Winglet optimisation

[Tim Swait]

Not a question, but hopefully this will be interesting to some of you. I've been using OpenVSP with the Python API and scipy.optimize functions to do an optimisation of the winglet shape for a hang glider, there's a blog post about it here: Winglet Optimisation. The notebooks I used are on Gitlab here. I recently flew the glider with them fitted and it handled very sweetly, much improved yaw stability and damping and also they look way cool! I've attached the photo below. To be honest any improvement in performance is very small, I couldn't feel it on that flight in those conditions, it will take a lot more testing and competition flying to see if they really are an improvement in performance. However the reason for them is primarily for handling, although at the same time I wanted to make sure the performance wasn't actually degraded. Winglets have been tried on hang gliders in the past and not worked, but the optimisation showed clearly that bad winglets were worse than no winglets, the initial guess for the optimisation (straight, no toe, no twist) degraded performance, so it's not surprising that in the past people haven't got them to work, they didn't have OpenVSP!

So I just wanted to say a big thank you to Rob, Brandon and everyone else that develops this awesome software and makes it available FOSS. If anyone wants to follow my progress I'm on all the socials (see links below). Mastodon is my favoured and I also make videos explaining aerodynamics on YouTube, I plan to make some featuring OpenVSP in the future.

Happy flying!
Tim Swait,

Avian Hang Gliders

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