The senior design program at Virginia Tech is a year long course. It is three credits a semester, although students maintain that the workload is at least double the normal three credit course. The course goal is to achieve the engineering design objectives that industry feels recent graduates are lacking and need to learn (recently Boeing has produced a list (McMasters and Lang, 1995), which we now give all our students):
How do we do this? In the first semester we have lectures at the regularly scheduled class time for the first half of the semester. The lectures are:
After the lectures are finished, we meet each week once with individual design teams and once with the groups by discipline (although we agree with Roskam (1990) that you must not reteach the engineering sciences, we find it useful to review the application of the disciplines to design). The educational style is much closer to an apprenticeship than a formal educational experience.
Four initial assignments are done in the first half of the semester. These provide an experience base to use on the design project:
1. Fabrication and flight evaluation of a tissue and balsa model aircraft. Most students have not built model airplanes. Here we hope they learn that someone has to build what they design. Also, they should learn that even a simple model is a system, and each part must work. Structures, aerodynamics, propulsion, weight and balance and stability and control are all equally important.
2. Evaluation of "comparator aircraft" that currently exist and are closest to meeting the design project requirement. This should help students establish a notion of the connection between requirements and form, while creating a relevant database for use in doing their own design.
3. Development of a traditional aircraft sizing program and initial estimate of TOGW. This shows them how key parameters such as range and L/D impact the weight. They learn about the growth factor.
4. Development of an aircraft concept sketch. Each student decides what arrangement should be used to meet the requirements. Each team member's concept forms the basis for the initial team concept matrix. Naturally, this assignment has to be coordinated with the sizing assignment.
The goal of the first semester work is to develop several candidate configuration concepts and arrive at a single preferred concept at the end of the semester. Starting with 6-8 concepts, one from each team member, they reduce the matrix to three concepts before making their selection. Each team has a mid-tern design review and a final design presentation and report to explain how they achieved the goal.
In the second semester the class is much more informal. We meet with each team once a week. The goal is to take the preferred concept selected at the end of the first semester and do a preliminary design. The teams develop their plan to do the design and write the report or proposal. Chapters of the final reports are submitted for initial evaluation as the semester progresses. Then, a draft final report is submitted. This report is marked up in industrial style and returned to be revised. The final revised report is due on the last day of class. The final design presentations are attended by many faculty and students from other classes. They are video taped.
Grades are almost entirely given as team grades. The teams are asked to provide peer evaluations of each other. These reviews almost always agree with our own, and form the basis for raising or lowering individual member's grades.Although students are initially reluctant to give honest evaluations (everybody gets a 10), as the works becomes hard and the importance of teamwork on their own grade becomes clear, students start to give honest reviews. If a team has some problem members we try to do these peer reviews more frequently to give team members a chance to improve their performance.
As a measure of our effectiveness, it may be worthwhile to review the results of the AIAA/Lockheed Martin Fort Worth Team Aircraft Design competition. We have done reasonably well, with the results of the last six years being:
The AIAA competition is always a challenge. The RFP is not released until around the first of August, so there is little time to prepare any special material related to the specific design competition problem. In addition, the engine is usually a problem, with details arriving well into the semester. In the 1994-95 competition even the payload weight didn't arrive until well into the semester! We had been told to carry a "Pegasus class" vehicle up to altitude to launch a payload to the space station. When the actual details arrived, the vehicle to be launched was a 1.2 million pound version of the space shuttle orbiter. Not only was the information late, but this illustrates an example of the reasonableness of some of the design projects. Projects such as the global range transport (850,000 pound payload delivered 6500nm away and with a vehicle return without refueling) and the space transportation system (1.2 million pound rocket powered vehicle carried to 30,000 feet and launched with a five degree flight path angle) are questionable from the point of trying to have students work reasonable problems. An example can be seen in the paper written by the students (Dyer, et al, 1994). Since they had graduated they certainly didn't want to let their design instructors review this paper before it was submitted) on the global range transport!
Another aspect of the senior design program has been the NASA/USRA ADP (the USRA stopped administering this program in the Fall of 1994, and the program ended in August 1995). In this program we adopted a broader design project which is done by one team each year. For three years this was the design of a vehicle to replenish the hole in the ozone layer. This was my attempt at introducing green engineering into the design program. Direct intervention by an airborne system may well be required, and this raises many ethical questions. For more insight into the problem, see the paper by Benoliel, et al., (1993). Although I thought all the students would select this topic, the reverse occurred. Aerospace engineering students taking design want to design airplanes, preferably fighters. They also like to compete in design competitions.
We have learned some lessons in the last six years. Perhaps the most important is the difficulty students have transitioning from the engineering science oriented curriculum to the senior design course. This consists of three critical items. First, the students are not used to having to define the problems that need to be solved, locate the required information, and then make decisions using relatively little specific detailed information from analysis. They have to use engineering judgment based on an understanding the fundamental ideas associated with the various disciplines. Frequently, it appears that the students "lose the forest for the trees" in the engineering science courses, and don't come away from these courses with the necessary overview understanding of the various disciplines.
The second problem is the experience of working in teams. Although all aerospace engineers will work in teams when they graduate, and potential employers expect students to have been taught to work in teams, there is essentially no information available on developing effective student teams. When I first started questioning other design teachers, the initial response was that they hadn't seen any problems with students teams. Further discussion almost always led to numerous war stories about team problems. Although everybody talks about teams, we don't supply students with good techniques for solving team problems. Although hired to be the design teacher, I had no expertise in team building. This is an area that I've been working to improve for several years, but the educational foundation in this area is extremely weak. I can however cite a few good references, which have been recommended by colleagues and I've found useful (Scholtes, et al., 1988, Varney, 1991, and Parker, 1990).
Student teams work well as long as there is relatively little pressure. When pressure is applied to produce a professional product, many problems arise. Because of our success in the past, students know that if they do good job they have a reasonable chance of wining the AIAA competition. Because of this, the pressure for excellence comes from some of the team members themselves more than from the instructors. Often team members have expectations that exceed the expectations of the instructors.
A third lesson is that students are not prepared to work in an environment where the work they do has to be corrected and resubmitted. In the real world, work has to be revised until it's right. Although this is precisely how engineers work, engineering students seem not to have experienced this before. Similarly, the normal "give and take" in design presentations and meetings with the groups and instructors is difficult for some students. Simply questioning students about why they made a specific choice, asking them if the result of an analysis seems reasonable, and requiring them to explain the consequence of a result are new experiences. Apparently, students often refer to this approach being used in design class as having been "raked over the coals." All the instructors are providing is a normal engineering environment. Unfortunately, in the engineering education delivery system this is highly unusual. In fact, the strong emphasis on using teaching evaluations as an indicator of good teaching, and the academic/educational system taboo of allowing a student to lose face in front of other students, provides a strong incentive not to expose engineering students to real world situations. Unfortunately, this leads to an approach to education as entertainment, where the students are passive observers, not equal participants. This is not possible in design (engineering).