3. Project Description
What is a hybrid rocket?
spacesafetymagazine.com
Project background and purpose:
• Sponsored by OSU chapter of AIAA
• Design and build a flight-viable hybrid rocket
• Research and optimize for the future
• Collaborative design experience
4. Multidisciplinary Collaboration
Fuel and Energetics - Chemical
Engineers
• Fuel composition
optimization
• Combustion reaction
energetics
Data Acquisition - Electrical
Engineers
• DAQ system for propulsion
test stand
bbc.co.uk
Hybrid Rocket Design - Mechanical Engineers
● Hot End 1 - injector, fuel, igniter
● Hot End 2 - combustion chamber, injector
manifold, nozzle
● Cold End - oxidizer feed system, remote
priming system
● Vehicle Engineering - recovery system,
aerodynamics, structures, integration
Launch Rail -
Mechanical
Engineers
● Large
enough for
hybrid
rocket
● Collapsible
for travel
5. General Design Process
Team Customer Requirements:
1. Safe 4. Can be assembled quickly
2. Reliable 5. Flight viable
3. Cost-effective 6. Lightweight
House of
Quality:
CRs and ESs
Simulation:
Solidworks
ANSYS
OpenRocket
NASA CEA
Sub-system
testing:
Sub-team
TPs
Full-scale
testing:
Test fires
Dry Run
Assemblies
8. Fuel Composition
• Function
– Provide the chemical energy
to propel the rocket
• Rocket Fuel Composition
– Composed of paraffin wax, corn starch, and aluminum powder
– Corn starch plasticizes the paraffin wax
– Aluminum powder increases the combustion temperature
• Customer Requirements
– Thrust to weight ratio
– Operating Temperatures
– Specific impulse of motor
9. Igniter
• Function
– Preheat the combustion chamber
– Decompose oxidizer
• Powderless solid igniter grain
– 65% potassium nitrate, 25% sugar, 10% corn syrup by mass
– Ignited using commercial E-match
– Located in pre-combustion chamber
• Customer Requirements
– Suitable chamber temperature
– High reliability
– Increase specific impulse
Source: https://www.youtube.
com/watch?v=BgyC1jXTY4c
10. Injector
• Function
– Inject oxidizer into combustion chamber
– Strong effect on motor performance
• Dictates flow field in rocket
• Swirling Injector
– Increases burning rate of fuel
– Increased combustion efficiency over
design alternative
• Customer requirements satisfied
– Increase specific impulse
– Combustion efficiency
– Reliable
– Flight Viable
11. Results
• Fuel
– Specific impulse 210 s
• Igniter
– Chamber temperature > 823K
– Burn time > 2s
• Injector
– 54% increase in thrust
– 76% increase in specific impulse
– Substantial improvement to combustion efficiency
– Subsystem weight within tolerance
12. Recommendations
• Increase melting temperature of the fuel
• Scale up motor for competition
• Lengthen the post combustion chamber
• Shorten the precombustion chamber
• Continue researching high energy fuels
• Refine igniter grain manufacturing process
14. Overview
• Injector Integration (Ben)
• Combustion Chamber (Frank)
• Nozzle (Kyle)
• Relevant Customer Requirements
– Lightweight
– Durability of parts
– Conform to size restraints
15. Injector Integration
• Manifold /Combustion Chamber
– 4-40 socket head cap screws
– Loaded in tension
• Injector Attachment
– Lip
– No fasteners in injector
16. Combustion Chamber
• Aluminum Chamber
• Initial design failed during testing
• Wall thickness: increase from 3.6
mm to 8.0 mm
• Maximum temperature: 600F
• Tensile Yield Strength: 4640 psi
• Design Pressure of 400 psi
Initial Design
Final Design
17. Nozzle
• Accelerate flow of combustion
products
- Conical nozzle for simplicity
• Rocket may not leave rail safely
- Optimized to help meet speed
requirement off launch rail
• Nozzle Design has uncertainty
– Combustion gases require mixing
– Design does not change much
18. Results and Recommendations
Results
• Maintained integrity during testing
• Nozzle produced phenomena indicative of flow acceleration
• Assembly fits in the rocket
• Some tests failed in order to fit the motor in the rocket.
Recommendations
• Design for manufacturing (Avoid boring!)
• More heat transfer analysis in the combustion chamber walls
• Further optimize nozzle for launch altitude
21. Oxidizer/Pressurant
• Nitrous Oxide
– Non-cryogenic
– Common
– Non-toxic
– Easy storage
– Better performance
– Cooling
• Self-pressurizing
– Single tank
– No pressurant
– Acceptable pressures
22. Feed System Components
• Single tank configuration
– Light weight
– Smaller size
• Material selection
– Stainless steel
– Zinc plated steel
– Aluminum
• Physical properties
– Length: 44.9 in
– Width: 4.65 in
– Weight:
• 11.55 lbs (dry)
• 19.00 lbs (wet)
23. Remote Oxidizer Priming
• Collapsible arm
– Quick disconnect fittings
– Worm drive and gear motor
– Servo to Initiate
• Accessibility
– Side of rocket
– Door
• Material selection
– Stainless steel
– Electronic disconnect
24. Results
Passed: 10 out of 12 testing procedures
Failed:
Specific Impulse Performance Test
Target: 221-270 s
Achieved: 211 s
Reason: Ambient temperature of 56℉ during test, optimal oxidizer
temperature between 70 and 74℉
Oxidizer Pressure Test
Target: 760-1500 psi
Reason unknown due to pressure transducer failure. May be
estimated with calculations from injector pressure data.
25. Recommendations
For better results:
• Test rocket motor vertically
• Use double valve carbon fiber tank
• Pressurize with inert gas
• Decrease plumbing pressure drop
– Test larger check valve
• Temperature control storage tank
For ease of data analysis:
• Ensure all sensors work for every test
• Advance method for cleaning up data
• Create a venturi flow meter
https://www.youtube.com/watch?v=ZyfvJF529no
For safety:
• Keep impressing other hybrid teams by enhancing
existing safety mechanisms, preventing spontaneous
nitrous oxide reactions
http://www.simmonsmfg.com/wp-
content/uploads/2012/11/PAGE-5-CC1b.
jpg
27. Structures
•Rolled carbon fiber body tubes (ICE)
•Fiberglass couplers
•Aircraft plywood bulkheads, centering rings
–Steel dowel pins where necessary
•Blue tube motor tube
Relevant Customer Requirements:
• Integrates with motor assembly, recovery, avionics
• Stable throughout all stages of flight
• Easy to manufacture
28. Recovery
Parachute:
• Modified cruciform, Nylon webbing shroud
lines, Kevlar shock cord, stainless steel
hardware
• Total weight 0.362 kg
• Provides 43.4 lb drag force, for a landing
velocity of 7.3 m/s
Deployment:
• Piston
• Aluminum charge holder
• 1.2 g Triple 7 ejection
charge, e-match ignitionRelevant Customer Requirements:
• Recoverable with minimal damage
• Easy to manufacture
• Lightweight
29. Aerodynamics
Fins
• Trapezoidal with Airfoil
• T6 6061 Aluminum
• Manufactured using CNC mill and
hand finished
Relevant Customer
Requirements:
• Stable throughout all stages of flight
• Recoverable with minimal damage
Nose Cone
• Von Karman with 5:1 Fineness Ratio
• Fiberglass with Aluminum tip
• Male mold manufacturing process
Relevant Customer Requirements:
• Stable throughout all stages of flight
• Lightweight
30. Integration
Motor assembly → Plumbing → Tank+Avionics → Recovery → Nosecone
Relevant Customer Requirements:
• Integrates with motor assembly,
recovery, avionics
• Requires reasonable assembly time
• Easy to manufacture
31. Results and Recommendations
Results
• Solutions provided good balance of simplicity and
reliable functionality
• Passed 10 of 14 testing procedures
– True failure: stability margin, pin shear force
– Failed body tube bending, body tube buckling due to
underestimation of performance (rocket is stronger than
anticipated)
Recommendations:
• Recovery bulkhead e-match connectors
• RF transparency to simplify wireless communication
• Female mold for nosecone
32. Avionics
Beaglebone Black embedded
computer to control ignition,
oxidizer valve
Redundant Stratologger
systems to deploy parachute
Xbee wireless module for
remote control and
communication
39. Budget
Rocket Sub-Team Amount
Hot End 1 $1406.46
Hot End 2 $1020.95
Cold End $1824.07
Vehicle Engineering $336.14
Data Acquisition $300 (approximate)
Avionics $158.99
Total (goal $5000) $ 5046.61
Launch Rail
Total (goal $2000) $1990
40. Overall Results and Recommendations
Results:
• Flight viable rocket
• Launch scrubbed due to time constraints
– Avionics communication issue
– Ball valve battery issue
• Excellent teamwork and collaboration
Recommendations:
• Divide up responsibilities differently
• More flight-like testing
• Larger motor
