The rocket itself was a construction of Florian's design; the initial test was done at dusk on and employed the use of speedlites and an ingenious flash trigger to get some high-speed shots of the rocket at launch. Shelly's pics of this can be found here.
We headed out the next day to get some daytime shots; my camera gear in this case was a bit better equipped for the task. Florian had estimated that the rocket was easily travelling at 145km/h just after launch, experiencing about 40g of acceleration. Briony was happy to trigger the launches, with the rest of us snapping away at the rocket.
Briony adding air pressure to the rocket - we used between 40 to 10 psi.
Launch! Note the awesome sputtering you get when the rocket runs out of propellant (a more spectacular example can be found here).