calculate_stability_derivatives

Calculate longitudinal stability derivatives for aircraft wings based on wing configuration and flight conditions to analyze aerodynamic stability.

Instructions

Calculate basic longitudinal stability derivatives for a wing.

Args: wing_config: Wing configuration parameters flight_conditions: Flight conditions

Returns: JSON string with stability derivatives

Input Schema

TableJSON Schema

Name	Required	Description	Default
`wing_config`	Yes
`flight_conditions`	Yes

Implementation Reference

aerospace_mcp/tools/aerodynamics.py:137-157 (handler)

The primary handler function for the MCP tool 'calculate_stability_derivatives'. It wraps the core implementation from integrations.aero, handles errors, and returns a formatted JSON string response.

def calculate_stability_derivatives(wing_config: dict, flight_conditions: dict) -> str:
    """Calculate basic longitudinal stability derivatives for a wing.

    Args:
        wing_config: Wing configuration parameters
        flight_conditions: Flight conditions

    Returns:
        JSON string with stability derivatives
    """
    try:
        from ..integrations.aero import calculate_stability_derivatives as _stability

        result = _stability(wing_config, flight_conditions)
        return json.dumps(result, indent=2)

    except ImportError:
        return "Stability analysis not available - install aerodynamics packages"
    except Exception as e:
        logger.error(f"Stability analysis error: {str(e)}", exc_info=True)
        return f"Stability analysis error: {str(e)}"

aerospace_mcp/fastmcp_server.py:102-102 (registration)
Registration of the 'calculate_stability_derivatives' tool in the FastMCP server.
```
mcp.tool(calculate_stability_derivatives)
```

aerospace_mcp/integrations/aero.py:435-474 (helper)

Core implementation of stability derivatives calculation using simplified lifting line theory approximations, including lift curve slope (CL_alpha) and pitching moment slope (CM_alpha). Accepts WingGeometry and flight conditions.

def calculate_stability_derivatives(
    geometry: WingGeometry, alpha_deg: float = 2.0, mach: float = 0.2
) -> StabilityDerivatives:
    """
    Calculate basic longitudinal stability derivatives.

    Args:
        geometry: Wing geometry
        alpha_deg: Reference angle of attack
        mach: Mach number

    Returns:
        StabilityDerivatives object
    """
    # Calculate wing area and aspect ratio
    S = geometry.span_m * (geometry.chord_root_m + geometry.chord_tip_m) / 2
    AR = geometry.span_m**2 / S

    # Get airfoil data
    airfoil_data = AIRFOIL_DATABASE.get(
        geometry.airfoil_root, AIRFOIL_DATABASE["NACA2412"]
    )

    # 3D lift curve slope
    e = 0.85  # Oswald efficiency
    beta = math.sqrt(max(0.01, 1 - mach**2))
    CL_alpha_2d = airfoil_data["cl_alpha"]
    CL_alpha = CL_alpha_2d / (1 + CL_alpha_2d / (math.pi * AR * e)) / beta

    # Pitching moment slope (simplified)
    # Typically negative for stable aircraft
    CM_alpha = -0.1 * CL_alpha  # Rough approximation

    return StabilityDerivatives(
        CL_alpha=CL_alpha,
        CM_alpha=CM_alpha,
        CL_alpha_dot=None,  # Would need unsteady analysis
        CM_alpha_dot=None,
    )

aerospace_mcp/integrations/aero.py:121-128 (schema)

Pydantic schema for output stability derivatives (CL_alpha, CM_alpha, etc.).

class StabilityDerivatives(BaseModel):
    """Longitudinal stability derivatives."""

    CL_alpha: float = Field(..., description="Lift curve slope (per radian)")
    CM_alpha: float = Field(..., description="Pitching moment curve slope")
    CL_alpha_dot: float | None = Field(None, description="CL due to alpha rate")
    CM_alpha_dot: float | None = Field(None, description="CM due to alpha rate")

aerospace_mcp/integrations/aero.py:91-108 (schema)

Pydantic schema for input wing geometry used in stability derivatives and other aero analyses.

class WingGeometry(BaseModel):
    """Wing planform geometry definition."""

    span_m: float = Field(..., gt=0, description="Wing span in meters")
    chord_root_m: float = Field(..., gt=0, description="Root chord in meters")
    chord_tip_m: float = Field(..., gt=0, description="Tip chord in meters")
    sweep_deg: float = Field(
        0.0, ge=-45, le=45, description="Quarter-chord sweep in degrees"
    )
    dihedral_deg: float = Field(
        0.0, ge=-15, le=15, description="Dihedral angle in degrees"
    )
    twist_deg: float = Field(
        0.0, ge=-10, le=10, description="Geometric twist (tip relative to root)"
    )
    airfoil_root: str = Field("NACA2412", description="Root airfoil name")
    airfoil_tip: str = Field("NACA2412", description="Tip airfoil name")

Aerospace MCP