AAE 451 Aircraft Design

Final Report

Team 4

Sean Bhise

Kyle Brite

Philip Catania

Thomas Horan

Timothy Ma

Jason Wirth

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Code of Ethics

Taken from the Purdue University Handbook, Student Code of Honor:

The purpose of the Purdue University academic community is to search for truth and to endeavor to communicate with each other. Self-discipline and a sense of social obligation within each individual are necessary for the fulfillment of these goals. It is the responsibility of all Purdue students to live by this code, not out of fear of the consequences of its violation, but out of personal self-respect. As human beings we are obliged to conduct ourselves with high integrity. As members of the civil community we have to conduct ourselves as responsible citizens in accordance with the rules and regulations governing all residents of the state of Indiana and of the local community. As members of the Purdue University community, we have the responsibility to observe all University regulations.

To foster a climate of trust and high standards of academic achievement, Purdue University is committed to cultivating academic integrity and expects students to exhibit the highest standards of honor in their scholastic endeavors. Academic integrity is essential to the success of Purdue Universitys mission. As members of the academic community, our foremost interest is toward achieving noble educational goals and our foremost responsibility is to ensure that academic honesty prevails.

The members of Team 4 agree with and uphold to the above Code of Ethics and maintain that the information contained within this report is original unless otherwise referenced.

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Table of Contents

1. Executive Summary1

2. Aircraft Introduction2

3. Mission Requirements, Concept Selection, Initial Sizing3

Jason Wirth; Sean Bhise; Philip Catania

3.1. Mission Requirements3

3.2. Concept Selection3

3.3. Initial Weight Estimation4

3.4. Constraint Diagrams5

4. Structures and Weights6

Timothy Ma

4.1. Introduction6

4.2. Material Properties6

4.3. Weight Determination7

4.4. Geometric Layout of Wing Structure8

4.5. Analysis of Wing Loads8

4.6. Landing Gear Configuration9

5. Aerodynamics10

Thomas Horan; Sean Bhise

5.1. Introduction10

5.2. Lift Production11

5.3. Drag Minimization12

5.4. Wing Design13

5.5. Stability13

6. Propulsion14

Philip Catania

6.1. Introduction14

6.2. Propeller Selection14

6.3. Motor/Gearbox Selection16

6.4. Speed Controller Selection17

6.5. Battery Selection17

7. Dynamics and Controls18

Jason Wirth

7.1. Introduction18

7.2. Tail Surface Sizing18

7.3. Control Surface Sizing21

7.4. Roll Mode Approximation21

7.5. Gain Selection21

7.6. Flight Characteristics22

8. Economics23

Kyle Brite

9. References25

APPENDIX A Initial Sizing and Concept Selection26

APPENDIX B Structures and Weights33

APPENDIX C Aerodynamics37

APPENDIX D Propulsion48

APPENDIX E Dynamics and Controls58

APPENDIX F Economics / Project Management81

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1. Executive Summary

The purpose for this project is to design, build, and successfully fly an aircraft within the confines of the Purdue Armory. This project is intended to demonstrate to Dr. Andrisani that an interdisciplinary team of senior-level aeronautical engineering students can successfully design an aircraft that meets all mission requirements. There are several mission requirements that must be met for this aircraft to be considered successful. The aircraft must navigate through several phases of flight before ultimately pitching up into a hover maneuver.

A roll rate gyro will be employed for this project to successfully maintain the hover. This gyro will assist the pilot in maintaining a steady roll angle while allowing him to keep the aircraft in a nose up configuration within the confines of the Purdue Armory. Team 4s aircraft uses an approximation of the roll mode to determine a nominal gain for the rate gyro..

The philosophy behind Team 4s aircraft is a simple to build, easy to repair aircraft. The aircraft that has been designed uses a large rectangular wing with a NACA 6412 airfoil in order to minimize stall and cruise speed. The optimum cruise speed for our aircraft is 19.5 ft/s, which allows an experienced pilot more than enough time to turn and avoid any obstacles inside of the Armory. Since this aircraft is being flown indoors, a considerable amount of the design reflects those considerations. Team 4 feels that our large, slow flying aircraft will be more controllable in an indoor environment than a smaller and faster aircraft.

Another mission requirement for this aircraft is to be built on an operating budget of $150. After careful evaluation and consideration, Team 4 found this to be insufficient for the mission that the aircraft is required to perform. With an eye on costs, Team 4s entire parts budget was kept under $200. As this aircraft is potentially being marketed to a teenage audience, the marketability of the aircraft is another concern. With this in mind, Team 4s aircraft will use a bright and bold paint scheme to increase possible sales.

The aircraft that Team 4 designed is anticipated to meet all mission requirements. The construction will be simple and easily repairable to prevent extended periods of downtime in the event of a crash. The aircraft is designed to be sufficiently maneuverable to be able to perform aerobatic maneuvers without significant effort by the pilot.

2. Aircraft Description

Figure 1 - Aircraft 3-View

Table 1 - Aircraft Specifications

3. Mission Requirements, Concept Selection, and Initial Sizing

3.1 Mission Requirements

There are several mission requirements that the aircraft must meet. Per the Request For Proposal (RFP), the aircraft must be able to be flown within the confines of the Purdue Armory. It must also be robust to crashes and be easy to fly. It must meet all Level IA military flying qualities. The aircraft must be built for less than $150. During takeoff, the total ground roll must not exceed 10 feet. During the climb stage, the aircraft must perform a 45 banked turn. It must then loiter for a period of three minutes while maintaining a stall speed of no greater than 15 ft/s. The aircraft must then perform a pitch up maneuver and maintain a 20 roll angle while in a hover for a period of two minutes. To assist the pilot during this maneuver, a roll rate feedback gyro will be used to assist in aileron control. Finally the aircraft must be demonstrated to land safely.

3.2 Concept Selection

After considering the requirements set forth in the RFP, all team members were asked to come up with an initial conceptual design for an aircraft capable of completing all aspects of the mission. Three designs were then chosen by the team as finalists. These three designs included a conventional single-engine aircraft, a twin-engine aircraft, and a single-engine design with a dual-boom fuselage with integrated vertical tails that resembled a double extruded plus-sign. Three-view drawings of these designs can be seen in Appendix A.

The next step in determining the final concept was using Pughs Method to compare pertinent design variables and qualities. Concept 1, which was the conventional single-engine aircraft, was chosen as the baseline because it is the most common design of the three. Concepts 2 and 3 were then compared with Concept 1 in each of the areas shown in Table , and even though Concept 3, the double plus-sign, shows a final value of +2, a decision was made that the complexity was not weighted heavily enough and would not be worth the benefits gained in other areas. This ended up ruling out both Concepts 2 and 3, leaving Concept 1, with some appropriate modifications, as the design of choice for Team 4.

(Table 2 - Pugh's Method Comparison of Three Final Conceptual Designs)

3.3 Initial Weight Estimation

To initially estimate the weight of this aircraft, a historical approach was employed. Team 4 used a database of 10 commercial radio controlled (R/C) aircraft and found a linear relationship between required battery weight and total weight for the aircraft. The table and resulting plot are located in Appendix A. However this trend line only gives data for historical r/c aircraft which may not have the same mission requirements as those given in the RFP. To determine an accurate estimation of the battery weight required for the mission given for this project, MATLAB code was used to analyze each phase of the flight. Detailed analysis for the estimation of battery fraction necessary for each flight phase is located in Appendix A.

Figure 2 - Aircraft Weight Estimation

3.4 Constraint Diagram

The constraint diagram shown below allowed us to pick a feasible design point for the aircraft. The condition that constrained the aircraft the most was the hover condition which can be seen on the graph as the horizontal lines. The loiter and cruise phases of the mission had no effect on picking a feasible design point. As our simulations showed the CLmax = 1.66 for the NACA 6412 airfoil, the design point was chosen to be at a CLmax = 1.61 in order to have a small buffer area. The stall constraints can be seen as the vertical lines in the graph. The results from choosing this design point yielded a wing loading of 0.405 lb/ft2 and