University of North Dakota
Frozen Fury
Critical Design ReviewFebruary 2, 2015
Length: 105 inchesDiameter: 6.155 inchesMass: 26.2 lbs
General Vehicle Dimensions
Center of Gravity: 57.579 inchesCenter of Pressure: 68.434Safety Margin: 1.76
Critical Flight and Payload Systems
Different subsystems of the rocket
Airframe – carbon fiber◦ Superior strength to weight ratio◦ Ease of workability
Fins – birch plywood in carbon fiber◦ Combines the strength of both materials for a more rigid,
strong, and lightweight fin
Bulk-Head/Centering ring – 0.5 inch birch plywood◦ Cabinet quality grain, few knots, and locally available
Materials and Justifications
Location of Launch Lugs (inches)
Location of Centering Rings (inches)Fin Dimensions (mm)
General Vehicle Dimensions
Fins ◦ Symmetric shape and quantity allows for ease of
construction, trapezoidal shape limits potential damage to fins upon landing
Diameter ◦ 6” diameter allows for ease of assembly and plenty of
workspace. ◦ Also allows for better utilization of scrap components, and
expansion of internal components if necessary
Materials and Justifications
Nose Cone Dimensions (mm)
General Vehicle Dimensions
Nosecone ◦ Will be purchased to insure proper functionality
West Systems Epoxy◦ Used to bind the above materials together as well as some
hardware (bolts, nuts, threaded rods)
Materials and Justifications
Parachute Attachment Bulkhead
Bulkhead Dimensions (inch)
Parachutes
Parachute type Parachute size Harness Type Harness Length Descent Rate
Drogue 36 in ripstop nylon 5ft 62 ft/s
Main 115 in ripstop nylon 5ft 16.08 ft/s
Payload 58 in ripstop nylon 5ft 22.47 ft/s
Deployment of Parachutes
Flight Analysis
Total motion vs. Time
Drift Analysis at 5 mph
Drift Analysis at 10 mph
Drift Analysis at 15 mph
Drift Analysis 20 mph
Drag Analysis
Drag Coefficient at 5 mph
AGSE Design
Rocket in Horizontal Position
Payload System
Linear Actuator
Ignition Insertion System
ElectricalBox
Lifted Rocket Position
Rocket in 5° to vertical Position
Square Tube Iron
Frame
Electrical Box
Basic electrical schematic Arduino board
All components for the AGSE will be housed in the black box that is on the frame.
Claw With Pan/Tilt Bracket
● Servo to open and close claw
● Another servo to tilt claw
Claw assembly (in)Claw assembled by the team
Belt/Slider Rail
Slider with belt assembly (in)
Payload Acquisition System
Payload acquisition assembly (in)
Belt/Slider Rail
Slider assembled by the team
Actuator Position
● Linear actuator has stall torque of 240 lbs.
Rocket actuator assembly (in)
Ignition Insertion System
Side view of the ignition system
Wire Funnel
● Mounted to the rail● Will help guide the
ignition wire into the rocket motor
Ignition system funnel (in)
Wire Extension Assembly
● 1, 16 tooth gear is driven by 51 RPM motor
● 2, 32 tooth gears spin rubber wheels
● Steel housing ● Will be mounted on rail
Ignition system gearbox (in)
Wire Spool Housing
● Steel housing for spool
● Ignition wire is coiled around spool
● Mounted to rail
Ignition system wire spool (in)
● If the stability of the rocket on the rail becomes an issue, there will be guides added to the rail.
● A counter weight will be added to the end of the rail behind the wire spool to alleviate motor stress of the actuator.
Final Design Changes to be Made
Design Justifications
Justifications 54.0 mm diameter allows
for easy downscaling Black Max Propellant
provides the high visibility tracking of dense black exhaust
Manufacturer: AeroTech
Mfr. Designation: K480W
Motor Type: reload
Diameter: 54.0 mm
Length: 57.9 cm
Total Weight: 2078 g
Average Thrust: 528.67 N
Maximum Thrust: 1017.8 N
Total impulse: 2273.3 Ns
Burn Time: 4.3s
Baseline Motor Selection and Justification
Motor Selection: Aerotech K480W
Aerotech K480W Thrust per second
Thrust-to-Weight Ratio
Thrust to weight ratio 7.75:1
Dual deployment system Two Perfect Flight altimeters
used as a backup system◦ Measures barometric
pressure◦ “Mach” delay for safety◦ Deploys drogue parachute at
apogee◦ Deploys main parachute at
3000 ft AGL and payload parachute at 1000ft AGL
Avionics
Avionics: Altimeter Bay
Altimeter Bay Schematics
Payload Securing
Payload Compartment 3-D View Payload Compartment Rear View
Sequence Code
Sequence Code
Code
Declaration of Switches and Pins
Sequence Code
Initialization of Switches and Pins
Code
Declaration of Switches and Pins
Starting Positions
Code
Claw Actions
Code
More Claw Actions
Code
AGSE Actions
Code
AGSE Actions
Payload acquisition ◦ Payload is in the launch vehicle and secured
Rocket Erection ◦ Rocket is lifted to a position of 85 degrees from the
horizontal
Wire Insertion◦ Wire is fully inserted in motor and no accidental charge
ignites motor
Success Criteria for AGSE
Rocket launch◦ Reaching an altitude of 3000 feet at apogee.
Rocket recovery◦ The recovery system deploying properly at the appropriate
altitude and recovering the rocket on the ground such that it is deemed reusable for future launches
Payload◦ The payload should be ejected from the rocket at 1,000 feet
and return to the ground with its own parachute.
Success Criteria for Launch Vehicle
Rocket Flight Stabilityin Static Margin Diagram
The center of gravity is forward of the center of pressure (closer to the nosecone)
Rocket Flight Static Margin10.855
Center of Pressure68.434 in
Center of Gravity57.579 in
Kinetic Energy ft-lbs
Drogue 1562.95
Main Parachute 68.17
Payload Parachute 70.29
The minimum rod speed that ensures a stable flight is generally between 30 fps (20 mph) to 45 fps (30 mph).
Exit rail velocity: 69.5 ft/s
A pair of rail beads will be used to ensure the rocket reaches adequate speed off of the rail while maintaining proper orientation
Vehicle Safety
Critique Score 1/51 = Bad
5 = Good
Comments
Is this design safe? 4 This design will allow for ease of construction and eliminate safety concerns associated with more complex construction methods
Is this design limiting? 4 Altitude is expected to be reached and the design will accommodate larger motors and payload components
Does this design meet the requirements of the payload/rocket?
4 This current rocket design satisfies the requirements for the projected payload.
Will this design land safely? Parachute sizes, impact absorbing design?
4 The current size rocket and parachutes have the rocket descending rapidly under drogue, but slowing to under 25 ft/s under main.
Does this design maximize performance?
3 The rocket has been designed to accommodate the payload as well as larger motors as the design is refined.
Are the materials selected the best for this scenario?
4 Carbon fiber is a strong yet lightweight material that we have had success with in years prior. Past experience with phenolic tubing has yielded structural failure.
Any additional comments?
------- Conduct additional tests and review plan to ensure continued safety
Plan for Vehicle Safety Verification and Testing
Physics Day at UND - November 12, 2014 This is a program for local middle school to high school
students to learn about the many different facets of physics.◦ Gave a presentation about rocketry◦ Introduced them to the USLI program and shared our past history
with the competition◦ 200 students attended
Educational Engagement
Outreach at Grand Forks area middle school
Our team is still in the process of scheduling a date to visit the local middle schools.
◦ Give a brief lecture about rocketry◦ We will build and launch balloon rockets◦ Have a Q & A session about rocketry◦ Expect to reach about 30-80 students.
Educational Engagement
UND Physics and Astronomy Talk -February 23rd.
○ In an hour long talk, we will detail rocketry throughout the ages and hold a demonstration of our current AGSE. The average attendance for these talks is 30-50 students and other interested parties.
Educational Engagement
Two sub-scale launches were performed to verify the recovery system and the main design (fins, nosecone).
There were minor complications in each of the launches.
Vehicle Testing
Length ratio of subscale I: 1:1.75
Length ratio of subscale II : 1:1.4
Fins ratio: 1:2.25
Diameter ratio: 1:2
Scale Launches
Aerotech 1211W-M
● Total Impulse: 460 N/s● Motor Diameter: 1.5 in● Motor Length: 9.82 in
Parachutes:
● Drogue: 30 inches● Main parachute: 28 inches● Payload Parachute: 36 inches
Motor and parachutes
Rocket: ● Length: 60.875 inches● Diameter: 3 inches● Mass with motors: 28.2 ounces● Stability Margin: 1.3
Subscale Launch I
Subscale Launch I Simulation
Apogee: 2815 ft Maximum velocity: 930 ft/s
Subscale Launch I Flight
Deployment of Time (s) Altitude (ft) Velocity (mph)
Drogue 13.65 2804 15
Main parachutes 71.90 600 35
Apogee: 2811 ft.
● Lack of space● Increased charge● Weakened bond
Flight I Complications
Rocket: ● Length: 73.75 inches● Diameter: 3 inches● Mass with motors: 31.9 ounces● Stability Margin: 2.37
Subscale Launch II
Subscale Launch II Simulation
Apogee: 2801 ft Maximum velocity: 881 ft/s
Subscale Launch II Flight
Deployment of Time (s) Altitude (ft) Velocity (mph)
Drogue 13.6 2619 18
Main parachutes 62.05 600 35
Apogee: 2621 ft.
● Obstruction when preparing break pin’s holes● Slight wobble during launch● Parachute Complications
Flight II Complications
In the coming weeks, the team will be working on:
- For the AGSE: Cutting the frame and welding itBuilding of Ignition and lifting systemFinishing the payload acquisition systemPositioning of the different switchesImplementing the electrical system
- For the rocket: Ordering of the rocket cylinders Building of the Fins
Building of the Payload securing
Near-Future Work
Questions?