Transcript Document

University of Florida Rocket Team
Third General Body Meeting
October 10, 2013
Today’s Meeting
 Project Updates
 Design Opportunities
 “Office Hours”
 Presentations
 Motor
Basics
 OpenRocket
 Recovery
Updates
Hybrid Competition
Propulsions Research
 Bringing 8 teams
 Six highest altitude
 Two 2,000 feet
 Sugar
 Meeting yesterday
Motors
 Potential
launch
Static Motor Test Stand
 Variable motor diameter
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24mm-98mm
 Withstand 3000 N with
reasonable factor of
safety
 Operate upwards and
downwards
 Measure force over time
(load cell)
 Clamp into ground.
Static Motor Data Acquisition
 LabVIEW VI
 Measure and interpret data from the load cell
 NI DAQ (OOTB or 6009)
 Needs to determine
 Total Impulse
 Average Thrust
 Max Thrust
 Thrust Curve
 Burn Time
Fin Mount Apparatus
 Apparatus to help mount fins symmetrically
 Multiple rockets
 Either 3 or 4 fins
 Multiple body diameters/motor mount tubes
 Account for changing location of centering rings
“Office Hours”
 MAE A 211
 Monday, 9:30 AM – 12:00 PM
 Tuesday, 2:30 – 4:00 PM
 Friday, 9:30 AM – 12:00 PM
Propulsion
BASICS OF ROCKET MOTORS
How Rockets Work
Newton’s Third Law of Motion:
For every action there is an equal and opposite reaction
Rocket motor = energy conversion device
- Matter (solid or liquid) is burned, producing hot gases.
- Gases are accumulated within the combustion chamber until
enough pressure builds up to force a part of them out an exhaust
port (a nozzle)
- Thrust is generated by a pressure buildup within the
combustion chamber and by mass ejection through the nozzle.
- Combustion chamber geometry, throat diameter, and nozzle
geometry govern performance and efficiency (Conservation of
Momentum-Fluids)
Different Types of Motors
Solid Motor Basics
Bates Grains
Rocketry
 Model Rocketry
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Uses motors A-G
Anyone can launch
Class 1
Is made of paper, wood, or
breakable plastic
Uses a slow burning
propellant
 High Powered Rocketry
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Needs certifications
Uses motor more than 160
N-seconds of total impulse
Uses motor more than 80 N
average thrust
Exceeds 125 g of propellant
Uses hybrid motor
Rocket weighs more than
1500 g
Includes any airframe parts
of ductile metal
Class 2
High Powered Rocketry
 Level Certifications
 Level 1- Uses H (320 N-seconds) or I motors (640 N-seconds)
 Level 2- J, K, L
 Level 3- M, N, O
 Beyond O is Class 3 and requires waivers (total impulse greater
than 40,960 N-seconds)
 Numbers of Motor
 Example H64-8
H is the total impulse (between 160-320 N-s)
 64 N is the average thrust
 8 seconds is the delay ejection charge
 To determine motor burn divide total impulse by average thrust

OpenRocket
INTRODUCTION TO FLIGHT DYNAMICS
Recovery
AN INTRODUCTION TO THE RECOVERY
SUBSYSTEM
Recovery
A reliable system to safely land the rocket.
“Must be reusable without repairs.”
Goal
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Consistently return a rocket to the ground without damage to
the rocket or objects on the ground.
Critical for continued testing of payload
Possible Designs
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Featherweight Recovery
Small rockets
 Flutter down
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Tumble Recovery
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Nose-Blow Recovery
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System induces tumble
Nosecone induces tumble
Parachute
Ejected from rocket
 Increases drag
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Glide Recovery
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Airfoil deployed
Possible Designs Continued
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Helicopter Recovery
Blades deployed
 Rocket autorotates
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DUAL
DEPLOYMENT
Rocket undergoes
powered and
unpowered
ascension
Ascension
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During ascension rocket naturally orients itself into wind
Drifts an amount up range depending on wind speed
Altimeter detects
apogee and sets off
ejection charges.
The nose cone is
ejected and the
drogue parachute is
deployed
Apogee
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Apogee is highest point the rocket attains
Apogee is detected by the altimeter
Altimeter controls the ejection charges
Ejection charges
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Forces the shear pins to break and deploys the drogue
parachute
E-fuses are detonated by the altimeter
Charge Types
Black Powder Substitutes
 CO2 Canister

Charge Testing
Drogue parachute
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Smaller X-Form Parachute
Sufficiently lowers the speed
without a large horizontal drift
Deployed at apogee
Selecting parachute size
FD = ½(r)(Cd)(A)v2
FG= mg
FD=FG
½(r)(Cd)(A)v2=mg
A=πD2/4
D = sqrt( (8mg) / (π*r*Cd*v2) )
V= sqrt( (8 m g) / (π*r*Cd*D2) )
Cd=Coefficient of Drag
r=density of air
v=velocity
At a preset
attitude, around
700ft, the second
ejection charge
will deploy the
main parachute
Main Parachute
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Detonated by the altimeter at a specified altitude
Also uses ejection charges to deploy
Allows for a much slower descent rate
Rocket is located
and recovered
Locating the rocket
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Transmits GPS coordinates to locate the landed rocket
Meeting
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Begin the design phase of the recovery sub-system
Friday Oct, 11
5:00PM Library West Room 230
Upcoming Meetings
Propulsions Research
Right here, right now (brief)
CanSats
Tuesday, Oct. 15, 6:30 at the Energy Park
GBM
Thursday, Oct. 24, 6:15 in Little 121