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Sound Test. Testing and Integration of a Rocket-Launched Video Imaging Platform. IniTech Engineering. Apoorva Bhopale Susan Schmidt Rob Wingo Brian Love. 1 May 2002. Project Background. Project is sponsored by Applied Research Labs Main Objective:

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Sound Test


Testing and Integration of a Rocket-Launched Video Imaging Platform

IniTech Engineering

Apoorva Bhopale Susan Schmidt Rob Wingo Brian Love

1 May 2002


Project Background

  • Project is sponsored by Applied Research Labs

  • Main Objective:

    • Prove the validity of a rocket launched balloon as a telecommunications platform

  • Possible uses, disaster relief, drug interdiction, inexpensive “throwaway” satellites

  • Rocket is to be launched this summer


Overview of the Presentation

  • Goals to accomplish

    • Description of each goal

    • Work completed for each goal

  • Future work

  • Questions


Semester Goals

  • Design and build payload canister with mountings for electronics

  • Size and build drogue chute

  • Test balloon buoyancy

  • Test Electronics

  • Test balloon deployment


Flight Profile


Chute Sizing

Brian Love


Drogue Chute

  • Required to deploy balloon after ejection

  • Will be used to slow descent after operations


Previous work concluded that a small chute will deploy the balloon

Limiting factors for design are descent constraints

Considerations

Weight of payload

Altitude

Allowable impact velocity

Sizing


D = drag force

W = weight

ρ = air density

Cd = coefficient of drag

A = area

Vt = terminal velocity

r = chute radius

d = chute diameter

m = mass

g = gravitational

acceleration

Algorithm


Calculations

Standard Atmosphere


Chute Design

108”

116”

Weight: 14.2 oz.


Balloon Tilt

  • Weight drop of 11 oz. from 25 to 14 oz.

  • Balloon used was ~1/4 scale


Neutral Buoyancy


Calculations

Need mass air inside balloon

4kg less than the STP value

for neutral buoyancy


Temperature Difference


Considerations

  • Absorbed solar energy

  • Air circulation inside balloon

  • Descent rate of inflated balloon vs. chute

  • Thermal updrafts

  • Need experimental data to prove theoretical

  • Testing difficult on ground


Payload Canister

Susan Schmidt


Initial Avionics CanisterDesign

Canister made of 4.25 inch

PVC pipe

Covered in carbon fiber

Electronic components

secured with bubble wrap

Plexiglas bottom

for camera


Previous Canister Design Changes

  • Components hit canister walls and each other

  • Bubble wrap was not sufficient vibration control

  • Foam was then used to secure items


Issues with Past Designs

  • Carbon fiber blocks radio waves

  • Electrical components not secure

  • Plexiglas fogs at higher altitude

  • Plexiglas cracks easily

  • Component constraints cannot handle temperatures of high altitudes


Requirements for the Avionics Canister

Structural integrity

Limit component vibration

Airtight seal

Temperature control


Structural IntegrityExternal Material Options

  • Metals

    • Possible Shrapnel

    • Weight

  • Porous materials, i.e. wood

    • Airtight seal

  • Plexiglas

    • Cracks easily

  • Lexan

    • High cost

    • Availability

      And the winner is…


PVC

  • Weather Resistant

  • High strength to weight ratio

  • Corrosion Resistant

  • Good thermal insulator

  • Self-extinguishing

  • Low cost!!


High impact resistance

Used to stabilize internal components

Used for the camera viewing area

Internal Structure


Limit Component Vibration

  • Two 0.09” thick Lexan perpendicular

    boards

  • Secured components with nuts and bolts

  • Ends capped with hobby plywood


Airtight Seal

  • Change in pressure from sea level to higher altitudes cause fogging on the Lexan

  • Seal end of canister with Teflon Tape

  • Teflon tape for extruding connections

  • Pump in Nitrogen through a gas fitting

  • Inert gas replaces the water vapor


Temperature Control

  • Camera’s operating range:

    -1.1°C to 37.77°C

  • Above 8,000 feet the temperature drops below this operating range

  • The rocket test in summer will not reach this altitude

  • The temperature limits of the components must be evaluated for higher flights


Electronics

Rob Wingo


Electronic Components

  • Accelerometer board

  • GPS/Video Overlay board

  • GPS receiver

  • Video camera

  • Telemetry system

  • Batteries


Semester Objectives

  • Connect all of components and make work

  • Range test telemetry system

  • Find problem with power source

  • Determine how to use accelerometer board as an event trigger

  • Mount electronics in canister


Component Connectivity

  • Successfully connected all components


Range Test: First try

  • Unsuccessful

  • Assumed power problem


Range Test: Second try

  • Made adjustments to power supply and connectivity board

  • Still unsuccessful


Range Test: Third try

  • Re-soldered connectivity board

  • Still unsuccessful

  • Contacted transmitter manufacturer

  • Discovered range can be drastically reduced by ground effects


Ground Effect Problem

  • Transmitter designed for aerial use only

  • Will not be able to accomplish range test on ground


Balloon Deployment

Apoorva Bhopale


Balloon Deployment

  • Objectives

    • Determine a method to pack the balloon

    • Determine an adequate amount of black powder to eject the canister


Balloon Size


Suggested Method


Pyrotechnic Ejection

  • Advantages

    • Reliable

    • Lightweight

    • Used extensively


Possible Failure Modes of the Ejection

  • Too Little Black Powder

    • Does not clear ejection tube

      • Inhibits the rockets main chute deployment

      • Payload crashes with the rocket

  • Too much Black Powder

    • Rocket tube explodes

    • Drogue chute rips from balloon

    • Burnt drogue chute or balloon


Theory of Pyrotechnic Ejection

  • Wp=Weight of Black Powder (lbs)

  • dP= Ejection Charge Pressure in Psi

  • V= Free volume in cubic inches

  • R= Combustion gas constant 22.16 ft- lbf/lbm-R

  • T= Combustion gas temperature, 3307 degrees R


Test Footage


Conclusions From Test

  • Place Canister closest to the ejection charge

  • Use 7 grams of Black Powder


Conclusion

  • Design and build payload canister with mountings for electronics

  • Size and build drogue chute

  • Test balloon buoyancy

  • Test Electronics

  • Test balloon deployment


Future Work

  • Verify range of the transmitter another way

    • Possibly send it back to manufacturer

  • Test the deployment method in a rocket

  • Determine a way to sever connection between balloon and canister

  • Neutral Buoyancy test

  • Setup accelerometer board to be used as event trigger


Dr. Ronald Stearman

Dr. Martin Barlett

Dr. Jennifer Lehman

Danny Linehan

Daniel Parcher

Rick VanVoorhis

Lixin Gong

Acknowledgements


Questions


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