Curtiss P - 1 Hawk The P - 1 Hawk ( Curtiss Model 34 ) was a 1920s open - cockpit biplane fighter aircraft of the United States Army Air Corps . An earlier variant of the same aircraft had been designated PW - 8 prior to 1925 . Design and development . PW - 8 . The Curtiss P - 1 Hawk was the first US Army Air Service aircraft to be assigned the " P " ( Pursuit ) designation which replaced seven designations for pursuit aircraft , including " PW " ( for " Pursuit , Water - cooled engine " ) . The P - 1 was the production version of the Curtiss XPW - 8B , an improved variant of the PW - 8 , 25 of which were operational with the Air Service ' s 17th Pursuit Squadron In September 1923 , the Army ordered production of the PW - 8 . The PW - 8 ( Curtiss Model 33 ) had been developed from the R - 6 racer and was acquired by the Air Service after a competition with the Boeing Model 15 , designated the PW - 9 , to replace the existing Army fighter , the Boeing MB - 3A . Although the PW - 8 was faster than the PW - 9 ( both having top speeds in excess of 165 mph ) , it was otherwise out - performed by the Boeing plane , and its cooling system appeared to be more difficult to maintain and vulnerable in combat . However Assistant Chief of the Air Service Brig . Gen . Billy Mitchell agreed to purchase 25 PW - 8s in return for assistance by Curtiss in making the Dawn - to - dusk transcontinental flight across the United States . P - 1 . The prototype of the P - 1 , the XPW - 8B , came about when the Air Service , which had selected the Boeing PW - 9 over the PW - 8 as its main production fighter , asked Curtiss to modify the last of its three original XPW - 8 prototypes with wings resembling those of the PW - 9 . Curtiss designated the modified aircraft its Model 34A and returned it to the Air Service for evaluation , from which the service ordered it into production as the P - 1 . The first production P - 1 , serial number 25 - 410 , was delivered on August 17 , 1925 , and was followed in successive years by the P - 1B and P - 1C variants with improved engines . The newest P - 1 variants remained in operational service until 1930 . The March 7 , 1925 order for the P - 1 also requested five aircraft with the more powerful 500 hp ( 373 kW ) Curtiss V - 1400 engine installed . These were completed in January 1926 . The first ( SN 25 - 420 ) was then modified with a supercharger mounted on the right side of the fuselage nose , and whose turbine was driven by engine exhaust ; the craft was designated XP - 2 . However , the Curtiss V - 1400 engine did not perform up to expectations , with or without the supercharger , and so after a year in service , three of the standard P - 2 Hawks had their engines replaced with the Curtiss V - 1150 and were consequently redesignated as P - 1s . The fifth machine ( 25 - 243 ) received a Curtiss V - 1570 Conqueror engine and became the XP - 6 . 93 production P - 1s were brought into service in the P - 1 , P - 1A , P - 1B , and P - 1C variants . 52 other P - 1s , variants P - 1D , P - 1E , and P - 1F , were made by conversion of other Hawk variants , primarily AT - 4 and AT - 5 trainers . P - 3 and P - 5 test variants . The P - 3 Hawk was similar to the P - 1 Hawk but with a radial R - 1340 - 3 Wasp radial engine . The first of the type , designated XP - 3A , was the last P - 1A ( serial 26 - 300 ) . Originally intended to be powered by a 390 hp ( 291 kW ) Curtiss R - 1454 , the engine was deemed unsatisfactory and the 410 hp ( 306 kW ) Pratt & Whitney R - 1340 engine substituted . A second XP - 3A ( serial 28 - 189 ) included a cowling and spinner to reduce the drag due to the radial engine ; entered in the National Air Races of 1929 , its speed of 186 . 84 mph ( 300 . 69 km / h ) gave it second place in the Thompson trophy race . The remaining four craft were production P - 3As , but primarily used to service test the Pratt & Whitney Wasp engine . In addition to the significant increase in drag , the radial engine also interfered with the pilot ' s view . Addition of a Townend ring cowling worsened the visibility problem , and had only a limited effect on speed . It was also tested with various types of deep - chord NACA cowls . Two of the XP - 3A aircraft were re - engined in 1929 and 1930 with the Pratt & Whitney R - 985 - 1 Wasp Junior engine . This aircraft was re - designated the XP - 21 . Tests were run with this aircraft , but it was never developed into a production aircraft , despite the designation . Five P - 5 Superhawks , similar to the P - 1C but with a turbocharged V - 1150 - 3 engine , were delivered in 1928 . They had a top speed of 166 mph ( 267 km / h ) at 25 , 000 ft ( 7 , 620 m ) , considerably higher than the maximum ceiling of the P - 1A , but their low - level performance was inferior AT - 4 and AT - 5 trainers . Two single - seat advanced trainer variants were placed into production , the AT - 4 and AT - 5A , using Wright - Hispano engines . All were re - engined with Curtiss D - 12D engines and reverted to use as fighters , designated P - 1D and P - 1F respectively . Five AT - 4 / XAT - 5 test variants were re - classified as P - 1E . A total of 202 PW - 8 , P - 1 , P - 2 , P - 3 , P - 4 , P - 5 , AT - 4 , and AT - 5 airplanes were delivered . Operational history . On June 23 , 1924 , taking off at 3 : 58 A . M . , Army test pilot First Lieutenant Russell Maughan left Mitchel Field , New York , in PW - 8 24 - 204 , modified with additional fuel and oil tanks , made a dawn - to - dusk transcontinental flight across the US . Refueling five times , he landed at Crissy Field , San Francisco , California , at 9 : 46 p . m . , one minute before dusk , covering 2 , 670 mi ( 4 , 297 km ) in 20 hours and 48 minutes . His flight time included four planned 30 - minute stops at McCook Field , Ohio ; Saint Joseph , Missouri ; Cheyenne , Wyoming ; and Salduro Siding , Utah ; and an unplanned stop in North Platte , Nebraska for additional fuel when a muddy field in Missouri did not permit him to take on a full load . He also lost an hour at McCook to repair a broken fuel valve after an over - eager mechanic had over - torqued the valve , damaging it . The original fifteen " P - 1s " served in the 27th and 94th Pursuit Squadrons , 1st Pursuit Group , Selfridge Field , Michigan . The first Hawk to serve with the Air Corps in quantity was the " P - 1A " ( 17th , 27th , and 94th Pursuit Squadrons ) beginning in 1925 . In October 1928 the largest order of 33 " P - 1s " was made . These were delivered by April 1929 as P - 1Cs . The " AT - 4 " and " AT - 5 " trainer variants served with the 43rd Pursuit Squadron ( School ) at Kelly Field , Texas . Variants . While a total of 202 Hawks were built in the basic variants PW - 8 , P - 1 , P - 2 , P - 3 , P - 5 , AT - 4 and AT - 5 , conversions resulted in 148 having a P - 1 designation . All variants increased in weight with each succeeding model , resulting in slight reductions in performance with each .