Rocket Team 2nd GBM

Report
University of Florida Rocket Team
Second General Body Meeting
September 27, 2013
Overview
 Energy Research and Education Park
 Sugar Motor Demonstration
 CanSat Details
 Rocketry Basics and Structures
Energy Park
 Off-campus facility for the Rocket Team
 Our own office
 Shared manufacturing space
 Drill Presses
 Table Saw
 Circular Saw
 Belt Sander
 Hand Tools
 Hardware
 Where we store rockets and equipment
Directions
2701 SW 23rd Terrace, Building 241
Sugar Motors
 Thursday, Oct. 3rd, at 6:00
 Energy Park
 Jimmy Yawn
(www.jamesyawn.net)
 Make and test
some propellant
CanSat
 Target Altitude: 1000 ft.
 Payload Specifications
 0.5-1.1 kg
 Cylinder
63.5 mm diameter
 About 122 mm high


Recoverable (Dedicated Parachute)
 H class motor
 Sketches/OpenRocket
 Lauren’s email: [email protected]
Next GBM and Other Events
 3rd GBM



Thursday, October 10th, 6:15 PM
Little 0121
Lessons
Propulsion
 Flight Dynamics
 Recovery

 SpaceX info session


10/1, 6:15, Little 109
Rocket team interns
 Career Showcase

10/2, O’Connell Center
Rocketry: The Basics
BRITTNEY LANE
LEAD STRUCTURES ENGINEER
Key Vocabulary
 Apogee- the highest altitude that the rocket reaches in its




ascent
Drag- the force that resists the motion of the vehicle
through the air and opposes thrust; due primarily to
friction between the surface of the vehicle and the fluid
through which it travels, air
Thrust- upward force generated by motor
Center of Gravity (CG)- Point at which you can balance
the rocket on one finger. The rocket rotates around this
point during flight.
Center of Pressure (CP)- Point at which all of the forces
(Drag, Thrust, Lift) can be realized as one point. The sum of
all of the forces acting on the rocket occurs at the center of
pressure.
Building a Rocket:
THE MAIN PARTS
Nosecone
• Very important for
aerodynamics; design to reduce
drag
• Drag is related to the surface
area of the nosecone and
velocity
• Different shapes of nosecones:
•
•
•
Ogive (most common)
Parabolic
Cone
• Attached to parachute
• Use lightweight material like
plastic
Body Tube/ “Airframe”
 Cylindrical body of rocket that houses the
parachutes, avionics bay, payload bay, motor and
more
 Length and weight affect flight performance
 Use durable but lightweight materials: plastic, Blue
Tube, phenolic tubing, etc
Avionics Bay
 Houses all the electronics
of the rocket
 Located between two
bulk heads
 Must be easily accessible
for quick repairs or
rewiring
 Secured to airframe with
screws or shear pins
Fins
 Add to stability of rocket
 Typically 3-4 fins
 Lightweight and durable
materials (wood, G-10
fiberglass)
 Usually attached to body
with epoxy
 Many different shapes:



Trapezoidal
Triangular
irregular
Motor Retention
 Motor tube made of stiff cardboard is secured
inside of body tube with epoxy between
centering rings.
 Motor tube holds the motor in the rocket
safely and keeps it centered. Transfers thrust
from motor to rocket.
 The motor is kept from falling out of the
rocket after burnout with screws, hooks, caps,
etc.
Building a Rocket:
THE DESIGN
How to Begin
 Consider the purpose of your rocket and what it must
hold to determine the minimum length and size

Ex. Satellite or quadcopter inside, 4 ft diameter parachute, 20
ft of shock cord
 Consider cost constraints in selecting materials or
designing parts that need to be manufactured
Stability
• Stability Margin =
(Distance between CG and
CP)/(Body Tube
Diameter)
• <1 : Under stable
• 1-3 : Good range for
model rocketry
• >3 : Over stable
• CG is above CP
Software
Open Rocket
Solidworks
 Free software
 Used to design parts to
 Helpful in determining
be manufactured in the
shop
 To create a detailed
full-scale model
stability and testing
rocket with different
motors
Building a Rocket:
OTHER USEFUL PARTS
Bulkheads
 Used to separate sections of the rocket (payload bay,
avionics bay, etc)
Centering Ring
 To center the motor tube in the body of the rocket
 Used to secure motor tube in place so that thrust is
transferred from the motor to the rocket
Railbuttons
 Used to put the rocket onto the launch rod
 Keeps the rocket on a straight, controlled path
during lift off
Building a Rocket:
MACHINES AND TOOLS
Table Saw
 Used for cutting fins,
making slots in body
tube, cutting motor tube,
etc
 Safety:




Wear safety glasses
Do not wear gloves or loose
clothing
Wait until the blade stops
moving before removing
your work piece
Make straight cuts only
Drill Press
 Used for drilling holes, cutting out bulkheads, centering rings, etc
 Safety:
 Wear safety glasses
 Do not wear gloves or loose clothing
 Wait until the bit stops spinning before
removing or inspecting your work piece
Sander
 Used for sanding down
fins, smoothing edges,
adjusting
bulkheads/centering rings,
etc
 Safety:





Wear safety glasses
Do not wear gloves or loose
clothing
Wear mask so as not to
inhale particles for certain
materials
Keep your hand at a safe
distance from the sander
Turn it off when you finish
The Flight:
PHASES AND EVENTS
Phases of Flight
• Powered Ascent – Rocket is
being forced upwards by the
motor’s thrust force.
• Unpowered Ascent
(coast) – Rocket continues
upward due to its vertical
momentum. Motor is no
longer burning.
• Descent – Rocket has
separated and is now falling
to the ground at a much
slower rate due to the
deployment of parachutes.
The Physics
 Lift- relatively small force
(since the flight is almost
vertical); generated by the fins
 Weight- depends on
materials and construction

Fg = mg
 Drag- the force that resists
the motion

FD= (1/2)ρv2 CD A




ρ= density of fluid
v = velocity
CD = drag coefficient
A = area
 Thrust- upward force
generated by motor; depends
on motor choice

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