Mass Measurements

[Joedang]

We need to know the magnitude and location of the center of mass of all the rocket components. Once measured, these values must be added to the OpenRocket model.

Items in bold must be physically measured.

• nosecone tip
  • 0.2655 lbm, 38.423 in upstream of the nosecone interface (via SW)
  • OR model (Mass is overridden to zero, since the nosecone uses the integrated mass/CoM.)
• nosecone shell
  • measurement
  • OR model (uses total mass/CoM of the shell-tip-rod assembly)
• recovery system
  • measurement
  • OR model
• 18" module
  • measurement
  • OR model
• 24" module
  • measurement
  • OR model
• fin can
  • measurement
  • OR model
• spider
  • 0.08 lbm (36 g), 0.39 in (10 mm) downstream of the male ring's interface (via SW)
  • OR model
• cradle mount
  • 0.3012 lbm, 0.4193 in upstream of the female ring, 0.2607 upstream of the male ring (via SW)
    Having it inside the next module upstream is a huge style no-no. Fortunately, we don't care about that for L-13.
  • OR model ()
• cradle frame
  • measurement
  • OR model
• cradle spacers
  • 0.0898 lbm, 0.1625 in downstream of the male interface, 0.6425 in upstream of the female interface
  • OR model
• These are probably already pretty accurate in the OR database:
  • engine casing
  • engine core
• thrust flange ("motor mount", "pizza", etc.)
  • 0.1771 lbm, 0.1800 in downstream of the female interface
  • OR model
• camera module
  • measurement
  • OR model
• umbilical module
  • measurement
  • OR model
• telemetrum
  • measurement
  • OR model
• RCS (any CoM estimate is vapor for now...)
  • measurement
  • OR model

[Joedang]

Update: Took Physical Measurements

Rather than put everything here, I put my measurements in this file. (See the file for more info.)

E: the values have been added to the OR model. The modules were lighter than expected, the nosecone was heavier, and the fin can was basically dead-on. So, the stability margin caliber at Mach 0.3 decreased by 0.03 (trivial).

[Joedang]

Hey @jejor, you should go measure the things. You'll need to get a recovery person to get the parachutes out for you... someone like @hmarie2 or @calvin-young.