MachUp

Machup is a Python 3 library for the design and analysis of fixed-wing aircraft. This includes things like calculating lift, drag, pitching moments, and stability derivatives. A web-based version of MachUp can be found at aero.go.usu.edu.

At the heart of machup is a modern numerical lifting-line algorithm that rapidly predicts flow over multiple lifting surfaces and can incorperate viscous effects. For a detailed explanation of the theory refer to the following sources.

W. F. Phillips and D. O. Snyder. "Modern Adaptation of Prandtl's Classic Lifting-Line Theory", Journal of Aircraft, Vol. 37, No. 4 (2000), pp. 662-670.

W. F. Phillips, "Flow over Multiple Lifting Surfaces," Mechanics of Flight, 2nd ed., Wiley, New Jersey, 2010, pp. 94 -107.

The following code demonstrates how machup might be used in a Python script:

import machup.MU as MU
import numpy as np
import matplotlib.pyplot as plt


muAirplane = MU.MachUp("Example_FlyingWing.json")

aero_state = {"V_mag": 10,
              "rho": 0.0023769,
              "alpha": 0,
              "beta": 0}
prop_state = {"electric_throttle": 0.2}
control_state = {"elevator": 0}

muAirplane.create_stl(filename="FlyingWing.stl")

trim_info = muAirplane.pitch_trim(L_target=0.2,
                                  aero_state=aero_state,
                                  control_state=control_state,
                                  prop_state=prop_state)
print(trim_info)

aero_state["alpha"] = trim_info["alpha"]
control_state["elevator"] = trim_info["elevator"]

forcesandmoments = muAirplane.solve(aero_state=aero_state,
                                    control_state=control_state,
                                    prop_state=prop_state)
print(forcesandmoments)

wing_dis, prop_dis = muAirplane.distributions(aero_state=aero_state,
                                              control_state=control_state,
                                              prop_state=prop_state)

dynamic_pressure = 0.5*aero_state["rho"]*aero_state["V_mag"]**2
spanwise_station = wing_dis["control_points"][:, 1][0:160]
CZ = wing_dis["forces_xyz"][0:160, 2]/(dynamic_pressure*wing_dis["area"][0:160])
plt.plot(spanwise_station, CZ, '^')
plt.xlabel("Span Position Y (ft)")
plt.ylabel("Section CZ")
plt.show()

plt.plot(prop_dis["radial_position"], prop_dis["induced_angle"], 'r--')
plt.xlabel("Radial Position (ft)")
plt.ylabel("Induced Angle, ei")
plt.show()

Features

• Scriptable
• Fast
• Incorperates viscous effects
• Handles multiple lifting surfaces that have sweep, dihedral, and twist
• Incorporates effects of prop wash on wings

Documentation

For documentation, please refer to the docstrings. This can be done either by using the built in python help command in the interpreter or by refering to the source. For example, to learn more about a given function or class, type

help(nameoffunctionorclass)

.

Note that the modules containing the class or function need to be imported first.

Installation

The MachUp package can be installed by navigating to the root directory of the project and using the following command.

'pip install .'

Prerequisites

• Python3
• Scipy
• Numpy
• numpy-stl
• Matplotlib (needed for plots used in the examples)

Getting the Source Code

The source code can be found at https://github.com/usuaero/MachUp

You can either download the source as a ZIP file and extract the contents, or clone the MachUp repository using Git. If your system does not already have a version of Git installed, you will not be able to use this second option unless you first download and install Git. If you are unsure, you can check by typing git --version into a command prompt.

Downloading source as a ZIP file

1. Open a web browser and navigate to https://github.com/usuaero/MachUp
2. Make sure the Branch is set to Master
3. Click the Clone or download button
4. Select Download ZIP
5. Extract the downloaded ZIP file to a local directory on your machine

Cloning the Github repository

1. From the command prompt navigate to the directory where MachUp will be installed
2. git clone https://github.com/usuaero/MachUp

Testing

Unit tests are implemented using the pytest module and are run using the following command.

'python3 -m pytest test/'

##Support Contact doug.hunsaker@usu.edu with any questions.

##License This project is licensed under the MIT license. See LICENSE file for more information.