Vanderbilt University Aerospace Club

1. USLI FRR Presentation March 24, 2011 Vanderbilt University Aerospace Club

2. Agenda for Meeting • Motor selection • Rocket flight stability in static margin diagram • Thrust to weight motor selection in flight simulation • Rail exit velocity • Parachute sizes and descent rates • Test plans and procedures • Dual deployment avionics test • Ejection charge amount test • Payload integration • Educational engagement plan and its status

3. Rocket Design

4. Unchanged Design Factors • Reach one mile AGL flight altitude • Provide relatively long burn time for experimental data collection • Allow routing of cryogen lines and electrical connections to aft payload

5. Design Revisions • Decrease size and weight • Return to 6” airframe design • More flexibility regarding payload weight • Increase thrust-to-weight ratio • Increase to 5.0 – 5.5 from ~4 • Bonus: increased rail exit speed (63 ft/s vs 52) • Motor selection criteria • Long burn motor [science requirement] • High T/W and rail exit velocity [stable liftoff] • Heavier rocket compared to 2010 [cryogenic payload] • Most suitable motors: M650W [add ballast if needed]

6. Revised Design Highlights • 6” Rocket body: • Design constraint requires more effective use of space • Lower aerodynamic drag [compared to 7.5”] • Lower pad weight, more efficient propulsion • Proven design from 2010 • Aerotech M650W motor • 75 mm motor [compared to 98 mm] • More space in rocket body to run cryogen conduits • Total impulse of M650 < M520

7. Revised Design • 6” dia x 10’-4” L • 75mm-class MMT • 59 lbs or less (vary for wind) • 2.47 calibers stability • Rail exit 63 ft/s • 5.3 nominal thrust-to-weight ratio • Dual deploy parachutes • One-mile-capable in any wind condition

8. Rocket Construction [Now Underway, Completion: 2/28] • Giant Leap “Magnaframe” airframe • 1/8” Nomex honeycomb fins reinforced with Carbon fiber • ½” plywood centering rings and bulkheads • West System Epoxy and ¼”-20 hardware in load-bearing components

9. Rocket Construction • Fincan • Three ½” plywood centering rings • Injected with expanding foam • Coupler tube / payload bay and avionics bay mounted with six ¼”-20 bolts • Pre-ejection retention via 4 [#6-32] nylon screws • Payload/avionics bay • 1” plywood caps • Two ¼” threaded rod lengths • Two ¼” U-bolts at each end

10. Projected Rocket Performance Parachute selection: 12 ft diameter main parachute  17 ft/s descent rate 3 or 4 ft diameter drogue parachute, depending on wind conditions

11. 3 Motors were considered

12. Aerotech M650W possible flight envelope [tbd by full scale flight]

13. Launch Rocket Total Value

14. Table 9. Scale Rocket Details. *These can be adjusted by adding ballast in order to model the competition rocket even more accurately. *These can be adjusted by adding ballast in order to model the competition rocket even more accurately. Scaled Rocket Selection *These can be adjusted by adding ballast in order to model the competition rocket even more accurately.

15. Scale Launch Results: All dressed up, nowhere to go • Launch manifest: • 1/22/2011 [canceled, weather] • 1/29/2011 [canceled, weather] • 2/5/2011 [canceled, weather] • 2/12/2011 [canceled, weather] • 2/19/2011]

16. Payload Design

17. 2 Payload Sections • Forward payload [rocket body]: • Cryogenic container • Solenoid valve and delivery lines • Data Acquisition Electronics • Aft payload [rocket exhaust]: • Thermoelectric engine with cryogen injectors • Will be optimized for new motor size

18. Cryogen Tank Overview • Custom modified liquid nitrogen tank with cryogen rated solenoid valve installed • Reverted to upright tank orientation • Inversion of tank was found to be unacceptable due to extreme cryogen leakage • Hydrostatic pressure advantage of high g launch determined to be negligible compared to chamber operating pressure • New assembly procedure simpler and no additional refill at launch pad

19. Cryogen Tank Testing

20. Cryogen Tank Testing • Approximately 25% of tank volume expelled per solenoid triggering

21. Payload Integration Filled and Sealed Dewar Sabot Halves

22. Cryogen Bay Assembly Cap secured by Threaded rods Vents Cryogen and electronics Routing tubes

23. Cryogen Bay Assembly Cryogen Tank Payload Electronics

24. Location in rocket Payload Bay

25. Cryogen Fill Procedure [revisited] • Determined that filling at the launch pad was not the best solution. • Small-bore filling tube would restrict flow to tank and could cause unwanted spills • Greater risk to team from exposure to LN2 • More difficult to tell when the tank is full • Better solution: Fill during assembly. • Tank can be filled directly, eliminating spills and ensuring a full tank

26. Cryogen Delivery Lines • -AN fittings and lines chosen for superior sealing, tolerances and temperature resistance • Flexible lines allow for thermal expansion • External lines at the aft payload steel braded for durability

27. Aft Payload and Injection • Aft payload machined in-house from aluminum • Welded to motor retaining cap for rocket attachment • Injector constructed from slotted stainless steel, similar to 3-D experiments • Determine number of TEGs based on 3D testing

28. Prototype injector for 3-D testing

29. Valve Control Electronics • VCCR camera controller g-switch • Pulse sent to 74121 ‘one shot’ IC • 40 kohm resistor and 1000 μF capacitor set time constant to 26s • Relay sends 24 V DC to cryogen valve

30. Valve Control Electronics Cont. • ULN 2068B Quad Darlington switch chosen as the relay • Excellent isolation of the upstream transistor logic from the large inductive load of the solenoid

31. Data Acquisition • RDAS system activated by ‘g-switch’ • One data stream each for the cooled and control TEG sets • Hot and cold side temperature measurements • Power measurement across an impedance matched resistor network

32. Payload Integration

33. 3D Test Platform

34. 3D Testing Setup VASA Fan Cryogen Delivery Lines TEG LN2 Tank Motor Exhaust DAQ

35. Static Fire Successful!

36. More testing this weekend [02/12/2011] Objectives: • Determine minimum achievable cold side temperature • Determine number of TEGs to be cooled during flight • Determine minimum number of thermocouples required to gather high quality temperature data • Determine maximum allowable hot side temperature for thermoelectric generator • Synchronize cryogen injection with motor burn

37. LN2 Safety Precautions

38. Cryogen Handling and Safety • Cryogen always handled and especially poured in large well ventilated area to avoid oxygen deficient environments • Proper safety equipment including approved insulated gloves, face shield and long sleeves and pants worn at all times while handling cryogen • Approved insulated Dewars used to transfer liquid nitrogen from storage tank payload system • Tank in vertical configuration assures proper and safe performance at all times

39. Activity Plans

40. Finance Management • Current amount spent is just over half total available budget. • ~$7,000.00 remaining before exceeding spending limit. • Anticipated future costs include: • Expenses associated with travelling to practice launch and USLI launch including food, transportation, lodging ~$1400 • Replacement or emergency rocket parts ~$1000 • Contingency fund ~$1000 • Budgeting strategy: frugality. Spend conservatively and reuse or cannibalize available parts whenever possible.

41. Educational Engagement Mission • Expose students in 5th to 12th grades to concepts of combustion, energy conversion and rocket propulsion • Build upon students’ prior scientific knowledge to identify new specific areas of interest • Provide opportunity for students to learn about mechanical and aeronautical engineering concepts, potentially leading to study in or careers in these fields

42. Current Status • Conducted Successful Outreach Event at Head Middle School in Nashville, TN

43. Head Middle School Visit: Overview • Two groups of students heard lesson; one group of 20 students, the other of 30 students • 45 minute lessons with each group • Lesson included demonstrations of compression ignition and TEG operation • Powerpoint presentation guided discussion and provided visual

44. Head Middle School Visit: Outcome Compression Ignition Demonstration Thermolelectric Energy Demonstration Students were engaged in discussion, actively questioned underlying principles and applications of topics discussed

45. Adventure Science Center TWISTER Event: Overview • Hands-on science summit led by women in science, technology, engineering and math careers • 1 hour session including background lesson, demonstrations and hands-on activity • Lesson Topics • Thermal energy – compression ignition demonstration • Thermoelectric energy conversion – TEG demonstration • Propulsion – Air pressure rocket activity

46. Adventure Science Center TWISTER Event: Outcome

47. Upcoming Outreach Schedule (All visits occur in Nashville, TN)

48. Questions ?