Finnish Curtiss P-36 Hawks or Hawk 75A
Curtiss P-36 Hawk
National origin:- United States Role:- Fighter Manufacturer:- Curtiss-Wright Corporation Location:- Buffalo, New York. First flight:- 16 May 1935 Retired:- 1954, Argentina Introduction:- 1938 Primary users:- United States Army Air Corps, Finnish Air Force, French Air Force, Royal Air Force Produced between 1939–1944:- 215 (P-36) plus 900 export Hawk 75 variants
245 (P-36) 600 (including Hawk 75 variants)
Unit cost:- $23,000 Development:- Developed into Curtiss P-40 Warhawk
The Curtiss P-36 Hawk, also known as the Curtiss Hawk Model 75, was an American-designed and built fighter aircraft of the 1930s and 40s. A contemporary of both the Hawker Hurricane and Messerschmitt Bf 109, it was one of the first of a new generation of combat aircraft—a sleek monoplane design making extensive use of metal in its construction and powered by a powerful radial engine.
Perhaps best known as the predecessor of the Curtiss P-40 Warhawk, the P-36 saw little combat with the United States Army Air Forces during World War II. It was nevertheless the fighter used most extensively and successfully by the French Armee de l'air during the Battle of France. The P-36 was also ordered by the governments of the Netherlands and Norway, but did not arrive in time to see action before both were occupied by Nazi Germany. The type was also manufactured under license in China, for the Republic of China Air Force, as well as in British India, for the Royal Air Force (RAF) and Royal Indian Air Force (RIAF).
Axis and co-belligerent air forces also made significant use of captured P-36s. Following the fall of France and Norway in 1940, several dozen P-36s were seized by Germany and transferred to Finland; these aircraft saw extensive action with the Ilmavoimat (Air Force) against the Soviet Air Forces. The P-36 was also used by Vichy French air forces in several minor conflicts; in one of these, the Franco-Thai War of 1940–41, P-36s were used by both sides.
From mid-1940, some P-36s en route for France and the Netherlands were diverted to Allied air forces in other parts of the world. The Hawks ordered by the Netherlands were diverted to the Dutch East Indies and later saw action against Japanese forces. French orders were taken up by British Commonwealth air forces, and saw combat with both the South African Air Force (SAAF) against Italian forces in East Africa, and with the RAF over Burma. Within the Commonwealth, the type was usually referred to as the Curtiss Mohawk.
With around 1,000 aircraft built by Curtiss itself, the P-36 was a major commercial success for the company. It also became the basis not only of the P-40, but two other, unsuccessful prototypes: the YP-37 and the XP-42.
Design and development
The Curtiss Model 75 was a private venture by the company, designed by former Northrop Aircraft Company engineer Don R. Berlin. The first prototype, constructed in 1934, featured all-metal construction with fabric-covered control surfaces, a Wright XR-1670-5 radial engine developing 900 hp (670 kW), and typical United States Army Air Corps armament of one .30 in (7.62 mm) and one .50 in (12.7 mm) machine gun firing through the propeller arc. Also typical of the time was the total absence of cockpit armor or self-sealing fuel tanks. The distinctive landing gear, which rotated 90° to fold the main wheels flat into the thin trailing portion of the wing, resting atop the lower ends of the maingear struts when retracted, was actually a Boeing-patented design for which Curtiss had to pay royalties.
The prototype first flew on 6 May 1935, reaching 281 mph (452 km/h) at 10,000 ft (3,000 m) during early test flights. On 27 May 1935, the prototype was flown to Wright Field, Ohio, to compete in the USAAC fly-off for a new single-seat fighter, but the contest was delayed because the Seversky entry crashed on its way there. Curtiss took advantage of the delay to replace the unreliable engine with a Wright XR-1820-39 Cyclone producing 950 hp (710 kW) and to rework the fuselage, adding the distinctive scalloped rear windows to improve visibility. The new prototype was designated Model 75B with the R-1670 version retroactively designated Model 75D. The fly-off finally took place in April 1936. Unfortunately, the new engine failed to deliver its rated power and the aircraft only reached 285 mph (459 km/h).
Although the competing Seversky P-35 also underperformed and was more expensive, it was still declared the winner and awarded a contract for 77 aircraft. However, on 16 June 1936, Curtiss received an order from USAAC for three prototypes designated Y1P-36. The USAAC was concerned about political turmoil in Europe, and about Seversky's ability to deliver P-35s in a timely matter, and therefore wanted a backup fighter. The Y1P-36 (Model 75E) was powered by a 900 hp Pratt & Whitney R-1830-13 Twin Wasp engine, and the scalloped rear canopy was further enlarged. The new aircraft performed so well that it won the 1937 USAAC competition with an order for 210 P-36A fighters.
The aircraft's extremely low wing loading of just 23.9 lb/ft² gave it outstanding turning performance,[N1] and its high power-to-weight ratio of 0.186 hp/lb gave superb climbing performance for the time. The lack of an engine supercharger was a serious handicap at high altitudes. Compared to the later Allison-engined P-40, the P-36 shared the P-40's traits of excellent high-speed handling, roll rate that improved at high speed, and relatively light controls at high speed. However, it was underpowered, affecting its acceleration and top speed, and it did not accelerate in a dive as well as the P-40.
In early 1937, the USAAC ordered Curtiss to adapt one P-36 to the new liquid-cooled turbo-supercharged Allison V-1710 engine with 1,150 hp (860 kW). Designated Curtiss XP-37, the aircraft used the original Model 75 airframe with radiators mounted on the sides of the fuselage around the engine. The cockpit was moved far to the rear to make room for the radiators and the bulky turbocharger system, and to balance the aircraft. The aircraft flew in April 1937, reaching 340 mph (550 km/h) at 20,000 ft (6,100 m). Although the turbo-supercharger was extremely unreliable and visibility from the cockpit on takeoff and landing was virtually nonexistent, the USAAC was sufficiently intrigued by the promised performance to order 13 service test YP-37s. Featuring improved aerodynamics and a more reliable turbo-supercharger, the aircraft first flew in June 1939. However, the powerplant remained unreliable and the project was cancelled in favor of another Curtiss design, the P-40.
In an attempt to improve the aerodynamics of the air-cooled piston engines, the fourth production P-36A (serial 38-004), designated the XP-42, was equipped with a long streamlined cowling resembling that of a liquid-cooled engine. Twelve different designs were tried with little success; although the aircraft was faster than a standard P-36A, engine cooling problems were never resolved. Since the new P-40 was faster, the project was canceled. Late in its service life, the sole XP-42 was fitted with a stabilator and used to study that control configuration.
Argentina bought a number of the simplified, fixed landing gear Hawk 75Os, (intended for rough-field operations and ease of maintenance) and purchased a manufacturing license for the type; 30 were built and delivered by Curtiss, and 20 produced locally. These aircraft used the same engine, Wright Cyclone R-1820-G5 as the Martin 139WAA's and Northrop 8A-2s used by the Argentine Army Aviation at the time. Usually armed with one 11.35 mm (0.45 in) Madsen machine gun and three 7.65 mm (0.30 in) Madsen light machine guns, there was provision for up to 10 30 lb (14 kg) bombs on underwing pylons. The last Argentinian Hawks remained in service until November 1954.
In March 1942, 10 USAAC P-36As were transferred to Brazil.
The Royal Air Force (RAF) also displayed interest in the aircraft. Comparison of a borrowed French Hawk 75A-2 with a Supermarine Spitfire Mk I revealed that the Hawk had several advantages over the early variant of the iconic British fighter. The Hawk was found to have lighter controls than the Spitfire at speeds over 300 mph (480 km/h), especially in diving attacks, and was easier to maneuver in a dogfight (thanks to the less sensitive elevator) and better all-around visibility. The Hawk was also easier to control on takeoff and landing. Not surprisingly, the Spitfire's superior acceleration and top speed ultimately gave it the advantage of being able to engage and leave combat at will.
Although Britain decided not to purchase the aircraft, they soon came in possession of 229 Hawks by way of diverted shipments to occupied France and aircraft flown by escaping French pilots. The aircraft received the designations Mohawk I through IV, mirroring French Hawk 75A-1 through A-4, and were fitted with 0.303-cal. Vickers K machine guns and conventional throttles (forward to increase power).
Although they were considered obsolete, a number saw service with the RAF and Royal Indian Air Force (RIAF) in India and Burma. In April 1941, the British government of India ordered 48 Cyclone-powered Mohawk IVz (Hawk 75A) for the RIAF, to be built by Hindustan Aircraft. The first such aircraft completed was test flown on 31 July 1942. However, only four additional aircraft were completed before the project was abandoned. The Indian-built series were used by RAF/RIAF units. Similarly, Chinese license production of the Hawk 75A-5 was moved to India, and these aircraft were also absorbed into RAF as Mohawk IVs. These aircraft were supplemented by 10 Hawk 75A-9s captured during the Anglo-Soviet invasion of Iran in August 1941, while 74 ex-French Mohawk IVs were shipped to India from the United Kingdom. The only RAF units to see combat in Mohawks were No. 5 Squadron RAF and No. 155 Squadron RAF, using the type mainly for Bomber escort and ground attack. The type was retired by the RAF/RIAF in 1944.
The South African Air Force received 72 Mohawks. Its first Mohawks were delivered to East Africa in mid-1941, where they were used by 3 Squadron SAAF to support operations in the East African Campaign, taking part in the Battle of Gondar which ended the campaign, and helping to patrol the border with Vichy French held Djibouti. These Mohawks were then sent to South Africa, where, supplemented by fresh deliveries, they were used for training and for home defence.
The prototype of the Hawk 75H—a simplified version with fixed landing gear, like the 75O—was eventually sold to the Chinese Nationalist government who presented it to Claire L. Chennault for personal use. China also received two similar demonstrators, the Hawk 75Q. They also used a number of simplified Hawk 75Ms against the Japanese. The Hawk 75A-5 was built under license in China, but production was later moved to India, and these aircraft were absorbed into the RAF as the Mohawk IV.
After the fall of France, Germany agreed to sell captured Curtiss Hawk fighters to Finland in October 1940. In total, 44 captured aircraft of five subtypes were sold to Finland with three deliveries from 23 June 1941 - 5 January 1944. Not all were from the French stocks, 13 were initially sold to Norway and captured when the Germans conquered that country. The aircraft were given serial codes CU-501 to CU-507 (A-4 submodel with Cyclone) and CU-551 to CU-587 (all other submodels with Twin Wasp).
In Finnish service, the Hawk was well liked, affectionately called Sussu ("Sweetheart"). The Finnish Air Force enjoyed success with the type, credited with 190⅓ kills by 58 pilots, between 16 July 1941 and 27 July 1944, for the loss of 15 of their own. Finnish ace Kyösti Karhila scored 12¼ of his 32¼ victories in the Hawk, while the top Hawk ace K. Tervo scored 14¼ victories.
The Finnish Hawks were initially armed with either four or six 7.5mm machine guns. While sufficient during the early phase of the Continuation War, the increasing speeds and armor of Soviet aircraft soon showed this armament was not powerful enough. From 1942, the State Aircraft Factory replaced the fuselage machine guns with either one or two .50 in (12.7 mm) Colt machine guns and installed two or four .303 in (7.7 mm) Browning machine guns in each wing. The 12.7mm Berezin UB or LKk/42 heavy machine guns were also used. The installation of heavier armament did not change the very good flying characteristics of the fighter, but the armament was much more effective against Soviet aircraft. The Finnish Hawks were also equipped with Revi 3D or C/12D gunsight.
Surviving Finnish aircraft remained in service with the FAF aviation units HLeLv 13, HLeLv 11 and LeSK until 30 August 1948, when the last operational Finnish Hawks were put into storage. In 1953, the stored aircraft were scrapped.
Even before the P-36A entered production, the French Air Force entered negotiations with Curtiss for delivery of 300 aircraft. The negotiating process ended up being very drawn-out because the cost of the Curtiss fighters was double that of the French Morane-Saulnier M.S.406 and Bloch MB.150, and the delivery schedule was deemed too slow. Since the USAAC was unhappy with the rate of domestic deliveries and believed that export aircraft would slow things down even more, it actively opposed the sale. Eventually, it took direct intervention from U.S. President Franklin Roosevelt to give the French test pilot Michel Detroyat a chance to fly the Y1P-36.
Detroyat's enthusiasm, problems with the MB.150, and the pressure of continuing German rearmament finally forced France to purchase 100 aircraft and 173 engines. The first Hawk 75A-1 (or H75A-1 n°1) arrived in France in December 1938 and began entering service in March 1939. Few months later, this aircraft was part of "Groupe de Chasse II/5 La Fayette" (heir of the Escadrille Lafayette that fought in France during World War I) and was wearing the famous Sioux Head on its fuselage side. After the first few examples, aircraft were delivered in pieces and assembled in France by the Société Nationale de Constructions Aéronautiques du Centre. Officially designated as the Curtiss H75-C1 (the "Hawk" name was not used in France), the aircraft were powered by Pratt & Whitney R-1830-SC-G engines with 900 hp and had instruments calibrated for the metric system, a seat for French dorsal parachutes, a French-style throttle which operated in reverse from U.S. and British aircraft (full throttle was to the rear rather than to the front) and armament of four (later models had six with two firing through the prop and four in the wings) 7.5 mm FN-Browning machine guns, aimed with a French-supplied Baille-Lemaire gun sight. The aircraft evolved through several modifications, the most significant being the installation of the Wright R-1820 Cyclone engine. The H75-C1 variant saw little operational use due to its late delivery and reliability problems with the Wright radial engine. A total of 316 H75s were delivered to France before the German occupation.
On September 20, Sergeant André-Armand Legrand, pilot of the H75A-1 n°1 in the Groupe de Chasse II/5 La Fayette was credited of the first Allied air victory of World War II on the Western front with shooting down one Messerschmitt Bf 109E of the Luftwaffe 3/JG 53, over Überherrn. During 1939–1940, French H75 pilots claimed 230 air-to-air kills (of a total of 1,009 air-to-air kills by the French Air Force during the 1939-40 time period) and 81 probable victories in H75s against only 29 aircraft lost in aerial combat. While making up only 12.6% of the French Air Force single-seater fighter force, the H75 accounted for almost a third of the air-to-air kills during the 1940 Battle of France. Of the 11 French aces of the early part of the war, seven flew H75s. The leading ace of the time was Lieutenant Edmond Marin la Meslée with 15 confirmed and five probable victories in the type. H75-equipped squadrons were evacuated to French North Africa before the Armistice to avoid capture by the Germans. While under the Vichy government, these units clashed with British aircraft over Mers el-Kébir and Dakar. During Operation Torch in North Africa, French H75s fought against U.S. Navy F4F Wildcats, losing 15 aircraft while shooting down seven American aircraft. From late 1942 on, the Allies started re-equipping the formerly Vichy-controlled French H75 units with P-40s and P-39s.
A total of 10 Hawk 75A-9s were delivered to Persia, but were captured by the British while still in crates. These were then used by the RAF in India as Mohawk IVs.
Dutch East Indies
In October 1939, The Netherlands ordered 24 Hawk 75A-7s for their Oost Indië colonies or the Dutch East Indies. These planes were powered by 1,200 hp Cyclones. Factory armament was one .50 and one .303 MG in the cowl with two .303 MGs in the wings. After delivery, the .50 cowl MGs were replaced to standardize parts and ammo. The plane could carry six 23 kg bombs. The fighters were shipped in 1940 and almost rerouted to the Netherlands when Germany invaded. But as the mainland surrendered, the aircraft came to the colonies where they were used extensively against the Japanese attack on the Far Eastern part of the kingdom. By that time, the aircraft had flown so many hours that the engines were showing serious wear and tear.
Most Dutch Hawks were assigned to the 1ste JachtVliegAfdeling - VliegtuigGroep IV (1ste JaVA - 1-VlG IV; "1st Fighter Squadron - Flying Group IV") of the ML-KNIL, although some flew with 1-VlG V. These aircraft saw action over Malacca, Sumatra and Java, successfully bombing the railroad and intercepting bombers and participated in the extensive dogfights over Soerabaja, where USAAF, RAF and ML aircraft fought Japanese bombers and fighters together.
Norway ordered 24 Twin Wasp-powered Hawk 75A-6s, of which 19 were delivered and seven assembled at the time of the German invasion. None of the aircraft were combat-ready. The disassembled aircraft were disabled by a single customs employee who smashed the instruments and cut all the wires he could reach. Thirteen Norwegian Hawks captured by the Germans were part of the first batch of 29 P-36s sent to Finland. Norway also ordered 36 Cyclone-powered Hawk 75A-8s. Most of this batch (a total of 30) were delivered as advanced trainers to "Little Norway" near Toronto, Ontario, Canada, a Norwegian training base established by the London-based government-in-exile. Still later, they were resold to the U.S. and redesignated the P-36G model.
In 1943, the U.S. sent 28 Hawks to Peru under the Lend-Lease agreement. These were ex-Norwegian P-36Gs that had served in Canada.
Portugal was officially neutral during World War II, although the Allies were allowed to use or establish ports and airfields on various Portuguese territories. One result of these friendly relations was the transfer by the British government of 12 Hawk 75A variants to the Força Aérea Portuguesa (FAP), which assigned them to air defense duties in the Azores.
A few Hawk 75Ns were used by Thailand during the French-Thai War. They also fought at the Battle of Prachuab Khirikhan against Japanese forces during the Japanese Invasion of Thailand. On 28 January 1941, the Royal Thai Air Force (RTAF) dispatched nine Ki-30 Nagoyas, escorted by three Hawk 75s, to bomb Pailin and Sisophon in French Indochina. Thailand was perhaps the only country operating both Japanese and American aircraft just before World War II.
The first production P-36As were delivered to the 20th Pursuit Group at Barksdale Field in Louisiana in April 1938. The aircraft's service history was marred by numerous teething problems with the engine exhaust, skin buckling over landing gear, and weak points in the airframe, severely restricting the performance envelope. By the time these issues were resolved, the P-36 was considered obsolete and was relegated to training units and overseas detachments at Albrook Field in the Canal Zone, Elmendorf Field in Alaska, and Wheeler Field in Hawaii.
The P-36s had been delivered to Hawaii in February 1941 by being loaded on the carrier the USS Enterprise in California, then in a first for the USAAC, flown off the carrier's deck by the P-36's U.S. Army Air Corps pilots when the Enterprise neared the coast of Hawaii. This saved considerable time over the traditional shipping method of having the fighters first disassembled, crated and then loaded by crane in the hold of a freighter, then unloaded and reassembled in Hawaii.
The only combat by U.S.-operated P-36s took place during the Pearl Harbor attack. Five of the 39 P-36A Hawks at Pearl Harbor, delivered previously by the USS Enterprise, were able to take off during the attack and were credited with shooting down two Japanese Mitsubishi A6M2 Zeros for the loss of one P-36, among the first U.S. aerial victories of World War II.
Company-owned demonstrator aircraft flown with several engine fits
Prototype with Wright R-1820 radial engine
First prototype, Wright Whirlwind R-1670 radial
Internal company designation for a simplified export version with fixed landing gear, two slightly differing aircraft built, first sold to China, second to Argentina
Company designation for the P-37.
Company-owned 75A temporarily fitted with an external supercharger
Unbuilt version, intended to use the Pratt & Whitney R-2180 Twin Hornet radial.
Production P-36A (serial 38-010) fitted with Allison V-1710 liquid-cooled engine, prototype for Curtiss P-40
Company-owned 75A temporarily fitted with R-1830-SC2-G with turbo-supercharger, attained 330 mph (530 km/h) but proved complex and unreliable
Y1P-36 (Model 75E)
USAAC prototype, Pratt & Whitney R-1830
P-36A (Model 75L)
USAAC version, P-36A-3 mounted four .30 in (7.62 mm) machine guns in the wings in addition to fuselage armament
production P-36A fitted with an R-1830-25 producing 1,100 hp (820 kW), reached 313 mph (504 km/h), returned to original P-36A configuration
An additional 0.30 in machine gun installed in each wing with external ammunition boxes under the wings, R-1830-17 of 1,200 hp (890 kW); last 30 production aircraft were completed as P-36Cs
Production P-36A modified with two .50 in (12.7 mm) machine guns in the nose and four 0.30 in machine guns in the wings
Production P-36A armed with four 0.30 in machine guns in the wings, retained standard fuselage guns
Production P-36A fitted with two 23 mm (0.91 in) Madsen autocannons under the wings, reverted to P-36A because guns imposed an unacceptable performance penalty with top speed of only 265 mph (426 km/h).
Hawk 75A-8 used by Norway for training in Canada; later delivered to Peru. R-1820-G205A of 1,200 hp.
First production batch for France, four 7.5 mm (0.295 in) machine guns, R-1830-SC-G of 900 hp (670 kW); 100 built
Second production batch for France, either R-1830-SC-G or 1,050 hp (780 kW) R-1830-SC3-G, six 7.5 mm machine guns; 100 built
Third production batch for France, similar with Hawk 75A-2; 135 built (133 delivered).
Last production batch for France, Hawk 75A-2 with Wright R-1820-G205A Cyclone radial with 1,200 hp: 285 built, 81 delivered to France; others to Great Britain as Mohawk IV
Similar to Hawk 75A-4. Built under license in China (production was later moved to India), absorbed into RAF as Mohawk IV
Version for Norway; aircraft captured during the German invasion were eventually sold to Finland
Version for Netherlands East Indies: 1,200 hp Cyclone, one .5 in (12.7 mm) and one .303 in (7.7 mm)in cowl and two .303 in (7.7 mm)in wings; later four .303 in (7.7 mm) (two in nose, one in each wing) and six 50 lb (23 kg) bombs.
Export version for Norway. Later redesignated P-36G.
10 aircraft delivered to Persia, captured still in crates and used by RAF in India as Mohawk IVs
Simplified version with fixed landing gear and Wright R-1820 Cyclone for China, built by both Curtiss and Central Aircraft Manufacturing Company in China
Simplified version for Siam (Thailand) with non-retractable landing gear and wheel pants.
Simplified version for Argentina, 30 built and delivered by Curtiss with additional 200 to be built under license locally by Fabrica Militar de Aviones, however only 20 were completed.
Two additional simplified demonstrators for China. At least one is reputed to have been given an armament similar to that of the XP-36F and to have engaged in combat over Shanghai during the Japanese attacks in September 1937, reportedly shooting down several bombers before being brought down with the loss of the American pilot.
Allison V-1710 inline, cockpit moved to the rear of the fuselage
Service test version of XP-37, 13 built
XP-42 (Model 75S)
Testbed for streamlining cowlings around air-cooled engines
P-36A at National Museum of the United States Air Force
H75C-1 at Duxford, United Kingdom
P-36A (s/n 38-001, the first P-36 to be delivered to the Air Corps) is on display at the National Museum of the United States Air Force at Wright-Patterson AFB in Dayton, Ohio. It is displayed in the markings of the P-36A flown by then-2nd Lt Phil Rasmussen (Lt Col USAF (Ret)) during the Japanese attack on Pearl Harbor.
A complete and restored Hawk 75N survives in the Royal Thai Air Force Museum; unknown serial number.
A French H75C-1 has been restored to flying condition and is owned by The Fighter Collection at Duxford, United Kingdom. It has been flown and is shown in French camouflage with markings on either side, for the same example (n°82) at two different periods in its career.
In addition, Duxford is also home to a P-36C (s/n 38-210, the last P-36 to be constructed), which was acquired by the Fighter Collection and restored to airworthy condition in Chino, California, in 2015. Shortly after the completion of its restoration it was shipped over to its new home at Duxford in June. It is painted in US Army Air Corps silver and yellow.
A Hawk 75 is under restoration to fly at Omaka Aerodrome, Blenheim, New Zealand with a private owner.
Specifications Specifications (Curtiss P-36A)
Data from Curtiss Fighter Aircraft: A Photographic History 1917–1948
Length: 28 ft 6 in (8.7 m) Wingspan: 37 ft 4 in (11.4 m) Height: 8 ft 5 in (2.6 m) Wing area: 235.94 ft² (21.92 m²) Empty weight: 4,567 lb (2,076 kg) Loaded weight: 5,650 lb (2,560 kg) Max. takeoff weight: 6,010 lb (2,732 kg) Powerplant: 1 × Pratt & Whitney R-1830-17 Twin Wasp air-cooled radial piston engine, 1,050 hp (783 kW) Performance Maximum speed: 313 mph (272 knots, 500 km/h) at 8,500 ft, 2,960 m Cruise speed: 270 mph (235 knots, 432 km/h) Range: 625 mi (543 nmi, 1,006 km) at 270 mph (419 km/h), 860 mi (748 nmi, 1,385 km) at 200 mph Service ceiling: 32,700 ft (9,967 m) Rate of climb: 3,400 ft/min (17 m/s) Wing loading: 23.9 lb/ft² (116.8 kg/m²) Power/mass: 0.186 hp/lb (306w/kg) Armament 1 × 0.30 in (7.62 mm) M1919 Browning machine gun
1 × 0.50 in (12.7 mm) M2 Browning machine gun
later production variants had two .50 MGs synchronized with the propeller mounted in the engine cowl and two or four .30 MGs mounted in the wings just outside the propeller arc some were also later fitted with a single hardpoint under each wing that could carry a bomb of up to 100 lb (45 kg) or a light bomb rack for three 50 lb (23 kg), five 20 lb (9 kg) or 30 lb (14 kg) bombs
The Curtiss P-36 was the first of the new generation of monoplane fighters to enter service with the USAAC. It was a contemporary of the Supermarine Spitfire, the Hawker Hurricane, and the Messerschmitt Bf 109, all of which were introduced within a few months of each other in the mid 1930s. Even though the P-36 owed very little to previous Curtiss biplane pursuits, the name *Hawk* was still generally applied to the aircraft.
The P-36 pursuit had its origin in the Model 75 project which was originally developed as the Curtiss entry in the US Army pursuit aircraft competition scheduled for May 1935. Curtiss lost the initial contest but was the real winner in the end, with 227 examples sold to the USAAC, 753 exported, and at least 25 built under license in other countries.
The Model 75 owed relatively little to previous Curtiss designs. The principal designer was Donovan A. Berlin, who had come over to Curtiss from Northrop, and the structure of the Model 75 was heavily influenced by earlier Northrop designs. The prototype carried the civilian registration of X-17Y. The Model 75 was an all-metal low-wing monoplane, with the metal-frame moveable control surfaces being fabric covered. The cockpit was enclosed by a sliding canopy, with the canopy being faired into a high rear turtledeck. Both the main undercarriage units and the tailwheel retracted, the main legs rotating backward 90 degrees and turning 90 degrees on their axes simultaneously to lay the wheels flat in the thin rear portion of the wing. This retraction mechanism had originally been developed by Boeing, which received a royalty whenever any other aircraft manufacturer used it. The wing was built in two halves joined on the aircraft's centerline. Portions of the outer wing structure were sealed to provide flotation in case of a forced landing in water. Hydraulically-actuated split flaps were fitted to the trailing edge of the wing. Initial armament was the standard US fighter armament of the time--one 0.30-in and one 0.50-in machine guns under the forward fuselage deck, firing through openings in the top of the cowling. No armor protection or self-sealing fuel tanks were fitted.
Prototype construction began in November 1934. Initially, the aircraft was powered by the unfortunate 900 hp Wright XR-1670-5 (SCR-1670-G5) twin-row air-cooled radial. The first flight of the Model 75 took place in May of 1935. During early tests, the prototype had demonstrated a maximum speed of 281 mph at 10,000 feet, a service ceiling of 30,000 feet, and a range of 537 miles. Weights were 3760 lbs empty, 4843 lbs gross. Length was 28 feet 3 1/2 inches, wingspan was 37 feet 0 inches, and wing area was 237 square feet.
On May 27, 1935, Curtiss submitted the Model 75 to the USAAC Material Division's single seat fighter competition which was to be held at Wright Field that very month. However, the Model 75 was the only competitor ready in time for the scheduled flyoff. The primary competitor, the two-seat Seversky SEV-2XP, had been "heavily damaged" during delivery to Wright Field, and did not arrive there until June 18. The SEV-2XP was soon returned to the Seversky factory where it was reworked into a single seater with retractable undercarriage. The competition was delayed until the SEV-1XP could be ready. It finally arrived at Wright Field on August 15, bearing the designation SEV-1XP. The only other serious competitor, the Northrop 2A had taken off on its maiden flight on July 30, headed out over the Pacific, and promptly disappeared into thin air, never to be seen again.
Curtiss protested that this delay had given the Seversky competitor an unfair advantage, and convinced the Army that it should defer its decision until after a further competitive evaluation which was to take place in April of 1936. During the early flight tests, the XR-1670-5 engine which powered the Model 75 had proven itself to be totally unsatisfactory. Don Berlin took the opportunity afforded by the delay to replace this engine by a 700 hp Pratt & Whitney R-1535. Since this engine model had passed its peak of development, a nine-cylinder single-row Wright XR-1820-39 (G5) Cyclone radial was quickly substituted. This engine was rated at 950 hp for takeoff and at 850 hp normal maximum output. With this engine, the prototype was designated Model 75B (Model 75A had been reserved for the export version of the Hawk). In its final form, the Model 75B had a strengthened cockpit canopy and introduced a scalloped aft fuselage decking behind the cockpit for a somewhat improved rear view.
The new Cyclone radial of the Model 75B proved to be almost as unsatisfactory as its R-1670 predecessor, and failed to deliver its full rated power. There were no fewer than four engine changes during the Wright Field trials. In addition, there were problems with incompatibility between the engine and the airframe. The Model 75B proved capable of attaining only 285 mph (versus the 294 mph at 10,000 feet guaranteed by Curtiss-Wright). Even though the Seversky entry also fell short on promised performance and in addition was more expensive than the Curtiss entry, the Model 75B lost out to the Seversky competitor, which won an order for 77 examples under the designation P-35.
Even though the prototype Model 75 never became Army property, some sources refer to the various configurations of this aircraft under the collective designation "XP-36". This was a matter of historical convenience only, since there never was any such official designation. The original configuration of the Model 75 prototype with the 900 hp Wright SCR-1670-G5 radial was given the retroactive company designation of Model 75D. The prototype aircraft was later rebuilt and delivered to the Army as the XP-37, of which more in a later installment.
On June 16, 1936, Curtiss got a consolation order from the Material Division for three examples of the Model 75B under the designation Y1P-36, perhaps because the USAAC was getting nervous about the inability of Seversky to meet its delivery schedules and was therefore hedging its bets. Serial numbers of the Y1P-36s were 37-68/70, and the company designation for these planes was Model 75E. At Army direction, they were to be powered with the Pratt & Whitney R-1830-13 Twin Wasp radial, virtually the same type of engine that was used by the P-35. The Twin Wasp was rated at 900 hp at 2550 rpm at 12,000 feet, having been de-rated from 1050 to 950 hp for takeoff. The engine drove a hydraulically-operated, constant-speed three-bladed Hamilton Standard propeller. Armament was the Army standard of the day, one 0.30-inch and one 0.50-inch machine gun under the cowling and synchronized to fire through the propeller arc. The Y1P-36 could be distinguished from the prototype by the R-1830 engine and also by the presence of modified and larger view scallops behind the cockpit.
The first Y1P-36 was delivered to the Army in March of 1937, and was tested at Wright Field in June of that year. The Wright Field test pilots were uniformly enthusiastic about the new Curtiss plane, commenting favorably about its maneuverability. The effectiveness and operation of all controls throughout the speed range of the fighter were excellent, and stability and ground handling were quite favorably rated. However, there was some criticism of the location of the undercarriage and flap controls, some complaints about the cabin ventilation, and some unfavorable comments about the curvature of the windshield which resulted in some distortion of vision during landing. With the R-1830 engine, the Y1P-36 did so well that it won a 1937 Army competition, and on July 7, 1937, the Army ordered 210 P-36As, the largest single US military aircraft order since the First World War. Curtiss's private venture had finally paid off.
Serials of the P-36As were 38-1/210. The principal difference between the P-36A and the Y1P-36 was the addition of engine cowl flaps and the addition of bulging "frog's eye" covers over the machine gun ports in the engine cowling. The P-36A had a fully-rated 1050 hp Pratt & Whitney R-1830-13 Twin Wasp engine driving a Curtiss Electric constant speed propeller. Empty and normal loaded weights were 4567 lb and 5470 lbs. Maximum speed was 300 mph at 10,000 feet. Normal range was 825 miles. Initial climb rate was 3400 feet/minute. An altitude of 15,000 feet could be attained in 4.8 minutes, and service ceiling was 33,000 feet.
Before completion, P-36A Ser No 38-10 was converted to the XP-40 (Model 75P) and 38-4 became the XP-42 (Model 75S). More of both of these later in the series!
The first Y1P-36 (Ser No 37-068) was briefly tested with two twin-bladed contrarotating propellers, the first such installation on an American aircraft.
The first production P-36A was delivered to Wright Field in April of 1938. The 20th Pursuit Group at Barksdale Field, Louisiana, comprising the 55th, 77th, and 79th Pursuit Squadrons, had been designated as the first recipients of the new Curtiss fighter, and they had relinquished their Boeing P-26s in anticipation of the deliveries of the new fighter. However, the new Curtiss fighters began to encounter an extensive series of teething troubles almost as soon as they reached the field. Severe skin buckling in the vicinity of the landing gear wells had appeared, dictating increased skin thicknesses and reinforcing webs. Engine exhaust difficulties and some weaknesses in the fuselage structure were also encountered. Despite both production line and field fixes, the P-36As were grounded again and again. At one time, the 20th Pursuit Group was down to six serviceable P-36As, and even these planes had to be flown under severe limitations on their speed, aerobatics, and combat maneuvers.
The 1st Pursuit Group at Selfridge Field, Michigan, consisting of the 17th, 27th, and 94th Pursuit Squadrons, had also been scheduled in 1938 for conversion to the P-36A. However, this Group was forced to await the efforts being made at Buffalo to wring out the new fighter's problems. In the event, only the 94th Squadron got any P-36As during 1938, operating them along with Seversky P-35s. The 27th Squadron received a few P-36As during early 1939, but neither the 27th nor the 94th Squadron ever got a full complement of P-36As, the balance being made up by Seversky P-35s. The 17th Squadron never got ANY P-36s, their strength being made up solely of P-35s.
In 1939, the 33rd, 35th, and 36th Squadrons of the 8th Pursuit Group at Langley Field, Virginia were equipped with P-36s.
By early 1941, the P-36 was already recognized as being obsolescent, and had been largely supplanted in first-line Army Air Force (as the Army Air Corps had been renamed) units by such aircraft as the Bell P-39 Airacobra and the Curtiss P-40. At home, the P-36s were largely relegated to training units. By the time of Pearl Harbor, P-36s were serving with the 35th Training Group based at Moffett Field, California and with the 36th Training Group based at Langley Field, Virginia. These outfits trained with the P-36 before they converted to more modern fighters. Other P-36s were transferred overseas. P-36s served with the 24th, 29th, and 43rd Squadrons of the 16th Pursuit Group and with the 51st, 52nd and 53rd Squadrons of the 32nd Pursuit Group, both groups being based at Albrook Field in the Canal Zone, where they flew alongside the now totally-obsolete Boeing P-26. During February of 1941, 20 crated P-36s were delivered to Alaska, and these planes served with the 23rd Squadron at Elmendorf Field in Alaska. At about the same time, 31 P-36s arrived in Hawaii from San Diego aboard the carrier *Enterprise*. These fighters entered service with the 78th Squadron of the 18th Pursuit Group and with the 46th and 47th Squadrons of the 15th Pursuit Groups, all being based at Wheeler Field, Hawaii.
At the time of the Pearl Harbor attack on December 7, 1941, 14 P-26As, 39 P-36As and 99 P-40s comprised the air defense of the islands. Most of these aircraft were destroyed or damaged on the ground, but four P-36As of the 46th Squadron managed to take off and attack a formation of nine Nakajima B5N1 torpedo bombers on the second wave. Two of the Najajimas were shot down, gaining the first USAAF "kills" of the Pacific War.
After Pearl Harbor, there was no other combat while in US service. P-36s were quickly withdrawn from combat outfits and relegated to training units. Ten P-36As (serials 38-39, 43, 51, 53, 54, 60, 106, 158, 159, and 175 were transferred to Brazil in March of 1942.
There is a P-36A on display at the Wright Patterson Air Force Base Museum in Dayton, Ohio. I am unaware of the service history of this particular airplane.
P-36A Ser No 38-020 was flown in November 1938 with an R-1830-25 engine offering 1100 hp for takeoff. This airplane was redesignated P-36B. It attained a maximum speed of 313 mph. The airplane was subsequently converted back to P-36A standards.
The P-36A had always been underarmed in comparison with contemporary foreign fighters (e. g. the Spitfire and Hurricane), and P-36A Ser No 38-085 had undergone an experiment in which the fuselage guns were supplemented by the addition of a 0.30-in machine gun in each outer wing panel. This installation was successful, and it was adopted for the last 30 aircraft in the original order (Ser Nos 38-181/210). These were redesignated P-36C. The P-36C also featured an R-1830-17 (S1C3-G) engine rated at 1200 hp for takeoff. These changes had been ordered on January 16, 1939, and the P-36C could be distinguished from the P-36A by the addition of cartridge case retainer boxes protruding underneath the wings. Despite the extra drag produced by the underwing cartridge boxes and the increased weight, the increased power of the engine raised the maximum speed of the P-36C to 311 mph, although the range was lowered to 600 miles. Service ceiling was 33,700 feet. Weights were 4620 lbs empty, 5734 lbs loaded. Wing span was 37 feet 4 inches, length was 28 feet 6 inches, and wing area was 236 square feet.
P-36A Ser No 38-174 was withdrawn from squadron service early in 1939 and fitted with four belt-fed 0.30-in machine guns in the wings. At the same time, the fuselage mounted armament was changed to a pair of 0.5-in machine guns. Thus armed, the modified aircraft was redesignated XP-36D.
P-36A Ser No 38-147 was fitted with new outer wing panels each housing FOUR 0.30-in machine guns (a la Spitfire and Hurricane). The fuselage-mounted 0.50-in gun was retained but rendered inoperable. As such, the aircraft was redesignated XP-36E. The XP-36E was retired to an Army mechanics' school in August of 1943.
The XP-36F was created by taking P-36A Ser No 38-172 and fitting it with two 23-mm Danish-built Madsen cannon in underwing fairings. The standard P-36A fuselage armament was retained. Unfortunately, this additional armament caused the maximum weight to rise to 6850 pounds and the maximum speed to fall to 265 mph. Consequently, the experimental armament was soon removed and the airplane reverted to a standard P-36A. It was surveyed in October 1944.
The Norwegian government had issued an order for 36 Hawk 75A-8 export versions of the P-36 just before the German occupation. These aircraft were powered by the export-model 1200 hp Wright R-1820-G205A Cyclone radial. Since Norway was under German occupation at the time these aircraft were completed in January of 1941, they were impounded by the US government.
These 36 planes were delivered to Free Norwegian forces in Canada in February of 1941, where they were operated as fighter trainers by the "Little Norway" training establishment near Toronto. They were used as advanced trainers for Norwegian fighter pilots after their initial training on Cornells and Harvards.
The training on the Hawk 75A-8s was halted in early 1943, and the 30 survivors were sold, 18 to Curtiss and 12 to the USAAF. All 30 of these planes were redesignated P-36G and were assigned the USAAF serial numbers 42-36305/36322 and 42-108995/109006. The export-model Wright R-1820-G205A Cyclone radial engine which powered these planes was redesignated R-1820-95 by the Army.
Since these aircraft were considered useless as combat types and in addition were incompatible with other P-36s because of their Wright engines, the P-36Gs were sent to Peru under Lend-Lease in 1943. One survives in the Peruvian Air Force Museum.
Curtiss Model 75A Demonstrator
Model 75A was the company designation for a Curtiss-owned demonstrator which carried a civilian registration of NX22028. This demonstrator aircraft was used to carry out several company-originated experiments. First, it was fitted with an external mechanical supercharger mounted underneath its Pratt & Whitney R-1830 engine and briefly designated Model 75J. Then, it was experimentally fitted with a turbosupercharged R-1830-SC2-G engine. The supercharger was fitted underneath the nose just aft of the engine cowling, and the intercooler was mounted underneath the trailing edge of the wing. The company designation for this modification was Model 75R. Empty and normal loaded weights went up to 5074 lbs and 6163 lbs. During trials in January 1939, it attained a maximum speed of 330 mph at 15,000 feet. However, the poor reliability and complexity of the turbosupercharger led the USAAC to decide not to proceed with a supercharged variant of the P-36, choosing instead to purchase the turbo-supercharged Seversky (Republic) XP-41, which had been converted from the last P-35. After trials at Wright Field, the aircraft was returned to the Curtiss plant in Buffalo, where it was fitted with a Wright R-1820 engine and resumed its role as a demonstrator.
Curtiss Hawk with Armee de l'Air
Although the P-36 saw very little combat in American hands, the Curtiss fighter was to see quite a bit of combat in foreign hands. In fact, it is one of the few military aircraft actually to see combat on BOTH sides during the Second World War.
The largest foreign operator of the Hawk was the Armee de l'Air, the French Air Force. Next to the Morane-Saulnier M.S.406, the Curtiss Hawk was numerically the most important fighter in French service during the German onslaught into Western Europe in May of 1940.
In February 1938, two months before the first P-36A had rolled off the Buffalo assembly lines for the USAAC, the French government entered into negotiations with the Curtiss company for the supply of 300 fighters of the Hawk 75A type which Curtiss had offered to the Armee de l'Air. The Hawk 75A was an export version of the P-36A, and was being offered for sale with either the Pratt & Whitney Twin Wasp or the Wright Cyclone engine.
However, the unit price asked by Curtiss was considered exorbitant by the French--almost twice as high as that of the Morane-Saulnier M.S.406. In addition, the proposed delivery schedule commencing in March of 1939 with 20 planes and continuing at a rate of 30 planes per month was considered totally unacceptable. Furthermore, the USAAC was itself unhappy with the Curtiss company's inability to meet delivery schedules for its P-36As, and felt that the French sale would only slow things up still more. Consequently, the USAAC opposed the French sale.
Nevertheless, the rapidity of German rearmament made the modernization of the Armee de l'Air's equipment a matter of the utmost urgency, so the French persisted with the negotiations. As a result of the direct intervention of President Roosevelt, a leading French test pilot, Michel Detroyat was permitted to fly a Y1P-36 service test prototype at Wright Field in March of 1938. He submitted a thoroughly enthusiastic report. In addition, Curtiss suggested that more acceptable delivery schedules could be offered if the French government would finance the construction and equipping of supplementary assembly facilities.
The French still felt that the unit price was too high, and on April 28, 1938 they decided to delay their decision until the completion of the test trials of the Bloch MB-150, the quoted price of which was scarcely half that of the Curtiss fighter. However, the MB-150 was suffering an extensive series of teething troubles (the first prototype couldn't even fly!) and had been subjected to a succession of modifications for nearly two years. By mid-1938, it was felt that the Bloch fighter's main problems had been overcome. However, it was soon realized that in order to adapt the design for mass production, a complete structural redesign would have to take place.
The rework of the Bloch MB-150 would obviously be a costly and time- consuming process, and time was something the Armee de l'Air did not have. Consequently, on May 17, 1938 the Minister for Air announced that the French would acquire the Curtiss Hawk, and that a French purchasing commission was instructed to order 100 Hawk airframes and 173 Pratt & Whitney R-1830 Twin Wasp engines. The contract stipulated that the first Hawk should be flown at Buffalo by November 25, 1938 and that the 100-th plane should be delivered by April 10, 1939.
The initial production version of the Hawk was designated Hawk 75A-1 by Curtiss, of which 100 had been ordered by France. According to the original plan, the majority of the Hawk 75A-1s were to be shipped by Curtiss in disassembled form to France, with assembly being completed in France by the Societe Nationale de Constructions Aeronautiques du Centre (SNCAC) at Bourges. The first Hawk 75A-1 was flown at Buffalo early in December 1938, only a few days after the committed date. The first Hawk 75A-1s (actually the fourth and fifth examples off the line) were delivered by ship to France on December 14, 1938. Fourteen more Hawk 75A-1s were delivered in fully-assembled form for Armee de l'Air trials, but the rest were delivered in disassembled form. The first assembly was commenced by SNCAC in February 1939.
During March and April of 1939, the 4e and 5e Escadres de Chasse had initiated conversion from the Dewoitine 500 and 501, and by July 1, 1939 the 4e Escadre had 54 Curtiss fighters on strength and the 5e Escadre had 41. The conversion had not been without problems, one Hawk 75A-1 having crash- landed when an over-speeding propeller had caused the engine to overheat, and another one had been destroyed in a fatal crash as a result of a flat spin that developed during aerobatic trials with full fuel tanks. Throughout the entire service history of the Hawk 75A, there were problems with maneuverability and handling when all the fuel tanks were completely full.
The Hawk 75A-1 was powered by the Pratt & Whitney R-1830-SC-G engine, with an international rating of 900 hp at 12,000 feet and 950 hp for takeoff. Armament comprised four 7.5 mm machine guns, two mounted in the upper decking of the fuselage nose and two in the wings. Apart from the altitude indicator, all instruments were metric calibrated. A modified seat was fitted to accommodate the French Lemercier back parachute. The throttle operated in the "French fashion", i.e. in the reverse direction to the throttles of British or US aircraft.
France used the manufacturer's model number as the official designation, and numbered the aircraft consecutively within the model. This information appeared in three lines on the rudder as so:
CURTISS H75-C1 No. 09
The C stood for Chasse (pursuit) and the 1 indicated a single-seater, and the 09 was the ninth H75 ordered by France.
Following the placing of the initial French order for the Hawk 75A in May of 1938, an option had been taken for 100 more machines. This option was converted into a firm order on March 8, 1939. These aircraft differed from the A-1 in having an additional 7.5 mm machine gun in each wing, some structural reinforcement of the rear fuselage, and the minor modifications necessary to permit interchangeability between the R-1830-SC-G and the more powerful R-1830-SC2-G, the latter affording 1050 hp for takeoff.
The new model was designated Hawk 75A-2 by Curtiss. The four wing guns and the new engine made the Hawk 75A-2 more or less equivalent to the US Army's XP-36D. The first A-2 was delivered to France at the end of May, 1939. The first 40 of these were basically similar to the A-1 in both powerplant and armament. The first A-2 to have both the uprated engine and the increased armament was actually the 48th off the Buffalo line. French Air Force numbering continued from the Hawk 75A-1, the first Hawk 75A-2 being numbered 101.
One hundred and thirty-five of the Hawk 75A-3 version were ordered by France on October 9, 1939, with improved 1200 hp R-1830-S1C3G engines and armament similar to that of the A-2 (six 7.5-mm machine guns). Maximum speed was 311 mph at 10,000 feet. Initial climb rate was 2350 feet per minute, service ceiling was 33,700 feet, and range was 820 miles. Wingspan was 37 feet 3 1/2 inches, length was 28 feet 7 inches, and wing area was 236 square feet. Weights were 4483 lbs empty, 5692 lbs gross. About sixty Hawk 75A-3s reached France before the surrender, with the rest being diverted to Britain.
The last French order before the Armistice was for 395 Hawk 75A-4 aircraft. These were armed like the A-3s but were fitted with 1200 hp Wright R-1820-G205A Cyclone engines. Cyclone-powered 75s could be distinguished from Twin Wasp models by their short-chord cowlings of slightly greater diameter and by the absence of engine cowling flaps and bulbous nose gun port covers. Maximum speed was 323 mph at 15,100 feet. Initial climb rate was 2820 feet per minute, service ceiling was 32,700 feet, and range was 670 miles. Weights were 4541 lbs empty, 5750 lbs gross. Wingspan was 27 feet 3 1/2 inches and length was 28 feet 10 inches. Only two hundred and eighty-four of these A-4s were actually built, and of these, only six A-4s actually reached France before the surrender.
Action with Armee de l'Air
The French Hawks were in action from almost the first day that the war began in Europe. On September 8, 1939, the Groupe de Chasse II/4, operating Hawk 75As succeeded in destroying two Messerschmitt Bf 109Es, the first Allied aerial victories of World War 2. However, during the invasion of France in May of 1940, the Hawks were generally outmatched by the Messerschmitt Bf 109E. The Hawk 75A served with Armee de l'Air Groupes de Chasse III/2, I/4, II/4, I/5 and II/5, these units claiming 230 confirmed kills and 80 "probables", as against losses totaling only 29 aircraft destroyed in aerial combat. Although these figures are probably over-optimistic, it seems likely that the French Hawks gave better than they got. The Hawk 75A was neither as fast nor as well-armed as the Messerschmitt Bf 109E, but it was more maneuverable and could take more punishment. The leading French ace of 1939/40 was Lt Marin La Meslee, who scored 20 "kills" while flying the Hawk.
Only 291 Hawk 75A fighters were actually taken on strength by the Armee de l'Air before the collapse of French resistance, but a number were lost en route to French ports. As mentioned before, only six A-4s actually reached France before the Armistice. Thirty A-4s destined for France were lost at sea during transit, seventeen were disembarked in Martinique and a further six were unloaded in Guadeloupe. These machines were, incidentally, shipped from the West Indies to Morocco during 1943-44, placed in flying condition and used for training, their unreliable Cyclone 9 engines being replaced by Twin Wasps. The rest of the French Hawk 75A-4 order was taken over by Britain as Mohawk IVs.
After the collapse of French resistance, those Armee de l'Air Hawks which had not escaped to unoccupied French territory or flown to England were taken over by the Luftwaffe. Some of the Armee de l'Air Hawk 75As were captured while still in their delivery crates. These were transported to Germany, whey they were overhauled and assembled by the Espenlaub Flugzeugbau, fitted with German instrumentation, and then sold to Finland. Finland received 36 former Armee de l'Air Hawk 75A-1s, A-2s and A-3s, along with eight former Norwegian Hawk 75A-6s. These Finnish Hawks participated in the war on the Axis side when Finland entered the war against the Soviet Union on June 25, 1941. These Hawks gave a good account of themselves in Finnish service, and some Hawks remained in service in Finland until 1948.
After the Armistice, Armee de l'Air Groupes de Chasse I/4 and I/5 continued flying their Hawks with the Vichy Air Force, the former unit based at Dakar and the latter at Rabat. These Vichy Hawk 75As were to fight against other American planes when the Allies made the Operation Torch landings in North Africa in November 1942. In an air battle between these Hawks and carrier-based Grumman F4F Wildcats, 15 Vichy planes were shot down versus the loss of seven Wildcats. This is one of the few occasions during the Second World War in which American-built planes fought against each other.
Considerable interest in the Hawk had been aroused in Britain as a result of a test flight carried out with an Armee de l'Air Hawk by an RAF pilot in France. The Hawk 75A possessed remarkably good controls and the ailerons were fairly light at high speeds in contrast with the early Spitfire which had ailerons which were almost immobile at speeds over 300 mph. At the end of 1939, the Royal Aircraft Establishment arranged for a loan of a Curtiss Hawk from France (the 88th production Hawk 75A-2) for comparative trials against a Spitfire I (K9944). In many respects, the Hawk turned out to be superior to the Spitfire. The RAE found that the Hawk did indeed have exceptional handling characteristics and beautifully harmonized controls. In a diving attack at 400 mph, the Hawk was far superior to the Spitfire I owing to its lighter ailerons. In a dogfight at 250 mph, the Hawk was again superior, because its elevator control was not over-sensitive and all-round view was better. However, the Spitfire could break off combat at will because of its much higher speed. When the Spitfire dived on the Hawk, the Curtiss could avoid its opponent by banking and turning rapidly. The Spitfire could not follow the Hawk around and would overshoot the target. The Hawk 75A displayed appreciably superior take-off and climb characteristics. The swing on takeoff was smaller and more easily corrected than on the Spitfire, and during the climb the Hawk's controls were more effective. However, the Hawk tended to be rather slow in picking up speed in a dive.
Based on these trials, the British government briefly toyed with the idea of ordering the Hawk for the RAF. For whatever reason, these plans were never carried out. However, the fall of France in June 1940 caused quite a few Hawks to fall into British hands.
Those Hawk 75As which had not yet been delivered to France before the surrender (most of them A-4s), plus those whose pilots had flown them to England to escape the German occupation were taken over by the RAF and given the name Mohawk. The total number of Mohawks impressed by the RAF was 229 planes. Most of them were former French machines, but a few former Persian Hawks and even some Indian-built machines were included in the Mohawk total as well.
There were four RAF sub-variants: Mohawk I, II, III, and IV.
Former French Hawk 75A-1s were named Mohawk I by the RAF, with Hawk 75A-2s being named Mohawk II. There was a total of 29 of these planes. Unfortunately, it is difficult to track which planes were A-1s and which were A-2s, since Mohawk I and Mohawk II aircraft were intermixed with each other and with Mohawk IVs in the RAF serial number blocks AX880/898, BK876/879, and BL220/223.
More than 20 former French Hawk 75A-3s were taken over by Britain as Mohawk IIIs. RAF serials for these Mohawk IIIs were BK569/588, but some A-3s were mixed in with Mohawk IVs in serial block AR630/694.
The name Mohawk IV was assigned to the remainder of the French Hawk 75A-4 order which was taken over by the RAF. The exact number of Mohawk IVs diverted to Britain cannot be determined from the RAF serial numbers alone, since some blocks applied to both IIIs and IVs without distinction. The total number of Mohawks appearing as IVs total 190, only six less than the total of Hawk 75A-4s built. However, some 75As other than A-4s became Mohawk IVs, including the ten A-9s originally intended for Persia and at least six of the former Chinese A-5s assembled in India. Mohawk IV RAF serials of record are AR630/694, BB918/937, BB974/979, BJ434/453, BJ531/550, BJ574/588, BK876/879, BL220/223, BS730/738, BS744/747, BS784/798, BT470/472, LA157/158 and LA163/165.
Mohawks taken on strength by the Royal Air Force were refitted with British equipment, including 0.303-calibre Browning machine guns. The French throttles were replaced by throttles which operated in the "British fashion", i.e., were pushed forward to increase the power. The RAF decided that its Mohawks were not suitable for the European theater, and sent 72 of them to the South African Air Force (where they were flown by the 3rd, 4th, 5th, 6th and 7th Squadrons which operated in East Africa), while others were flown by the 5 and 155th RAF squadrons based in India. At one time, eight Mohawks provided the sole fighter defense of North-East India, and the fighter remained operational on the Burma front until finally replaced by more modern types in December 1943.
12 Mohawks were sent to Portugal.
Hawk 75A-5 for China
The Hawk 75A-5 was the Curtiss company designation for a Cyclone-powered model which was to be assembled in China by the Central Aircraft Manufacturing Company (CAMCO). At least one complete airplane and some kits of unassembled parts were delivered to China. After assembling some aircraft in China, the CAMCO firm was reorganized as Hindustan Aircraft Ltd. in Bangalore, India. In April 1941 the Indian government placed a contract with Hindustan for the construction of 48 Cyclone 9-powered Hawk 75As, together with the necessary spares. Hindustan acquired a manufacturing license from Curtiss, and the first Indian-built machine flew on July 31, 1942. However, shortly after this flight, a change in policy resulted in the decision to abandon the construction of complete aircraft in India. After four more machines were constructed, the Hindustan program was terminated. These Indian-built machines were eventually absorbed into the RAF as Mohawk IVs.
Hawk 75A-9 for Iran
The government of Persia (now Iran) ordered ten Hawk 75A-9 versions powered by Wright R-1820-G205A engines. These reached Persia shortly before that country was occupied by British and Russian forces on August 25, 1941. The Hawk 75A-9s were discovered there still in their shipping crates. These aircraft were taken over by the British from Persia and were transferred to India as Mohawk IVs, where they were operated by the 5th Squadron of the RAF.
Hawk 75A-6/75A-8 for Norway
In the autumn of 1939, the Norwegian government ordered twelve Hawk 75A-6s with 1200 hp Pratt & Whitney R-1830-S1C3G Twin Wasp radials and four-gun armament. This order was later supplemented with an order for twelve more, to bring the total to 24.
Deliveries began in February 1940. By the time of the German invasion in April of 1940, 19 planes out of the 24 had arrived in Norway. However, none of these planes were ready for combat, and did not participate in the vain attempt to stop the German advance. 7 of the 75A-6s were assembled and were based at Kjeller Airfield close to the capital at Oslo. Not all of these planes had their guns installed, and the ones that did had guns that were not calibrated. Secondly the airplanes at Kjeller Airfield were equipped with wheels and the winter of 1940 was not quite over and the airfield was still covered with snow - enabling only ski equipped aircraft to take off. The other 12 airplanes that also had arrived in Norway were still sitting in the customs building down at the harbour. Recognizing that the planes in storage would likely soon fall into German hands, an employee decided singlehanded to crush all the instruments with a hammer and to cut all visible wires with a wire cutter. The last 5 aircraft from the first order of Hawks were underway by sea to Norway as the war broke out. They were redirected to England and were later given to France.
The Norwegian Hawk 75A-6s were captured by the Germans and were delivered to Finland. These were later supplemented by 36 partially-completed Hawk 75As that had been seized by German forces from France at the time of the Armistice and assembled in Germany. These participated in the war on the Axis side when Finland entered the war against the Soviet Union on June 25, 1941. These gave a good account of themselves, and some Hawks remained in service in Finland until 1948.
Norway had ordered an additional 36 Hawk 75A-8s with 1200 hp Wright R-1820-G205A Cyclone engines just before the German occupation. The German occupation caused the A-8s to be impounded by the US government before delivery. . A Norwegian financed training base known as "Little Norway" had been established at Toronto in Canada, and the airplanes were sent here. Here, they were used as advanced trainers for the coming Norwegian fighter pilots after their initial training on Cornells and Harvards. The advanced training on the A-8s was stopped in early 1943 and the surviving 30 aircraft were sold in May of 1943. 18 went back to Curtiss and 12 went to the US government. They were redesignated P-36G and were assigned USAAF serials 42-36305/36322 and 42-108995/109006.
Hawk 75A-7 for Netherlands
Twenty Hawk 75A-7s with Cyclone engines were ordered by the Netherlands, but the German occupation of Holland caused all of the A-7s built to be diverted to the Netherlands East Indies starting in May 1940. They served with the 1st Squadron of the Royal Netherlands East Indies Army Air Corps, where they were caught up in the Japanese advance from December 8, 1941. They were outnumbered and outperformed by the nimble Japanese Zero fighter. By February 1, 1942, they had all been destroyed by the enemy.
Early in 1937, Curtiss began the development of a simplified version of the Y1P-36 intended specifically for export. Curtiss was aware that some potential customers whose air arms operated under relatively primitive conditions would look askance at a sophisticated feature such as a retractable undercarriage which promised to afford difficult maintenance problems. The "simplified Hawk" project was given the company designation of Model 75H.
The construction of the Model 75H was similar to the Y1P-36, but a lower-powered engine was provided and a fixed, single-strut undercarriage with streamlined fairings was fitted. These modifications were first applied to a demonstrator aircraft which was re-engined with a Wright Cyclone GR-1820-GE rated at 875 hp for takeoff. This airplane was given the civil registration of NR1276, and publicized in Curtiss sales brochures as "Hawk 75". Emphasis was placed on ease of maintenance, rough field performance, and the amenability of the aircraft to accommodate different brands of engines and different types of armament in order to suit the customer's individual requirements.
A second and more definitive demonstrator aircraft was built which differed from its predecessor in some respects, including the adoption of the more deeply-scalloped decking immediately aft of the cockpit and revised windshield arch and canopy framing. Armament was supplemented by an additional pair of 0.30-cal machine guns in the wings, firing outside the propeller arc. Provision was made for the attachment of underwing bomb racks capable of carrying ten 30-lb or six 50-lb bombs, plus a centerline rack for a single 500-lb bomb. This aircraft was given the civil registration of N1277.
The first 75H carried the US civil registration of NR-1276. It was sold to China. The Chinese government presented this airplane to General Claire L. Chennault for his own personal use. The second one was registered as NR-1277 and was sold to Argentina.
Hawk 75M for China
The first overseas customer for the Hawk 75 was the Chinese Nationalist government, which ordered a total of 112 Hawk 75 non-retractable undercarriage models with R-1820 Cyclone engines and four 0.30-in guns (two in the fuselage and two in the wings). These planes were to be built by Curtiss and delivered as major components to the Central Aircraft Manufacturing Company at Loi-Wing, where they would be assembled and delivered to Chinese units. These airplanes were retroactively assigned the designation Hawk 75M by the Curtiss company. Aside from the additional wing guns and some minor revisions to the undercarriage fairings, these planes were identical to the second "simplified Hawk" demonstrator.
The Hawk 75M was powered by an export-approved 875 hp Wright GR-1820-G3 Cyclone radial. Wingspan was 37 feet 0 inches, length was 28 feet 7 inches, and wing area was 236 square feet. Empty weight was 3975 lbs, and gross weight was 5305 lbs. Maximum speed was 280 mph at 10,000 feet, service ceiling was 31,800 feet, and range was 1210 miles with fuel overload. Armament was four 0.30-in machine guns--two in the nose and two in the wings.
It is uncertain just how many Hawk 75Ms actually ended up in Chinese service. Only 30 Hawk 75Ms are accounted for in Curtiss records, with deliveries beginning in May of 1938. Tooling and kits for an unspecified number were delivered to the Central Aircraft Manufacturing Company Wing for assembly in China, and an unspecified number were built there. Three full squadrons of Model 75Ms are known to have been operational. These fighters achieved few successes against the Japanese forces, largely owing to poor serviceability and the inadequate training of both pilots and ground crews.
Hawk 75N for Thailand
The government of Siam (Thailand) also exhibited interest in the Hawk 75, and ordered somewhere between 12 and 25 examples (the exact number is uncertain, and depends on which source you pick). These were given the designation Hawk 75N by Curtiss, and were generally similar to the Chinese Hawk 75Ms except for some minor revisions to the undercarriage mainwheel fairings and some differences in the armament. Sources also differ in the armament fitted--one claims that the armament was two nose guns (one 0.30-in and one 0.50-in nose guns and four 0.30-in guns in the wings, another claims that that there were two 23-mm Danish Madsen cannon housed in detachable underwing fairings.
Twelve Hawk 75Ns were delivered to Siam (Thailand) starting in November, 1938. They These Hawk 75N fighters were involved in the Thai invasion of Indo- China in January 1941, the first recorded combat taking place on January 11 when four 75Ns escorted nine Martin 139-Ws in an attack on the French airfield at Nakorn Wat. The formation was intercepted by four French Morane-Saulnier M.S.406s. In the resulting air battle, the Thai Hawks claimed two Morane fighters shot down (although the claim was later refuted by the French). On December 7, 1941, the Thai Hawks were in action once again, this time against invading Japanese forces. In the brief battle, one third of the serviceable Hawks were destroyed. Those not destroyed were taken over by the Japanese. One example is now in the Royal Thai Air Museum in Bangkok.
Hawk 75O for Argentina
After purchasing the NR1277 75H demonstrator (c/n 12328) from Curtiss, the Argentine government ordered twenty-nine production examples of the non-retractable undercarriage Hawk 75 with 875 hp Cyclone engines. Designated Hawk 75O by the Curtiss company, these planes had a similar undercarriage to the Thai Hawk 75N and featured a redesigned engine exhaust system with a semi-circle of electrically-operated gills at the rear of the cowling. Armament consisted of four 7.62-mm Madsen machine guns. The first Hawk 75O was completed by Curtiss in late November, 1938. The planes were serialed C-601 through C-630.
Maximum speed was 239 mph at sea level and 280 mph at 10,700 feet. Initial climb rate was 2340 ft/min. An altitude of 23,000 feet could be attained in 12.52 minutes. Service ceiling was 31,800 feet. Empty and loaded weights were 3975 lbs and 5172 lbs.
At the same time, Argentina acquired a license to manufacture the Hawk 75O at the Fabrica Militar de Aviones. The first FMA-built Hawk was delivered on September 16, 1940. A total of 20 was built, with serials being C-631 to C-650. Some of these Hawks remained in service for over a decade, the last ones operating from El Plumerillo in western Argentina until 1953, when they were transferred to training units until being withdrawn during 1954.
Model 75Q for China
Model 75Q was the designation assigned to two additional non-retractable undercarriage demonstrators with R-1820 engines. One was converted to retractable undercarriage configuration and was presented to Madame Chiang Kai-Shek. She gave the plane to General Claire Chennault who was then reorganizing the Chinese Air Force. The other was flown as a demonstrator in China by American pilots but crashed after takeoff on May 5, 1939.
1. Curtiss Aircraft, 1907-1947, Peter M Bowers, Naval Institute Press, 1979
2. The Curtiss Hawk 75, Aircraft in Profile No. 80, Profile Publications, Ltd. 1966
3. War Planes of the Second World War, Fighters, Volume Four, William Green, Doubleday, 1961.
4. Air Enthusiast, Volume 1, William Green et al, Doubleday, 1971.
5. Hawk Dynasty: The Curtiss Hawk Monoplanes, Ken Wixey, Air Enthusiast, Vol 71, 1997.
Photographs of the Curtiss Hawk H-75A in the Finnish Air Force
Finnish Air Force Lentolaivue 24 or LLv.24, from 3 May 1942 Le. Lv.24)
renamed No. 24 Fighter Squadron Hävittäjälentolaivue 24 or HLe.Lv.24 mixed photo's
Hawk in Finland
After the fall of France, Germany agreed to sell captured Curtiss Hawk fighters to Finland in October 1940. In total, 44 captured aircraft were sold to Finland with three deliveries from 23 June 1941 to 5 January 1944. Not all were from the French stocks, but some were initially sold to Norway and captured in their wooden crates when the Germans conquered the country. The aircraft were given serial codes CU-551 to CU-585.
In Finnish service, the Hawk was well-liked, affectionately called Sussu 'Sweetheart'. The Finnish Air Force enjoyed success with the type, credited with 190 1/3 kills by 58 pilots, from 1941-44. Finnish ace Kyösti Karhila scored 13 1/4 of his 32 victories in the Hawk, while the top Hawk ace K. Tervo scored 15 3/4 victories. The Hawks were flown by Lentolaivue 32 throughout their wartime operational service.
The Finnish Hawks were initially armed with either four or six 7.5 mm machine guns. While sufficient during the early phase of Continuation War, the increasing speeds and armour of Soviet planes soon showed this armament was not powerful enough. From 1942 the State Aircraft Factory replaced the fuselage machine guns with either one or two 12.7 mm Colt machine guns and installed two 7.7 mm Browning machine guns to each wing. The 12.7 mm Berezin UB or LKk/42 heavy machine guns were also used. The installation of heavier armament did not cause changes to the very good flying characteristics of the fighter but the armament was much more powerful against Soviet planes. The Finnish Hawks were also equipped with Revi 3D or C/12D gunsight.
Surviving Finnish aircraft remained in service until 1948.
- Flight Simulators
IL-2 Sturmovik 'Cliff's of Dover' Blitz
IL-2 Sturmovik Battle of Stalingrad
DCS World - has no 3D model
Finnish pliots who have won victories with the Curtiss Hawk 75 Name Victories with Curtiss Hawk 75 Victories total Kalevi Tervo 15.5 23 Kyösti Karhila 13 32 Eino Koskinen 11.5 12.5 Yrjö Pallasvuo 9 13 Jaakko Hillo 8 8 Aulis Bremer 8 8 Väinö Virtanen 7 7 Niilo Erkinheimo 6.5 10.5 Kullervo Lahtela 6 10.5 Pentti Nurminen 6 6 Aimo Gerdt 6 6 Pauli Salminen 5.5 6 Aaro Kiljunen 5.5 5.5 Mauno Kirjonen 5 10 Sakari Alapuro 5 5 Arvo Koskelainen 5 5 Paavo Berg 4.5 9.5 Lauri Jutila 4 7.5 Olavi Ehrnrooth 2 5 Mauno Fräntilä 1.5 5.5 Veikko Evinen 1.5 5 136
Finnish Aces of the Winter War[W-9] Pilots Name confirmed unconfirmed Lt. Jorma Sarvanto 13 4 Lt. Tatu Huhanantti 6 4 S/M. Viktor Pyötsiä 7 ½ 2 S/M Kelpo Virta 5 1 Lt. Urho Nieminen 5 1 Lt T. Vuorimaa 4 2 ½ Capt. Erkki Olavi Ehrnrooth 7 4
Notes: According to Czech ace František Peřina, the P-36 was "terrific. It was not as fast as the Messerschmitt, but it could outmaneuver any German aircraft. If one got on your tail, in one 360-degree turn, you were behind him. Compared to the Hawker Hurricane, Peřina said the Hurricane was "a good aircraft, but heavier than the P-36 and, with a higher wing loading, not as easy to handle as a P-36.
- Curtiss P-36 Hawk fact sheet. National Museum of the United States Air Force. Retrieved: 7 March 2009.
- Guttman, Jon. "World War II: Interview with Czech Ace František Peřina." Military History, October 1995.
- Padin 1999, pp. 9, 15.
- March 1995, p. 68.
- Shores Air Enthusiast 1983, p. 2.
- Shores Air Enthusiast 1983, pp. 2–9.
- Thomas 2003, pp. 67-69.
- Thomas 2003, p. 69.
- Curtiss Hawk 75A. Backwoods landing strip: Finnish Air Force aircraft. Retrieved: 28 October 2010.
- Persyn, Stenman and Thomas 2009, p. 50
- Crawford, Bruce. "Hawk 75: Promise unfulfilled?" curtisshawk75.bravepages.com, 2002. Retrieved: 9 August 2010.
- Persyn, Stenman and Thomas 2009, p. 88
- Persyn, Stenman and Thomas 2009, p. 71
- Facon, Patrick. "Slowing Down Blitzkrieg - A Curtiss Fighter Ace in the Battle of France." AIR FAN International, Publitek Ltd, March 1996, pp. 54–62. ISSN 1083-2548.
- Brindley, John F. (1971). French Fighters of World War Two, p. 52. Hylton Lacy, London.
- Persyn, Stenman and Thomas 2009, p. 9
- O'Leary, Michael. USAAF Fighters of World War Two. Harrisburg, PA: Harrisburg Historical Times, 1986. ISBN 0-7137-1839-0., p. 53
- Trirat. "A Briefer History of the Royal Thai Air Force." nationmultimedia.com, October 2007. Retrieved: 13 August 2012.
- Williford 2010, p. 26.
- Aircraft at Pearl Harbor." World War II in the Pacific via www.ww2pacific.com. Retrieved: 7 March 2009.
- Persyn 2007
- Dunn, Richard L. "Uncertain Wings: Curtiss Hawk 75 in China." warbirdforum.com, 2008. Retrieved: 13 August 2012.
- Curtiss P-36A Hawk. National Museum of the United States Air Force. 4 February 2011. Retrieved 20 August 2011.
- Dean and Hagedorn 2007, p. 201.
- Swanborough and Bowers 1963, p. 185.
- Bowers, Peter M. Curtiss Aircraft, 1907-1947. Annapolis, Maryland: Naval Institute Press, 1979. ISBN 0-87021-152-8.
- Bowers, Peter M. The Curtiss Hawk 75: Aircraft in Profile No. 80. London: Profile Publications, 1966.
- Bridgwater, H.C. Combat Colours Number 3: The Curtiss P-36 and P-40 in USAAC/ USAAF Service 1939-1945. Bletchley, Buckinghamshire, UK: Guideline Publications Ltd., 2001. ISBN 0-9539040-5-9.
- Brindley, John F. French Fighters of World War Two. London: Hylton Lacy, 1971. SBN 85064 0156
- Dean, Francis H. and Dan Hagedorn. Curtiss Fighter Aircraft: A Photographic History 1917-1948. Atglen, PA: Schiffer Publishing, 2007. ISBN 0-7643-2580-9.
- Fleischer, Seweryn and Jiri Chodil. Curtiss P-36 Hawk, Cz.3 (Monograpfie Lotnicze 63) (in Polish). Gdańsk, Poland: AJ-Press, 2000. ISBN 83-7237-038-9.
- Green, William. War Planes of the Second World War, Volume Four: Fighters. London: MacDonald & Co. (Publishers) Ltd., 1961 (Sixth impression 1969). ISBN 0-356-01448-7.
- Green, William and Gordon Swanborough. WW2 Aircraft Fact Files: US Army Air Force Fighters, Part 1. London: Macdonald and Jane's Publishers Ltd., 1977. ISBN 0-356-08218-0.
- March, Daniel J., ed. British Warplanes of World War II. London: Aerospace Publishing, 1998. ISBN 1-874023-92-1.
- Padin, Jorge Núñez, ed. Curtiss Hawk (Serie Fuerza Aérea Argentina: No. 5) (in Spanish). Bahía Blanca, Argentina: Fuerzas Aeronavales, 1999.
- Persyn, Lionel. Les Curtiss H-75 de l'armée de l'Air (in French). Outreau, France: Éditions Lela Presse, 2007. ISBN 2-914017-46-4.
- Persyn, Lionel; Kari, Stenman; Thomas, Andrew (2009). P-36 Hawk Aces of World War 2. Oxford: Osprey Publishing. ISBN 978-1-84603-409-1.
- Rys, Marek. Curtiss P-36 Hawk, Cz.1 (Monograpfie Lotnicze 61) (in Polish). Gdańsk, Poland: AJ-Press, 2000. ISBN 83-7237-036-2.
- Rys, Marek and Seweryn Fleischer. Curtiss P-36 Hawk, Cz.2 (Monograpfie Lotnicze 62) (in Polish). Gdańsk, Poland: AJ-Press, 2000. ISBN 83-7237-037-0.
- Shores, Chris. "The RAF's Little Indians". Air Enthusiast, Twenty-three, December 1983-March 1984. Bromley, UK:Fine Scroll. ISSN 0143-5450. pp. 1–9.
- Swanborough, Gordon and Peter M. Bowers. United States Military Aircraft Since 1909. London:Putnam, 1963.
- Swanborough, Gordon and Peter M. Bowers. United States Military Aircraft Since 1909. Washington, DC: Smithsonian, 1989. ISBN 0-87474-880-1.
- Thomas, Andrew. "Indians Over Africa: Curtiss Mohawks in SAAF Service". Air Enthusiast, No. 107, September/October 2003, pp. 66–69.
- United States Air Force Museum Guidebook. Wright-Patterson AFB, Ohio: Air Force Museum Foundation, 1975.
- Williford, Glen M. Racing the Sunrise: The Reinforcement of America's Pacific Outposts, 1941–1942 . Annapolis: Maryland : Naval Institute Press, 2010. ISBN 1-59114-956-8.
Magazine References: +
- Airfix Magazines (English) - http://www.airfix.com/
- Avions (French) - http://www.aerostories.org/~aerobiblio/rubrique10.html
- FlyPast (English) - http://www.flypast.com/
- Flugzeug Publikations GmbH (German) - http://vdmedien.com/flugzeug-publikations-gmbh-hersteller_verlag-vdm-heinz-nickel-33.html
- Flugzeug Classic (German) - http://www.flugzeugclassic.de/
- Klassiker (German) - http://shop.flugrevue.de/abo/klassiker-der-luftfahrt
- Le Fana de L'Aviation (French) - http://boutique.editions-lariviere.fr/site/abonnement-le-fana-de-l-aviation-626-4-6.html
- Le Fana de L'Aviation (French) - http://www.pdfmagazines.org/tags/Le+Fana+De+L+Aviation/
- Osprey (English) - http://www.ospreypublishing.com/
- Revi Magazines (Czech) - http://www.revi.cz/
Web References: +
- History of RAF Organisation: http://www.rafweb.org
- Wikipedia, the free encyclopedia: http://en.wikipedia.org/
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