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

Hybrid Competition Propulsions Research Bringing 8 teams  Six highest altitude  Two 2,000 feet Meeting yesterday Sugar Motors Potential launch Updates

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

BASICS OF ROCKET MOTORS Propulsion

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 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

INTRODUCTION TO FLIGHT DYNAMICS OpenRocket

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  System induces tumble  Nose-Blow Recovery  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)v 2 FG= mg FD=FG ½(r)(Cd)(A)v 2 =mg A=πD 2 /4 D = sqrt( (8mg) / (π*r*Cd*v 2 ) ) V= sqrt( (8 m g) / (π*r*Cd*D 2 ) ) 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