Medusa Booster and Sustainer Motor Case

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
• available tube size

Design Specs:

• 6' ish OD
• Internal pressure expected to be around 1500-2000 psi max
• Safety factor 2
• min. thickness: 0.350" - closest thickness is 0.5"

Motor Case:

• order from Online Metals (lengths: 1', 2', 3', 4', 6', 8')
• 1/2" thick
• ID: 5.5', OD: 6.5'

Phenolic Tubes:

• order from Franklin Fibres (lengths: 48", 53.1", 59.1", 65")
• 1/8" thick for liner
  • ID: 5.25', OD: 5.5'
• 1/16" thick for casting tube
  • ID: 5.125', OD: 5.25'
• long lead times, order in bulk this semester

Constraints:

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

Design Specs:

• 4' ish OD
• Internal pressure expected to be around 1500-2000 psi max
• Safety factor 2
• min. thickness: 0.241" - closest thickness is 0.25"

Motor Case:

• order from McMaster or Online Metals
• 1/2" thick
• ID: 4', OD: 4.5'

Phenolic Tubes:

• order from Franklin Fibres (lengths: 48", 53.1", 59.1", 65")
• long lead times, order in bulk this semester
• 1/8" thick for liner
• 1/16" thick for casting tube
• ID: 4.75', OD: 4'

Case calcs done using 2000 psi as internal pressure

Thin vs Thick Case Assumption: thin case assumption can be used if   $//<![CDATA[ \begin{array}{l}\frac{Diameter}{thickness} < 20\end{array} //]]>$

Booster

Booster thin case assumption if t < 0.3"

Calculated with thin case assumption -> safety factor = 2, case thickness = 0.371"

Move onto thick case assumption -> safety factor = 2, case thickness = 0.350"

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