast of air from the sustainer.
  
  The crumple zone on the sustainer was now a lot more crumpled so we straightened it once again. We also replaced the broken nozzle cap. The failed staging though was a bit of a worry and so we removed a piece of plastic we had been using to try to reduce the metal on metal friction between the locking pin and the locking arm.  We increased the tension on the rubber bands, and gave everything that moved on the inside and out a good coating of silicon grease.
• We pressurised the rocket again to 110psi and launched it. This time the staging occurred when expected and the sustainer went higher than on the first flight. According to time of flight and simulations it went over the 100m (330') mark. The sustainer again needed a bit of repair, but was good to fly once more.
• We set it all up again as in the previous launch and everything went well again with the staging and parachute deployment. The booster sustained no damage over the four flights.
  
  We were happy with the staging mechanism performance after it was tuned and we only went home because the sun was starting to set which would have made it hard to video tape and photograph the rockets.

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

We will now be fitting the staging mechanism to a larger booster and sustainer for more test flights before fitting it to the big Acceleron booster. The final configuration of this has not been decided yet, but because of the potential of higher altitudes we will need to fly it at Doonside. Also because there are often quite a few people and cars at Doonside we will have to fit the sustainer with a recovery system.

As far as other rocket development goes, we are still working on repairing the Polaron rocket. It takes a while to find/drink around 20  2L bottles for the job.