At a very early stage, the Curtiss P-40 attracted the attention of foreign air forces. On May 10, 1939, the French government ordered 140 export versions of the P-40 for the Armee de l"Air. These aircraft were designated Hawk 81-A1 by the manufacturer. The Hawk 81-A1s were identical to the US P-40 except that they had French instruments and equipment and were equipped with reverse-movement "French-fashion" throttles.
The first of the French-ordered H81-A1s flew on June 6, 1940, and a few were actually completed with French markings. However, before any of their H81-A1s could be delivered, France had surrendered. Britain agreed to take over the entirety of the French order, and gave the H81-A1 the name Tomahawk I in RAF service. RAF serials were AH741/AH840 and AH841/AH880.
In September of 1940, the USAAC agreed to defer deliveries of their P-40s so that the Tomahawk Is could be supplied to Britain as soon as possible. The first Tomahawk Is reached England in September of 1940. The two 0.5-inch machine guns in the nose were retained, but they were supplemented by four wing-mounted 0.303-inch Browning machine guns in place of the 7.5-mm FN-Brownings originally specified by the French. Such was the urgency of their delivery to Britain that many of the 140 machines still had French instruments and bore cockpit lettering in French when they arrived.
This was in the days before Lend-Lease, and so the aircraft had only RAF serial numbers and markings, and were not issued USAAC serials or designations. The Curtiss construction numbers were 14446/14545 and 14091/14130. RAF serials were AH741/AH880. At least three (AH774, AH793, and AH840) were retained in Canada but still retaining their RAF serials.
However, Britain quickly concluded that these planes were not suitable for combat, since they lacked armor protection for the pilot, armor-glass windshields, or self-sealing fuel tanks. Nevertheless, since a German invasion was feared to be imminent, they were actually issued to several operational squadrons.
However, the Hun never invaded England, and so the Tomahawk Is were used only for training roles within Britain. Overseas, the first Desert Air Force squadron to be equipped with Tomahawks was No. 112 which exchanged its Gloster Gladiators for the Curtiss fighter. No 112 Squadron became famous for its "shark's tooth" insignia on the engine cowling, and this scheme was later adopted by the American Volunteer Group in China
Tomahawk II was the designation given to a new and improved export Tomahawk, one which was better equipped for combat. It was functionally equivalent to the P-40B and P-40C then being issued to USAAC units. Unfortunately, some discrepancies exist in Curtiss records matching Tomahawk designations to RAF serial numbers and correlations to P-40s.
The Tomahawk IIA (Model H81-A2) was generally equivalent to the US P-40B. It had protective armor and externally-covered self-sealing tanks. 110 were built for the RAF under a direct-purchase contract. . RAF serials were AH881/990, with Curtiss construction numbers being 14131/14220 and 14582/14601. It carried four 0.303-inch machine guns in the wings in addition to the two 0.50-in guns in the fuselage. A British radio was fitted. Tomahawk IIA AH938 was transferred to Canada as an instructional airframe. AH936, 952, 965/971, 974/895, 987, 989, and 990 were delivered to the Soviet Union.
The Tomahawk IIB (Model H81-A2) was generally equivalent to the US P-40C. It had four 0.303-inch Browning machine guns in the wings in addition to the two nose-mounted 0.50-in guns. Whereas the Tomahawk IIA had a British radio, the Tomahawk IIB had US equipment. The British did not like the externally sealed tanks of the Tomahawk IIA, so these were replaced by internally-sealed tanks on the Tomahawk IIB. A total of 930 of these planes were produced in four lots. RAF serials were AH991/999 (c/n 14658/14666), AK100/570 (c/n 14582/14951, 15243,/15522), AM370/519 (c/n 15823/15972), and AN218/517 (c/n 17817/18116). AK210/224 and AK226/241 were lost at sea in transit.
After the German invasion of the USSR in June 1941, one hundred and ninety-five Tomahawk IIBs were shipped to the USSR. Some were shipped directly from the USA, others were selected from the reserve forced based in the United Kingdom in anticipation of the German invasion which never came. I don't have a full listing of all the Tomahawks that were diverted to the USSR, but AH1991/999 and AN469/517 are among the list. These Russian Tomahawks went into action on the Moscow and Leningrad fronts in October 1941, and were the first US-built planes to be used by the Russians in the new battle area.
An unspecified number of Tomahawk IIBs were sent to bolster Turkish neutrality in November 1941. It is curious to note that Turkey was supplied with planes from both the Allies and the Axis during World War II.
AK254, 434, 40, 448, 470, and 561 were transferred from the RAF to the Royal Egyptian Air Force.
The Tomahawk IIs were active in the Middle East from October of 1941 onward. They shared in the strafing of the retreating Axis troops. The ability of the Tomahawk to absorb an incredible amount of punishment became almost legendary. They served with Nos 2, 26, 73, 112, 136, 168, 239, 241, 250, 403, 414, 430 and 616 Squadrons of the RAF. They also served with Nos 2 and 4 Squadrons of the South African Air Force and No 3 Squadron of the Royal Australian Air Force. At low altitudes, the Tomahawk II was actually superior to the Bf 109, but this advantage rapidly disappeared when combat took place at altitudes above 15,000 feet. The weight which handicapped the performance of the Tomahawk did have one tangible benefit--the rugged structure could absorb a terrific amount of battle damage and still allow the airplane to return to base. Although generally outclassed by the Bf 109, the Tomahawk was a capable fighter in the hands of experienced pilots such as Neville Duke. Wing Commander Clive Caldwell of the RAAF scored 15.5 kills while flying a Tomahawk in the Middle East (his other 5 victories were with a Kittyhawk). However, much of the opposition to the Tomahawk was provided by obsolescent fighter biplanes (e.g. Fiat CR-42) and underpowered, lightly armed fighter monoplanes such as the Fiat G-50 of the Regia Aeronautica. It had difficulty with the more advanced Macchi C-202 Folgore.
Perhaps the best-known aircraft of the Tomahawk series were those supplied to the American Volunteer Group (AVG)--the famous Flying Tigers. In 1941, the Chinese government asked for US military assistance in its fight against the Japanese invaders. President Franklin Roosevelt wanted to help out as much as he could, but almost the entire US aircraft production at that time was dedicated to American and British production. Nevertheless, because of the urgency of the situation, the British agreed to exchange 100 of the Tomahawk IIBs on order for later model Kittyhawk Is. These Tomahawk IIBs were then diverted to China. Since US law at the time allowed only for cash-and-carry sales of arms to belligerents, A China-based corporation known as the Central Aircraft Manufacturing Company (or CAMCO) was formed to purchase these aircraft.
There persist to this day some confusion about which version of the Tomahawk that was actually delivered to China. Was it the Tomahawk IIA (equivalent to P-40B) or Tomahawk IIB (equivalent to P-40C)? Curtiss company records list them as Model H81-A3, which would seem to make them Tomahawk IIBs (equivalent to the P-40C). There are some discrepancies between Curtiss records matching Tomahawk designations to RAF serials and to equivalent US Army P-40 models, so there is confusion on this point. However, the AVG planes couldn't be Tomahawk IIAs, since only 172 of these were built and there is no record of any of them being delivered from the RAF to China. Therefore, many historians have concluded that the AVG planes had to have been Tomahawk IIBs, which would make them equivalent to the USAAF P-40C. However, Erik Shilling, who was a member of the AVG and who was also a flight leader and an engineering officer for the group, maintains that the airplanes with the AVG were actually export models of the P-40B and not the C. After all, he was there and he ought to know! He says that the Flying Tiger airplanes did not have the equipment to carry the external 52-gallon drop tank, nor were they equipped with bomb shackles. In addition all of the fuel tanks had external self-sealing material, not internally-mounted sealing material as in the "C" model. Also the Model "C" had armor plate in the front, ahead of the pilot, installed on the firewall between the two fifties, but the AVG's planes did not.
The resolution of the problem seems to be be in the fact that the AVG Tomahawks were actually built to a special order. The planes were indeed diverted from Tomahawk IIB contracts, which was equivalent to the P-40C, but when the the planes were actually built they were equipped with the externally-sealed fuel tanks that had been used on the Tomahawk IIA. It seems that Curtiss had some surplus externally-sealed fuel tanks lying around that the British did not want, and decided to use them on the Chinese contract. In addition, the Chinese contract did not specifically ask for plumbing or shackles for an external fuel tank, so this was deleted. Consequently, the AVG Tomahawks were functionally equivalent to Tomahawk IIAa, even though they were taken from a Tomahawk IIB production batch. So they are basically P-40Bs and not P-40Cs.
It is with the Flying Tigers that the P-40 achieved immortality. Newly-promoted to Brigadier General in the Chinese Army, Claire Chennault went to the USA in November 1940 to recruit pilots for the AVG. The AVG came into existence in August 1941, and was backed by the US government in recognition of China's fight against the invading Japanese. The Tomahawks on the Chines order were shipped to Rangoon, Burma, arriving in June of 1941. They were reassembled there and were flown to the AVG base at Toungoo, Burma, where they were intended to defend the Burma Road between Chungking and Lashio. After Pearl Harbor, the AVG moved to Kunming. By the time of Pearl Harbor, some 80 American pilots were serving with the AVG based at Kunming and Mingaladon. Contrary to popular understanding, the AVG did not actually enter combat until AFTER Pearl Harbor. The famous "shark's teeth" marking did not originate with the Flying Tigers, but was adapted from the markings used by the Tomahawks of the RAF's No. 112 Squadron in North Africa.
The AVG drew first blood on December 20, destroying six out of ten attacking Japanese Ki 21 bombers. When the AVG encountered Japanese fighters for the first time, they initially underestimated the maneuverability of their opponents, and they lost two pilots on December 23. It was soon learned that it was wise not to mix it up with Japanese fighters on a one-to-one basis because of the inferior maneuverability and climb rate of the Curtiss, but instead to use the P-40's superior speed and diving ability to maximum advantage. The most effective tactic against the Japanese was found to be a diving pass followed by a rapid exit from the scene. The Tomahawk gained a reputation for ruggedness which enabled many an AVG pilot to return safely home after his plane was damaged in combat. However, the stress of combat and lack of spares had taken their toll, and by March of 1942, only 20 Curtiss machines were serviceable. At that time, 30 P-40Es were issued to the AVG. By the time that the AVG was incorporated as the 23rd Fighter Group of the USAAF in July 1942, the AVG pilots had clamed 286 confirmed kills, with four Curtiss machines having been lost in combat. However a lot more had been lost in Japanese strafing attacks and many had to be cannibalized to keep others in the air.
Contrary to popular myth, the AVG Tomahawks never encountered the Japanese A6M Zero-sen in combat. At that stage in the war, all the Zeros had been moved out of China and eastward into the Pacific or southward to the Netherlands East Indies. The fighter that the Tomahawks actually encountered was the Japanese army fighter, the Nakajima Ki 43 Hayabusa (code named Oscar). However, at that stage of the war, virtually every Japanese single-seat fighter was called a "Zero"
An ex-Soviet P-40C has been restored in the livery of Erik Shilling's AVG machine (number 71). It had been delivered to the Soviet Union early in the war and had been shot down but had been recovered and shipped to England. It was later sent to the United States to be restored at Chino, California.