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Curtiss XP-37 (Allison Hawk)

United States (1937)

Detailing the development and operational history of the Curtiss XP-37 (Allison Hawk) Fighter Prototype.

 Entry last updated on 5/13/2016; Authored by Staff Writer; Content ©

  Curtiss XP-37 (Allison Hawk)  
Picture of Curtiss XP-37 (Allison Hawk) Fighter Prototype
Picture of Curtiss XP-37 (Allison Hawk) Fighter Prototype Picture of Curtiss XP-37 (Allison Hawk) Fighter Prototype

The Curtiss XP-37 was an attempt by the USAAC to transform the radial-powered P-36 Hawk into an inline piston-engined fighter.

The American Curtiss P-36 "Hawk" marked one of the earliest of the all-modern fighters to appear in the years leading up to World War 2 (1939-1945). It was joined by the likes of the British Hawker Hurricane and the German Messerschmitt Bf 109 but failed to find the same wartime success as its contemporaries. Completed with a Pratt & Whitney "Twin Wasp" air-cooled radial piston engine, 215 examples were built as the P.36 and a further 900 were exported under the "Hawk 75" designation. The design was eventually developed into the classic P-40 "Warhawk".

The United States Army Air Corps (USAAC) sought additional value in their P-36 to the point that they commissioned Curtiss in 1937 to develop the aircraft with the Allison V-1710 turbo-supercharged inline piston engine of 1,150 horsepower. This begat the prototype "XP-37" monoplane fighter which retained much of the original's components including its well-streamlined airframe. To compensate for the length and weight of the new engine installation at the nose (and to better balance the revised center-of-gravity), the cockpit was positioned further aft along the dorsal spine which immediately differentiated it from the earlier P-36.

In this configuration, the aircraft was flown for the first time during April 1937 and managed a maximum speed of 340 miles per hour against the P-36A's 313 mph top speed. However, the all-important turbo-supercharger proved troublesome during testing and there grew concern about the nose length and position of the wing mainplanes which considerably inhibited the pilot's forward vision. Views to the rear of the aircraft were no better as the raised fuselage spine and tail planes further masked any approaching danger from the rear.

Nevertheless, USAAC authorities were sold on the potential performance gains of this sleek entry and ordered the XP-37 in a service test form as the "YP-37" through a thirteen-strong batch order. Engineers continued to work on the turbo-supercharger but reliability remained an issue. A developmental-minded YP-37 managed a first flight during June of 1939 but the temperamental aircraft was soon passed over for a more promising - and conventional - venture, this to become the P-40 Warhawk which became an ultra-critical American fighter of the early-war years.
Picture of the Curtiss XP-37 (Allison Hawk) Fighter Prototype
Picture of the Curtiss XP-37 (Allison Hawk) Fighter Prototype

Any available statistics for the Curtiss XP-37 (Allison Hawk) Fighter Prototype are showcased in the areas immediately below. Categories include basic specifications covering country-of-origin, operational status, manufacture(s) and total quantitative production. Other qualities showcased are related to structural values (namely dimensions), installed power and standard day performance figures, installed or proposed armament and mission equipment (if any), global users (from A-to-Z) and series model variants (if any).
Curtiss YP-37 Specifications
National Flag Graphic
United States
Year: 1937
Type: Fighter Prototype
Manufacturer(s): Curtiss-Wright - USA
Production: 14
Supported Mission Types
Ground Attack
Close-Air Support
Airborne Early Warning
Electronic Warfare
Aerial Tanker
Passenger Industry
VIP Travel
Business Travel
Special Forces
Crew: 1
Length: 28.54 ft (8.7 m)
Width: 37.73 ft (11.50 m)
Height: 8.20 ft (2.50 m)
Empty Weight: 4,575 lb (2,075 kg)
MTOW: 6,030 lb (2,735 kg)

Installed Power
1 x Allison V-1710 inline piston engine developing 1,150 horsepower and driving a three-bladed propeller in the nose.

Standard Day Performance
Maximum Speed: 342 mph (550 kph; 297 kts)
Maximum Range: 621 mi (1,000 km; 540 nm)
Service Ceiling: 32,808 ft (10,000 m; 6.21 mi)
Rate-of-Climb: 3,400 ft/min (1,036 m/min)

None Fitted.

Operators List
United States (cancelled)

Series Model Variants
• XP-37 - Prototype designation
• YP-37 - Service Test aircraft; batch of thirteen ordered.
• P-37 - Assumed in-service designation

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