Breguet Range Equation Calculator

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Thermodynamics, Fluids & Aero

Tranche

tranche-5

Evidence ID

t5-055

Ledger rows

1

No ledger note is attached.

Review findings

The algebra is correct under the stated unit assumptions. The specification needs an explicit definition and unit requirement for c for each aircraft type, explicit validation constraints for W1, W2, c, eta, and L/D, and a declared output-unit policy. The honest label is appropriate but should also state that the estimate assumes constant cruise parameters and excludes climb, descent, maneuvering, reserves, and other operational fuel.

Formula and scope findings

• The jet formula is standard only when c is thrust-specific fuel consumption (TSFC) with units of inverse time, such as 1/s or 1/h.
• The propeller formula is standard only when c is power-specific fuel consumption expressed as fuel weight flow divided by power, which has units of inverse length; using mass-specific consumption requires an explicit gravitational conversion.
• The input description says only “specific fuel consumption” and does not distinguish jet TSFC from propeller power-specific fuel consumption.
• The output range unit is not specified; it is determined by the consistent units used for V and c in the jet formula or c alone in the propeller formula.

Unit assumptions

• W1 and W2 must use the same units; because they occur as a ratio, either both weights or both masses are acceptable.
• For jets, V and c must use compatible time units: for example, m/s with c in 1/s, or km/h with c in 1/h.
• For propeller aircraft, c must be in inverse length, such as 1/m, when the formula is used directly; eta is dimensionless.
• The natural logarithm ln is used.
• The formulas assume steady, level cruise with constant speed, efficiency, specific fuel consumption, and L/D.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The raw formulas produce an undefined result when c=0, so validation must reject that input. Additionally, an unspecified speed unit can change the computed range from 1673.5766349 to 860.9614583 for the same numerical speed value.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "aircraft_type": "jet",
    "cruise_speed": 250,
    "cruise_speed_unit": "m/s",
    "specific_fuel_consumption": 0.00025,
    "specific_fuel_consumption_unit": "1/s",
    "lift_to_drag_ratio": 17,
    "initial_weight": 240000,
    "final_weight": 180000,
    "weight_unit": "N"
  },
  "expected_outputs": {
    "range": 4890595.23,
    "range_unit": "m"
  },
  "working": "W1/W2 = 240000/180000 = 4/3. ln(W1/W2) = ln(4/3) = 0.28768207245. V/c = 250/0.00025 = 1,000,000 m. L/D × V/c = 17 × 1,000,000 = 17,000,000 m. R = 17,000,000 × 0.28768207245 = 4,890,595.23 m."
}

Related workflows

No source-defined multi-instrument workflow membership is recorded.

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche5/tranche5-results.json
• BOUNDARY_HAZARD_CATALOG.json