300 likes | 563 Views
Preliminary Design Review Presentation University of Louisville USLI November 12 th , 2012. Meet the 2012-2013 Team. 18 Members Total – 7 Returning, 11 New Members Mechanical, Electrical, Computer, and Industrial Majors. Overall vehicular design. Main Material Selections: Carbon Fiber
E N D
Preliminary Design Review Presentation University of Louisville USLI November 12th, 2012
Meet the 2012-2013 Team • 18 Members Total – 7 Returning, 11 New Members • Mechanical, Electrical, Computer, and Industrial Majors UofL USLI PDR Presentation
Overall vehicular design • Main Material Selections: • Carbon Fiber • Fiberglass • 6061 T6 Aluminum • PETG Transparent Plastic • 6 Ply Birch Plywood • Kraft Phenolic • Carbon Steel • A focus on efficiency by: eliminating unused space within the rocket, choosing lighter weight materials, and choosing a lower thrust motor. • Modular design to aid in transportation and inner accessibility. • Ease and reliability of assembly. UofL USLI PDR Presentation
Nose Cone Design • The equation used to model the nose cone was the Von Karman equation, otherwise known as the LD-Haack. • Optimal usage in ranges of Mach 0.8-1.2. UofL USLI PDR Presentation
CO2 Deployment System • Safer then black-powder ejection. • Less risk of parachute damage due to heat. • Mounted on nose cone bulkhead. • Machined from aluminum stock to meet team’s customized needs. UofL USLI PDR Presentation
How CO2 Device Works • Ignited by electric matches. Room for back e-match on each system. • Less than 1 gram of black powder used per launch versus ~15 grams per launch last year. • CO2 canister seal is punctured, allowing the trapped gas to expand and pressurize the airframe. UofL USLI PDR Presentation
Recovery altimeters • Redundant PerfectFlite Stratologgers will be used for deployment. • Individually wired, Energizer 9 volt batteries will be used. • Individual magnet activated switches will be used for each altimeter. UofL USLI PDR Presentation
Continuous Disreefing System overview • Payload Objective: • Precisely control the descent velocity of the rocket. • Main parachute will be deployed at apogee, fully reefed. • Parachute will be allowed to open via prescribed descent velocities. • Allows for the elimination of a drogue parachute. UofL USLI PDR Presentation
Disreefing System design • A reefing line will be looped through the parachute opening preventing it from opening. • A microcomputer, altimeter, and servo will work in unison to control descent velocity. • The servo will open and close the parachute to adjust velocity to match a prescribed target velocity. UofL USLI PDR Presentation
Parachute selection • A disk-gap-band parachute has been chosen for this year’s parachute design. • Published data has shown it to be stable between extremely low and Mach numbers when reefed. • Published data: Cd~1.1 for Ma < 0.4 • Experiments will be conducted to confirm drag coefficient. • Will be using a 12.5% geometric porosity design UofL USLI PDR Presentation
Parachute construction • Parachute will be fabricated out of MIL-C-44378 1.1 oz Calendared Rip Stop Nylon. • Seams will be a flat pressed French seam. • Seams reinforced with nylon flat tubing or Dacron tape. • Suspension lines are 100-lb nylon Para-cord. One line per gore. • Parachute will connect to two harness lines, 500-lb 1/2” tubular nylon. UofL USLI PDR Presentation
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 UofL USLI PDR Presentation
Avionics bay – Disreefing Control • Bay houses servo, altimeter, microcomputer, line drum, and line tensioner. • Designed to be as compact as possible. • Measures 5.5” across and 8” tall • Servo drives line drum via two 1” plastic gears. • Line drum releases and retracts reefing line. • Line tensioner clamps down on line drum to prevent reefing line from slipping off the drum. Reefing Line Tensioner Lever Servo Line Drum Shaft UofL USLI PDR Presentation
Simulated Kinetic energy during descent and landing • Assumed flat disk diameter of 14 feet. • Minimum reefing ratio of 8% • Increasing minimum reefing ratio will decrease peak values. • Increasing diameter will decrease landing values. Peak Controlled Landing UofL USLI PDR Presentation
Parachute control system Algorithm UofL USLI PDR Presentation
Science mission directorate payload • Utilization of a Samsung Dart smartphone for SMD processing and communication. • Data transmission over T-Mobile’s cell network. • Link with social media such as Twitter and live team website updates. UofL USLI PDR Presentation
Smd payload integration • Rapid prototyped SMD sled. • Vibration dampening. • Ease of assembly with customized sizing for smartphone. • Elimination of multiple wire harnesses. • 40% of the size of last year’s configuration. • ABS plastic is lighter than birch plywood. UofL USLI PDR Presentation
Transition bay • Storage bay for both parachute control system and SMD payload. • Main connection point for upper airframe and propulsion bay. • Transitions from 6.0” to 5.0” • Transfer provides a 16.7% weight reduction. • Machined aluminum plate connected to double bulkhead. • Transparent transfer provides storage space and visibility for HackHD cameras. UofL USLI PDR Presentation
Vacuum forming • In an effort to build most components “in-house,” the team will be vacuum forming the transparent transition section. UofL USLI PDR Presentation
Propulsion Bay • Houses the motor and fin mounting. • Mates with the Transition Bay. • Fin shape subject to change as mass develops to improve stability margin. UofL USLI PDR Presentation
Fin Mounting • Design uses no epoxy to secure fins in place. • Allows rapid replacement, with superior centering ability. UofL USLI PDR Presentation
A Motor retention • Allows separate removal of the motor and casing, from the fins. • Machined out of 6061 T6 Aluminum. B UofL USLI PDR Presentation
Nozzle Design • Replacing the standard phenolic 12° conical nozzle with a custom designed bell nozzle. • Increased efficiency from motor. • Nozzle catered to suit the L995-RL. • Static testing to prove design value. • Reusable design by using graphite material. Standard Configuration Custom Configuration Nozzle Cross Section UofL USLI PDR Presentation
Motor selection • Cesaroni 3 Grain: L995-RL • Projected Altitude: 5963 ft. • Max Acceleration: 253 ft/s2 • Burn Time: 3.66 seconds • Max Thrust: 1280 N • Average Thrust: 987 N • Total Impulse: 3618 Ns UofL USLI PDR Presentation
Stability margin Overall Rocket Length: 117.0” Stability Margin: 2.0 caliber Rail Exit Velocity (10’ rail): 69.6 ft/s Diameter: 6.0” to 5.0” Weight of Rocket: 32.8lbs Thrust to Weight Ratio: 6.76 UofL USLI PDR Presentation
Subscale testing – vehicle verification • A half scale model will be launched to verify a sound aerodynamic design. • A “universal” payload bay will allow four separate tests: • Cell phone communication • CO2 system operation • Disreefing system • Standard dual deployment • Vehicle can be constructed for less than $200.00 and run on 38mm motors. • Altitude flexibility: 800-4800 ft. range. UofL USLI PDR Presentation
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 -They will be responsible for completely the safety checklist and reporting back to the Safety Officer • A motor test stand is in development for thrust testing • -To verify NAR, TRA, and CRA motor ratings. • -Tests will be conducted at our Level 3 TRA mentor’s farm. UofL USLI PDR Presentation
Launch pad integration • Guide tower launch system. • Friction reduction to increase efficiency. No point of contact on the rocket. • Leveling screws to allow for complete control over launch tilt. • Designed to be completely disassembled. UofL USLI PDR Presentation
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 • Main focus this year is quality -Detailed space education programs -Pre and post evaluations UofL USLI PDR Presentation
2012-2013 Expenses UofL USLI PDR Presentation