📘 Dispositivos de Recuperação e + | AULA 4 🚀Curso Introdução à Simulação de Foguetes com OpenRocket

Main ideas / lessons conveyed

• Purpose of Lesson 4 (OpenRocket):

  • The instructor is not building a rocket live; instead, they review the recovery-related accessories and other critical internal components needed for a rocket to be safe and recoverable.
  • Key focus: how recovery devices are configured and how OpenRocket models their deployment and separation mechanics.

• Core recovery concept: separation enables deployment

  • Recovery devices require stage/section separation to work correctly.
  • This separation is triggered by an ejection charge (internal pressurization) that:
    • pressurizes the rocket internally,
    • separates rocket parts,
    • allows a recovery object to emerge into the air (e.g., parachute).

• Types of recovery/safety devices

  • Parachute
    • High drag coefficient → air pushes it easily in different directions.
    • Connected using a shock-absorbing cable between rocket parts.
  • Streamer (flag)
    • Acts like ribbon/tape: provides slower deceleration than a parachute.
    • Makes the rocket lose speed on impact more gently, potentially giving better directional control of fall.
    • Compared drag coefficients in the lesson:
      • Parachute drag coefficient: 0.8
      • Streamer drag coefficient: 0.08
  • Both devices are modeled as configurable elements with drag-related behavior.

• Engine-driven timing for recovery

  • Deployment timing is linked to the engine’s ejection charge delay:
    • Example set in lesson: 2-second delay
    • Meaning: after the engine burns out, 2 seconds later the internal charge activates and deploys the recovery device.
  • This delay is described as the “ejection load moment”—a characteristic tied to the engine.

---

Methodology / configuration steps highlighted

A) Parachute configuration (deployment-related)

• Place parachute strategically for emergence

  • The instructor positions it “exactly at the division” between the warhead and body tube to help it come out after separation.

• Configure parachute size and material

  • Increase parachute diameter (circular fabric size).
  • Choose fabric material, given in grams per m² (surface area focus).

• Set aerodynamic resistance

  • Choose/adjust drag coefficient via parachute material/surface interaction:
    • Higher drag coefficient → more air interaction → more slowing.
    • Lower drag coefficient → less slowing.

• Configure suspension lines

  • Set number of lines (line count).
  • Adjust line length.
  • Adjust line linear density (described with units like grams-per-meter).

• Packaging / storage configuration

  • Parachute packaging is modeled as cylindrical storage.
  • Adjust packaging length by changing how it’s stored.

• Activation approach recommendation

  • The instructor recommends not configuring certain activation options in the current parachute box immediately.
  • Instead, activation should be configured through:
    • motors / staging / recovery mechanisms, especially using ejection charges.

B) Ejection charge (engine-driven separation)

• Use an injection charge / internal pressurization element concept:

  • Triggered by an engine after burnout (modeled via delay).

• Configure engine charge delay

  • Example used: set 2 seconds
  • Meaning: after the engine completes normal burn, wait 2 seconds, then activate internal gas separation for parachute deployment.

C) Shock-absorbing cable configuration (for parachute connection)

• Connect parachute to rocket parts using a shock-absorbing cable (modeled as a large rope).
• Configure parameters similar to parachute “momentum”/drag modeling:
  • Packaging modeled cylindrically.
• Set:
  • cable length
  • radial position (distance from rocket central axis)
  • Example radial distance: 1.1 cm

D) Internal structural components for engine mounting and safety

• Centering ring

  • Role: center and position engine within the body tube.
  • Modeled as a hollow cylinder.
  • Can be made from rubber/plastic/other centering-filling materials.

• Engine block / isolating hollow cylinder

  • Role:
    • structurally holds engine,
    • isolates engine from the rest of rocket,
    • protects against heat/pressure.
  • Also modeled as a hollow cylinder (often more elongated by default).

• Baffle (isolation barrier for fragile electronics)

  • Purpose: prevent sensitive components (like an onboard computer) from being hit by separation/ejection events.
  • Implemented as a partially filled/filled barrier, positioned (example) to protect the computer near the top of the warhead.
  • Described as a safety isolation structure.

E) Mass component / onboard computer modeling

• Add a mass component (treated like a payload/weight used by calculations).
• Configure its weight.
• The instructor explains its purpose as:
  • providing weight for rocket calculations,
  • representing devices such as:
    • onboard computer,
    • battery (example alternative).
• Caution:
  • Since it’s fragile, it must be protected from pressurization/separation impacts (hence the baffle).
• Visual/UI note:
  • Different icons represent different mass types/components in technical drawings.

F) Streamer (flag) recovery device configuration

• Add streamer/flag as a recovery device for the relevant stage (example: stage 1).
• Customize streamer properties:
  • length (via ribbon icon)
  • area
  • width
  • overall aspect (editable together using an index; default example: 10)
  • material and drag coefficient (compared to parachute drag)
• Set activation conditions:
  • Example altitude activation: 400 m

G) Stage connection and guidance system (structural/launch)

• Coupler

  • Connects stage components internally (modeled as an internal projection connecting pieces).

• Guide tube

  • Guides the rocket during initial moments on a launch rod/rail system.
  • Prevents tipping early; supports rocket while on the launch rod in the first seconds.

• Launch base alternatives mentioned:

  • Rod launch with a tube/guide.
  • Rail launch options:
    • rail buttons/pins
    • rocket wheels/butterfly-like guide points passing through the rail.

H) Learning from OpenRocket examples (internal tubes / clustering)

• The instructor recommends checking Rocket Examples projects within OpenRocket.

• Example focus:

  • Inner tubes
    • Like additional hollow cylinders inside the rocket body.
    • Allow inserting engines inside them.
    • Can also represent clustering: multiple engines within a central/cluster tube.

• Group section / clustering

  • Configure groups to multiply engines inside the inner tube.
  • Example shown:
    • two internal tubes allow inserting different motor types
    • separate grouping (e.g., “group one” and “group three”)
  • Additional adjustable parameters mentioned generally:
    • radial positions
    • displacement/placement of the inner tube
    • rotational configuration

---

Overall progression / outcome at the end of the lesson

• By the end, the instructor claims the viewer now has a three-stage rocket model (sustainer, stage 1, boosters) ready for deeper analysis in the next lesson.
• Next lesson planned:
  • visualize simulation graphs
  • interpret flight dynamics from ejection charges through stage separation using graph data

---

Speakers / sources featured

• Vinícius Leandro (instructor/monitor)
• UziFog / Brazilian Rocket Simulation Olympiad (contextual program mentioned: “Uzifog”)
• OpenRocket software (tool used; no additional named sources)