Friday, 5 August 2011

Launch Day 3/8/2011

Wednesday saw our first proper launch day in a few months. So here is the write up of the events of that day.

Everything setup and ready to go

Launch site: Sheep Field located behind our crew member Matthew Butcher's (Butch)
Weather: Cloudy with sunny spells
Wind: 0-6MPH
Crew: Doug, Matt & Ryan


Nexus I Pre-Flight

Launch 1. Nexus I
  • 100psi
  • 1.3l of water
  • This was the maiden flight of the In-Line Deployment System, The rocket had a relatively straight flight up and got good height, the parachute (to our amazement based on previous experiences as you tell in the video) opened just a little after apogee and glided down safely, a little head first admittedly, after this we moved the parachute tether up a little.
Launch 2. Nexus I

  • 100psi
  • 1.3l of water
  • The rocket flew straight up and got good height it then.......... came straight back down :( In my excitement of the success of the previous launch I had forgotten to arm the Servo Timer the rocket was written off and the Parachute system damaged.

Fracture I Pre-Launch

Launch 3. Fracture I

  • 90-100psi
  • 1.1l of water
  • This flight was the maiden flight of any splice for us in this case it was the Symmetric splice. The splice developed a nasty leak during pressurisation and due to an event earlier that day the launch abort mechanism was out of action we had launch quickly. The rocket flew relatively straight and due to the lower launch pressure the parachute came out well after apogee.

Fracture II Pre-Launch

Launch 4. Fracture II

  • 130psi??
  • 1.1l of water
  • This was the maiden flight of our first Asymmetric splice. This flight had an unexpected launch as during pressurisation the rocket released itself itself, it got good height and the parachute deployed perfectly at apogee. no footage was caught.
Launch 5. Fracture II

  • 130psi??
  • 1.1l of water
  • The same as the previous flight reoccurred due to this we lowered the launch pressure to 120psi for the rest of the day

Launch 6. Fracture II

  • 120psi
  • 1.1l of water
  • The rocket had a good straight accent and the parachutes deployed right at apogee however they got caught on one of the fins, luckily in the last 7m of decent one of the chutes suddenly flared preventing any damage.
Launch 7. Fracture II

  • 120psi
  • 1.1l of water
  • The rocket flew up at a slight angle due to the wind this flight, the parachute deployed a little after apogee and the rocket drifted a fair way from the launch pad.
Launch 8. Fracture II (Final Launch)

  • 120psi
  • 1.1l of water
  • The rocket flew up dead straight and the parachute deployed just after apogee, the rocket landed without damage and not far from the launch pad. Nothing like a textbook flight to end a day.

Main Report

Overall we had our best flight day to date despite the odd hiccup, we originally didn't think we would fly due a thunderstorm which happily for us blew over.

Once we had set up and gotten Nexus I filled up and on the pad we started pressurising we reached around 30psi and our launch abort valve popped apart, we thought at first we may have just not connected it properly first time round so we plugged it back in and reset. Unfortunately it happened again so we ended up detaching it from the pad leaving it dangling as we thought the expansion in the pressure line could be causing it to move. This solution worked for a time but when it came to Fracture II with its higher launch pressures the connector gave up on us again, luckily Butch had a spare connector which we could use for the time being.

We are still unsure of the cause of this problem, the locking tabs appear to be completely undamaged and the locking sleeve is not any looser than before. We haven't had this problem with any of the other connectors but we feel it may be advisory to uprate our connectors for brass ones or some other metallic connector.

We discovered the cause for the premature launches, it was the o-ring seal on our nozzle being pushed up in the launcher due to the higher pressures and pressing against the locking tabs in the release head releasing the rocket itself.

Damage done to the In-Line Deployment System in its unfortunate flight on Nexus I was repairable on the field so we could use it again. however its shell does now need to be remade. After this incident we put the Servo Timer II back to option 0 so that it would self arm.

To-Do List:

Uprate launcher or Solve abort valve locking problem.

Order a harder rubber compound seal for the nozzle

Remake In-Line Deployment System

Make a electronics pod with room for a camera and other flight electronics

Make or Order a larger parachute as the two 20inch chutes aren't quite good enough.

Make a larger deployment system ready for the bigger rockets

The end of a successful day


A brilliant day that could have gone better minus the few hiccups but what ya gonna do eh? :P
I need to make sure the to do list is taken away and everything done and tested by next launch day.

A massive thanks goes to George over at Air Command, your servo timer has given us the best launch day we've had despite my momentary idiocy with not arming it.
Until then

Thank You for reading

Regards Doug

1 comment:

  1. Hi Doug and team, great write up and video too! It sounds like you guys had a good launch day. :)
    It was interesting what you said about the rockets self launching. The only time we’ve experienced self launches was when the Gardena nozzle wasn’t locked all the way down. It looked like it was and even clicked in but it didn’t take much pressure to release it. This was because of how we make our nozzles and the top of the release head needed about 1mm shaved off it. When using the same nozzles with a brass release head, the clearance was fine. I notice you have single piece nozzles, so you may be experiencing a different problem though. One easy way to test is to insert the nozzle with the rocket into the release head and lock it in. Then give the rocket a nice strong pull, if it comes out then the nozzle wasn’t locked properly. If it’s properly locked in it should never release. Perhaps it may be that the tolerances are such that the nozzle doesn’t quite match the release head? Perhaps it’s the same issue with the abort valve?

    Good stuff guys!

    - George