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Solid motors Oct 14

Two types of engine

  • solid engine vs ligquid engine,
    • which will talk about the simlicty of the solid geninge

SOlid engine

  • There are two types
    • RMS
      • come in two pieces, because
      • it comes hollow, and you shove the propelant inside it.
      • the case has the casing around and the seal disk, which is metal
      • the rest is what will get consumed.
      • only the casing is reaousable.
      • R means reusable.
    • DMS
      • preassembeled and glueded together
      • d means disposiable

How it burns

  • this accounts for logid engines,
  • for solid engines, its more in the geometry of the thing itself
  • creates different thrust curves
  • creats a smoother trhust curve
  • try to have them burn evenly all throughout.
  • star shaped components create more flat shaped
  • Ignoring drag, it doesnt matter,

How it burns

  • also contiains the thrust curtve of the motor on the spec sheet

Buold a solid motor

  • you have your grains, you ususally have multiple that you stuack up.
  • Alighn them end to end, see if your rocket has likle therr of them. Any fissure of them will.

O rings

  • the o ring is a rubbery ring that goes in between each grain, it also goes in other places that we care about.
  • also in the ends of the grains,

Nozzle

  • bernoulli's eqn is so ass, and it doesnt work

Seal disk

  • We just added the nozzle. what does the seal disk do?
  • its the thing that will go on top, is always reusable. (except DMS)

if you transport an empty motor casing, people might think its broken if you put the seal inside

Liner

  • just a cylynder
  • made of a material called phenolic
  • abrasive material, will destroy itself by absorbing heat. No complexity
  • cannot reuse it
  • have to replace it.
  • usually put the liner around the grains.

Casing

  • Aluminum cylinder

For and Aft Closure

  • see the threads on the ends? The closures are just to retain the nozzle.
  • for closure.

Smokecharge

  • smoke/delay grain.
  • it effectively has a delayed charge,
  • can use that to activate the recovery system

Ignition

  • Ideally, you have a small igniter at every stage,
  • the burn is so fast, by the time the electricty ignites, it could prevent the other igniters from igniting and puringin itself.

Naming and classification

  • buty the DMS
  • HP = HIGH POWER!!!!
  • L is the rating
  • the number is the average thrust
  • W = Propelent type white litghtnitng
  • 18A refers

Cato (Catastrophe at Takeoff)