The Pacific War Online Encyclopedia

P-40 Warhawk, U.S. Fighter

Curtiss P-40E Warhawk

Crew	1
Dimensions	37'4" by 31'9" by 12'4" 11.38m by 9.68m by 3.76m
Wing area	236 square feet 21.9 square meters
Weight	6350-9200 lbs 2880-4200 kg
Maximum speed	355 mph at 5,000 feet 571 km/h at 1520 meters
Cruising speed	195 mph 314 km/h
Landing speed	96 mph 155 km/h
Climb rate	30 feet per second 9.1 meters per second
Service ceiling	29,000 feet 8800 meters
Power plant	1 1150 hp (857 kW) Allison V-1710-39 vee-12 engine driving a three-bladed propeller
Armament	6 0.50 fixed wing machine guns with 281 rounds per gun
External stores	1 500 lb (227 kg) or 2 100 lb (45 kg) or 6 20 lb (9 kg) bombs or one 52 gallon (197 liter) drop tank
Range	670 miles (1080 km) normal 900 miles (1450 km) with drop tank
Fuel	157 gallons internal 594 liters internal
Production	13,738 from 1940-3 at Curtiss-Wright Airplane Division, Buffalo, NY. 199 P-40 131 P-40B 193 P-40C 140 Tomahawk 1 110 Tomahawk IIA 930 Tomahawk IIB 22 P-40D 820 P-40E 560 Kittyhawk I 1500 Kittyhawk IA 1311 P-40F/Kittyhawk II 700 P-40L/Kittyhawk II 1300 P-40K 600 P-40M 5216 P-40N
Variants	The P-40 was produced in great variety throughout the war. The P-40B used a a 1040 hp (775 kW) V-1710-33 engine and was armed with two 0.50 machine guns in the cowling and two 0.30 machine guns in the wings. The C used a 1040 hp (775 kW) V-1710-33 engine and added two more 0.30s in the wings. Neither the B or C had any provisions for bombs, but the C could accommodate a 52 gallon (197 liter) drop tank. The F used a 1300 hp (969 kW) Packard V-1650-1 Merlin engine with a two-speed supercharger. This improved the performance somewhat at high altitude. Most of these aircraft were deployed to the Mediterranean. The K used a 1325 hp (988 kW) V-1710-73 engine that significantly improved performance. The L was essentially an F with just four 0.50 machine guns and other weight saving measures, including a reduction in fuel capacity to 120 gallons (450 liters). This failed to improve performance significantly, and production was halted so that the Merlin engines could be diverted to production of the P-51 Mustang. The N used 1200 hp (895 kW) V-1710-81, -99, or -115 engines and could carry three 500 lb (227 kg) bombs. It had a maximum speed of 378 mph (608 km/h) at 15,000 feet (4570 feet), but sacrificed fuel capacity and was armed with just 4 0.50 machine guns. The N-5 later reverted to six machine guns. The –B and –C were known as the Tomahawk and the later models, which used a new series of Allison engines permitting a shorter nose, as the Warhawk.

Although generally regarded as outclassed by the Zero, the P-40 was the best fighter the U.S. Army Air Force had available in any quantity at the start of the Pacific War. It reflected an American design philosophy that called for heavily armed, rugged, fast fighter aircraft with self-sealing fuel tanks and armor for the pilot. The most serious defect of the earlier models was the lack of any kind of supercharger, which severely limited the high altitude performance. At the time, turbochargers were in short supply and all were reserved for bomber construction. The P-40 was much tougher than the Zero, and slightly faster at sea level, but it was also much less maneuverable at low speeds and had a poor climb rate.

The P-40 had its roots in the P-36 Hawk, which was an excellent aircraft in its day, but distinctly obsolescent by 1939. Curtiss designer Donovan Berlin redesigned the aircraft around the Allison V-1710 inline engine, which was just coming into production in 1938, and the first prototype XP-37 achieved a speed of 340 mph (550 km/h). However, the engine proved mechanically unreliable and the cockpit had dismal visibility, and the design was abandoned. Berlin tried again with the XP-40, doing away with the super-turbocharging system of the XP-37 based on the Air Corps' belief that maximum performance was needed at just 15,000 feet (4600 m). The new aircraft was built around an improved V-1710 with ordinary supercharging, greatly simplifying the design. The prototype flew on 14 October 1938. In spite of a disappointing top speed of 340 mph (550 km/h), the Air Corps liked its handling and dive rate. More important, the aircraft would relatively cheap to manufacture using existing P-36 jigs and could be available relatively quickly in considerable numbers. In 1939, the Air Corps was desperate to get new fighters quickly and in large numbers, and more promising designs such as the P-38 were at least two years away from production.

The first production aircraft were delivered in early 1940 and proved able to reach 357 mph (575 km/h) at 15,000 feet (4600 m). However, this model lacked armor or self-sealing fuel tanks and was relatively lightly armed, with two cowling 0.50 machine guns and two wing 0.30 machine guns. Pilot armor and self-sealing tanks were added in the P-40B, at significant cost in speed and climb rate. By the time war broke out in the Pacific, Curtiss was producing the P-40E, which used an improved Allison engine, gave better cockpit visibility, improved the armament, and incorporated a number of other refinements. Although it never became an official capability, some U.S. air units in China were improvising bomb racks for 1000lb (454 kg) bombs for the P-40 by 1943.

Because of its poor high-altitude performance, the P-40 almost always had to surrender the initiative to higher-flying opponents. Here its ruggedness and protection were critical to allowing it to survive the enemy's first pass. Pilots who understood its strengths and weaknesses, such as Australian Clive Caldwell (20.5 kills), were able to make good use of the aircraft; but the consensus of aviation historians is that the P-40, though it was continually improved, never became a great aircraft.

Those exported to the British were known as Tomahawks or Kittyhawks.

About 63% of P-40 squadrons were deployed to the Pacific, and the P-40 continued in service in China until the surrender.