Testing Processes
Aim.
I aim to test and calculate the acceleration of the water rocket as its released and to calculate the G force experienced during flight.
Methods.
A Microbit will be used to send and receive data that can then be stored and processed to give relevant data in the form of charts. There are two sets of JavaScript, one is “Z-RECIEVER” and the other is “Z-SENDER” The step-by-step guide on how to program the Microbits will be on the website.
Z Sender JavaScript.
radio.onReceivedNumber(function (receivedNumber) {
led.toggle(4, 4)
serial.writeValue(“z”, receivedNumber)
})
basic.showString(“Z RECIEVER”)
radio.setGroup(69)
serial.writeLine(“Acceleration”)
basic.forever(function () {
})
Z Sender JavaScript
basic.showString(“Z SENDER”)
input.setAccelerometerRange(AcceleratorRange.EightG)
radio.setGroup(69)
basic.forever(function () {
radio.sendNumber(input.acceleration(Dimension.Z))
})
Theory.
I started by using a water rocket simulator by Sciencebits.com to get a predicted flight as I can compare it to later tests and see if this initial simulator is accurate, the chart below shows its simulation that would peak at 17m/s and travel a max height of 12.5m.
These are the calculations and methods used by the simulator to create the chart.
The next charts show the acceleration of the water rocket during actual testing, it was tested on a day that had minimal wind and was pressurized to 40PSI, the charts below shows the acceleration in G hits up to 8G at 40PSI holding 500ml of water, to test the calculations of the simulator I then added more weight by adding more water and lowered the pressure to 20PSI.
The added weight and less pressure shows the effect on acceleration by it not reaching the same level of G compared to the first test, this is because added weight and less pressure results
References / sources
http://www.sciencebits.com/RocketEqs- Rocket simulator calculation page
http://www.sciencebits.com/RocketCalculator- Rocket calculator
https://makecode.microbit.org/- Microbit JavaScript code