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?