One in a series of posts about an aeronautical engineering course I created this year.
This project has the rather broad aim of studying the design of an airliner wing by integrating constraints related to aerodynamics, overall design fitness, aircraft operation, and structural efforts. Contrary to most other projects in the course the lecture’s scope exceeds what is strictly needed for solving the project problem.
The lecture squarely tries to answer the question “why do airliner wings look the way they do?” in terms that will satisfy an engineer already a little familiar with aeronautics. In doing so I hoped to connect with existing student knowledge, extend their English aeronautical vocabulary, and cover important notions in aerodynamics in a rather light and visual way.
The first part (“2D Lift”) furthers the notion of two-dimensional lift that was already explored in the first two projects. None of the figures are quantitative but they give, I think, good insight on airfoil selection1.
The second part (“3D Lift”) tackles the very, very tough task of going from two- to three-dimensional lift, and I am left with the intensely satisfactory feeling of having done it right2. I did lose students along the way for not relating closely enough to a project or in-class application, however.
The last chapters cover wing design in a loose, very graphical way —great, stress-free fun.
Overall the lecture is a success. It assembles an enormous amount of useful media (there are weeks’ worth of drawing furiously on Inkscape in these slides) and does, I believe, a good job of answering its missionary question.
The project problem is rather simple, even if it is buried beneath rich and tortuous phrases3. A rough sketch and calculation for a working answer might only take two hours to come up with. The project provides a good opportunity to finely explore the notions of bending moment and shear force, as well as their inter-relation. I also trusted4 students would take advantage of their structures and materials knowledge, which far exceeds mine.
There was also room for experimentation (wing layout, load cases, safety margins, etc.). My favorite proposition is asking why, if the wingtip contributes more weight than lift, it is not simply suppressed…
In practice the project did not go very well. The long and rich lecture took its toll on the time budget5 and once again we started late. I felt there was enjoyment and exploration in some groups but I found out in the following weeks that most had left the session without a clue as to what the final result should look like. We were also in the wake of the previous project which had engulfed considerable amounts of energy. None of the groups obtained a result that was correct or even remotely realistic.
This project suffered most strongly from poor work techniques and human resources management within the class. I have a share of responsibility for that, and will be much more active in the future to ensure better learning can happen.
Overall then, a good project and lecture; here too better execution is needed.
- These figures are derived from those found in a book discovered in a Staadtbibliothek many years ago, Engmann et al. 1994 [↩]
- Please, please let me know if you find mistakes or room for improvement [↩]
- That was intentional, since one of the course objectives is to increase English language skills, but in retrospect I believe I went too far. [↩]
- and also somewhat feared… [↩]
- See my remarks in the post on the course background for a discussion of this issue. [↩]