Characterization of Model Rockets in Flight Section 4, Team 1 Student 1, Student 2, Student 3 and Student 4

Introduction Using prototypes can prevent costly errors in complicated systems Different types of sensors are required to collect a wide variety of data The current set of rockets follow in the footsteps of Mudd I and Mudd II

Preparation: Rocket Launch Following a series of checklists: Configure R-DAS and Video Load parachute and ejection charge Install motor Followed NAR and Tripoli guidelines

Procedures: Data Collection R-DAS - Rocket Data Acquisition System Three batches of sensors: IMU Strain Gauges Thermistor and Pressure Transducers These batches are used to model: Velocity and position Vibration and response Atmospheric variables Calibration curves are used to convert from digital signals to physical variables Video camera © Bruce Yan

Theory: Rocket Flight Simulation The MATLAB script numerically integrates acceleration given by an experimental thrust curve It makes several simplifying assumptions: The rocket only moves in two dimensions The wind exerts a constant lift force The rocket travels straight for 6 feet along the rail. Then it instantaneously changes direction towards the wind The coefficient of drag is.75

Theory: IMU The IMU contains: Accelerometers Gyroscopes Sensors are mutually orthogonal to create a local set of axes Can convert between local axes to global variables by using a rotational matrix Data were used to recreate the rocket flight path The global variables can be found from the local variables by using a rotation matrix.

Theory: IMU IMU Calibration Curve

Medium Rocket: IMU A variety of engines were used Theoretical models were created using MATLAB and RocSim Flights were modeled using the IMU data in conjunction with a MATLAB script Both the theoretical models overestimated the altitude of the apogee

Rocket Flight Model: Medium IMU Experimental Modeling of IMU Rocket Flight 2 (Motor G79W, 4/26/2008)

Rocket Flight Model: Medium IMU Experimental 3D Modeling of IMU Rocket Flight 2 (Motor G79W, 4/26/2008)

Rocket Flight Video: Medium IMU © Masanori Honda

Small Rocket: IMU Tragedy Strikes! The R-DAS did not detect apogee and deploy the parachute Data was irrevocably damaged by the fall © Masanori Honda

Rocket Flight Model: Small IMU

Theory: Thermistors The locations of the Thermistors are shown below Temperature can be found as a function of the resistance of the thermistor using the Steinhart – Hart (S-H) Equation displayed below.

Theory: Pressure Sensors The rocket has two pressure sensors R-DAS IMU The two pressure sensors were calibrated with an desiccation chamber The altitude of the rocket can be calculated using the relationship between altitude and the atmospheric pressure shown below.

Smoothing Function

Medium Rocket: Temperature and Pressure Apogee R-DAS: m IMU: m Medium Temperature and Pressure Flight 1(Motor G67R, 4/19/2008)

Theory: Vibration The Modal shape of a linear objects can be given by the following equation The first three Modal shapes should have the shapes below The following diagram displays the location of the strain gauges on the rocket

Medium Rocket: Vibration Plot of time vs raw data for 3-4 secondsPlot of time vs raw data for seconds

Medium Rocket: Vibration

Plots of sensor positions to corrected magnitude

Conclusions The IMU rocket showed: Theoretical models consistently overestimate the actual apogee by 30-40% The temperature pressure rocket: Consistency between two pressure sensors Temperature of the rocket during flight The vibrational rocket: Only the first mode was observed The first resonance occurred at 43 Hz © Masanori Honda

Further Work Suggestions for design improvement: Change from the R-DAS to another type of data acquisition system due to issues: The R-DAS altitude sensor does not reliably detect apogee due to low resolution The R-DAS doesn’t sample at high enough of a frequency to detect higher vibration modes Further rocket flights to determine any inefficiencies in the rocket design © Masanori Honda

Acknowledgements Professor Spjut Professor Cardenas Professor Miraghaie Professor Yang Professor Wang Proctor 1 Proctor 2

Acknowledgements And the E80 students who have risked their lives for the course © Med Temp. Press. Rocket

Questions?