Static test pads are often used to conduct systematic tests on rocket motors and engines of various sizes and types. To produce time-resolved thrust data, a programme controls both the motor ignition and data gathering devices
Rocket Motor Static Test Pad
What is a Rocket Motor Static Test Pad? • Static test pads are often used to conduct systematic tests on rocket motors and engines of various sizes and types. To produce time-resolved thrust data, a programme controls both the motor ignition and data gathering devices.
Basic working principle of Rocket Motor Static Test Pad:
Design: The rocket engine is held in place by the frame, which also provides stability and support while the rocket motor is fired for testing. The avionics bay, which houses the avionic components, is likewise housed in the frame. Avionics: The avionics include components that collect and analyse data, such as the load cell (for measuring thrust), Temperature sensor, and the SD Card (for storing the data of thrust and temperature). The rocket motor is mounted on or near to the motor mount depending on the orientation of the rocket motor, and when it is fired, the load cell is deflected/compressed, resulting in the rocket motor's thrust, which is processed and stored using the avionic circuit.
AVIONICS • Acquire and process data • Design electrical power system • Build a test control system • Data storage • Facilitate real-time data transmission & reception
As I was Avionics designer, I will primarily discuss about the procedure to build the avionics and little bit touch on design side. My individual contribution was Ignition, thrust measurement, GUI and complete avionics.
Procedure to build avionics is separated into three parts:
1.Igniton:
Fig 1
The fig 1 shows the first most part which was designed and simulated to perform ignition.
It consists of Relay, a 10 volts battery. And a ignitor . First turn off the safety switch, then the ignition button to be pressed in order for the ignition to begin. Once the button is pressed, around 10 secs wait time for the relay to be turned on in order to ignite the motor. The LED D1 will indicate if safety switch is turned on.
Output of ignition:
it can be seen that, once the safety switch is switched off and the button is pressed, the ignition period begins, which is around 10 seconds, and then the ignition is started for approximately 2 seconds.
2. Thrust measurement and LCD:
It can be deduced from the preceding diagram that the simulation of thrust will be presented on the LCD as well as serial monitor. It consists of load cell, hx711 amplifier, capacitors, resistors, transistors and LCD. We connected the outputs of hx711 to A0 and A1 of Arduino analog pins. It can be connected to digital pin as well. Due to limited pins in digital, we planned to use the analog pins.
Output:
The output of thrust and time can be seen in above picture. It was programmed to show that first column is where time can be seen and in second column thrust in newton can be visualized. At 0.80 secs I have changed the load cell value and the thrust is changed can be observed. 3.SD card and Temperature sensor:
From the above image it can be deduced that, it is the simulation diagram of SD card and temperature sensor. The working is that once ignition starts the temperature start to log the data to SD card in a notepad or excel sheet ,which can be used for plotting the graph between thrust ,time and temperature.
GUI for plotting graphs:
Above picture is the GUI which I created for plotting graphs of any two column, which can be selected from first data and second data in the GUI. For plotting we can select different type of plots.
Complete Avionics:
Ignition, thrust measurement, and SD card with temperature has been combined and simulated in order to create complete avionics.
Output:
The accompanying illustration shows the overall output of avionics. The safety switch is turned on in the virtual terminal, then it is turned off since I have switched SW1, and then a countdown from 0 to 10 seconds begins once the ignition button is hit. Then, as previously said, the ignition system operates. Then The time is displayed in the first column, and the thrust value measured from the load cell is displayed in the second column. With these two, the graph can be plotted, and the nature of our motor can be understood.
Procedure to build Design stand for Static Test Pad:
