 Kawanishi designed a single-engined low-wing monoplane, powered by a 1,460 hp (1,090 kW) Mitsubishi MK4D Kasei 14 14-cylinder radial driving two Contra-rotating two-bladed propellers, the first installation of contra-rotating propellers produced in Japan, while a laminar flow airfoil section was chosen to reduce drag.It had a single main float under the fuselage and two stabilising floats under the wing.The stabilising floats were designed to retract into the wing, while the central float was designed to be jettisoned in case of emergency, giving a sufficient increase in speed (estimated as approximately 50 knots (90 km/h)) to escape enemy fighters.