Preliminary Design Review
Agenda • Overall Vehicle Design • Recovery Design • Stability • Payload Design • Motor Selection • Requirement Compliance • Thrust to Weight Ratio • Education • Vehicle Subsystem • Timeline Design • Next Steps
Vehicle Dimensions Vehicle Sub Section Length (Inches) Universal Outer Diameter- 5 inches • (1) Nose Cone 20 Universal Inner Diameter- 4.842 inches • (2) Payload Bay 18 Thickness- 0.079 inches • (3) Main Parachute Bay 18 Nose Cone Shape- Ogive • (4) Electronics Bay 9* (5) Drogue Chute Bay 15 (6) Lower Body Assembly 30 6 *Internal coupler 3 4 2 5 1
Vehicle Design – Nosecone • Original Design • 5-inch diameter • Filament wound fiberglass • 5:1 Von Karman style • Metal tipped • New Design • 5:1 Von Karman --> 4:1 Ogive style • Justification • More cost effective • Reduced the length • Reduced weight by 5 oz
Vehicle Design – Payload Bay • Design • G12 Filament Wound Fiberglass • 5 inches diameter • 18 inches length • Connected to nosecone via 4 shear pins • Attached to coupler that houses the CO2 deployment system • 2 rail system and T frame holds payload in place
Vehicle Design – Main Parachute Bay • G12 Filament Wound Fiberglass • 5 inch outer diameter • Stores 80 inch Parachute • ¼" quick link connected to the welded eye bolt • SkyAngleCert-3 • Rip stop nylon • ½ Inch tubular nylon shock cord • attached to coupler and electronics bay • Bears brunt of shock forces during separation
Vehicle Design – Electronics Bay • G12 Filament Wound Fiberglass • 5" tube coupler • 5" coupler bulkheads • Coupler retained using two threaded steel rods • Outer 1 inch ring allows easy access to the arming switches. • Eye bolt on bulkhead have the parachute and shock cord attached.
Vehicle Design – Lower Body Assembly • Drogue Chute Bay • Fins • Motor Mount • G12 Filament Wound Fiberglass • 5 inch diameter
Vehicle Design – Drogue Chute Bay • Built into the Lower Body Assembly • Attached to the aft section of the electronics bay • Stores 24 inch Parachute • Connected via forged eye bolt • ¼ inch quick link • Easy installation and removal of parachute. • ½" Tubular Kevlar shock cord
Vehicle Design – Motor Mount • Built into the Lower Body Assembly • 3 Fiberglass centering rings • G12 Filament Wound Fiberglass motortube • Epoxied to lower body tube with fins • Greater strength and retention • Third centering ring is 1 inch from the back • Accommodates motor retainer • Better secures fins
Vehicle Design - Fins Characteristics Justification • Stability margin of 2.53 calibers • 0.1875-inch sheet of G12 fiberglass • Simulated maximum velocity is 1424ft/s • 4 symmetrical trapezoidal fins • Good balance between stability and risk of weather cocking • 11-inch root chord • Low risk of fins breaking during recovery • 3-inch tip chord • 6-inch sweep length • 4.5 inches height
Material Overview • Fiberglass • Plywood • • Light weight Very light weight • • Durable Easy to work with • • Kevlar Readily available • • Easy to work with Extremely Durable • Steel • Flexable • • Nylon Very Durable • • Cheap Very flexible • • Easy to find Easy to deploy • Easily folds into bays
Stability Margin • Static Stability: 2.53 • Center of Pressure: 65.91 in • Center of Gravity: 53.266 in
Motor Selection • Motor: Aerotech K1000T-P • Apogee: 5355 ft • Max Velocity: 660 ft/s • Burn Time: 2.47 s • Total Flight Time: 118 s
Thrust to Weight/Rail Exit • Thrust to Weight Ratio: 9:1 • Rail Exit Velocity: 69.5 ft/s • Distance to Stable Velocity: 3.5 ft • Stability Caliber: 2.53 • Rail Choice: 8 ft
Recovery Subsystem Two StratologgerCF altimeters • Two new 9V batteries • Four Blast caps with 2g of black powder • Two bulkheads and two threaded rods • • Lower half contains the 32in drogue parachute, upper half contains the 80 in main parachute Sections are tethered with tubular nylon • and a nonslip knot
Recovery Subsystem • On launch rail altimeters are keyed on At apogee the main altimeter • ignites a lower ejection charge, ejecting the drogue parachute At 700 feet above ground the main • altimeter ignites an upper ejection charge, ejecting the main parachute The backup altimeter ignites its • lower ejection charge one second after apogee The backup altimeter ignites its • upper ejection charge at 650 feet above the ground
Drift Calculations With a simulated crosswind of zero mph and zero standard deviation in wind velocity, the response lateral drift for the current model and expected motor is less than 8 feet from the launch rod position when modeled as launching vertical at a ninety-degree angle to the ground.
Drift Calculations cont. Trial wind velocity Nominal Drift Distance 0 mph crosswind 8 feet 5 mph crosswind 460 feet 10 mph crosswind 1000 feet 15 mph crosswind 1500 feet 20 mph crosswind 2232feet
Payload Subsystem • CO2 nosecone deployment • Autonomous deployment of rover and solar panels • Radio transceiver • 433 MHz • Electric coupling from rover to CO2 deployment circuit • GPS/IMU positioning system • Local and remote data logging
Rover Design • Geared wheel deployment • Four wheel drive • Sliding solar panel system • GPS/IMU distance tracking • Operates independent of orientation • Can drive upside down or right side up • IMU to detect orientation of rover
Rover Wheel Design Gear Wheel Design Pure Wheel Design • Rests easily on the rack and pinion in the • Provides traction on the terrain of the payload bay. launch field. • Determined to have sufficient traction on • Harder to find off the shelf wheels with the terrain of the launch field. correct dimensions of the rover. • Majority of team supported gears for • Less supported by the team for use. wheels.
Initial Solar Panel Design Solenoid Deployed Design Clam Shell Design • Spring loaded tray with a solenoid release • Three different possibilities for this route: folding mechanism. out in an X- shape, folding out in a diamond shape, and folding out off of itself. • Solenoid requires lots of power which would • Risks possible issues with having enough ground require more power. clearance. • Bad because the solenoid is large and • Issue becomes that springs are passive which decreases ground clearance. causes risk for not being deployed. • Bad: springs are passive and risks not deploying.
Solar Panel Design • Six 1.378" x 1.654" x 0.079" panels • Output 223 mW at 6.3 V • Produced by IXYS Solar as a part of their IXOLAR series • Deployed with a HiTec Ultra-Nano Servo • 11.11 oz/in of torque • Total deployed surface area of 6.838 sq. in.
Initial Payload Deployment Designs Solenoid Latch Rotary Latch • Four solenoids actuate to free the nosecone • Rotary disk actuates pins to free the nosecone • Power requirements for solenoids would • Solves power issues from solenoid system require additional power supply • Rover may have insufficient torque to move • Does not solve issues with mass of nosecone nosecone or binding • Nosecone could bind as it extracted
Payload Deployment • Peregrine CO2 ejection system to deploy nosecone • Nosecone attached to payload bay with shear pins • Rover deploys itself after nosecone has been ejected. • Alleviates risk of nose mass or binding preventing deployment of the rover.
Payload Electronics • Battery and control electronics all mounted on the rover • GPS • IMU • 5 servos • 2S LiPoBattery • Transceiver • Electrical coupling to CO2 e-match triggering system • Spring-loaded pogo pins • Simply drive away rover to 'release' from system
Payload Electronics • ATMega32U2 Development Board • Breadboard compatible • 8MHz, 3.3V Operation
Payload Electronics • AX5043 Development Board • 433MHz 1/4λ monopole antenna • Breadboard compatible
Payload Electronics • SAM-M8Q-O Development Board • GPS chip and antenna all in one • Integrated module • Breadboard compatible
Distance Evaluation System • GPS • Low update rate • Positional accuracy only 2.5m • Can safely overshoot minimum required distance • IMU • High update rate • Use accelerometer and gyroscope to evaluate distance • Error builds up over time • Combine • Reduce total error • Kalman Filter Approach
Requirement Compliance • UT Rocketry team has created a plan to follow all NASA USLI guidelines. All systems have team leaders that have read the NASA handbook and understand the requirements. • After Team Leads have demonstrated they are competent in their area, they create checklists that all team members must abide by. • Many major systems pertaining to flight safety and stability have redundant checks and hardware to ensure NASA requirements are met.
Education • Boy Scouts Rocket Camp • 317 Youth (K-6th) • Assisted kids in the building and launching of kits • Helped adult educators • Hallow-engineering • 35 Youth (K – 8th) • Helped local kids launch balloon rockets
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