> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ntop.com/llms.txt
> Use this file to discover all available pages before exploring further.

# nTop–AVL Aerodynamic Integration

> AI context for nTop–AVL Aerodynamic Integration. Not linked in navigation.

> This page is for AI assistant context only. To use this package, visit [community.ntop.com](https://community.ntop.com/packages/TianxiangGu/ntop-avl-integration).

> **Community submission — not verified by nTop.** This package was submitted by an outside community member and has not been reviewed or verified by nTop. Treat its accuracy, safety, and compatibility claims with appropriate caution.

## Summary

Automate vortex-lattice aerodynamic analysis of a conventional UAV by driving AVL directly from nTop geometry parameters — outputs CL, CD, stability derivatives, static margin, and trim deflections in a single run.

## Package Details

| Field            | Value                                                                                        |
| ---------------- | -------------------------------------------------------------------------------------------- |
| **ID**           | `ntop-avl-integration`                                                                       |
| **Type**         | Bundle                                                                                       |
| **Author**       | TianxiangGu                                                                                  |
| **Version**      | 0.1.0                                                                                        |
| **nTop Version** | 4.12+                                                                                        |
| **Domain**       | Aerospace                                                                                    |
| **Application**  | Analysis                                                                                     |
| **Complexity**   | Advanced                                                                                     |
| **Tags**         | `avl`, `vortex lattice`, `aerodynamics`, `uav`, `stability`, `wing`, `trim`, `static margin` |
| **License**      | MIT                                                                                          |
| **Verified**     | No                                                                                           |

***

Automate vortex-lattice aerodynamic analysis of a conventional UAV by driving [AVL (Athena Vortex Lattice)](https://web.mit.edu/drela/Public/web/avl/) directly from nTop geometry parameters. The included nTop notebook passes wing, tail, and flight-condition parameters to a Python orchestrator that generates AVL input files, runs the solver, and returns aerodynamic coefficients and stability derivatives back to nTop — all in a single evaluation.

## Prerequisites

* **nTop 4.12+**
* **AVL 3.52** — `avl352.exe` must be on your system `PATH`
* **Python 3.8+** — uses the standard library only (no extra packages required)

## Workflow

1. Open `Cool-1V1.1.2.ntop` in nTop.
2. Set your wing geometry, tail sizing, CG location, and flight condition variables inside the notebook.
3. nTop calls `AVL_prototype.py` as an external process, passing all parameters as command-line arguments.
4. The script generates `Conventional_UAV.avl`, a `.mass` file, and a run-command script, then invokes `avl352.exe`.
5. AVL runs four analyses (base trim, roll, pitch, yaw) and writes `.ft` / `.st` output files.
6. The script parses those files and prints a single CSV line that nTop reads back as output variables.

## Inputs

| Parameter                                               | Description                                     |
| ------------------------------------------------------- | ----------------------------------------------- |
| `wing_area`                                             | Wing reference area (m²)                        |
| `wing_ar`                                               | Wing aspect ratio                               |
| `wing_taper`                                            | Wing taper ratio                                |
| `wing_sweep_c4`                                         | Quarter-chord sweep angle (degrees)             |
| `z_wing`                                                | Wing vertical position (m)                      |
| `aileron_y_start_frac` / `_y_end_frac`                  | Aileron span extent as fraction of semi-span    |
| `aileron_chord_frac`                                    | Aileron chord as fraction of local chord        |
| `hstab_area` / `_ar` / `_taper`                         | Horizontal stabilizer geometry                  |
| `z_htail`                                               | Horizontal tail vertical position (m)           |
| `hstab_incidence`                                       | Horizontal stabilizer incidence angle (degrees) |
| `elevator_y_start_frac` / `_y_end_frac` / `_chord_frac` | Elevator sizing                                 |
| `vstab_area` / `_ar` / `_taper`                         | Vertical stabilizer geometry                    |
| `z_vtail`                                               | Vertical tail root height (m)                   |
| `rudder_z_start_frac` / `_z_end_frac` / `_chord_frac`   | Rudder sizing                                   |
| `tail_moment_arm`                                       | Distance from wing LE to tail LE (m)            |
| `x_cg` / `y_cg` / `z_cg`                                | Centre of gravity location (m)                  |
| `mach`                                                  | Freestream Mach number                          |
| `alpha`                                                 | Angle of attack (degrees)                       |
| `roll_rate` / `pitch_rate` / `yaw_rate`                 | Body rates (deg/s, optional)                    |
| `mass` / `ixx` / `iyy` / `izz`                          | Mass properties (kg, kg·m²)                     |

## Outputs

| Output          | Description                                      |
| --------------- | ------------------------------------------------ |
| `CL`            | Lift coefficient                                 |
| `CD`            | Drag coefficient                                 |
| `Cm`            | Pitching-moment coefficient                      |
| `Cma`           | Pitch-moment-per-alpha derivative (stability)    |
| `Cmq`           | Pitch-damping derivative                         |
| `Cnb`           | Yaw-moment-per-sideslip derivative               |
| `Clb`           | Roll-moment-per-sideslip (dihedral effect)       |
| `Clp`           | Roll-damping derivative                          |
| `static_margin` | Static margin (% MAC)                            |
| `elev_trim`     | Elevator deflection at trim (degrees)            |
| `ail_req`       | Aileron deflection for roll maneuver (degrees)   |
| `elev_req`      | Elevator deflection for pitch maneuver (degrees) |
| `rud_req`       | Rudder deflection for yaw maneuver (degrees)     |

## Files

| File                       | Description                                                                      |
| -------------------------- | -------------------------------------------------------------------------------- |
| `Cool-1V1.1.2.ntop`        | nTop notebook with the full integration workflow                                 |
| `AVL_prototype.py`         | Python orchestrator — generates AVL inputs, runs AVL, parses outputs             |
| `Conventional_UAV.avl`     | Sample AVL geometry file (auto-generated on each run)                            |
| `sd7062.txt`               | Selig SD7062 airfoil coordinates used for the main wing                          |
| `nTop_AVL_Integration.pdf` | Full integration guide with methodology, worked example, and parameter reference |

## License

MIT.

***

## Source

[https://community.ntop.com/packages/TianxiangGu/ntop-avl-integration](https://community.ntop.com/packages/TianxiangGu/ntop-avl-integration)