Curtiss P-40B
Reviewed by Brad Hagen
Photos by: Raymond Chung, Vernon Rabbetts, Scott Murphy, Buz Busby
Curtiss knew that their radial engined P-36 couldn’t be developed any more, so to increase its life they decided in July 1937 to install an Allison V-1710 inline engine with integral supercharging. Curtiss gave it the designation of Model 75P and the USAAC gave it the designation of XP-40.
In order to adapt the liquid cooled Allison, a considerable amount of replumbing needed to be done. The carburetor intake for the single stage supercharger was installed on top of the nose between the nose guns, the oil cooler was mounted under the nose, and the radiator was located under the fuselage just aft of the wing.
The XP-40 flew for the first time on October 14, 1938, the early flight trials were disappointing and the radiator was gradually moved forward until it reached its final location. The new radiator intake was designed to include both the oil cooler and the two coolers for the ethylene/glycol engine coolant.
On January 25th, 1939 the manufacturers were invited to submit proposals for a new pursuit aircraft, Curtiss submitted their XP-40 and were up again such planes as the XP-39, the XP-43, and the XP-38. Even though the XP-40 couldn’t match the performance of some of the other types, it was chosen because it was based on already proven airframe, it was less expensive, and could reach production in quantity at least a year ahead of the others so on April 26, 1939, the Army ordered 524 production versions under the designation P-40 (Curtiss Model 81).
The P-40 was armed with two .50 machine guns in the nose and one .30 machine gun in each wing. Flush riveting was used to reduce drag. Since the P-40 lacked armor for the pilot, self sealing fuel tanks, and a bulletproof windshield, it was not considered suitable for combat and was pulled from combat duty on October 22, 1942.
There was no P-40A, although one aircraft was later given that designation when it was converted to a photo reconnaissance plane at Bolling Field in March, 1942.
In September, 1940, 131 P-40B’s (Model H81-B) were ordered by the Army and the first P-40B flew on March 31, 1941. This model received an additional .30 machine gun in each wing, armor plating, and externally covered self sealing fuel tanks. The British ordered 110 for the RAF and they went under the designation Tomahawk IIA (Model H81-A2).
The P-40C (Model H81-B) first flew on April 10, 1941 and there were 193 built. It received improved self sealing fuel tanks as well as a 52 gallon drop tank. The British ordered 930 and designated this version Tomahawk IIB (Model H81-A2) and they replaced the wing guns with four 0.303 Browning machine guns. The IIA had British radio’s installed, the IIB had US radios. 23 of the IIB’s went to the Soviet Union, and an unknown number went to Turkey and Egypt, 100 went to China, the rest were used heavily by the RAF and South African Air Force in the North African theatre where the 112 squadron of the RAF with its shark mouth insignia became famous.
The Flying Tigers gave the P-40 everlasting fame, but there has been a lot of confusion as to whether they used the P-40B or P-40C. It turns out that when the British deferred part of their order for the P-40C, Curtiss received the order for 100 planes from the Chinese and they had a number of the P-40B self sealing fuel tanks left over which they installed. Since the Chinese order didn’t specify drop tanks, they were left off. Even though they were technically P-40C’s, they were actually closer to P-40B’s in how they were equipped.
Tags: AVG, famous WWII aircraft, Flying Tigers, WWII China
