Add Skywalk Mescal 6 Glider Model

[junwoo091400]

About

This adds Skywalk Mescal 6 glider to the extras/wings package and the simulation script to draw polar curves. Data was obtained from: https://skywalk.info/project/mescal/

By the way, very cool project! And thanks for a thorough documentation, paper and open-sourcing the codebase! 🪂

Note

• Certain parameters are quite hard to guess / empirical. And most were copied from Nivuk hook 3 😢
• Only XS size has been added, and details on other parameters in the model need to be tuned

Comparison of flattened model with line chart of datasheet

• Seems like the cell sizes are really big in the middle & smaller on the outside, so the discrepancy in cell division lines arises. In the actual simulated model, however, do we consider the differences in cell opening lengths in spanwise direction?
• The projected map differs slightly, especially how the outermost chord diminishes much smoothly in actual glider, compared to the simulated one. Is this also a common trait with Nivuk glider? Or does this indicate that I didn't set the model correctly?

Questions

How would we accurately measure the following?:

1. kappa_C: For Mescal 6, the lineplan shows that C-risers are not connected just spanwise, but also cordwise. In this case, which value should be chosen for the C risers's attach point along the chord?
2. s_delta_start/stop0/1: These are really tricky, are the videos the only way to measure this?
3. kappa_z: I added the 'middle line length excluding length of risers' from the technical data, is it accurate to assume that the tip of the riser is matching the Riser-Midpoint?
4. kappa_x: We can't really tell what this value should be (chordwise offset from leading edge to pilot's position hung under the glider. How did you initially come up with the number 0.45 * Chord_root?
5. kappa_b: I initially thought this should be the brake-line range (specified also in Technical data), but after reading the paper it seems like this range can't be directly translated into the kappa_b (actual movement of TE) that we desire. But, is there some way to calculate this?
6. SimpleFoil/aerodynamics_config: We use v_ref_mag of 10, and alpha_ref of 5. I didn't read in detail, but how would changing these values affect the final aerodynamic calculation of the glider? Are these values from some reference?

[junwoo091400]

Improved chart visualization example

NOTE: I need to remove comments on 'breakpoint' stuff 😆 (I commented it out, as it was annoying for iterating the plotting code)

[pfheatwole]

Hi Junwoo, sorry for the delays. I answered your private messages, hope that helps; I'll try to address these questions too when I get time. Good luck with your license and studies!