High-school aerospace engineers design real-world light sport aircraft

By John Isaac, director of market development, Mentor Graphics Mechanical Analysis Division

Some might find it hard to believe that high-school students could improve the wing design of a 737 aircraft, or design the wing and tail sections of a Cessna corporate jet, or design a light sport aircraft (LSA) given very aggressive specs for performance, environmental impact, and carrying capacity. Yet, students have been doing so for the past five years in the Real World Design Challenge (RWDC) competition in the United States.

The competition this year at the state and national levels, which will include more than 750 high school teams, is the design of a commercial UAV (unmanned aerial vehicle) that must meet weight, performance, and efficiency specifications and be able to fly a specified task. These teams create their designs with professional-level software supplied by Mentor Graphics and PTC (Parametric Technology Corp.), basically the same software used by leading aerospace engineers in their design processes.

RWDC was started in 2007 with the goal of encouraging more students to pursue education and careers in aerospace engineering. The program is supported by government agencies such as NASA, the FAA, and some of the world’s leading 40 aerospace companies including Northrup Grumman, Pratt and Whitney, Boeing, Lockheed Martin, SPACEX, and Cessna. The program is conducted at the state level and then winners from each state compete in nationals in Washington, DC. Each year, Mentor Graphics and PTC donate over 700 million dollars’ worth of software products as well as training to the schools. Industry experts act as volunteer mentors to guide the students through typical aerospace design processes. And to broaden participation, competing is free of charge and even the teams’ travel expenses to DC for nationals are covered by the sponsors.

This article will step through the design process used by a two-time winner, Baldwin High School in Baldwin, Kansas, to illustrate the complexity of the challenge these students face and some of the results they are able to achieve. It will cite specific challenges and the methodology they employed to win the competition at the national level in the spring of 2012. Like many other teams, they organized themselves similar to how a commercial company would with a project manager, engineers dedicated to specific responsibilities, documentation and marketing, and a teacher as a coordinator.

The Challenge and Process

In the fall of 2011, RWDC launched the FY12 challenge. As stated in Baldwin High School’s final report:

“The goal of the challenge was to design an efficient, low carbon-emission and environmentally friendly personal Light Sport Aircraft (LSA). The aircraft must be able to accommodate two team members and fly 200 miles in less than two hours at a minimum cruise altitude of 1000 feet above ground level. To achieve this goal, we utilized a design process organized by project management guidelines, used engineering software tools and sought guidance from mentors from industry and academia.”

Figure 1 – The design variables and constraints as defined in the challenge.

Baldwin High School formed a team of eight members each with distinct responsibilities, who defined a project plan of attack, and under the guidance of their teacher coach, Pam Davis, started the design process. The team and process were structured similar to those found in any major aerospace development organization. Brainstorming, trial design approaches and testing, conflict resolution, “management” reviews, schedule status, task assignments, formalized digital communication, and status meetings, etc. were all part of the process. The team had access to four industry and academic mentors who they consulted periodically for process and technical advice. They employed a process just like any other industry product development organization (Figure 2) in which design concepts are explored, the most promising concepts designed and analyzed, and then the best design fine-tuned to optimization.

Figure 2 – The team used a process typically followed in the aerospace industry to arrive at the optimum design.

Meeting the Challenge

The team had access to professional software, the same software used by the aerospace industry in the design of their products. The Baldwin team members used this software to perform the mechanical design, computational fluid dynamics (CFD) analysis, and the management of the data as shown in Figure 3. Key to the successful use of this software was not only a high level of accuracy and performance but also ease-of-use. Just like in industry, you want your team members to be able to focus their time and efforts on solving the technical challenges versus having to struggle with difficult-to-use tools. The Mentor Graphics FloEFD and PTC Creo software are provided with ease-of-use as a key differentiator from classical CFD solutions targeted only at specialists. FloEFD is “embedded” into Creo using the same graphical user interface (GUI), performing meshing automatically, quickly converging to a solution, and accessible without having to go through database translations and manual adjustments.

Figure 3 – The team used professional-level software from Mentor Graphics and PTC to perform the design and analysis tasks. This same software is used by many aerospace companies to design their products.

Optimizing the Design

Given the challenge specifications, several design options had to be considered simultaneously. For example, they could not just design a wing that was optimized for lift/drag without consideration for overstressing the wing structure and possible failure or the possibility of not meeting target aircraft mileage. The wing design task was approached in steps from concept proposals to design to analysis to fine-tuning. Variables included the wing length, the angle, the shape, and the structural materials. Several designs were modeled in Creo and then analyzed for lift, drag x/z direction forces, and torque using FloEFD CFD analysis. The analysis results (Figure 4) from multiple designs were compared in graphs so the best could more easily be chosen. The designs were fully CFD tested at “virtual windtunnel” air speeds of up to 138 mph.

Figure 4 – FloEFD CFD analysis calculated key variables in the wing design such as lift, drag, x and z component forces, and created data to determine high structural torque areas.

The same process was followed for the fuselage design and for the tail design where the Baldwin team started out choosing between a “V” and “T” tail structure (Figure 5). Throughout the entire development process, the students had to consider aircraft weight and distribution, engine power, etc. to guarantee that their endproduct would be able to achieve the target speed and efficiency goals as defined in the challenge.

Figure 5 – Fuselage geometry and CREO/Elements Pro tail section.

The end result of Balwin’s LSA development entry was an aircraft that met or exceeded all of the challenge goals. They won the Kansas state competition and then went to Washington, DC, to compete against all the other state winners. There they were judged by a distinquished panel of judges from industry, government, and academia. The panel included Dr. Erich Buergel, general manager of the Mentor Graphics Mechanical Analysis Division, who stated, “The level of creativity, organization, understanding of the technology, and professionalism exhibited by these high school teams was unbelievable. They are using design and CFD analysis tools that I could have only dreamed of using in my graduate years at the university.”

Effects of the Rewal World Design Challenge

Is the program successful in encouraging careers in engineering? As stated in the Baldwin students’ final entry documentation: “Our current team is discovering that STEM (Science, Technology, Engineering Mathematics) skills learned in the classroom really do apply to real world problems and that working together to solve a real-world-challenge has required much dedication and a selfless behavior. This team has four returning members, and continues to attract motivated students each year. The Real World Design Challenge is an amazing opportunity for students to get excited about honors and advanced placement level classes in our high school as well as learn how to use outside resources for learning.”

One Baldwin team member, who is applying to top engineering schools in the USA, said at the 2013 RWDC kickoff event that he has placed his winning experience as the highlight in his applications.