History
Background
With the Curtiss P-40 Warhawk entering production by 1940, Curtiss began an ambitious effort to develop a superior aircraft that could replace the P-40. The US Army Air Corps (USAAC) was interested in supporting these efforts and awarded a contract to fund the development of potential successors.
Curtiss initially designed the XP-46 prototype, which shared similarities with the P-40, except it was built to be smaller and equipped with an inward-retracting undercarriage. The XP-46 took its first flight on February 15, 1941, but it offered no meaningful performance improvements over the P-40 and was outright rejected by the USAAC.
After the XP-46 did not secure production orders, Curtiss shifted focus to a new design: the Model 88, later designated the XP-53 by the Army. This model was intended to use a Continental XIV-1430-3 engine. However, engine development issues led to the cancellation of the XP-53 before it could be built.
Curtiss then moved on to the development of Model 90, which was designated XP-60. At the Army’s request, the XP-60 was initially designed to be powered by a Rolls-Royce Merlin engine and include laminar-flow wings, a type of airfoil designed to reduce drag and make the aircraft fly faster. Curtiss produced four airframes during this project, which resulted in nine different designations: XP-60, XP-60A, YP-60A, P-60A, XP-60B, XP-60C, XP-60D, XP-60E, and YP-60E. These versions represented Curtiss’ long and desperate attempts to develop a worthy successor to the P-40—efforts that lasted until late 1944.
XP-60E - Model 95D
Following the XP-60C’s first flight on January 27, 1943, a partially built XP-60B was reworked to incorporate a Pratt & Whitney R-2800-10 radial engine with a General Electric B-14 turbo-supercharger, replacing the original Merlin V-1710-75 inline engine. Unlike the XP-60C, which used six-bladed contrarotating propellers, the XP-60E featured a simpler four-bladed single-rotation propeller. The aircraft retained its armament of four M2 Browning machine guns but was slightly lighter than the XP-60C. As a result, the Army redesignated it as the XP-60E.
To accommodate the lighter propeller, the R-2800 engine had to be shifted forward by ten inches, which addressed the balance issues. The XP-60E also encountered engine problems during initial ground testing, leading to delays that caused it to miss a critical fly-off at Patterson Field, Ohio. With the XP-60E unavailable, Curtiss sent the heavier XP-60C in its place for the April 1943 evaluations. Unfortunately, the XP-60C’s rushed construction negatively affected its performance, undermining its high-speed potential.
Once repaired, the XP-60E took to the skies for its maiden flight on May 26, 1943. In January 1944, it was transferred to Elgin Field, Florida, for official Army trials. However, an engine failure during testing caused a crash landing, damaging the aircraft. Curtiss subsequently rebuilt the XP-60C to XP-60E specifications to continue evaluations.
During these tests, Army pilots found that while the XP-60E matched the P-47 and P-51 in climb rate, it offered no significant advantages over them. Additionally, the aircraft’s four-gun armament was deemed inadequate, and pilots reported that it required constant trimming for stable flight.
With the program showing little promise, Curtiss requested permission to abandon the P-60 project in May 1944. The Army agreed but made a final request for a YP-60E variant with an R-2800-18 engine and a bubble canopy. After only two flights, the project was terminated for good.
The fate of the XP-60E, formerly the XP-60C, remains unknown to this day, as its disposition following the war is unclear.
