Curtiss P-60
Encyclopedia
The Curtiss 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.
was for an aircraft 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 in (12.7 mm) machine guns. This proposal was accepted and a contract for two prototype
s 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P-40 design to a new inward retracting version, which allowed a wider wheelbase and a smooth wing surface when the gear was retracted.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 18 September 1941 with a British
-built Merlin 28 engine. The XP-53 prototype was then converted into a static test airframe for the XP-60.
Considering delivery delays of quantities of the Packard-built Merlin engines due to its use in other fighters, the use of a turbo-supercharged
Allison V-1710-75 engine was considered in its place. Consequently, on 31 October 1941, a contract for 1,950 P-60A fighters using the Allison engine, was awarded.
drag
(compared to the North American P-51 Mustang, which was then flying), and less than specified engine output performance. Consequently, work on the P-60A was stopped on 20 December 1941, when the USAAC recommended that Curtiss concentrate on licence production of Republic P-47 Thunderbolts.
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 propeller
s. 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 10 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 contemporary aircraft designs. 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 (1,566 kW) R-2800-18 engine as well as the fitting of an all-round vision bubble
canopy.
With the development contracts cancelled in June 1943, the program ended ignobly when the last prototype was scrapped on 22 December 1944.To replace the P-60, Curtiss built 354 Republic P-47Gs instead for the USAAF. The XP-60E survived to be sold as an entry for the 1947 National Air Races
, but crashed during a qualifying flight before the competition was held.
XP-60
XP-60A
P-60A
YP-60A-1
P-60A-1
XP-60B
XP-60C
XP-60D
XP-60E
YP-60E
XP-60F
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
single-engine single-place, low-wing monoplane
Monoplane
A monoplane is a fixed-wing aircraft with one main set of wing surfaces, in contrast to a biplane or triplane. Since the late 1930s it has been the most common form for a fixed wing aircraft.-Types of monoplane:...
fighter aircraft
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...
developed by the Curtiss-Wright
Curtiss-Wright
The Curtiss-Wright Corporation was the largest aircraft manufacturer in the United States at the end of World War II, but has evolved to largely become a component manufacturer, specializing in actuators, aircraft controls, valves, and metalworking....
company as a successor to their P-40
Curtiss P-40
The Curtiss P-40 Warhawk was an American single-engine, single-seat, all-metal fighter and ground attack aircraft that first flew in 1938. The P-40 design was a modification of the previous Curtiss P-36 Hawk which reduced development time and enabled a rapid entry into production and operational...
. 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 CorpsUnited States Army Air Corps
The United States Army Air Corps was a forerunner of the United States Air Force. Renamed from the Air Service on 2 July 1926, it was part of the United States Army and the predecessor of the United States Army Air Forces , established in 1941...
was for an aircraft based upon the P-40 design but featuring a low drag laminar flow
Laminar flow
Laminar flow, sometimes known as streamline flow, occurs when a fluid flows in parallel layers, with no disruption between the layers. At low velocities the fluid tends to flow without lateral mixing, and adjacent layers slide past one another like playing cards. There are no cross currents...
wing, a Continental XIV-1430-3 inverted vee engine, and eight wing-mounted 0.5 in (12.7 mm) machine guns. This proposal was accepted and a contract for two prototype
Prototype
A prototype is an early sample or model built to test a concept or process or to act as a thing to be replicated or learned from.The word prototype derives from the Greek πρωτότυπον , "primitive form", neutral of πρωτότυπος , "original, primitive", from πρῶτος , "first" and τύπος ,...
s 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
Rolls-Royce Merlin
The Rolls-Royce Merlin is a British liquid-cooled, V-12, piston aero engine, of 27-litre capacity. Rolls-Royce Limited designed and built the engine which was initially known as the PV-12: the PV-12 became known as the Merlin following the company convention of naming its piston aero engines after...
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 18 September 1941 with a British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
-built Merlin 28 engine. The XP-53 prototype was then converted into a static test airframe for the XP-60.
Considering delivery delays of quantities of the Packard-built Merlin engines due to its use in other fighters, the use of a turbo-supercharged
Turbocharger
A turbocharger, or turbo , from the Greek "τύρβη" is a centrifugal compressor powered by a turbine that is driven by an engine's exhaust gases. Its benefit lies with the compressor increasing the mass of air entering the engine , thereby resulting in greater performance...
Allison V-1710-75 engine was considered in its place. Consequently, on 31 October 1941, a contract for 1,950 P-60A fighters using the Allison engine, was awarded.
Operational history
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 radiatorRadiator (engine cooling)
Radiators are used for cooling internal combustion engines, mainly in automobiles but also in piston-engined aircraft, railway locomotives, motorcycles, stationary generating plant or any similar use of such an engine....
drag
Drag (physics)
In fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...
(compared to the North American P-51 Mustang, which was then flying), and less than specified engine output performance. Consequently, work on the P-60A was stopped on 20 December 1941, when the USAAC recommended that Curtiss concentrate on licence production of Republic P-47 Thunderbolts.
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
Pratt & Whitney R-2800
The Pratt & Whitney R-2800 Double Wasp is a two-row, 18-cylinder, air-cooled radial aircraft engine with a displacement of 2,804 in³ , and is part of the long-lived Wasp family....
radial engine
Radial engine
The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders point outward from a central crankshaft like the spokes on a wheel...
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 propeller
Propeller (aircraft)
Aircraft propellers or airscrews convert rotary motion from piston engines or turboprops to provide propulsive force. They may be fixed or variable pitch. Early aircraft propellers were carved by hand from solid or laminated wood with later propellers being constructed from metal...
s. 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 10 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 contemporary aircraft designs. 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
Wright-Patterson Air Force Base
Wright-Patterson Air Force Base is a United States Air Force base in Greene and Montgomery counties in the state of Ohio. It includes both Wright and Patterson Fields, which were originally Wilbur Wright Field and Fairfield Aviation General Supply Depot. Patterson Field is located approximately...
. The YP-60E differed mainly from the XP-60E in being powered by a 2,100 hp (1,566 kW) R-2800-18 engine as well as the fitting of an all-round vision bubble
Bubble canopy
A bubble canopy is a canopy made like a soap bubble, which attempts to provide 360° vision to the pilot.-History:Bubble canopies have been in use since World War II. The British had already developed the "Malcolm hood", which was a bulged canopy, but the British Miles M.20 was one of the first...
canopy.
With the development contracts cancelled in June 1943, the program ended ignobly when the last prototype was scrapped on 22 December 1944.To replace the P-60, Curtiss built 354 Republic P-47Gs instead for the USAAF. The XP-60E survived to be sold as an entry for the 1947 National Air Races
National Air Races
The National Air Races were a series of pylon and cross-country races that took place in the United States from 1920 to 1949. The science of aviation, and the speed and reliability of aircraft and engines grew rapidly during this period; the National Air Races were both a proving ground and...
, but crashed during a qualifying flight before the competition was held.
Variants
XP-53- Curtiss Model 88; derivative of XP-46 to Request for Data R40-C specifications. Laminar flow wing and Continental XIV-1430-3Continental I-1430-See also:-Bibliography:* Neal, Robert J.; Packard as an Aero Engine Builder - Spark-Ignition Engines: 1923-1939 Torque Meter Vol. 7 No. 3 Summer 2008 at -External links:* *...
engine. Contracted for 1 October 1940; cancelled in favour of XP-60 in November 1941. One static test airframe built.
XP-60
- Curtiss Model 90; Rolls-Royce MerlinRolls-Royce MerlinThe Rolls-Royce Merlin is a British liquid-cooled, V-12, piston aero engine, of 27-litre capacity. Rolls-Royce Limited designed and built the engine which was initially known as the PV-12: the PV-12 became known as the Merlin following the company convention of naming its piston aero engines after...
engine, armament 8 .50-cal machine guns. One built, first flight 18 September 1941; modified to XP-60D.
XP-60A
- Curtiss Model 95A; Allison V-1710-75 engine with B-14 turbosupercharger; armament: six .50-cal MG. One built.
P-60A
- Planned production version of XP-60; 1900 ordered, all cancelled.
YP-60A-1
- Pre-production version of P-60A-1 with single prop. Twenty-six ordered; two built; one rebuilt as YP-60E.
P-60A-1
- Planned production version of XP-60C with Pratt & Whitney R-2800Pratt & Whitney R-2800The Pratt & Whitney R-2800 Double Wasp is a two-row, 18-cylinder, air-cooled radial aircraft engine with a displacement of 2,804 in³ , and is part of the long-lived Wasp family....
-18 engine and contraprop; armament: four .50-cal MG. 500 ordered; cancelled before any built.
XP-60B
- Curtiss Model 95B; V-1710-75 engine with SU-504-2 turbosupercharger; armament: six .50-cal MG. One built, modified to XP-60E.
XP-60C
- Curtiss Model 95C; planned for Chrysler XIV-2220 engine, built with R-2800-53 and contraprop; armament: six .50-cal MG. One built. Rebuilt as XP-60E; original XP-60E rebuilt as XP-60C.
XP-60D
- Rebuilt XP-60. Curtiss Model 90B; Packard V-1650Packard V-1650The Packard V-1650 was a liquid cooled 27 litre 60° V12 piston aircraft engine variant of the Rolls-Royce Merlin produced under licence by the Packard Motor Car Company...
-3 engine; crashed 6 May 1943.
XP-60E
- Rebuilt XP-60B. Curtiss Model 95D; R-2800-10 engine; crashed January 1944. XP-60C reconfigured to XP-60E status.
YP-60E
- Modified YP-60A-1 with bubble canopy. First flight 15 July 1944; cancelled 22 December 1944.
XP-60F
- Planned modification of YP-60A-1 with different model of R-2800; cancelled before conversion.