In 1927 two parallel, designs were developed to meet an Italian naval requirement for a two-seat catapult-launched seaplane. One was a small flying-boat, the Piaggio P.6bis powered by a single 194kW Isotta Fraschini V.6 engine mounted between the wings and driving a pusher propeller; the other was the P.6 floatplane with a large central float, two wing-tip stabilising floats, and a 288kW A.20 engine in the nose. The two aircraft had identical wing structure, with rigid strut bracing, and each mounted a single defensive machine-gun, that of the flying-boat in the bow, and the floatplane's in the rear cockpit.
The P.6ter of 1928 was similar to the P.6, but had an engine boosted to 306kW to provide a maximum speed of 195km/h. Wing span was 13.50m and maximum take-off weight 2360kg. A batch of 15 P.6ter floatplanes was built, and the type was used for a period aboard several Italian capital ships and cruisers.
Engine: 1 x 194kW Isotta Fraschini V.6
Engine: 1 x 288kW A.20
Engine: 1 x Fiat A.20, 306kW
Max take-off weight: 2360 kg / 5203 lb
Wingspan: 13.5 m / 44 ft 3 in
Max. speed: 195 km/h / 121 mph