These things are, technically, proper rockets, in that they are propelled by ejecting mass carried onboard, but rather than smoke and flame all that comes out the back is water and air. The water comes from a tap, the air from a bicycle pump and the rocket is made out of old pop bottles, which makes them sound a bit of a joke, but despite this even a fairly simple rocket should be able to get close to 100 knots, so probably best to treat them with a certain amount of respect!

Current Silliness

Pondering weird new flying machines of the future involving long burn, low thrust, motors...

Engine Tests:  -  bottles half full in all cases.
	500 ml, 80 p.s.i., 5.1 mmφ exhaust		MPEG 269 kb
	500 ml, 160 p.s.i., 5 mmφ exhaust		MPEG 432 kb
	2000 ml, 80 p.s.i., 5.1 mmφ exhaust		MPEG 576 kb
	2000 ml, 160 p.s.i., 5 mmφ exhaust		MPEG 491 kb

Links

This site:

[There was no M.R.F. team at NPL this year due to the poor weather forecast.  ...perhaps next year.]

M.R.F. at the 2003 NPL Water Rocket Challenge   -   including video from launch pad camera (MPEG 445 kb).

M.R.F. team at the 2002 NPL Water Rocket Challenge   -   including pictures and building instructions for the winning rocket.

A salutary tale about transporting your rocket.

M.R.F. at the 2001 NPL Water Rocket Challenge.
        NEW!   Movie clip of round three flight (MPEG, 500 kb).

Previous Rockets. These are a bit of fun, not an example of quality aeronautical engineering! I do not have actual flight data for any of these rockets but have included data from simulations carried out using Paul Grosse's water rocket computer model.
	Mark IVb:	Current. 8 l, flown at as Met Research Flight entry at NPL competition.
	Mark IV:	8 l, parachute & camera test vehicle.
	Mark III:	9 l, development exercise.
	Mark IIb:	Flown at the NPL Water Rocket Challenge 2001 and pictured above.
	Mark IIa:	6 l, fin-stabilised.
	Mark I:	500 ml, stick-stabilised, proof-of-concept.

Other sites:

NPL's water rocket pages are a good starting point, particularly their
links to some other water rocket web sites.

Paul Grosse's water rocket site including download of computer model used here (and how to get it to run under Windows XP.

United Kingdom Rocketry Association. Almost exclusively pyrotechnic but occasionally some water rocket content including the International Rocket Week at Largs which has a small (relatively restricted) competition for water rockets.