Vanderbilt University PDR Presentation

1. November 28, 2011 Vanderbilt University PDR Presentation

2. Agenda • Vehicle Criteria • Vehicle Safety and Verification • Subsystems and Recovery • Payload Overview • Payload Testing • Outreach Update

3. 2011-2012 Project Introduction • Build, ground test and refine, flight-enable, fly and verify the design and instrumentation of a scaled, subsonic ramjet engine that is externally mounted to a high-powered rocket • Prove that inexpensive rocket flights can serve as experimental test beds for engine and component design.

4. Changes Made Since Proposal • New Motor Selection: Pro-75 L1115 • Changed Impulse from 5,120 to 5,015 N-s • Initial concern from NASA and NAR that the ramjet would qualify as an “experimental” motor • No net thrust produced from the ramjet • Received Approval • Outreach STEM agenda has been changed to cover three area middle schools and reach a total of 350 students

5. Vehicle Criteria: Dimensions • Rocket • Length: 120” • Diameter: 6” • Weight: 46.5 lbs • Confidence +/- 3 lbs • Possibility for rocket to be overweight

6. Aft Body Tube Coupler Forward Body Tube

7. Vehicle Criteria: Materials • The body tubes are made out of Dyna-Wind from Giant Leap Rocketry. • Phenolic tubing compression bonded with fiberglass. • Strong and easy to work with. • Fins are Nomex honeycomb fin stock from Giant Leap Rocketry • Strong, light-weight, and easy to work with.

8. Vehicle Criteria: Stability • Rocket Diameter • 6” nominal ID • Center of Pressure • 101” aft • Center of Gravity • 89.6” aft • Stability Ratio: 1.89 calibers

9. Vehicle Criteria: Motor Selection • Pro75 L1115- Chosen because of it’s fast burn time and high thrust • 4 grain 75mm motor • 5015 N-s total impulse • Max Thrust – 385 lb. • Average Thrust – 251 lb. • Burn Time – 4.48 s.

10. Vehicle Criteria: Motor Selection

11. Vehicle Criteria: Launch Parameters • Thrust-to-weight ratio • 385 lbs thrust/46.5 lbs weight • 8.3:1 ratio • Rail exit velocity • 78 ft/s • Final Altitude • 4883 ft • Depends on wind conditions • Can be adjusted by changing the rocket’s weight

12. Vehicle Safety Verification • Follow sound/proven construction methods. • Subscale test launch to verify the launch parameters and construction methods. • Enhance the fin strength with carbon-fiber • Follow safety protocols at all times for hazardous materials and equipment.

13. Vehicle Verification and Testing • Begin with ejection charge testing • Test with complete rocket set up, including parachutes and shear pins. • Test for smooth fits between couplers and body tubes. • Test for altimeter functionality. • Use sub-scale launch as verification for full scale development

14. Recovery System • Dual deployment controlled by redundant MAWD altimeters • Separation occurs: • at the nosecone joint • at the joint between the body tubes • Rocket descends as one unit • Parachutes • Main parachute • 144” dia. = 14 ft/s descent • Housed in nosecone • Drogue parachute • 48” dia. = 46 ft/s descent • Housed in the forward body tube, aft of the avionics bay

16. Recovery System • Electronics • Two-way redundancy • Identical MAWD systems • Completely isolated from each other • Each fires its own set of ejection charges and has its own batteries (2 x 9V each) • Housed in avionics bay, separate from all payload electronics • Avionics bay drilled with pressure sampling holes according to MAWD documentation • Avionics bay will be pressure isolated from the ejection charge blasts to mitigate false pressure readings

17. Recovery System • Black powder charges • Sized according to equations referenced in PDR • 2.7 g for drogue • 4.0 g for main • Designed to effect 450 lbs of separation force • #6-32 nylon shear pins: 4 x 110 lbs = 440 lbs (max) needed for separation

18. Recovery System • Ground testing • Entire deployment system will be ground tested • Remote-controlled firing of deployment charges • Ensure adequate charge sizing, shear pin selection • Performed under supervision from Safety Officer, with approval from Mechanical Engineering safety coordinator

19. Vehicle Subsystems- Coupler • The coupler will stick into the forward body tube 6” and 5” into the fin can to hold the body together • It will be sanded and shear pins will be attached to ensure a smooth recovery

20. Vehicle Subsystems- Fin-Can • Through the Wall Design • Four fins to make the rocket symmetrical • Extra Centering ring for attaching the ramjets • Devcon 2-ton epoxy as well as a carbon fiber layer on the fins will increase strength and reduce fluttering

21. Vehicle Subsystems- Launch • Interface • Pair of ¼” launch lugs that are 1.5 inches long • 33” apart from each other • Used with ¼” launch rail owned by the team

22. Payload Overview • Design validation of a scaled, subsonic, neutral-thrust ramjet engine using rocket flight. • Ramjet thrust will be measured using stain gages as well as thermocouples • Two identical ramjet engines will be mounted to the side of the rocket

23. Payload Background • Ramjets have no moving parts • Compression is achieved by slowing down high speed air from the mother vehicle (the rocket in our case) • Air entering is slowed down through the diffuser to generate working pressure • Kerosene, used for combustion, is added through pressurized injection and ignited • Flame-holder allows flame to develop by protecting it from the high-speed air • Performance will be measure based upon on-board thrust and temperature measurements

24. Design Philosophy • Performance is determined by the amount of thrust it produces and the amount of drag induced by its physical presence • Based on calculations shown in the PDR, the ramjet will produce 7.75 N of thrust and the same force in drag • No net thrust is produced by the engine

25. Ramjet Design • Ramjet • Length: 12” • Diameter: 3” • Three sections • Welded Together • Weight: 18 oz. per ramjet • Material: 0.015” thick galvanized low carbon steel, ASTM A653 • Lightweight, high strength and stiffness, workability, uniform quality, and weldability

26. Ramjet Design • Three separate Parts • Diffuser: Inlet diameter of 2”, transitions to 3” with a length of 3” • Cylindrical Section: 3” diameter, 4” long • Nozzle: 1” long, 3” diameter cylindrical section with a 3” long transition to 1.5” • Welded using TIG

27. 3” 7” 5”

28. Fuel Injector and Flame Holder • Fuel Injector • Delivers correct amount of fuel to ramjet prior to combustion • 40-50 psi provides 10 cc/s of kerosene • Rigidly attached to the ramjet, but not the rocket • Flame Holder • Two sections of 0.015” thick steel, ASTM A635 • Welded together

29. Other Payload Elements • Cryogen is being used to source the pressure for the fuel line • The cryogen dewar and fuel tank will be mounted using the design developed by last year’s team • The cryogen container will be connected to the fuel tank • A steel fuel line will run from the tank, through holes in the bulk heads and centering rings

30. Interaction between Fuel and Ramjet

31. Ramjet Mount • The extra centering ring is used as a base for the aluminum beam used to measure thrust • The beam will have a strain gage attached • Needs to be rigidly attached to the rocket to ensure accurate strain measurements • Two Conflicting Issues • 1) Strength of strain signal, decreases with stiffness • 2) Stability of strut at high-g takeoff will improve with stiffness

33. Instrumentation • One thrust signal and two temperature signals will be fed to the R-DAS flight computer • The connecting pylon, “beam”, will be instrumented with a pair of strain gages • SGD-10/1000-LY43 1 kilo Ohm resistors from Omega • Mounted symmetrically, in a half-bridge configuration • Very stable platform for strain gage reading • Thermocouples are mounted to the ramjet • Best candidate- P13R-003 thermocouple from Omega • Voltages sent to EMBSGB preamplification board from Tacuna systems • Linearize and amplify signal

35. 23 V Lipo NTE 1960 5V supply NTE 1972 15V supply 9V ULN 2038 Solenoid 74121 74121 G Switch XCC1 G-trigger Delay Fuel Delivery (4”) (5”) Ignition delay RDAS

36. Payload Testing • Significant testing will go into the injection of fuel and sustaining combustion of this fuel • Flow Rates • Differing pressures • Working with cryogen versus compressed air • Sustaining Combustion • High-wind • Flame holder

37. Outreach Overview & Goals • Goal: Provide an authentic STEM learning experience for underserved urban middle school students in the MNPS • Wanted students to actively engage in the engineering design process while acquiring science content and skills • Collaborated with VU’spreservice teachers to design an approach that would support teachers in local schools • Developed complete unit/lesson plans, student workbooks, and assessments aligned to Tennessee curricular standards.

38. Outreach Update • Four Planned Outreach Events • Outreach Activity 1: Cora Howe Middle School (Activity completed November 10th, 34 participants) • Outreach Activity 2: Wright Middle School (Activity completed December 1st, 220 students) • Outreach Activity 3: Bailey STEM Magnet MS (Scheduled December 12-16; 120 students expected) • Outreach Activity 4: “Visit to Vanderbilt” (Scheduled for early spring, 10-12 students expected)

39. Outreach Activity 1 • Cora Howe Middle School • MNPS for students with learning or behavioral differences • Partnered with the school to create a special “Rocket Day with Vanderbilt” • Introduced students to the USLI, engineering design cycle, and design challenge of building a water-bottle rocket • Students rotated across stations to build & test the rocket • Evaluation: Success!!! • Significant student engagement throughout the day • Pre-post assessment indicated a 33% improvement in students’ understanding of key physics principles • “I already know that I can build on this…” Science Teacher

40. Outreach Activity 1

41. Summary • Rocket: • 120” tall, 6” diameter, 46.5 lbs, dual deployment • Pro75 L1115 provides 8.3 : 1 thrust-to-weight • Payload: • Dual Ramjet’s mounted to side of rocket • Thrust and drag will be measured • Outreach: • Developed curriculum and have planned and participated in educational engagement events

42. Questions