the comparative analysis of airflow around a rocket

The Comparative Analysis of Airflow Around a Rocket

• February 1 Begin work on full-scale vehicle and payload.

• February 15 Full-scale vehicle completed.• February 21 First test flight of full-scale vehicle

• 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 500ft 8. Main parachute deploys,

slowing rocket to safe landing speed of 15-20 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 158”Diameter 6”Liftoff weight 38.0 lb.Motor K1275 Redline (54mm)

CP 117.0” (from nosetip)CG 104.26” (from nosetip)Static Margin 3.15 calibers

Length 94”Diameter 4”Liftoff weight 12.7 lb.Motor J540 Redline (54mm)

CP 79.6” (from nosetip)CG 59.0” (from nosetip)Static Margin 5.15 calibers

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

• 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

Booster SustainerFlight Stability Static Margin

3.15 5.15

Thrust to Weight Ratio 6.27 8.88

Velocity at Launch Guide Departure:

54 mph(launch rail length 144”)

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 charges will be verified in static testing when the vehicle is fully constructed.

Section Ejection ChargeBooster 3.0 g (of FFFF black powder)

Sustainer (Drogue) 3.0 g

Sustainer (Main) 2.2 g

Stage Separation Charge 1.0 g

Component Weight Parachute Diameter

Descent Rate

Booster 399 oz 92 in.(main)

17.6fps

Sustainer 211 oz 24 in.(drogue)

49.1 fps

Sustainer 211 oz 60 in.(main)

19.6 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 P F P

C 2 F F F

C 3 P P P

C 4 F P

C 5 F P P

C 6 P P P

C 7 F P

C 8 F

C 9 F P

C 10 F

C 11 F F F

C 12 P F F

C 13 F

• Liftoff Weight: 2850 g

• Motor: I357T, G104T

• Length: 79 inches

• Diameter: 2in to 3in

• Stability Margin (both stages): 4.16 calibers

• Stability Margin (sustainer): 6.50 calibers

• Test dual deployment avionics

• Test full deployment scheme

• Test ejection charge calculations

• Test separation

• Test validity of simulation results

• Test rocket stability

• Apogee: 2944 ft.– RockSim Prediction: 3110 ft.

• Time to apogee: 13 seconds

• Apogee events: drogue

• Sustainer main parachute: Unplanned non-deployment

• Apogee: 1163 ft.

• Time to apogee: 8 seconds

• Apogee events: Main deploymentMaterial failure

Apogee events

Booster Main Parachute Deployment

True apogee

Description Initial Pointtime, altitude

End Pointtime, altitude

Descent Rate

Sustainer descent with drogue

14s, 2980ft 75s, 500ft 40.65 fps

Booster velocity at impact (material failure) 11s, 1150 ft 16s, 0ft 275fps

(not intended)

Recorded data

Simulation results

Apogee = 2944ft

Apogee = 3110ft

• The rocket is stable.

• We will be able to reach our target altitude

• Staging works

• Fiberglass is a must for construction

• Static ejection charge testing is necessary

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

The payload will measure the airflow around the rocket using an array of pressure and temperature sensors.

The location of the pressure/temperature sensors are shown in red and obstacles are

shown in blue.

Sampling rate: 100 times per secondSampling locations: 12 on sustainer and

16 on booster

Each sensor package consists of: • one pressure sensor• one temperature sensor• analog/digital converter

The sensor package:

The "Shepherd“ (master) Propeller microcomputer drives the two “Sheep” (slave) Propeller microcomputers which collect data from sensor modules located throughout the rocket. The Shepherd Propeller also collects data from the three accelerometers and a pressure sensor.

1. Shepherd instruct all Sheep to collect data 2. Each Sheep read all its sensors3. After obtaining the data, each Sheep transmits

collected data to its Shepherd4. Shepherd stores the data and repeats the process

Data Acquisition, Processing and Storage is done by linked Parallax Propeller Chips (part number P8X32A). Each Propeller chip has 8 independent cores, each core running at 80MHz.

The shepherd chip maintains a template in its RAM with the time stamp and a space for the temperature and the pressure data from each sensor.

The shepherd also gathers data from a three-axis accelerometer and a pressure sensor.

These are used to get accurate atmospheric pressure data and velocity data.

The pressure/temperature sensors (2) are located on either side of the obstacle (1),

one on the fore end and two on the aft end.

2 1

Components

1.Pressure Sensors2.Battery Pack3.Altimeter4.3D Accelerometer5.Obstacles6.Temperature Sensors

Verification Tests

1.Drop Test2.Connection and Basic Functionality Test3.Pressure Sensor Test4.Scale Model Flight5.Temperature Sensor Test6.Durability Test7.Acceleration Test8.Battery Capacity Test

P=PLANNEDF=FINISHED

T E S T S

1 2 3 4 5 6 7 8

COMPONENTS

1 F P P

2 F P F F

3 F F F F

4 P P P

5 P P

6 F P P

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

Fin Tab

Sensor package

Diagram of the sustainer showing the payload integration.

DPSUnit

TimerAlt

Sensor package

Diagram of the Booster showing the payload integration.

Fin Tab

Fin

Motor

Alt

Alt

Parachute

DPS&S

• Commercially available sensors will be used

• Sensors will be calibrated

• Extensive ground testing of all electronics

• 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.

• Independent Variables– Type and location of obstacles………….…. L– Air density outside of rocket……..……..…. D– Speed of air flow…………………………………. S– Air pressure………………………………………… P– Air temperature………………………………….. T– Acceleration profile…………………………….. X,Y,Z

• Dependent Variables– Pressure at each sensor………….………….. Yi

– Temperature at each sensor…................ Ti

• 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– temperature vs. selected independent variables – pressure vs. selected independent variables

Test Measurement

Temperature

Temperature will be collected 20 times per second by the sensor array

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