The OCD Rocket

1
The OCD Rocket

• An Obsession with Compression via Diffusion

2
Outline of Talk

• Mitchell USLI
• Safety Presentation
• Rocket Build
• Payload Outline
• Website Development
• Outreach Plan
• Budget
• Summary

3
Mitchell USLI

• MCC Nerdherd Team Members
• Rocket Team
• Payload Team
• Outreach
• Budget
• Safety
• Website

4
Recovery Subsystem Safety and Failure Analysis

• Ejection Charges
• Shock-cord
• Parachute

5
Vehicle Safety and Environment

• Failure Modes and Mitigations
• Vehicle
• Payload Integration
• Launch Operations
• Personnel Hazards
• Environmental Concerns

6
Payload Safety and Environment

• Failure Modes and Mitigations
• Payload
• Payload Integration
• Launch Operations
• Personnel Hazards
• Environmental Concerns

Avoid This Situation
7
Mission Statement

• The MCC Nerdherd Rocket teams mission is to
  build a rocket that is capable of attaining
  super-sonic air flow through the diverging nozzle
  while reaching an altitude of one mile.

8
The Rocket

• Three main sections
• Payload
• Altimeter Bay
• Fin Can
• Overall Dimensions
• Length- 87 inches
• Diameter- 6 inches
• Materials
• Plywood
• Fiberglass
• Phenolic
• Static Margin

9
Rocket Flight Simulation AeroTech L2200G Motor
Max. Accel 15.4 Gs
Max. Vel 562 mph
Max. Alt 7608 ft.
Actual Altitude will be reduced by approximately
35 due to Payload induced Drag.
10
Fin Can

• The construction of the fin can is key to the
  success of the rocket.
• Motor Mount Assembly and Motor
• Retention
• Fins
• Reinforcement
• Body Tube Integration

Motor Mount Tube
Fins (X4)
Notched Centering Rings
11
Altimeter/Parachute
The rocket will utilize two altimeters to ensure
that the deployment and recovery is successful.
(Perfectflite MiniAlt/WD primary and Loki Arts 2
secondary).

• Altimeter Housing and Setup
• The chosen parachute is the 114 in O.D. SkyAngle
  XL.
• Descent Rate
• - Ground Testing Ejection Charge Amount

12
Scale Model Tests
Actual 1/2 Scale Flight Data

• The First Scale Model
• - Tested Design Feasibility
• - An idea of future performance
• The Second Scale Model
• - ½ Scale
• - Improvements from first scale model
• - Launch Results

Max. Alt. 1568ft
13
Motor Selection

• The Selected motor is the AeroTech L2200G.
• - Rocksim preformance
• - Rail Exit Velocity- 55.4mph (8 ft rail)
• - Real time prediction

14
Payload Integration

• The Ease of Integration
• - Coupler joints
• - Shock Cord Connection
• - Payload Isolation

Tape assisted friction fit
Shear pins inserted
Shock cord connection
15
Conditions of a Nozzle

• Subsonic Flow
• Fluid flow not sufficient for choked flow
• Just choked
• Fluid flow at the choke has reached sonic levels
• 250mph external airspeed

16
Conditions of a Nozzle

• Shock in the Nozzle
• Supersonic flow extends to within the divergence
• Shock at Exit
• Supersonic flow throughout the nozzle stopping
  the end

17
Conditions of a Nozzle

• Over-expanded Flow
• Shockwave just after the exhaust
• Design Condition
• Supersonic flow throughout
• Under-expanded Flow
• Back pressure too low
• Expansion waves at exit

18
Function of the Diffuser

• The rotating diffuser allows the back-pressure to
  be adjusted.
• Allows for future optimization to specific
  airspeeds due to the pressure change in the
  ambient airflow.
• Must be within the diverging duct
• Ability to alter the flow from shock in the
  nozzle to shock at the exit

19
Payload Section Overview

• Nozzle
• 16 inches long
• 3-D Printed
• ABS Plastic
• Carbon Fiber Supports
• Sensor Board mounted behind the interior wall

20
Electronics

• Pico ITX form factor computer
• 6 pressure sensors
• 65 samples per sec
• 12 bit samples
• 1.5 margin of error
• Servo Motor
• Modified for continuous rotation

21
Payload Goals

• Choked flow is achieved at the throat of nozzle
• Supersonic airflow is measured inside the
  divergence
• Supersonic airflow is adjusted by the rotating
  diffuser
• Data retrieved post landing
• Relationship between rotation speed of the
  diffuser and the velocity of the rocket effects
  on shock wave in diverging duct shown by the
  pressure data

22
Payload Testing

• Test pressure sensors functionality
• Test servo motor control of rotating diffuser
• Axial Load Test of Diffuser Motor
• Ground test of air moving through duct effect on
  diffuser
• Ability to acquire, store, and retrieve data on
  flight computer

23
Website

• Using text editor, not template
• Inserted documents, pictures, videos, and e-mail
• Team has own Google Group
• Plan to use frames in future
• Main, Documents, Media

24
Outreach Completed

• Rocket Day at East Alexander Middle School
• Presentations to 7th grade classes
• Water Rocket Launches
• Award Ceremony
• Newspaper article in Taylorsville Times
• Sponsorships
• - Hobby Town
• - Tom Henderson

25
Outreach To Do

• Statesville Christian School
• Presentation
• Water Rocket Flights
• Boys and Girls Club
• MCC Board of Trustees
• Presentation to MCC student body
• Possible
• Business/Rotary Club Presentation
• Sponsor TARC Team

26
Budget
Build/Recovery 1975 Payload 1250 Outreach
300 TOTAL 3525
27
Summary

• Project Purpose
• Mission Statement
• Progress
• First Scale Launch
• Second Scale Launch
• Rocket Specs
• Payload Progression
• Outreach/Website
• Budget

To