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
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
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
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
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
Featherweight Recovery
Small rockets
Flutter down
Tumble Recovery
Nose-Blow Recovery
System induces tumble
Nosecone induces tumble
Parachute
Ejected from rocket
Increases drag
Glide Recovery
Airfoil deployed
Possible Designs Continued
Helicopter Recovery
Blades deployed
Rocket autorotates
DUAL
DEPLOYMENT
Rocket undergoes
powered and
unpowered
ascension
Ascension
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
Apogee is highest point the rocket attains
Apogee is detected by the altimeter
Altimeter controls the ejection charges
Ejection charges
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
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
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
Transmits GPS coordinates to locate the landed rocket
Meeting
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