In 1941, it became clear that the R-60A aircraft would not meet the U.S. Air Force’s flight performance requirements, leading to the suspension of the contract. Instead, on January 2, 1942, three different XP-60A prototypes were ordered to be built in one copy, The XP-60B and XP-60C (Model 95A, 95B and 95C) were to be fitted with Allison V-1710-75 engines with General Electric turbocharger, V-1710-75 with Wright turbocharger and Chrysler XIV-2220 in-line engine.
USAAC management expressed dissatisfaction with the work carried out and actually refused to continue work on this aircraft. Instead, he ordered the next fighter, designated the Model 90B (XP-60D). In August 1942, the first XP-60 was brought to the XP-60D variant, replacing the British engine with its American version of the Packard V-1650-3 (“Merlin” 61) with a capacity of 1250 hp with a four-bladed propeller. The plane did not fly for long and was lost in an accident on May 6, 1943.
The XP-60D was given to the original XP-60 aircraft after the Packard Merlin 61 was installed on it. Eventually, the H-60S, powered by Pratt and Whitney R-2800-53, made its maiden first flight on January 27, 1943. These modifications were released on one copy.
Interest in the P-60 declined sharply, but Curtiss managed to convince the army leadership that it was appropriate to continue work on the prototype of the XP-60C, as the variant of the XP-60B was also rejected due to the unsatisfactory TTH shown by the first prototype. In addition, instead of the experimental engine Chrysler decided to install a radial Pratt and Whitney R-2800 with two coaxial three-blade screws rotating in opposite directions. The calculations promised an increase in speed even without the use of unreliable turbochargers, which dramatically changed the turnover of the case.
According to the project, the HR-60S was to have a fuselage from the HR-60A’B, only its bow was converted to the installation of a radial engine, and the weapons were limited to six 12.7 mm machine guns. Its tests began on January 27, 1943, just three months after the issuance of the technical task. The substantially revamped fighter was better than its predecessors. Test pilots noted only a slightly protracted take-off and lack of stability in the flight.
|Wing area, m2||25.56|
|Engine type||1 DD Pratt Whitney R-2800-53 Double Wasp|
|Power, hp||1 x 2000|
|Top speed, km/h||667|
|Cruise speed, km/h||587|
|Practical range, km||507|
|Maximum speed, m/min||1524|
|Practical ceiling, m||11550|
|Weapons:||four 12.7 mm machine guns mounted in the wing.|
Encyclopedia of American Military Aircraft