Medusa Characterization Hardware

Responsible Engineers: Justin, Aimee, Tamara, Alex

Week 1 Assignments:

• Calculating yield strength in a thread/maximum load on a thread & cases with screw on forward closures - Alex My name jeff
• Work with Cruz to figure out 3d experience - Aimee
• How thick does case need to be to reach pressure - Elizabeth
• Reach out to Kelly - Elizabeth
• Integrated forward closure case design - Justin
• Test stand - Aimee & Tamara

Medusa Characterization Motor Design

• New characterization motor design
  • propellant casting tube & liner
    • how to get around?
    • 38mm or 54mm liner (contact Kelly)
      • can make about 10 motors
    • thicker phenolic liner that Kelly used https://www.mcmaster.com/8527K244/?SrchEntryWebPart_InpBox=garolite+xx+phenolic
  • case can be reused
    • maybe make 2 in case one breaks
  • very thick case to accommodate a range of pressures
    • 300 psi to 2000/2500 psi
    • case should be rated for 3000 psi
  • need to test at pressures expected during flight
  • drill hole in liner to read pressure transducer
  • make forward closure part of the case
    • disassembly is harder
    • saves on O-rings
    • test with blue thunder ring 
  • adding o-ring on nozzle side
  • glue disk to bottom
  • Put steel ring on top w/small hole and clock accordingly
• Pour propellant in layers into liner
• Propose changing nozzle size to change pressure
• Smaller setup (less propellant) than large motors tested for Phoenix
  • Scaling issues?
  • No mandril
  • Could 3d print casting hardware
  • Plug and Play 
  • Easier to do in blast chamber
    • Cheaper
    • Less travel
  • Data collection is easier (each fire is one data point w/one burn rate)
  • Need to keep length of motor constant (affects burn rate)
  • Pressure transducer on bottom
• RTV use
  • very time consuming waiting to dry
  • need to use RTV on nozzles
  • to minimize time make nozzle integration faster
  • all phenalic and graphite must be replaced
• Clocking
  • also time consuming
  • less of an issue if tolerancing is better
• Nozzles
  • on the order of 2 inches
  • will be machining lots of nozzles
  • need to figure out nozzle range to get desired pressure values

Segmented Motors

• Done on Hermes
• Scale back on erosive burning
  • Have a less complex grain geometry
• Separate layers using RTV
  
  

Phoenix Issues

• Experienced leakage
  • No seal (tolerancing issues with O-rings)
• Data analysis was done badly