LMO / Engine File Builder

LMO Engine Builder

Create a standalone .lmo_engine file, simulate a first-pass thrust curve, then import it into Rocketry.

Rocketry

Engine typeSolid

Total impulse637.495 N*s

Average thrust205.858 N

Specific impulse185.732 s

Peak thrust219.582 N

Burn time3.000 s

Identity

Engine nameDesignationManufacturerRocket engine type

Dimensions + Mass

Diameter (m)Length (m)Casing diameter (m)Chamber length (m)Dry mass (kg)Propellant mass (kg)Loaded mass (kg)

Storage + Materials

Propellant: single solid grain
Storage: case only

Propellant grain

Materials

RoleMaterialPhaseMixture ratio

Combustion + Flow

Chamber pressure (Pa)Chamber temperature (K)Mixture ratio O/FCharacteristic velocity (m/s)Combustion efficiencyMass flow (kg/s)Exhaust velocity (m/s)

Nozzle

Nozzle typeThroat diameter (m)Exit diameter (m)Divergence half angle (deg)Material

Throat area

0.000 m2

Effective exit area

0.001 m2

Expansion ratio

6.250

Performance Simulation

Burn time (s)Curve pointsThrust shapeAmbient pressure (Pa)

Mass flow: 0.120 kg/s
Exhaust velocity: 1900.000 m/s
Pressure thrust estimate: -22.142 N
Loaded mass: 0.900 kg
Propellant mass: 0.350 kg

Export Preview

{
  "kind": "little-man-operating.rocket-lab.engine",
  "extension": ".lmo_engine",
  "format": "LMO_ROCKET_ENGINE",
  "version": 1,
  "exportedAt": "2026-08-07T15:47:52.292Z",
  "engine": {
    "sourceType": "lmo_engine",
    "name": "Untitled LMO Engine",
    "designation": "Untitled LMO Engine",
    "manufacturer": "",
    "importedFileName": "",
    "dimensions": {
      "diameterM": 0.075,
      "lengthM": 0.45,
      "casingDiameterM": 0.075,
      "chamberLengthM": 0.32
    },
    "mass": {
      "dryMassKg": 0.55,
      "propellantMassKg": 0.35,
      "loadedMassKg": 0.9
    },
    "thrustCurve": [
      {
        "timeS": 0,
        "thrustN": 0
      },
      {
        "timeS": 0.0967741935483871,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 0.1935483870967742,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 0.2903225806451613,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 0.3870967741935484,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 0.4838709677419355,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 0.5806451612903226,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 0.6774193548387096,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 0.7741935483870968,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 0.8709677419354839,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 0.967741935483871,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 1.064516129032258,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 1.1612903225806452,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 1.2580645161290323,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 1.3548387096774193,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 1.4516129032258065,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 1.5483870967741935,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 1.6451612903225807,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 1.7419354838709677,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 1.8387096774193548,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 1.935483870967742,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 2.032258064516129,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 2.129032258064516,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 2.225806451612903,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 2.3225806451612905,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 2.4193548387096775,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 2.5161290322580645,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 2.6129032258064515,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 2.7096774193548385,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 2.806451612903226,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 2.903225806451613,
        "thrustN": 219.58150643031195
      },
      {
        "timeS": 3,
        "thrustN": 0
      }
    ],
    "burnTimeS": 3,
    "totalImpulseNs": 637.4946960880023,
    "performance": {
      "specificImpulseS": 185.73247922524948,
      "totalImpulseNs": 637.4946960880023,
      "averageThrustN": 205.85766227841745,
      "peakThrustN": 219.58150643031195,
      "burnTimeS": 3
    },
    "details": {
      "engineType": "solid",
      "fuelStorage": {
        "fuel": "APCP",
        "oxidizer": "",
        "pressurePa": 0,
        "tankVolumeM3": 0,
        "storageTemperatureK": 0
      },
      "fuelMaterials": [
        {
          "id": "material-propellant",
          "role": "propellant",
          "material": "APCP",
          "phase": "solid",
          "mixtureRatio": 1
        },
        {
          "id": "material-liner",
          "role": "liner",
          "material": "phenolic liner",
          "phase": "solid",
          "mixtureRatio": 0
        },
        {
          "id": "material-case",
          "role": "case",
          "material": "aluminum casing",
          "phase": "solid",
          "mixtureRatio": 0
        }
      ],
      "combustion": {
        "chamberPressurePa": 3500000,
        "chamberTemperatureK": 2800,
        "mixtureRatio": 0,
        "characteristicVelocityMps": 0,
        "combustionEfficiency": 0.92
      },
      "flow": {
        "massFlowKgPerS": 0.12,
        "exhaustVelocityMps": 1900,
        "fuelMassFlowKgPerS": 0,
        "oxidizerMassFlowKgPerS": 0
      },
      "performance": {
        "specificImpulseS": 185.73247922524948,
        "totalImpulseNs": 637.4946960880023,
        "averageThrustN": 205.85766227841745,
        "peakThrustN": 219.58150643031195,
        "burnTimeS": 3
      },
      "nozzle": {
        "type": "converging-diverging",
        "throatDiameterM": 0.012,
        "exitDiameterM": 0.03,
        "throatAreaM2": 0.00011309733552923255,
        "exitAreaM2": 0.0007068583470577034,
        "expansionRatio": 6.25,
        "halfAngleDeg": 15,
        "material": "graphite"
      }
    }
  }
}