Victoria Pham 11/2/2024

  1. Fin Can Assembly
    1. Material composition
      1. fins
        1. G-10 Fiberglass Core; 5 carbon fiber layups alternating grain direction; clipped delta shape
          1. Clipped Delta Shape
        2. Max Flutter Velocity was not within our margins of safety, so the fin dimensions will change accordingly
      2. Fin can (4 fins)
        1. epoxy filets (.75" - 1") for each side of conjoining fin
        2. tip to tip fiberglass (better than carbon fiber for thermal protection at higher speeds)
  2. Stability (RASAero Simulations)
    1. With a max altitude of 33,829 ft, stability ranges from 2-4.5 with and without wind. After burnout, exceeds 4 → very stable
  3. Preliminary Calculations
    1. Lift Force
      1. account for if the rocket deviates from expected path. 
      2. Subsonic flight: 200lbf
      3. Supersonic: 226lbf 
    2. Bending Moment
      1. Idealized calculation: assuming uniformly distributed pressure, and isotropic material behavior 
        1. 564 lbf*in
      2. Because we are using composite materials, we want to conduct real testing than rely on theoretical upper bounds for loads. 
    3. Sheer Force
      1. Drag and Inertia ||: 18lbf//8.6lbf
      2. Lift Perpendicular: 226lbf
  4. Fin Load Tests
    2. Max F applied: 375lbf (1.5x expected lift shear force)
    3. Moment 4" from joint (2.5x expected bending moment)
    4. Difference from .75" fillet and 1" fillet is marginal 
    5. Jig bent from load (we assume this is why the graph doesn't match the elastic deformation curve) and couldn't test until failure.
      1. Idea for Better Test
        1. 2 fins instead of one for a more accurate representation of force
          1. symmetric force, testing 10% load increments
  5. Flutter Velocity/ Divergence Velocity
    1. Assuming elastic axis is .5 and fin CG is at .71, Max Divergence velocity is 2.36 Mach and max flutter velocity is 2.73 Mach.
      1. Both don't fit within factor of safety, need to work on better ways to model, especially with the composite make of the fin.
  6. Stagnation Temperature
    1. Max is 239 degrees F
    2. System 2000 epoxy has a glass transition at 196 degrees F
      1. need to use epoxy with higher glass transition bound (system 400 at 275 degrees F
  7. Materials: need DP-420 NS Epoxy for fillets and System 4000/4600 Hardener
  8. Fin Manufacturing
    1. Waterjet G-10 Cores
    2. 5 Carbon fiber layups and sanding
    3. Leading edge 
      1. emphasis on symmetry 
      3. Sanding board at angle is constrained by the 2 x 4s, fin is slowly slid in with different holders for each leading edge. 
      4. need to calculate geometry for a defined inner angle
    4. Alignment Jigs
    5. Jig for fiberglass layups
  9. Camera Shells
    1. TLDR: old prometheus camera shell works better at Mach 1
      1. enacting ANSYS simulations need work because the results we have gotten are off in terms of magnitude
    2. Manufacturing
      1. 3D printed mold and fiberglass layups 
    3. Testing Plans
      1. Need to test shell and camera under heat and load from drag









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