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. 3 rd, at 6:00 Energy Park Jimmy Yawn ( Make and test some propellant

CanSat Target Altitude: 1000 ft. Payload Specifications kg Cylinder 63.5 mm diameter About 122 mm high Recoverable (Dedicated Parachute) H class motor Sketches/OpenRocket Laurens

Next GBM and Other Events 3 rd GBM Thursday, October 10 th, 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, OConnell Center

BRITTNEY LANE LEAD 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 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 Free software Helpful 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 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 motors 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 F g = mg Drag- the force that resists the motion F D = (1/2)ρv 2 C D A ρ= density of fluid v = velocity C D = drag coefficient A = area Thrust- upward force generated by motor; depends on motor choice