Critical Design Review
Agenda 1) OverallVehicle Design 2) Motor Selection 3) Flight Stability Margin 4) Thrust toWeight Ratio 5) Flight Stability Margin 6) Sub-scale Model 7) Kinetic Energy 8) Drift Calculations 9) Recovery Subsystem 10) Payload Subsystem 11) Education 12) Requirement Compliance 13) Next Steps 14) Timeline
Vehicle Dimensions Payload Ejection Bay • Overall length is 86.97 inches Vehicle Sub Section Length (Inches) • Weighs 25.1 pounds Nose Cone 20 Payload Bay 18 • Universal Outer Diameter: 5 inches Main Parachute 18 • Universal Inner Diameter: 5 inches Electronics Bay 9* Drogue Chute Bay 15 • Wall Thickness: 0.079 inches Lower Body Assembly 30
Vehicle Design - Nosecone • 4:1 Ogive style nosecone • Material of Construction: G12 Fiber glass with aluminum tip • Base Diameter: 5” • Length: 20”
Vehicle Design - Airframe • Material of Construction: G12 Wound Fiberglass tubing • Single Diameter Airframe • Length: 67 inches • Outer Diameter: 5 inches • Wall Thickness: 0.079 inches
Vehicle Design – Payload Bay • Design • G12 Filament Wound Fiberglass • 5“ diameter • 18” 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 stationary
Vehicle Design – Main Parachute Bay • SkyAngle Cert 3 Large 80” parachute • Attach to ¼" welded eyebolt by self-tightening knot • After tied will epoxy knot • ½” tubular nylon shock cord • Length 25’ • Ejected at 700’
Vehicle Design – Electronics Bay • G12 Filament Wound Fiberglass • 5" tube coupler • 5" coupler bulkheads • 2 threaded steel rods • Used to retain coupler • Outer 1” ring • Allows easy access to the arming switches • Eye bolt on bulkhead • Will have parachute and shock cord attached
Vehicle Design – Lower Body Assembly • 5” diameter • Length 30” • Motor Mount supported by 3 centering rings • 75” diameter • 16” length • Motor retainer that uses screw compression • Fins mounted by Through-the-Wall Construction • Contains the drogue chute bay
Vehicle Design – Drogue Chute Bay • 32” SkyAngle parachute • Built in lower body Assembly • Connected to aft section of the electronics bay by ¼” wield eye bolt • Attach to eye bolt with tightening knot and epoxy • 4 mil-spec tubular nylon shroud lines
Vehicle Design – Motor Mount & Retainer • Motor Mount • Material of Construction: 75mm G12 Fiberglass tubing • Length: 16” • Supported in place by fiberglass centering rings • Each ring is filleted on both inner and outer sides of mating edge • Motor Retainer • AeroPack • Material of Construction: Aluminum • Secured to body utilizing epoxy and screws
Vehicle Design - Fins • Material of Construction: G12 Fiberglass • Thickness: 0.1875” • Method of Attachment • Through-the-wall mounting method • Secured to motor tube with epoxied fin tabs • 3/8" ≤ fillet desired • 4 symmetrical trapezoidal fins • 11” root cord • 3” tip cord • 6” sweep length • 4.5” height
Material Overview • Fiberglass • G12 body tube, couplers, nosecone, and fins • Balance of weight and strength • Readily available and easy to work with • Steel • Threaded rods, washers, bolts, and eyebolts • Cheap, easy to find, and durable • Plywood • Sled of electronics bay • Light weight • Easy to work with
Material Overview • Kevlar • Blast shield and shock chord • Strength and fire resistant • Nylon • Parachute, shear pins, gears, and gear tracks • High tensile strength • Quick to deploy • Readily available
Final Motor Selection • Motor: Aerotech K1000T-P • Motor Diameter: 75 mm • Weight: 90.8 oz • Thrust to Weight Ratio: 9:1 • Rail Exit Velocity: 70.7 ft/s on 8’ 1515 rail • Max Thrust: 1,140 N • Average Thrust: 1,012 N • Impulse: 2,497 N*s • Max Velocity: 645 ft/s • Mach Equivalent: 0.575 Mach • Burn Time: 2.47 seconds
Flight Stability Margin • Static Stability: 2.15 • Dynamic Stability: 2.75 • Center of Pressure: 65.91” • Center of gravity: 55.15”
Sub Scale • Was made with a LOC IRIS 3.10" Kit and an AeroTech DMS H100 motor • Similar shape fins • Flight was recorded using an AltusMetrumTeleGPS • Max altitude 1325’ • Max velocity 301 ft/sec
Kinetic Energy at Landing Single Separation Scenario • Total mass 10.202 kg • Zero Separation Scenario • Terminal velocity 55.94 ft/sec • Kinetic energy of section one 679.898 Lbf • Single separation Scenario • Terminal velocity 55.94 ft/sec • Kinetic energy of section one 679.898 Lbf • Kinetic energy of section two 413.814 Lbf • Dual separation Scenario • Terminal velocity 19.4 ft/sec • Kinetic energy of section one 70.181 Lbf • Kinetic energy of section two 11.592 Lbf • Kinetic energy of section three 49.771 Lbf
Drift Calculations Tail wind velocity Nominal Drift Distance 0 mph 0.00 5 mph 582.30 10 mph 1164.60 15 mph 1746.90 20 mph 2329.20
Recovery Subsystem • Two StratologgerCF altimeter • Two new 9V batteries • Two initial blast caps each with 2g of black powder • Two backup blast caps each with 3g of black powder • Two bulkheads connected with two threaded rods • Lower half contains 32” drogue parachute • Upper half contains 80” main parachute • Sections are tethered by tubular nylon shock chord
Recovery Subsystem • On launch rail altimeters are keyed on • At apogee, the main altimeter ignites the first lower ejection charge, that ejects the drogue parachute • One second after apogee, the backup altimeter ignites the second lower charge as a backup • At 700’ above the ground the main altimeter ignites a upper ejection charge, ejecting the main parachute • At 650’ above the ground the backup altimeter ignites the second upper ejection charge as a backup
Payload Subsystem • CO 2 nosecone deployment • Autonomous deployment of rover and solar panels • Radio transceiver • 433 MHz • ~40mW output power • Electric coupling from rover to CO 2 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 • Rests easily on the rack and pinion in the payload bay • Determined to have sufficient traction on the terrain of the launch field. • Allows use of one system for driving and deployment
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 • Total deployed surface area of 6.838 sq. In.
Payload Deployment System • Peregrine CO 2 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 LiPo Battery • Transceiver • Electrical coupling to CO 2 e-match triggering system • Spring-loaded pogo pins • Simply drive away rover to 'release' from system
Payload Electronics • Rover Board • ATMega32U2 • 8MHz, 3.3 V Operation • GPS chip and antenna all in one • Inertial moment unit • AX5043 Radio Transceiver • 433MHz ¼ monopole antenna Rover board • Ground Station • ATMega32U2 • AX5043 Radio Transceiver Ground station board
Payload Electronics • Servos control • Each servo driven by a PWM pin from the microcontroller • Will handle turning by slowing one side • CO 2 ejection system • Main activation is controlled by key switch • Secondary control is continuity check between the rover and e-match control circuit • Setting off the E-match will require the rover to verify that it is not moving and the radio signal to go has been received
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
Education • Boy Scouts Rocket Camp • 317 Youth (K-6th) • Assisted kids in the construction and launching of kits • Helped adult educators • Hallow-engineering • 35 Youth (K-8th) • Helped local kids launch balloon rockets
Education Cont. • Engineering Design Challange • 160Youth (10th-12th) • Designed and carried out rules of competition • Winter Banquet • 210 Youth (5th-12th) • 20 Adult • Assisted in the construction and launching of rockets with A-B engines
Education Cont. • Future Events • Clay High School • 9th-12th grade • Present to upper level physics classes • Launch a rocket with F motor • Boy Scout Troop in Akron, Ohio • 5th-12th grade • Space Exploration merit badge
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