Launch Day 10

Launch Day: 10
Date: 19/10/08 Midday
Location: Montview Oval
Rockets: H2

This launch day was again to test the dual parachute deployment system. A lot of ground based testing was performed prior to the launch day on the launcher, the pressure bottles and both parachute modules, all was in readiness for launch day.

The pressure bottles were fitted with both the drogue and main chute modules and the Large Dummy PPNC nosecone was fitted. The new revision of H2 weighed in at 333g and was exactly 100cm tall.

H2 prior to launch

H2 prior to launch

The conditions were hot with almost no wind when we arrived so we setup quickly. It was a good decision to go to the park on a Sunday instead of a Saturday as there was only us and 2 guys flying remote control planes. We just had to make sure we co-ordinated the launch with them so we didn’t chance knocking one of out the sky … :)

We had set the drogue release at 3.4 seconds and the main at 5.75 seconds. These figures were based on a projected height of 250ft (simulator) and an apogee at 4.06 seconds (simulator) with a launch pressure of 110psi and 800ml of water.

Here is the result of launch 1

As you can see we were partially successful. The elastic band didn’t release from the timer on the drogue chute but the main chute deployed as intended and we recovered the rocket successfully.

We made some minor modifications to the drogue timer and setup for another launch. All was going well until a bit of wind picked up and the rocket started tilting over at about 15 degrees. The pressure at this stage was about 80psi, we stopped pressurising and waited for the wind to die down, unfortunately it didn’t, we decided to abort but it was too late, the rocket tipped over further (away from us) and the gardenia on top of the launcher gave way. The rocket took off like a ground hugging cruise missile. It went approx 40m horizontally before touching down and skidding another 15 or so metres.

When we reached it, the drogue had deployed (at least that worked), one of the fins had broken away from the RFA, the upper modules were full of dirt and the top of the dummy PPNC had popped out. It looked ok, we gave the timers a quick test and they seemed ok as well. At the launcher the top gardenia fitting had come away.

All these items we fixed onsite within about 20 minutes, cleaned the wrocket up and filled for another launch. We waited until there was no wind before placing the wrocket on the launcher and pumped quickly to fill it before the wind picked up again. At 100psi the foot pump broke (internally) so we launched at 100psi, the timer settings the same as the first launch.

Flight 3 crashdown

Flight 3 crashdown

Unfortunately none of the chutes deployed, they didnt even look like doing so.  IT looked like the main chute door was open  but the crash may have caused this and the drogue door was closed. With the wrocket unflyable, the pump broken and the temperature quite high we decided to to call it a day.

Things we learned

  • We need a launch rail … our wrockets are getting taller and they have a lot of surface area for the wind to act on. So for safety’s sake we will build a rail.
  • The reliability of the side deploy is not good at the moment but we will persevere. Its possible the cruise missile crash loosened the timer attachments enough for them to fail on our last launch.
  • Our preflight testing of the pressure bottles was worthwhile, no leaks were encountered.
  • We may look at a 12V pump to replace the foot pump

This entry was posted on Wednesday, October 22nd, 2008 at 6:42 pm and is filed under Launch Days. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.


2 Responses to “Launch Day 10”

  1. Mitch Says:

    Any chance you could post details of when your next launch day may approx be. I’d love to come watch you guys. I’m in beecroft. Just finished my first wrocket/launcher and am itching to try it out…

  2. todd Says:

    Hi Mitch, we are hoping for a launch either this coming sunday 16/11 or the following one. Email me directly at for more details. Would be great to have you come along and launch your new wrocket as well