The Comparative Analysis of Airflow Around a Rocket

March 21Second test flight of full-scale vehicle April 12Rocket ready for launch April 16Rocket Fair/Hardware & Safety check April 19SLI Launch Day

1.First stage burn 2.Stage separation. 3.Booster coasts to its apogee and deploys main parachute. 4.Booster lands safely 5.Second stage motor burn 6.Sustainer reaches apogee, deploys drogue parachute 7.Sustainer descends under drogue parachute to 700ft 8.Main parachute deploys, slowing rocket to safe landing speed of fps. 9.Sustainer lands safely.

Stable launch of the vehicle Target altitude of one mile reached Smooth stage separation. Proper deployment of all parachutes Safe recovery of the booster and the sustainer

Length 156.5” Diameter6” Liftoff weight37.4 lb. Motor K1275 Redline (54mm) CP118.8” (from nosetip) CG ” (from nosetip) Static Margin 4.23 calibers

Length 94” Diameter4” Liftoff weight12.7 lb. Motor J380 Smokey Sam (54mm) CP83.8” (from nosetip) CG63.6” (from nosetip) Static Margin 5.04 calibers

LetterPartLetterPart ANoseconeHPayload Bay B Main Parachute I Payload Electronics C Sustainer E-Bay J Drogue Parachute DFinsKMotor Mount E Transition L Main Parachute F Booster E-Bay M Payload Electronics GFinsNMotor Mount

Fins: 1/32” G10 fiberglass + 1/8” balsa sandwich Body: fiberglass tubing, fiberglass couplers Bulkheads: 1/2” plywood Motor Mount: 54mm phenolic tubing, 1/2” plywood centering rings Nosecone: commercially made plastic nosecone Rail Buttons: large size nylon buttons Motor Retention system: Aeropack screw-on motor retainer Anchors: 1/4” stainless steel U-Bolts Epoxy: West System with appropriate fillers

BoosterSustainer Flight Stability Static Margin Thrust to Weight Ratio Velocity at Launch Guide Departure: 54 mph (launch rail length 144”)

Wp - ejection charge weight in pounds. dP - ejection charge pressure, 15psi V - free volume in cubic inches. R - combustion gas constant, ft- lbf/lbm R for FFFF black powder. T - combustion gas temperature, 3307 degrees R

Ejection charges have been verified using static testing. SectionEjection Charge Booster2.15 g (of FFFF black powder) Sustainer (Drogue)2.0 g Sustainer (Main)3.15 g Stage Separation Charge1.0 g

ComponentWeightParachute Diameter Descent Rate Booster (predicted) 399 oz92 in. (main) 17.6fps Sustainer (measured) 211 oz24 in. (drogue) 54.7 fps Sustainer (measured) 211 oz60 in. (main) 17.5 fps

Tested Components C1: Body (including construction techniques) C2: Altimeter C3: Data Acquisition System (custom computer board and sensors) C4: Parachutes C5: Fins C6: Payload C7: Ejection charges C8: Launch system C9: Motor mount C10: Beacons C11: Shock cords and anchors C12: Rocket stability C13: Second stage separation and ignition electronics/charges

Verification Tests V1 Integrity Test: applying force to verify durability. V2 Parachute Drop Test: testing parachute functionality. V3 Tension Test: applying force to the parachute shock cords to test durability V4 Prototype Flight: testing the feasibility of the vehicle with a scale model. V5 Functionality Test: test of basic functionality of a device on the ground V6 Altimeter Ground Test: place the altimeter in a closed container and decrease air pressure to simulate altitude changes. Verify that both the apogee and preset altitude events fire. (Estes igniters or low resistance bulbs can be used for verification). V7 Electronic Deployment Test: test to determine if the electronics can ignite the deployment charges. V8 Ejection Test: test that the deployment charges have the right amount of force to cause parachute deployment and/or planned component separation. V9 Computer Simulation: use RockSim to predict the behavior of the launch vehicle. V10 Integration Test: ensure that the payload fits smoothly and snuggly into the vehicle, and is robust enough to withstand flight stresses.

V 1 V 2 V 3 V 4 V 5 V 6 V 7 V 8 V 9 V 10 C 1 C 2 C 3 C 4 C 5 C 6 PP C 7 C 8 C 9 C 10 C 11 C 12 C 13

Full Scale Vehicle Launch

Liftoff Weight: 34 lbs Motor:BoosterK1100 T SustainerI599N Length: 157 inches Diameter:6in Stability Margin:Booster4.53 Sustainer5.88 Vehicle Parameters

Test dual deployment avionics Test full deployment scheme Test validity of simulation results Test rocket stability Test staging scheme Flight Objectives

Apogee: 2519 ft – RockSim Prediction:2479 ft Time to apogee: 12 seconds Apogee events: drogue Sustainer main parachute: 700 ft Sustainer Flight Results

Apogee Events Sustainer Main Parachute Deployment Sustainer True Apogee Sustainer Flight Data Temporary Altimeter #2 Power Failure Booster Apogee

DescriptionInitial Point time, altitude End Point time, altitude Descent Rate Sustainer Descent with Drogue 13.5s, 2466ft54.5s, 700ft 43.0 fps Sustainer Descent with Main 58.0s, 588 ft97.5s, 0ft 14.9 fps Booster Descent with Main (unopened) 10.6, 845ft18.7, 0ft 104 fps Measured Decent Rates

Recorded data Simulation results (updated CD) Apogee = 2519ft Apogee = 2479ft Flight Simulations vs. Data

We will use an array of pressure sensors to observe the airflow characteristics around several obstacles during a two stage flight. After flight, we will test the rocket in a wind tunnel and compare the results.

Artificial protrusions (obstacles) will be placed on the sustainer body to create disturbances in airflow. Airflow Pressure sensors will measure the local pressure before and after the protrusions

The sequence of our payload as it goes from flight to the final report.

Determine the effect of obstacles on the surface of rocket on airflow around the rocket Determine the accuracy of wind tunnel testing

Obstacles remain attached to the rocket during flight. Sensors will successfully collect and store measureable data during flight. Data collected is reliable and accurate.

The payload will measure the airflow around the rocket using an array of pressure sensors. The location of the pressure sensors are shown in red and obstacles are shown in blue.

Sampling rate: 100 times per second Sampling resolution:16 bits (2 LSB noise expected) 100kPa full scale range (15kPa ~ 115kPa) Sampling locations: 12 on sustainer and 12 on booster

Each data acquisition board (DAB) reads and stores data from 6 pressure sensors Analog signals from the sensors are carried to the digitizer (ADC) using a shielded cable All DABs in the same stage are activated by the same G-switch shielded cable Common G-switch sensor Dataacquisition

Electronics Data Acquisition Board: controls signal digitization, receives and stores digitized data from pressure sensors Sensor Board: hosts a single pressure sensor and signal conditioning (noise suppression) circuitry Electrical schematics for DAB: shows the components and connections between them

1.Fin 2.Parachute 3.Data Processing and Storage 4.Motor        Sensor package

Diagram of the sustainer showing the payload integration. DPS Unit Timer Alt Sensor package Parachute Compartment

Diagram of the Booster showing the payload integration. Fin Tab Fin Motor Alt Parachute DPS&S Parachute Compartment

Independent Variables – Type and location of obstacles………….…. L – Air density outside of rocket……..……..…. D – Speed of air flow…………………………………. S – Air pressure………………………………………… P – Acceleration profile…………………………….. X,Y,Z Dependent Variables – Pressure at each sensor………….………….. Y i

Identical rocket in wind tunnel and actual flight Identical obstacles on rocket in wind tunnel and actual flight Similar wind speeds in wind tunnel and actual flight of first stage Identical sensors and method of data storage

Primary correlations – Yx = f(L) (local pressure vs. location) – Yx = f(S) (local pressure vs. airspeed) – Data from wind tunnel test and actual flight will be compared Further correlations from actual flight – pressure vs. selected independent variables

TestMeasurement PressurePressure will be collected at least 100 times per second by the sensor array

Components 1.Pressure Sensors 2.Battery Pack 3.Altimeter 4.3D Accelerometer 5.Obstacles Verification Tests 1.Drop Test 2.Connection and Basic Functionality Test 3.Pressure Sensor Test 4.Scale Model Flight 5.Durability Test 6.Acceleration Test 7.Battery Capacity Test

P=PLANNED F=FINISHED T E S T S COMPONENTSCOMPONENTS 1FFP 2FFF 3FFFFF 4FFFP 5FFF

Simulated pressure profile at 100mph Predicted pressure changes: -400Pa Pa

Simulated pressure profile at 250mph Predicted pressure changes: -2,000Pa.. +1,500Pa

Resolution: true 14 bit (16 bit digitization with 2 LSB noise) 14 bits = 16,384 signal levels Sensor range: 100,000Pa (15,000 – 115,000Pa) 100,000Pa / 16,384 levels = 6.10Pa / level Expected pressure 100mph: -400Pa ~ +300Pa  mph: -2,000Pa ~ +1,500Pa  573 levels

Questions?