Where No One Has Gone Before… E80: The Next Generation Section 1, Team 1 Student 1, Student 2, Student 3, and Student 4 May 5, 2008.

Where No One Has Gone Before…

E80: The Next Generation

Section 1, Team 1

Student 1, Student 2, Student 3, and Student 4

May 5, 2008

IntroductionOverall Objectives

Use various data to piece together an accurate picture of rocket flight

Model rocket flight and compare predicted values to collected data from actual rocket flight

Overall Strategy

Develop a method for reading and interpreting data retrieved

Determine the physical properties of the rocket used

Test and verify the sensors that would be used to obtain the desired data

Background: The RocketsThree rocket designs

Large, medium, and small

RockSim Simulates the

launches to give predictions

Background: The SensorsR-DAS

5 V range Onboard storage and

telemetry

Sensors IMU Temperature and

Pressure Modal vibrations

Launch ProcedureLaunch site: Lucerne Valley Dry Lake

3000 ft. elevation

Telemetry and rocket prep stations Timed deployment of parachute as backup

Extensive safety precautions Range safety officers Extreme care handling motors and other

explosives All spectators alert during launch

Immediate recovery and data access

Rocket 1: Large IMULaunched on April 19th with a G339N motor

Notable windspeed during launch (15-25 mph)

Objective: Use data from accelerometers and gyroscopes to model the rocket's flight

Did not have all calibration equations

Rocket 1: Large IMUZ accelerometer

data, integrated twice, yields an informative plot

RockSim predicts apogee at about 180 m. Small error in

calibration propagates significantly

0

20

40

60

80

100

120

140

0 4 8 12 16 20 24 28 32

Position (m)

Time (s)

Rocket 1: Large IMUTime (seconds after launch)

Rotational Event

0.5 Change from CCW to CW

5.5 Parachute deploys

7.5 Stop; continue CW

11 Change from CW to CCW

18.5 Change from CCW to CW

27 Change from CW to CCW

31.17 Impact

Rocket 2: Large Vibration

Launched on April 26th with a G339N motor

Equipped with 16 piezoelectric strain gauges: 6 selected along the rocket body

Objective is to collect data on modal vibrations experienced by the rocket during flight

Rocket 2: Large Vibration

All sensors read two large spikes Spike at ignition Spike at parachute

deployment

Spikes tend to be larger on sensors nearer the nose

Rocket 2: Large Vibration

Fourier transform does not reveal any resonant peaks

Results consistent across all sensors

Rocket 3: MediumTemperature and

PressureLaunched on April 26th with a G61W motor

Sensors on board 4 Thermistors 2 Pressure Transducers 2 Accelerometers

Flight Objective Observe temperature fluctuations during flight Determine flight profile from pressure and

acceleration readings

Rocket 3: MediumTemperature and

Pressure

Spike in fin thermistor reading at landing

Internal avionics are protected

Temperature offset between different makes of thermistors

Rocket 3: Medium Temperature and

Pressure

IMU noise can be neglected

Data does not compare well with RockSim predictions

Bad accelerometer data and calibrations

Converted pressure readings from both IMU and RDAS show an identical flight profile

Rocket 4: Small IMULaunched on April 19th with a G149 motor

Parachute fails to deploy Fatal flat spin; rocket destroyed

Objectives Cope with poor data Consider data immediately prior to rocket

destruction

Rocket 4: Small IMUSpikes caused

by significant changes to forces acting on the rocket

Substantial oscillation upon downward flight

Rocket 4: Small IMU

Strange shape of height trajectory caused by a lack of gravitational force on the R-DAS accelerometer

Reaches apogee at time and altitude consistent with RockSim prediction

RecommendationsSome calibrations curves were inaccurate or

missing

200 Hz sampling rate of R-DAS limits accuracy of vibration and acceleration analysis

Limited sensor sensitivity Pressure changes measured in discrete steps No measured vibration for most of the flight

ConclusionsDespite limitations, enough data and tools were

provided to establish a coherent picture of each flight

Learning to cope with deficient tools and bad data is worthwhile

Valuable field experience

AcknowledgementsE80 Faculty: Professors Spujt, Cardenas,

Miraghaie

E80 Proctors

Mudd Amateur Rocket Club (MARC)

ReferencesSpjut, Erik and Cardenas, Mary (2008). E80 The

Next Generation Spring 2008. Retrieved 25 Apr. 2008 from http://www.eng.hmc.edu/NewE80/.