Critical Design Review Presentation University of Louisville USLI January 31st, 2013
Overall vehicle design • Final Launch Vehicle Dimensions: • 117.0” Overall Length • 6.0” to 5.0” Diameter Transfer • 5:1 Von Karman Nose Cone • Main Material Selections: • Fiberglass • 6061-T6 Aluminum • PETG Transparent Plastic • 6 Ply Birch Plywood Key Features: Locking Fins 3-Piece Modular Design Transparent Camera Section
Final Motor selection Two half grains provide better takeoff acceleration! • Cesaroni 3 Grain: L995-RL • Projected Altitude: 5313 ft. • Max Acceleration: 229 ft/s2 • Burn Time: 3.66 seconds • Max Thrust: 1280 N • Average Thrust: 987 N • Total Impulse: 3618 Ns
Flight stability Static Stability Margin: 1.77 Thrust-to-Weight Ratio: 6.11 Avg. / 7.73 Max Rail Exit Velocity: 65.3 ft/s Max Velocity: 606 ft/s or 0.54 Ma Max Acceleration: 229 ft/s2 Projected Altitude: 5,313 ft Dynamic Stability Margin shown in graph to left.
Mass Statement • Initial Mass (with motor): 36.3 lbs • Initial Mass (without motor): 28.3 lbs • Burnout Mass: 31.82 lbs • Mass estimated with weight for every component. • Design set to use 28.3 pounds as target without compensation.
CO2 Deployment System • Safer than black powder. • Less risk of parachute damage. • Mounted on nose cone bulkhead. • Machined from aluminum stock to meet team’s customized needs.
How CO2 Device Works • Ignited by electric matches. Two e-matches used in each of the two systems. • About1 gram of black powder used per launch versus ~15 grams per launch last year. • Zero cleanup or soot buildup. • CO2 canister seal is punctured, allowing the trapped gas to expand and pressurize the airframe. • Aluminum casing doubles as shielding for all e-matches.
CO2Device testing • Testing has been done on first CO2 device. • All CO2 gas ejects in about 1 second. • Use 0.5 grams of black-powder to propel plunger. • Ground test successfully separated subscale.
Pressure vessel information • Manufacturer of 16gram CO2 cartridges is Leland Limited, Inc. • Factor of Safety for Burst Pressure (8000psi) vs. Max Expected Operating Pressure (1850psi) is 4.32:1 • Cartridges are disposable, therefore no fatigue cycles. • Patented Safety Sealing Cap acts as pressure relief device. • Built to Military Specification: MIL-C-603.
Recovery altimeters • Redundant Featherweight Raven3’s will be used to initiate both CO2 systems. • Individually wired, Duracell 9 volt batteries will be used. • Individual magnet activated switches will be used for each altimeter. • Accelerometer based design means no vent holes will be needed in the cone.
Continuous Disreefing System overview • Payload Objective: • Precisely control the descent velocity of the rocket. • Main parachute will be deployed at apogee, fully reefed. • Disk-Gap-Band • Drogue-assist deployment • Parachute will be allowed to open via prescribed descent velocities. • Allows for the elimination of a drogue parachute.
Recovery harness • Upon deployment, nose cone/drogue will pull deployment bag out. • 20 inch SkyAngle Recon drogue. • Nose cone/drogue will dangle from rocket during descent. • Parachute will connect to a bulk head via two eyebolts. • To prevent twisting of the suspension lines. • Shock cord – 1 inch Tubular Nylon • Risers – 1 inch Tubular Nylon
Reefed Parachute drag characterization • Adhere a force transducer to the parachute harness and the other side of the force transducer to a car. • Measure the force produced by drag with different vehicle velocities and dis-reefing ratios. • Parachute will be at least 5 vehicle widths away from the car. • Calculate drag coefficient via parachute geometry and force measurements. Connection Harness Force Measuring Device ~30 feet behind vehicle
Tow Test Results • 7.3 – 44 ft/sec, 12.5-100% Disreefing was tested. • Higher speeds were not tested due to safety concerns • Over 60 data points obtained • A “Surrogate Drag Model” was created through a third order polynomial fit. • Believed the 7.3 ft/s 100% result is an anomaly. • CD may reduce with speed due to vehicle wake becoming larger.
Kinetic Energy and Landing Velocity • Predicted 12 foot disk-gap-band will be required to meet minimum kinetic energy requirements. • 15% disreefment on deployment • Terminal velocity of 72 ft/sec • Disreefing begins at 2500 feet • Minimum “fully deployed” altitude of 500 feet. • Chosen configuration that keeps drift within competition boundaries. Controlled Peak Landing
Drift calculations • Combination of Matlab and Open Rocket simulations were used. • Open Rocket – Used to find upwind drift during ascent. • Matlab – Used to find downwind drift with parachute after deployment. • Net drift was calculated.
Subscale testing Procedure • Exact half-scale replica has been designed and constructed. • Testing plan includes: • H125 to 1433 feet with standard dual deployment. • I223 to 2256 feet with CO2 system. • I297 to 3066 feet with PCS system. • J425 to 4909 feet with Samsung Galaxy Exhibit. • Each test focuses on one portion of the overall design. Universal bay system allows the team to test each system .
Subscale Test #1 – H125 • 4 foot disk-gap-band used on subscale flight. • No disreefing system. • Custom deployment bag. • Parachute was allowed to fully deploy. • Descent velocity of 18 ft/sec • Measured CD=0.81 • Predicted CD=0.83 • Line twisting was observed, due to rotation of the chute or parachute packing error. A beautiful dual deploy recovery!
Subscale test – PCS (JAN 26th or Feb 2nd) • 4 foot disk-gap-band used on subscale flight. • Disreefing system will be integrated into subscale. • Fully capable of replicating full scale functionalities. • Will deploy main at apogee, at a disreefed ratio of 25%. • Parachute fully deployed by 500 feet. • Secondary “Main” will also deploy at 500. • Acts as emergency back up incase parachute does not disreef Line Drum Servo
Science mission directorate Payload • Utilization of a Samsung Galaxy Exhibit Android smart phone for SMD processing, communication, orientation measurements, photography • Real time data transmission over T-Mobile’s GSM network via SMS • Link with social media such as Twitter and live team website updates.
SMD Payload • Only 6 distinct components, 8 total. Only 2 cables required. • Activated via SMS from ground station • Phone includes magnetometer, accelerometer, GPS, GSM connectivity, camera • Power class 1 GSM device. Transmission power capped at 1W. Actual power varies. • Android OS naturally modular in design, secure • IOIO affords phone multiple I/O, embedded protocol access • Redundant HackHDs for video recording
IOIO Science Shield • Completely redundant atmospheric sensor arrays • Op amp photodiode amplifiers, not resistors • On board gyroscope • Communication via I2C • Diagnostic power LEDs • On board power switch • Seats directly to IOIO via perimeter headers (“Shield” concept)
Smd payload integration • Laser cut SMD sled • Birch plywood construction • Fast prototyping • Vibration dampening • Ease of assembly with customized sizing for smartphone • Approximately 6” tall, 1.5” thick, 5.25” wide (30% size reduction) • Camera and light sensors centered vertically
Propulsion Bay • Houses the motor and fin mounting. • Mates with the rest of the rocket for full motor access. • Fin thickness increased from 1/16” to 3/16” for added rigidity.
A Motor retention • Allows separate removal of the motor and casing, from the fins. • Machined out of 6061 T6 Aluminum. • Added holes for further weight reduction. B
Fin Mounting • Design uses no epoxy to secure fins in place. • Allows rapid replacement, with superior centering ability. • Machined on a CNC mill.
Launch pad interface • Guide tower launch system. • Friction reduction to increase efficiency. No point of contact on the rocket. A .030” gap was determined between the rocket and the tower. • Leveling screws to allow for complete control over launch tilt. • Designed to be completely disassembled. • Blast deflection included.
Safety and Launch procedures • Comprehensive checklist including: -Required tools -Step by step assembly instructions -Spaces for pre and post launch observations • Prior to launch, safety representatives will be selected who will be responsible for following all checklist steps and requirements. • Finalized checklist will be reported to the team Safety Officer. • Troubleshooting for all systems has been completed. Initial Here Sign Here
Educational engagement • Middle School Water Bottle Rocket Competition -At Engineering Expo on March 2, 2013 -3 Award Categories • TARC Mentoring -Mentoring a local TARC team • Engineering is Elementary -Weekly volunteering at schools • Louisville Science Center • Multiple Boy Scout troop launches for the “Space Exploration” merit badge.
2012-2013 ExpensesAND funds For next year’s team!
Status of Requirements Verification • Action Items: • Verify preparation time is no longer than 2 hours. • Successfully launch the full-scale rocket in its final flight configuration. • Verify actual kinetic energy is below 75 ft-lb upon landing. • Ground test SMD payload in final configuration. • Verify total vehicle reusability upon first test flight.