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Curtiss XP-31 Swift

Single-Seat Monoplane Fighter Prototype

The Curtiss XP-31 Swift monoplane fighter prototype lost out to a Boeing product that would become the P-26 Peashooter series.
Authored By: Staff Writer | Last Edited: 4/14/2017
Curtiss Aeroplane and Motor Company was a major player in the fighter industry during the 1920s and 1930s. One of the many contributions of the period became the prototype XP-31 "Swift" monoplane. Only one was ever built as it lost in competition to a Boeing design which became the famous P-26 "Peashooter" monoplane fighter (detailed elsewhere on this site).

The XP-31 was a product of its time, appearing in-between the major World Wars where spatted undercarriages, enclosed cockpits and metal skinning were becoming the norm. Work began in 1931 by Curtiss and involved a braced, low-mounting monoplane wing structure with traditional single-finned tail unit. The main landing gear legs were heavily faired over (from leg to wheel) and the engine was set within a streamlined nose. The single pilot sat in an enclosed cockpit space just aft of the wing mainplanes.

In its original form, the Swift was powered by a Wright T-1820 "Cyclone" air-cooled radial engine of 700 horsepower at the nose driving a two-bladed propeller unit. A first-flight was recorded in July of 1932. This aircraft carried with it full-span, retractable leading-edge slats and trailing edge flaps for maximum low-speed control. When performance was shown to be lacking in this initial iteration, the aircraft was re-engined to carry the Curtiss GIV-1570-F "Conqueror" 12-cylinder engine of 600 horsepower with Prestone cooling (now driving a three-bladed propeller). This model was formally accepted for the USAAC competition against the Boeing entry.

However, despite the testing scheduled for Match 1st, 1933, the XP-31 had already been surpassed by the superior Boeing design and chosen as the next fighter for the USAAC. As such, the XP-31 quickly fell to history and the sole example was ultimately scrapped in 1935.

As completed, the XP-31 sported a length of 8 meters, a wingspan of 11 meters and a height of 2.4 meters. Empty weight was 1,512 kilograms against an MTOW of 1,880kg. Maximum speed reached 335 kmh (208mph) and range was out to 595 kilometers (370 miles). Its service ceiling was 7,440 meters (24,400 feet).

Proposed armament was 2 x 7.62mm M1919 Browning machine guns in fixed, forward-firing mountings within the engine cowl and 2 x 7.62mm M1919 Browning machine guns in fixed, forward-firing mountings at the "cheek" positions of the fuselage.


[ 1 Units ] :
Curtiss Aeroplane and Motor Company - USA
National flag of United States United States (cancelled)
- Fighter
- X-Plane / Developmental
26.25 ft (8 m)
36.09 ft (11 m)
7.87 ft (2.4 m)
(Showcased structural dimension values pertain to the Curtiss XP-31 Swift production model)
Empty Weight:
3,340 lb (1,515 kg)
4,145 lb (1,880 kg)
(Diff: +805lb)
(Showcased weight values pertain to the Curtiss XP-31 Swift production model)
1 x Curtiss GIV-1570-F Conqueror 12-cylinder liquid-cooled engine developing 600 horsepower and driving a three-bladed propeller at the nose.
(Showcased powerplant information pertains to the Curtiss XP-31 Swift production model)
Maximum Speed:
208 mph (335 kph; 181 kts)
Service Ceiling:
24,409 feet (7,440 m; 4.62 miles)
Maximum Range:
373 miles (600 km; 324 nm)
(Showcased performance values pertain to the Curtiss XP-31 Swift production model; Compare this aircraft entry against any other in our database)
2 x 0.30 caliber Browning M1919 machine guns in cowling.
2 x 0.30 caliber Browning M1919 machine guns in fuselage cheek positions.
(Showcased armament details pertain to the Curtiss XP-31 Swift production model)
XP-31 "Swift" - Base Series Designation; single prototype completed.

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