Aqua Flap
An untethered flapping-wing robot bursts from water into flight in a single motion. Tune wing flexibility, span, and leg assistance — then launch to watch the three-phase transition play out. Inspired by July 2026 research investigating how wing design and leg mechanics enable aerial–aquatic locomotion.
Wing Parameters
Wing FlexibilitySemi-flex
Rigid (good underwater)Flexible (good in air)
Wing SpanMedium
Narrow (less drag)Broad (more lift)
Leg Assist
Push off water surface on burst
idle
swimming
surfacing
flying
Transition Mechanism
The Science
🦅 First untethered aquatic-aerial robot
Researchers built the first untethered robot that can flap its wings underwater for propulsion, then burst through the water surface and transition directly into powered flight — all without external tethers or control cables.
💪 Wing flexibility is the key variable
Rigid wings store energy from fluid drag better during underwater strokes, while flexible wings adapt their camber to generate lift more efficiently in air. The optimal design tunes stiffness at the root and compliance at the tip.
🦵 Legs break surface tension
Small articulated legs provide the critical push off the water surface during the burst phase, overcoming surface tension and drag — the hardest part of the air–water transition — giving the wings time to generate aerodynamic lift.
🐦 Nature's blueprint: the gannet
Northern gannets (Morus bassanus) dive into water at 90 km/h and resurface instantly into flight. This robot's mechanism draws directly from how gannets fold their wings on entry and snap them open at exit.
🌊 The density problem
Water is 800× denser than air. Wings sized for flight stall underwater; wings sized for swimming stall in air. The team solved this with a single adaptive planform that changes effective aspect ratio during the transition.