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Design pressure: 1500 psi

Sustainer:

Aluminum Case: OD: 4", ID": 3.75" (thickness 1/8")

Phenolic Liner: OD: 3.75", ID: 3.5" (thickness 1/8")

Casting Tube: OD: 3.5", ID: 3.375" (thickness 1/16")

Booster:

Aluminum Case: OD: 6", ID: 5.625" (thickness 3/16")

Phenolic Liner: OD 5.625", ID: 5.375" (thickness 1/8")

Casting Tube: OD: 5.375", ID: 5.25" (thickness 1/16")

Constraints:

• Manufacturing capability
  • Lathes can machine up to 6" diameter
• Available liners' specs (lengths)
  • 48", 53.1", 59.1", 65"
• Need for a casting tube within liner
  • Unless multicast in one liner is feasible
    • While potentially feasible, many have told us it is better practice to use a casting tube with each grain in sections with o-rings in between each ring
• Available tube size
• Tolerances of the tubes are not within rocketry tolerance (+-.001")
  • Solution: Use a simulator piece while machining the parts to achieve as good of a seal as possible
    
    • Simulator piece is a cut piece of the case stock. Get part to nominal diameter then test fit with simulator until it fits by hand
    • Use 300 or 400 series o-rings to hold a better seal.

Design Specs:

• 6" OD
• Internal pressure expected to be around 1000 psi max
• Safety factor 1.5
• Thickness: 3/16"

Phenolic Tubes:

• Order from Franklin Fibres (lengths: 48", 53.1", 59.1", 65")
• 1/8" thick for liner
  • ID: 5.375.", OD: 5.625"
• 1/16" thick for casting tube
  • ID: 5.25", OD: 5.375"
• long lead times, order in bulk this semester

Bolts:

2 rows of 16x 1/4-20 bolts.

Total of 64 bolts on the booster.

Constraints:

• available liners' specs (lengths)
  • 48", 53.1", 59.1", 65"

Design Specs:

• 4" OD, 3.75" ID
• Internal pressure expected to be around 300 psi max
• Safety factor 3
• Thickness: 1/8"

Motor Case:

• Order from Online Metals
• 1/8" thick
• ID: 3.75', OD: 4'

Phenolic Tubes:

• Order from Franklin Fibres (lengths: 48", 53.1", 59.1", 65")
• 1/8" thick for liner
  • ID: 3.5", OD: 3.75"
• 1/16" thick for casting tube
  • ID: 3.375", OD: 3.5"
• long lead times, order in bulk this semester

Bolts:

1 rows of 8x 10-20 bolts.

Total of 16 bolts on the sustainer.

Case calcs done using 1800 psi as internal pressure

Thin vs Thick Case Assumption: thin case assumption can be used if  

Booster

Booster thin case assumption if t < 0.3"

Calculated with thin case assumption -> safety factor = 1.5, case thickness = 0.191"

Sustainer

Sustainer thin case assumption if t < 0.2"

Calculated with thin case assumption -> safety factor = 2, case thickness = 0.229"

Calculated with thick case assumption -> safety factor = 2, case thickness = 0.241"

MATLAB file for case calculations: case calcs.m

Python file for case calculations: case_calcs.py

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