The Curtiss P-5 Superhawk was a version of the P-1 Hawk fitted with turbo-supercharged engines. On 14 May 1927 the USAAC issued a contract for the production of five aircraft similar to the P-1A, but with turbo-supercharged Curtiss V-1150-4 (D-12F) engines.
The first of these aircraft was delivered in January 1928 as the XP-5, not because it was a prototype but because it was used for tests. The remaining four arrived by June 1928. The P-5 had a side mounted turbo-supercharge which added nearly 500lb to their weight. They also had cockpit heating, providing by running warm air from the exhaust into the canopy. The heat was kept in by a cape that snapped around the cockpit rim and fitted around the pilot.
The turbo-supercharger raised the service ceiling of the aircraft to 31,000ft, nearly ten thousand feet above the absolute ceiling of the standard P-1! Speed at sea level was reduced to 142mph, but at 25,000ft the P-5 could reach 166mph. Two of the P-5s were lost in accidents soon after being delivered, but the remaining two served with the 94th Pursuit Squadron until April 1932.
The P-5 proved that a turbo-supercharger could be effective on the Hawk airframe, but by the time it entered service its D-12 engine was obsolete, and had been replaced in new service aircraft by the Curtiss V-1570 Conqueror engine.
Engine: Curtiss V-1150-4 (D-12F) 12-cylinder water-cooled engine with turbo-supercharger
Span: 31ft 6in
Length: 23ft 1in
Height: 9ft 0in
Empty weight: 2,520lb
Loaded weight: 3,349lb
Max speed: 146mph at sea level, 173mph at 25,000ft
Climb Rate: 8.4 mins to 10,000ft
Service ceiling: 31,000ft
Range: 310 miles
Armament: Two .3in machine guns