Curtiss YP-60

Infobox Aircraft
name=Curtiss-Wright XP-53/P-60
type=Fighter aircraft
manufacturer=Curtiss-Wright Corporation


caption=XP-60 with Rolls-Royce Merlin engine.
designer=
first flight=1 November 1942
introduced=
retired=
status=Cancelled 20 December 1941
primary user=United States Army Air Forces
more users=
produced=1942-1944
number built=6
unit cost=
variants with their own articles=The Curtiss XP-53/P-60 was a 1940s United States single-engine single-place, low-wing monoplane fighter aircraft developed by the Curtiss-Wright company as a successor to their P-40. It went through a lengthy series of prototype versions, eventually evolving into a design that bore little resemblance to the P-40. None of these versions reached production.

Design and development

The initial design contained in proposals to the United States Army Air Corps was for an airplane based upon the P-40 design but featuring a low drag laminar flow wing, a Continental XIV-1430-3 inverted vee engine, and eight wing-mounted 0.5 inch machine guns. This proposal was accepted and a contract for two prototypes was issued on 1 October 1940 with the aircraft designated the XP-53.

Within two months the Army Air Corps modified the contract to require the second prototype be completed with a Rolls-Royce Merlin engine in place of the XIV-1430. That aircraft was re-designated XP-60. The airframe design for the XP-60 was modified for the different engine, and the main landing gear was changed from the rearward retracting P-40 design to a new inward retracting version, which allowed a wider wheelbase and a smooth wing surface when the gear was retracted. This aircraft first flew on September 18 1941 with a British-built Merlin 28 engine. The XP-53 prototype was then converted into an airframe static test vehicle for the XP-60.

Considering delivery delays of quantities of the Packard-built Merlin engines due to its use on other fighters, the use of a turbo-supercharged Allison V-1710-75 engine was considered in its place. Thus, on October 31 1941 a contract for 1,950 P-60A fighters was awarded using the Allison engine.

Testing

In the meantime, flight tests of the XP-60 prototype were not progressing smoothly. In addition to landing gear problems, expected top speed was not being met due to shortcomings in the laminar-flow wing surface finish, relatively high radiator drag (compared to the P51 Mustang, which was then flying), and less than specified engine output performance. Consequently, work on the P-60A was stopped on 20 December 1941, and then on 2 January 1942 the order was changed to produce one XP-60A with the Allison V-1710-75 engine and a General Electric B-14 turbo-supercharger, one XP-60B with the Allison V-1710-75 engine and a Wright SU-504-1 turbo-supercharger, and one XP-60C with the massive Chrysler XIV-2220 sixteen cylinder inverted vee engine.

At the time, availability of the Chrysler engine was coming into question, and after Curtiss noted that several hundreds of pounds of lead would be needed in the tail of the existing airframe for balance, a decision was made to install a Pratt & Whitney R-2800 radial engine in the XP-60C. In the meantime, Curtiss installed a Merlin 61 engine in the original XP-60 and after enlarging the vertical tail surface, this aircraft was re-designated XP-60D.

The XP-60A first flew on 1 November 1942. While official interest in the P-60 waned during summer 1942, interest due to the promise of improved performance with the installation of the R-2800 engine resulted in a contract for 500 R-2800 powered P-60A-1-CU fighters with contra-rotating propellers. With concern that the contra-rotating propellers would not be available on time, the XP-60B was modified to take the R-2800-10 engine driving a four bladed propeller. This modification was re-designated XP-60E.

On 27 January 1943, the XP-60C flew for the first time, powered by a R-2800-53 engine with contra-rotating propellers. The aircraft's flying characteristics were found to be generally satisfactory. The first flight of the XP-60E with the four-bladed propeller, was delayed until 26 May 1943 after it was found that due to its lighter weight, the engine installation had to be moved ten inches forward compared to the XP-60C.

In April 1943, the US Army Air Force decided to conduct an evaluation of the various fighter aircraft in development and use in order to eliminate the least desirable models. Curtiss was requested to have the XP-60E participate. As the XP-60E was not available, the company hurriedly prepared the XP-60C for the evaluation at Patterson Field. In the event, due to various issues, the XP-60C performed poorly, resulting in reduction of the production run of 500 aircraft to two aircraft.

In January 1944, the XP-60E was flown to Eglin Field for official trials, where Army Air Force pilots found that it did not compare favorably to later aircraft. When Curtiss expressed the desire to abandon further work on the P-60 series, the Army Air Force insisted upon completion of one of the two aircraft in production. The aircraft when originally ordered was designated YP-60A-1-CU was re-designated YP-60E. This aircraft flew on 13 July 1944 and was subsequently delivered to Wright Field. The YP-60E differed mainly from the XP-60E in being powered by a 2,100 hp R-2800-18 engine and an all-round vision bubble cockpit canopy.

pecifications (XP-60C)

Aircraft specifications

plane or copter?=plane
jet or prop?=prop

crew=1
length main=33.92 ft
length alt=10.34 m
span main=41.33 ft
span alt=12.60 m
height main=12.33 ft
height alt=3.76 m
area main=275 ft²
area alt=25.6 m²
empty weight main=8,698 lb
empty weight alt=3,945 kg
loaded weight main=10,785 lb
loaded weight alt=4,892 kg
max takeoff weight main=
max takeoff weight alt=
engine (prop)=Pratt & Whitney R-2800-53
type of prop=radial engine
number of props=1
power main=2,000 hp
power alt=1,492 kW
max speed main=414 mph
max speed alt=360 knots, 666 km/h
range main=
range alt=
ceiling main=37,900 ft
ceiling alt=11,600 m
climb rate main=3,890 ft/min
climb rate alt=19.8 m/s
loading main=39.2 lb/ft²
loading alt=191 kg/m²
power/mass main=0.19 hp/lb
power/mass alt=300 W/kg
guns=4× .50 in (12.7 mm) M2 Browning machine guns

ee also

aircontent
related=
* Curtiss P-40
similar aircraft=
lists=
* List of fighter aircraft
* List of military aircraft of the United States

References

Notes

Bibliography

* Bowers, Peter M. "Curtiss Aircraft, 1907-1947". London: Putnam & Company Ltd., 1979. ISBN 0-370-10029-8.
* Green, William. "War Planes of the Second World War, Volume Four: Fighters". London: MacDonald & Co. (Publishers) Ltd., 1961 (Sixth impression 1969). ISBN 0-356-01448-7.
* Green, William and Gordon Swanborough. "WW2 Aircraft Fact Files: US Army Air Force Fighters, Part 1". London: Macdonald and Jane's Publishers Ltd., 1977. ISBN 0-356-08218-0.