UAV-Code

Summary

This program streamlines the initial design phase of a tiltrotor aircraft. This type of aircraft helps fill the need for efficient cargo-carrying drones that can operate without a runway or landing strip. It was built for AerospaceNU, the aerospace club of Northeastern University, during the Fall 2021 semester. The image below shows an example of a prototype that could be built from the outputs.

About the program

The model is intended to be a useful, if approximate, tool for the initial design phase. It is not without assumptions but represents a helpful starting point for novel aircraft design. Some of the physical phenomena that are modeled include:

• Skin-friction drag with boundary-layer theory
• Form drag from airfoil data
• FAA structural loading limits
• Disk loading to estimate hovering power costs
• Taper ratio and induced drag
• Euler bending-beam theory for thin structures (torsion and bending)
• Battery considerations for electric flight

Setup

This project uses uv and go-task.

1. install uv and task
2. git clone https://github.com/Tsmorz/UAV-Code.git
3. task init to create the virtual environment and install the pre-commit hooks

Running

Edit inputs.csv with your chosen airfoil coefficients and aircraft dimensions (mass, wingspan, coefficient of lift, etc.), then run the design sweep:

task run

The package modules are:

• uav_design/read_inputs.py — reads aircraft data (mass, wingspan, lift coefficient, etc.) from inputs.csv
• uav_design/aero_drag.py — skin-friction, form, and induced drag calculations
• uav_design/hover.py — power and energy requirements for hovering flight
• uav_design/structures.py — Euler beam theory and associated equations
• uav_design/wing_calculations.py — iterative process to minimize wing mass
• uav_design/__main__.py — puts everything together and produces the plots and terminal output
• uav_design/airfoil.py — standalone airfoil profile plot

Expected output

The plots below give an example of the expected output. The red dot denotes the ideal starting design to maximize flight duration given the current constraints. Adjust inputs.csv to tailor the program to your needs. The far-right image is the expected terminal output — use these dimensions to design the aircraft model.

Important things to note:

• The white area in the upper-right corner of each plot is beyond the structural limit and the aircraft will fail!
• The rotors always extend past the wing tips. See the photo above for an example model.
• The program assumes all structural load is carried by carbon-fiber spars in the wings.

Adding to the repo

1. Create a new branch before making changes:
   git checkout -b new-branch-name

2. Track changes as you go:
   git add file_that_changed
git commit -m "a useful message"
git push

3. Add unit and integration tests for new functionality in the tests directory. Run them with task test.

Cited Works

Numerous studies were used to find relevant equations for a realistic model. Some links may be behind a paywall.

• https://www.researchgate.net/figure/XV-15-tiltrotor-aircraft-layout-Ref-9_fig3_23847162
• https://www.sciencedirect.com/science/article/pii/S2352146518300383
• https://books.google.nl/books?id=-PnV2JuLZi4C&pg=PA42&lpg=PA42&dq=power+required+to+hover+watts+per+kg
• http://www.epi-eng.com/propeller_technology/selecting_a_propeller.htm
• http://airfoiltools.com/airfoil/details?airfoil=sd7062-il
• https://www.risingup.com/fars/info/part23-337-FAR.shtml