MATLAB Project: Aircraft Designer

This is the master program which all the functions described in previous posts feed into. This takes inputs from the fuselage designer, wing designer, and empennage designer and puts all the components together. The motivation for this project was to be able to quickly and easily iterate through aircraft designs. All of the performance calculations were done in an excel spreadsheet, but Excel is not good at making custom plots or managing data. This program receives the geometric parameters of the airplane calculated by the Excel sheet, and uses them to 'build' the airplane for visualization and accurate component layout.

The component layout in the spreadsheet does not account for the form of the volume components (passenger cabin, cockpit, galley, wing box, etc.). On more than one occasion we had designed a fuselage that seemed to contain all the components, only to realize that the calculated cabin length was longer than the fuselage of the aircraft! This program was intended to solve that problem by visualizing the components for instantaneous feedback on the quality of the layout. 

The other main goal of the program was to facilitate the rapid 3-D modeling of the aircraft. Unlike most other objects undergraduates are used to CADing, aircraft often have complex curvatures and geometries that take a long time to make manually. This program produces curves for the fuselage, main wing, and tail surfaces and positions them according to the design specifications. The coordinates for the curves are then exported as .txt files, which can be uploaded into SolidWorks as curves and lofted together. This drastically reduces the time required to produce a solid model and thus enables more rapid design iteration and evaluation.

I'd like to continue adding more to this program, but it looks like there simply isn't enough room on the UI to add more input boxes. Already, many of the parameters cannot be changed from the UI; the code must be manually altered. I was thinking of adding tabbed panels to increase the number of inputs possible, but from my [limited] research they don't seem to be well supported. I think this version should do for now.

MATLAB Mini Project: Propeller Design

As part of my ongoing aircraft design project, I wrote another MATLAB function to produce propellers whose cross sections could be exported for making models in SolidWorks. The function takes inputs from the design calculations of an Excel spreadsheet. The diameter of the rotor, the number of blades, the twist of the blade, and the airfoils comprising the blade are all used to determine the shape of the propeller. For now, only straight tapered blades defined by a root and tip airfoil can be produced. But this code serves as a first step for designing and plotting more complicated blades with curved planforms and nonlinear twists. Right now the twists are user defined, whereas in reality the twist is set to produce a certain coefficient of lift stated in the Hamilton Standard propeller efficiency chart; this is something else that must be accounted for in the future.

I considered having this function calculate all performance parameters of the propeller, but the only performance estimation method that seemed feasible was the blade element method. This method is far less accurate than the Hamilton Standard propeller efficiency charts used to calculate performance in the Excel sheet. So I decided to stick with the standard method of propeller sizing using the propeller charts and just let my program calculate the propeller's shape.

MATLAB Project: Fuselage Designer

This project builds off my previous MATLAB project for designing and making wings in CAD. I have added basic fuselage plotting capabilities. The user simply defines the maximum diameter and fineness ratios to determine the fuselage length. Then, 11 cross sections are defined by their widths and heights. The shapes of the cross sections are assumed to be ellipses. The tail angle can also be changed. Wing twist has also been added; root and chord angles can now be set.

10/14/15 - Added 3 additional plots: fuselage side view, top view, and max diameter section view. The program can now display seating arrangements, galley, and lavatory locations.

MATLAB Project: Wing Designer

Introduction

This semester I am taking an aircraft design and performance class. The term project is to complete a conceptual aircraft design - each group will be designing a different type of aircraft. Our group is designing an MSA, or Maritime Surveillance Aircraft. The purpose of this aircraft is to loiter for long periods of time at low altitudes to observe/monitor maritime vessels, act as an airborne control center for nearby aircraft, and even deliver payloads (sonobuoys) and ordnance (torpedoes, air-surface missiles). Our professor provided us with Excel spreadsheets that have many of the calculations programmed into them; our goal is to optimize the parameters to meet the requirements. We also need to produce a 3-D model of our design. This is where the Excel sheets lack in ability. They provide very rudimentary 3-views of the aircraft. I decided to use MATLAB to take the results from the Excel spreadsheet and produce coordinates for a wireframe model of the airplane, which could be loaded into CAD software and turned into a 3-D model.

Currently, my MATLAB program can only produce the wireframe of a wing (or any similar aerodynamic surface). I am actively working on expanding it to create fuselage cross sections which will be used to create a 3-D model.

Design

I adapted this program for one I previously made for an aerodynamics class. The inputs were reversed - for that class, the area needed to be calculated for a given wingspan, whereas in the design scenario the wingspan is determined by the area and the aspect ratio, so the inputs needed to be changed. I also added the capability to sweep the wing. I also added the a section on the planform view to show the MAC - this is an important thing to visualize. The 'Export' button creates .txt files with the tip and root airfoil coordinates. These can be loaded into SolidWorks or any other CAD program as a curve, and the tip and root curves can be lofted together into a solid wing. Then the wing is simply mirrored about the root to create the other half and complete the wing.

Capabilities

Plot any 4-digit or 5-digit airfoil (uses my airfoil generator function). Create basic trapezoidal aerodynamic surfaces with airfoil cross sections. Wing twist or washout, and angle of incidence (not visible in GUI yet). Parameters include NACA airfoil, wing reference area, aspect ratio, taper ratio, and LE sweep. Plots MAC and spanwise location of MAC. Export coordinates of root and tip airfoils to create a 3-D model in CAD software.

Improvements

The current method in which the wing is swept is inaccurate, as it 'drags' the tip rearwards (or forwards) to achieve the required leading edge sweep. However the wing should really be rotated such that the airfoils are no longer parallel to the airstream; this is what makes a swept wing effective. Rotating is difficult though, because then you have to account for the fact that tip and the root will be at the incorrect angle, and you have to adjust for that. This is okay to make a model for viewing/aesthetics, but I should look into updating this in the future.  I should also plot points on the quarter chord MAC as this is another important location. I will continue working on this GUI to add fuselage plotting capability. Also the wing washout/twist/angle of incidence parameters can only be accessed from within the code; I need to make boxes on the interface to change these parameters.

MATLAB Project: Airfoil Generator

I'm taking a class in aerodynamics this semester, and I know we will be working a lot with airfoils. So for fun I decided to write a MATLAB GUI to display any NACA series airfoil. Currently it only works with the 4-series airfoils, but soon I will expand it to work with 5, 6, 7,  8 series airfoils as well.

The program takes inputs of the NACA airfoil number, desired chord length, angle of incidence (AOI), and the wing length. The program then plots each individual airfoil, and lofts the two together in an isometric view. The 'export airfoils' button doesn't work right now, but soon it will export XY coordinates for the airfoils to a text file, so they can be loaded into SolidWorks or another CAD program to make a 3-D model of the wing. 

Download the files to run the program here.