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: lekrueger@ufl.edu

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