University of Florida Rocket Team Second General Body Meeting September 27, 2013
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Transcript of University of Florida Rocket Team Second General Body Meeting September 27, 2013
University of Florida Rocket Team
Second General Body MeetingSeptember 27, 2013
Overview
Energy Research and Education ParkSugar Motor DemonstrationCanSat DetailsRocketry Basics and Structures
Energy Park
Off-campus facility for the Rocket TeamOur own officeShared 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 6:00Energy ParkJimmy 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 motorSketches/OpenRocketLauren’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
BRITTNEY LANELEAD STRUCTURES ENGINEER
Rocketry: The Basics
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 motorCenter 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 performanceUse 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 finsLightweight 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 cordConsider 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
Free softwareHelpful in
determining stability and testing rocket with different motors
Solidworks
Used to design parts to be manufactured in the shop
To create a detailed full-scale model
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 rodKeeps 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