Overview This procedure is used for testing the the static thrust produced by a water rocket. Accurately measuring the thrust curve can be used for evaluating the effectiveness of various modifications made to the rocket.

Caution

Due to the high pressures involved perform this experiment behind a safety barrier.

Equipment

• Air source. This includes pumps, tanks, compressors etc.
• Pressure gauge
• Thrust measurement test stand 1 or Thrust measurement test stand 2
• Video Camera (optional)
• Remotely activated release head

Procedure

1. Setup the test stand according to the test stand's specifications.
2. Calibrate the test stand to cover the desired thrust range.
3. Fill the rocket with water.
4. Attach air supply to the rocket via the remotely activated release head.
5. Attach the rocket to the test stand.
6. Pressurise the rocket to the desired pressure.
7. Start recording / logging software
8. Start cameras
9. Launch.
10. Suspend calibration weight from nozzle, and wait a few seconds.
11. Stop cameras
12. Stop recording software.
13. Save captured data and optionally perform further analysis in other applications.

Notes

1. It is useful to video tape each test firing, as the video can give clues to events seen in the thrust curve.
2. Inspect the data after each firing to make sure good data was recorded and that the thrust did not exceed the dynamic range of the test stand. Ie. that the data is not clipped.
3. Perform multiple firings of the same rocket modifications so that an average can be taken.