Meeting Minutes (2013 Nov 4)

Rocket Team Meeting 

November 4, 2013

 

Level 1 Certification

  • We got 13 people Level 1 certified à everything went really smoothly…except for retrieval
  • In the future, should put trackers or radio beacons for easier retrieval
  • Should put full name, phone, and MIT on outside of rocket
  • Short pre-launch check-list – the parachute, did you set delay charge, etc. – before launch

 

  • If people want to try for Level 2, need bigger engine and take a test
  • Need to get under altitude limit of 3,000 ft in Amesbury (weigh rocket down, drag streamers, etc)
    • Might want to try for another launch site with higher altitude (Maine w/ 10,000 ft?)
    • Should fiberglass upper section of rocket and definitely need to put radio beacon; possibly need to use dual-deployment parachute system à altimeter and avionics bay

 

  • Next launch is November 16!!

 

Pyralis!

Sensors & Instrumentation

  • Strain gauges & pressure transducers
  • Letendre has pressure transducers that will work; borrow amplifiers and strain gauges from Perridichi

 

Test Stand

  • Stop test stand from moving à sandbags for weights (portable weights à easy setup)
  • Test stand main structure idea = uni-strut
    • Con for wood – wood + fire = EHS very, very nervous
    • Need several strain gauges rosettes around the pedestal so we can measure whether the thrust is not aligned with the axis

 

Manufacturing

  • For spike and liner for cold flow as mock-up, want to use some sort of plastic instead of ceramic à options?
    • Nylon = cheapest and easiest to machine; also softest (might compress at lip; if aerospike stretches and closes the gap à really bad!!)
    • Polycarb = harder but more expensive
    • Delrin = already on hand; still a good option
    • PET = harder than nylon but still pretty cheap

 

Propellant Flow

  • Pipe sizes for cold flow? 3/8”
  • Eric has software and MATLAB code for modeling losses in pipe, etc
  • Need solenoid valve to turn engine on without being in room à anything we can use in Talaris?

 

Optical Sensors

  • Schlieren photography – how large of a mirror? 6” spherical mirror for $70. Any bigger and want to use parabolic
    • Trade-off between spherical and parabolic = parabolic has some distortions but cheaper
    • Want to image 6” section at tip of engine
    • Already have camera; might need plexiglass for case for camera
    • Need to pick mirror and order by Weds?

 

Engine Geometry & Design

  • Material to make the engine? Trade-off = aluminum vs. steel
    • Big factor is ductility in metal, especially for a pressure vessel (if it fails)
    • Steel more brittle than Al and therefore using Al might be safer?
    • Steel Acetenic 300 Series (316 or 304 stainless steel alloy) à ductility similar to that of Al and maintains its tensile strength
    • Both Al and steel will support vessel during firing but Al might deform under own weight and fail after firing
    • Steel = more expensive and harder to machine but machining difficulties of steel worth not replacing our pressure vessel after every single firing
    • Ceramic materials to make liner
      • Two types fairly cheap and come in castable powder
      • Make a mold for part and cast it (for hot fire)
      • While mold cures, we want to keep it under light vacuum to suck up all the air bubbles when we can
        • Borrow Unified vacuum chamber for this

 

Injector Plates

  • Make injector out of a stack of 3 plates
    • Top plate with arrangement of 4 holes (pressure sensor, spark plug, oxidizer, fuel)
    • Middle plate w/ 2 channels (1 loops from fuel port to distribute fuel; other loops from oxidizer port to distribute oxidizer)
    • Bottom plate w/ ring of holes for fuel and concentric ring of holes for oxidizer
      • Holes angled so fuel and oxidizer mix à stream of fuel & oxidizer mist finely mixed
      • Talk to Edgerton – do they have a 5-axis mill?
      • Surface Solutions – contact him for machining complex parts; do not use Central Machining

 

Master Equipment List

  • Management tool to keep track of all components you have for each subgroup of project
  • Name, description, cost and useful properties (time to arrive, mass, who last ordered, etc)
  • 1st stop at auditing budget & checking mass!

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