Two hardware build-logs: an ocean-drifting hull and a 56g flying wing

I write up hardware designs before they're built, using the real numbers from the design work itself. Two so far.

HULL-4 is a 56 g, 520 mm-span flying wing I sized to fly on a single salvaged 1S battery and four small coreless motors. At that scale the Reynolds number is around 40,000, low enough that normal airfoil data stops applying — the wing has to be designed around thin-plate, low-Reynolds aerodynamics instead. The write-up covers why an 18° sweep and a specific washout window were chosen, with the lifting-line stall-margin analysis and CAD render included: https://j4zz.eu/rc-plane-hull4/

Rose Mk2 is a proposed autonomous hull meant to drift 373 km from Bonn to the open North Sea with no engine, riding the river current and then anchoring through each incoming tide near Rotterdam (the power budget shows fighting the tide with more motor power doesn't work). I ran a 17,500-candidate search scored on drag, wetted area, a stability floor, and fit to real small-craft proportions to find the hull shape; self-righting itself is checked separately with the Capsize Screening Formula and a pendulum model, since the search alone can't settle that question: https://j4zz.eu/rose-mk2/

Honest limits: neither design has been physically built yet. Both are CAD and hand-hydrostatics stage, with bench/pool/river/open-water test stages still ahead. Both pages are free, with an optional Ko-fi/PayPal tip jar, and GoatCounter shows zero visits site-wide as of today. I'm posting here because Indie Hackers has been the one channel that's actually reached a reader for other pages of mine.