The Curtiss Mohawk IV was the most numerous version of the Hawk 75 to enter RAF service, and saw front line service with the RAF in India and with the South Africa Air Force in East Africa.
The RAF's Mohawk IVs came from at least three different sources. The majority of them were part of a French order for 795 Hawk H75A-4s. These were powered by a 1,200hp Wright R-1820-G205A Cyclone engine, replacing the Pratt & Whitney engines of the earlier French aircraft and the Mohawk I, II and III. They were armed with six 7.5mm guns, two in the nose and four in the wings.
A total of 284 aircraft were completed to this specification. Of these aircraft six reached France, four were lost at sea and twenty three were sent to Martinique, where they sat out the war. This left 251 that were taken over by the RAF, given British equipment and the designation Mohawk IV. They were joined by ten H75A-9s built for Persia, and at least six H75A-5s that were to have been built under licence in China but that were actually completed in India. This gives a total of 266 aircraft, although RAF records suggest that there were a total of 278 Mohawk IVs.
The Mohawk IV was not seen as suitable for service with the RAF in Britain. A number were given to Portugal, and more to the South Africa Air Force, but a significant number did see service with the RAF, operating over Burma from bases in India.
The Mohawk IV saw a surprising amount of service in India and Burma, where it remained in use until the start of 1944. The Japanese entry into the war found the RAF in the Far East very badly equipped, and their rapid conquest of Burma left India desperately short of fighter aircraft. So short in fact that No.5 Squadron was ordered to fair over the second cockpit on its Audax biplanes and use them as fighters!
At the end of December No.5 Squadron received its first Mohawk IVs, and by March 1942 it was operational with the type, providing fighter cover from its base at Dum Dum. The first clash with the Japanese came during their incursion into the Indian Ocean in April 1942. On 6 April a flight of Mohawks from No.5 Squadron found a force of three Japanese cruisers that had attacked a convoy, and claimed the destruction of a E8N 'Dave' floatplane (actually only damaged), the Mohawk's first victory for the RAF.
The squadron scored its first aerial victory on 20 August, when Sergeant Stuart Garnett shot down a Ki 27 'Nate' while returning from a mission over Burma. No.5 Squadron retained the Mohawk until June 1943, using for a mix of fighter defence, bomber escort and ground attack missions (using 20lb bombs).
No.146 Squadron was the second RAF squadron to operate the Mohawk in India, but it only used the type from March to April 1942, providing fighter defence for Assam, before passing the aircraft onto No.5 Squadron.
Finally No.155 Squadron used the type, getting it when it reformed in August 1942 (after a previous incarnation during the First World War) and retaining it until January 1944. No.155 Squadron used its Mohawks for reconnaissance, bomber escort duties and increasingly for ground attack.
Both main squadrons found that the Mohawk has a smaller turning circle than the Japanese Army's Ki-43 'Oscar', but direct clashes with Japanese fighters became less common during 1943, and the Mohawk was increasingly used for ground attack missions.
The Mohawk IV was used by five squadrons of the South African Air Force. No.5 Squadron received the Mohawk when it formed in South Africa in May 1941, before converting to the Curtiss Tomahawk at the end of the year when it moved to Egypt. No.7 Squadron followed the same pattern, receiving the Mohawk in January 1942 but converting to the Hurricane when it moved to Egypt in April-May 1942. No. 4 Squadron received a few Mohawks while it was based in Kenya in the summer of 1941, but replaced them with the Tomahawk when it moved to Egypt in September.
No.41 was the first South African squadron to use the type in combat. Most of the squadron was an Army Co-operation unit, equipped with the Hawker Hartbees, but starting on 1 September 1941 it gained one flight of Mohawks, which were used to form No.41 Squadron Fighter Detachment. On 5 October 1941 this detachment scored the only Mohawk victory in Africa. On 16-18 September three Mohawks from the detachment had moved up from Nairobi to the Kenya border town of Aiscia, to intercept Italian transport aircraft. After a series of unsuccessful missions on 5 October Captain Jack Parsonson found and destroyed a Savoia S.75 on the ground at Dkibouti.
Soon after this the detachment became 'B' Flight, No.3 Squadron. On 11 December a Potez 63 from Djibouti was damaged by Lt Gazzard, flying a Mohawk. Soon after that the squadron returned to South Africa.