One in a series of posts about an aeronautical engineering course I created this year.
Lecture 2 — Runway performance
Project 2 — Runway performance
This lecture focuses on the tools and knowledge required to study and predict an aircraft’s performance on take-off. The project’s aims were to practice analytical techniques in Newtonian mechanics by working on an applied and highly visual aeronautical problem, and to gain familiarity with the complex operational concepts involved in a typical airliner take-off.
It was by far the most interesting and difficult project of all. It met only very moderate success.
The lecture, I believe, had merit.
The first part (“Problem-solving tools in mechanics”) focused on two techniques for solving Newtonian mechanics problems — but I lost many students in this chapter by not giving detailed concrete examples of their use. It is understandably hard for a third-year student to be attracted by a section titled “Newton’s second law”! In the in-class project session that followed, I ended up coming back multiple times to points I brought up in this chapter but that were simply overlooked. So this section will need re-work.
The second part (“Definitions”) was satisfactorily succinct and clear.
The third part (“A take-off”) was frankly good. I took the approach of exploring the important flight mechanics concepts at play during a take-off by narrating an imaginary one. This was terrific fun. I also like my way of tackling the notion of Balanced Field Length.
The project was split in two parts. The first one, a purely in-class analytical exercise, took too long. I blame the lack of perspective and appeal of the lecture’s first chapter for that: I should have given examples, as well as real hints towards how to start when stuck. Hopefully and if anything at all, the exercise was an effective demonstration of the sometimes immense difficulty of coming up with the rather trivial mathematics that describe ordinary problems.
As for the second part, the only word that comes to mind to describe it is “epic”. To be frank, I feel it was extremely good, in that it provides a good framework for true learning: conceptualizing new notions (V1, the Balanced Field Length, Rotation, etc) instead of having them fall from the sky, and solving a challenging, realistic problem.
In practice, the students had great difficulties with that part. Not only is there no obvious path to a solution, but one is also forced to make simplifications and estimates if s/he is to obtain any result at all. This clashes spectacularly with the learning patterns and habits within the school. I made several mistakes in handing such a challenging project.
First and foremost, I should have invested more effort in describing problem-solving techniques. In particular, we are used to proceed “from the top down”, working our way from an all-encompassing, most-general heavy mathematical expression down to a specific application case. By contrast, in such cases it is much more efficient to work “from the bottom up”, starting from a dummy, extremely-simplified case, and gradually adding layers of complexity whilst monitoring the sanity of the calculations.
Second, I mis-managed our energy during the session and within the course. We were only able to get in the heart of this project very late in the 6- or 7‑hour session, which makes for an un-wise context for hard-core thinking. The project came too early within the course, the session was slightly overloaded, and then too much was left for the students to do by themselves afterwards.
By then, the student teamwork and work planning issues that I described in the background remarks on the course had fully kicked in.
The result was that the class, whose generosity and motivation keep amazing me year after year, threw in tremendous amounts of effort and energy into the project without most students obtaining meaningful calculations, satisfying results, and indeed, much motivation feedback. That is hardly a successful learning experience and I feel that most of the responsibility for missing this opportunity is mine. Many improvements come to mind for next time without modifying the core. Great project, perfectible implementation.