📘Como aumentar apogeu com Estágios | AULA 3 🚀Curso Introdução à Simulação de Foguetes com OpenRocket

Main ideas / lessons conveyed

• Goal of the lesson: Increase the rocket’s apogee (maximum altitude) by improving the rocket configuration made in earlier classes.
• Core engineering maxim introduced:
  • To increase range/apogee, add more engines and plan the ignition sequence (which engine lights when the previous one stops).

Paradox explained: “Tyranny of rockets”

• Adding engines increases thrust, but it also adds mass (the engines and structure).
• The added mass then requires even more engines to lift it.
• This creates an escalating, “infinite” mass/engine problem.

Mathematical “solution” given: Tsiolkovsky’s idea

• Referencing Konstantin Tsiolkovsky, the lesson states that the way around the tyranny is to use staging:
  • When an engine burns out, detach the dead weight instead of carrying it for the rest of the flight.

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Methodology / step-by-step instructions (OpenRocket workflow)

A) Create a new stage (Stage separation concept)

• In the software:
  • Click Supporter → Stage to create Stage 1 (a new detachable stage).
• (Optional) You may ignore intermediate screens except to:
  • Rename stage items (e.g., edit “stage one”).
• Add a transition to match the next engine’s size:
  • Create a transition where the rocket diameter changes.
  • Example choice mentioned: transition geometry set to parabolic (rounded airflow improvement).
  • Note: a highlight can be created on the front/back (mentioned as covered in Class 1; not done here to save time).

B) Adjust the stage body (geometry)

• Select Body tube and resize it.
  • Example: set to 50 cm to accommodate a larger motor.

C) Add fins (as learned previously)

• Add fins to the stage configuration (fins approach stated to be from Class 2).

D) Configure the stage’s engine mounting and select the motor

• Choose an engine for Stage 1:
  • Go to Motors → Configuration.
  • Select the body tube as the engine mounting object.
• Use the resulting engine configuration columns:
  • Select the column corresponding to Stage 1.
• Motor selection strategy:
  • Filter/sort motors to match the ideal length and diameter for Stage 1.
  • Sort by highest impulse to lowest impulse and pick the top-ranked one (highest impulse).
• Check key burn performance:
  • Verify combustion/burn time.
  • Example given: 3.5 seconds burn time.

E) Set firing order / ignition timing for engines

• Configure Stage 1 ignition:
  • Stage 1 engine should ignite at launch (lift rocket for the first seconds).
• Configure burnout logic (when the next stage should start):
  • Set the next engine to ignite starting from the moment Stage 1 has finished in the chosen burnout/burn-complete configuration.
  • (This is described as ensuring previous-stage burnout occurs first.)

F) Configure when Stage 1 separates

• Select stage separation timing:
  • Stage 1 should separate after its engine becomes useless, i.e., when it has fully completed its burn.
• The lesson emphasizes separation at “dead weight removal” time.

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Additional alternatives: boosters/pods (side engines)

G) Use boosters instead of pods

• Difference:
  • Booster: detachable, used as a stage-like component.
  • Pod: fixed, attached structure (not detached).
• Instruction choice:
  • Use boosters for this lesson (pod principles would be similar).

H) Build and position booster sets

• Starter steps:
  • The booster configuration screen is mentioned as something to ignore for this best workflow (already added).
• Fix overlap issues (example: warhead overlaps fins):
  • Adjust booster general settings, e.g., radial distance (initial approach described, then corrected).
• Position boosters properly:
  • Use angle setting:
    • Example: set to 45° so boosters sit between fins.
• Symmetry:
  • Choose number of booster copies:
    • Example: set to four.
• Finish booster assembly:
  • Modify ogive diameter:
    • Example: set to 3 cm.
  • Add/adjust body tube and other rocket elements within the booster structure.
  • Add trapezoidal fins and adjust to remove overlaps:
    • Example: set fin height adjustment to 1.5 to resolve collisions.

I) Select engines for the boosters

• In booster engine setup:
  • Go to Motors → select motors configuration for the booster body tube.
  • Confirm the configuration mapping and select a motor from the filtered list.
• Key warning driven by the tyranny paradox:
  • Highest-thrust engines are often heavier.
  • Therefore the “best” motor may not be the top-by-thrust choice; efficiency/lightness matter.
• Example motor choice:
  • Aerotech E F39T
  • Mentioned mass target: ~59 g (chosen for best balance of thrust/total impulse vs low mass).
• Burn-time constraint:
  • Booster engine must not exceed Stage 1’s 3.5 s window because:
    • once Stage 1 ends, boosters separate/eject and would lose efficient burn matching.
  • Example burn time detail:
    • Booster burn time described as ~1.25 (within the acceptable limit compared to 3.5 seconds).

J) Set booster ignition and booster separation timing

• Ignition timing:
  • Boosters’ engine ignition should occur with launch, aligned with Stage 1’s central engine.
• Separation timing:
  • Do not separate during the ejection charge.
  • Instead, separate when the booster becomes useless:
    • from the moment the current stage booster motor has completed its total burning.

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Results / conclusion from the lesson

• Despite adding four booster engines, the rocket’s peak altitude increased only about 24 meters.
• This outcome is presented as evidence of the rocket tyranny principle:
  • Adding engines increases mass carried by the rocket, limiting gains in apogee.

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Speakers / sources featured

• Vinícius Leandro — speaker/teacher; course monitor for this session
• Konstantin Tsiolkovsky — referenced as the scientist/mathematician physicist associated with the staging equation and rocket engineering