Source: https://guthlabs.ai/docs/instruments/lift-coefficient-lift-force-calculator/implementation/

instrument implementation / implementation-contract

# Lift Coefficient / Lift Force Calculator implementation

A source-bound implementation contract for Lift Coefficient / Lift Force Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t5-033

**Effect**: Computation or source lookup only

## Input and validation requirements

Required-Cl calculations divide by zero when V=0 or S=0 and must reject the input rather than emit a numeric result. The specification also provides no genuine formula branch, so signed negative velocity handling and the sign convention for lift and Cl remain ambiguous.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "Cl": 0.5,
    "S_m2": 16,
    "V_mps": 50,
    "rho_kg_m3": 1.225,
    "weight_N": 12000
  },
  "expected_outputs": {
    "lift_N": 12250,
    "required_Cl": 0.4897959184
  },
  "working": "Dynamic pressure q = ½ρV² = ½ × 1.225 × 50² = 0.6125 × 2500 = 1531.25 Pa. Lift L = q × Cl × S = 1531.25 × 0.5 × 16 = 1531.25 × 8 = 12250 N. Required Cl = W/(qS) = 12000/(1531.25 × 16) = 12000/24500 = 0.4897959184."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/lift-coefficient-lift-force-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/lift-coefficient-lift-force-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/lift-coefficient-lift-force-calculator/qualification/>)

## Sources and evidence

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

- `VERIFIED_LEDGER.json`

- `evidence-tranche5/tranche5-results.json`