The Comparative Analysis of Airflow Around a Rocket

PART I: VEHICLE

MAJOR MILESTONE SCHEDULE

• March 21 Second test flight of full-scale vehicle

• April 12 Rocket ready for launch• April 16 Rocket Fair/Hardware & Safety check• April 19 SLI Launch Day

1. First stage burn 2. Stage separation.3. Booster coasts to its apogee

and deploys main parachute.4. Booster lands safely5. Second stage motor burn6. Sustainer reaches apogee,

deploys drogue parachute7. Sustainer descends under

drogue parachute to 700ft 8. Main parachute deploys,

slowing rocket to safe landing speed of 15-20 fps.

9. Sustainer lands safely.

FLIGHT SEQUENCE

SUCCESS CRITERIA• 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”Diameter 6”Liftoff weight 37.4 lb.Motor K1275 Redline (54mm)

CP 118.8” (from nosetip)CG 101.8” (from nosetip)Static Margin 4.23 calibers

ENTIRE ROCKET

Length 94”Diameter 4”Liftoff weight 12.7 lb.Motor J380 Smokey Sam (54mm)

CP 83.8” (from nosetip)CG 63.6” (from nosetip)Static Margin 5.04 calibers

SUSTAINER

Letter Part Letter PartA Nosecone H Payload Bay

B Main Parachute I Payload Electronics

C Sustainer E-Bay J Drogue Parachute

D Fins K Motor Mount

E Transition L Main Parachute

F Booster E-Bay M Payload Electronics

G Fins N Motor Mount

ROCKET SCHEMATICS

• 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

CONSTRUCTION MATERIALS

THRUST CURVE

ACCELERATION PROFILE

VELOCITY PROFILE

ALTITUDE PROFILE

Booster SustainerFlight Stability Static Margin

4.23 5.04

Thrust to Weight Ratio 6.15 5.29

Velocity at Launch Guide Departure:

54 mph(launch rail length 144”)

FLIGHT SAFETY PARAMETERS

Wp - ejection charge weight in pounds. dP - ejection charge pressure, 15psiV - free volume in cubic inches. R - combustion gas constant, 22.16 ft- lbf/lbm R for

FFFF black powder.T - combustion gas temperature, 3307 degrees R

EJECTION CHARGE CALCULATIONS

Ejection charges have been verified using static testing.

CALCULATED EJECTION CHARGES

Section Ejection ChargeBooster 2.15 g (of FFFF black

powder)Sustainer (Drogue) 2.0 g

Sustainer (Main) 3.15 g

Stage Separation Charge 1.0 g

Component Weight Parachute Diameter

Descent Rate

Booster(predicted)

399 oz 92 in.(main)

17.6fps

Sustainer (measured)

211 oz 24 in.(drogue)

54.7 fps

Sustainer(measured)

211 oz 60 in.(main)

17.5 fps

PARACHUTES

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 MATRIX

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.

VERIFICATION MATRIX

VERIFICATION MATRIXV 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 P P

C 7

C 8

C 9

C

10

C

11

C

12

C13

Full Scale Vehicle Launch

• Liftoff Weight: 34 lbs

• Motor:Booster K1100 T

Sustainer I599N

• Length: 157 inches

• Diameter: 6in

• Stability Margin: Booster 4.53

Sustainer 5.88

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 #2Power Failure

BoosterApogee

Description Initial Pointtime, altitude

End Pointtime, altitude

Descent Rate

Sustainer Descent with Drogue

13.5s, 2466ft 54.5s, 700ft43.0 fps

Sustainer Descent with Main

58.0s, 588 ft 97.5s, 0ft 14.9 fps

Booster Descent with Main (unopened)

10.6, 845ft 18.7, 0ft 104 fps

Measured Decent Rates

Recorded data

Simulation results(updated CD)

Apogee = 2519ft

Apogee = 2479ft

Flight Simulations vs. Data

PART II: THE PAYLOAD

EXPERIMENT CONCEPT• 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.

EXPERIMENT CONCEPT

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

PAYLOAD SEQUENCE

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

PAYLOAD OBJECTIVES

• Determine the effect of obstacles on the surface of rocket on airflow around the rocket

• Determine the accuracy of wind tunnel testing

PAYLOAD SUCCESS CRITERIA

• 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.

DATA ACQUISITION

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

DATA ACQUISITION

DATA CONNECTIONSEach 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 storesdigitized 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

INTEGRATION PLAN

1. Fin2. Parachute3. Data Processing and Storage4. Motor

Fin Tab

Sensor package

SUSTAINER

Diagram of the sustainer showing the payload integration.

DPSUnit

TimerAlt

Sensor package Parachute Compartment

BOOSTER

Diagram of the Booster showing the payload integration.

Fin Tab

Fin

Motor

Alt

Alt

Parachute

DPS&S

Parachute Compartment

VARIABLES• 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………….………….. Yi

CONTROLS• 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

CORRELATIONS• 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

TEST AND MEASUREMENT

Test Measurement

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

VERIFICATION MATRIXComponents

1.Pressure Sensors2.Battery Pack3.Altimeter4.3D Accelerometer5.Obstacles

Verification Tests

1. Drop Test2. Connection and Basic

Functionality Test3. Pressure Sensor Test4. Scale Model Flight5. Durability Test6. Acceleration Test7. Battery Capacity Test

VERIFICATION MATRIXP=PLANNEDF=FINISHED

T E S T S

1 2 3 4 5 6 7

COMPONENTS

1 F F P

2 F F F

3 F F F F F

4 F F F P

5 F F F

RELEVANCE OF DATA, ACCURACY AND ERROR ANALYSIS

Simulated pressure profile at 100mphPredicted pressure changes: -400Pa .. +300Pa

RELEVANCE OF DATA, ACCURACY AND ERROR ANALYSIS

Simulated pressure profile at 250mphSimulated pressure profile at 250mph

Predicted pressure changes: -2,000Pa .. +1,500Pa

RELEVANCE OF DATA, ACCURACY AND ERROR ANALYSIS

Resolution: true 14 bit(16 bit digitization with 2 LSB noise)

14 bits = 16,384 signal levelsSensor range: 100,000Pa (15,000 – 115,000Pa)

100,000Pa / 16,384 levels = 6.10Pa / level

Expected pressure differences:

@ 100mph: -400Pa ~ +300Pa 114 levels @ 250mph: -2,000Pa ~ +1,500Pa 573 levels

Questions?