In response to a US Navy (USN) pro¬posal for a new dive bomber, Curtiss came up with its Model 84. From half a dozen designs submitted, those of Brewster and Curtiss were considered most suitable, both incorporating the new 1700 hp Wright R 2600 Cyclone 14 cylinder two row radial, conforming adequately with the Navy Bureau of Aeronautics specifica¬tion. Work on the design that would become the SB2C started in late 1938 and the US Navy Bureau of Aeronautics ordered a prototype, the XSB2C, on May 15,1939, and of the XSB2A1 (Brewster). However, before the prototype flew, the US Bureau of Aeronautics ordered 370 production models, designated SB2C 1. Named Helldiver, the aircraft turned out to be possibly the most complex single engined aircraft developed for the USN at the time. Its Wright R 2600 engine was reliable and proven, but the overall design was beset by design and systems problems.

Curtiss 84 / SB2C Helldiver Article

The Helldiver was conceived as a mostly all-metal, low-monoplane wing design fielding a crew of two seated in tandem within a long cockpit – the pilot in the forward area and the tail gunner in the aft. The fuselage sported straight wings with a tapered trailing edge and rounded tips.
The US Navy Helldiver was produced with a reinforced and retractable undercarriage as well as an arrestor hook for carrier operations. Ordnance could be held in the internal bomb bay (including a single torpedo) as well as along two underwing hardpoints. Standard armament included a pair of fixed forward-firing 20mm cannons (4 x 12.7mm heavy machine guns in earlier production models) in the wings and a pair of 7.62mm M1919 Browning air-cooled machine guns in the rear cockpit.

Curtiss and the Helldiver became the focus of several Congressional investigations, one being led by Harry Truman. Recommendations were made that production of the aircraft should be stopped or drastically curtailed because of seemingly insurmountable problems. Another major problem was that Curtiss did not have the production facilities to build its new aeroplane in quantity, so the USN erected a new factory at Columbus, Ohio, for that pur¬pose. As each problem was resolved, another appeared, but this did not deter the US Army from ordering the aircraft as the A 25. This contract was a direct result of the effectiveness of the Luftwaffe’s Junkers Ju 87 Stuka, and the army’s machines were to be constructed at the Curtiss plant in St Louis. However, as orders poured in for a range of variants, licensed pro¬duction was set up at the Canadian Car & Foundry and the Canadian Fairchild factories. Problems aside, the various factories would eventually deliver a total of 5,516 Helldivers, the last rolling off the production line in October 1945.
The Curtiss design followed that of such predecessors as the P 40 Hawk and SBC Helldiver series, but had a short, stubby fuselage to comply with the stowage require¬ment. First flight of the prototype XSB2C-1 was made on December 18, 1940. During subsequent tests, excessive weight and positioning of the rear gun instal¬lations posed problems; the wing area had to be increased by nearly 10%, to 39.2 sq m (422 sq ft), to give adequate maximum lift; and the dive brakes were modified to reduce the excessive dive speed experienced during experimental flight tests.
The prototype, powered by a Wright R 2600 8 of 1,700 hp, was plagued with problems. The prototype XSB2C 1 was badly damaged in a crash on February 9,1941, rebuilt and flying again by May 6 that year with numerous changes, and then completely destroyed in another crash on December 21 the same year. Production aircraft incorporated more than 800 changes including larger, self sealing fuel tanks, increased armour and a larger tail. Armament for the first 200 aircraft consisted of four 0.5in wing guns (later models had one 20mm cannon in each wing panel) and two 0.3in guns for the observer. The bomb bay could house a 1,00 lb bomb to be dropped in a steep dive slowed by the massive perforated wing flaps. Underwing pylons could carry depth charges or auxiliary fuel tanks.
A production order for 370 SB2C 1s had been issued by the US Navy in November 1940, calling for deliveries to begin in December 1942, and from then onwards at a rate of 85 aircraft per month. By January 1941 the order had been increased to 578 machines; but matters were not improved when the prototype again crashed in December 1941, a fortnight after Pearl Har¬bor, due to wing and tail failure during a dive. This left the production team without a flight ¬test aircraft, but trials continued on mock¬ups and components, with improvements being made on the production design to include two 0.50 in (12.7 mm) guns (instead of one) in each wing, leakproof wing fuel tanks, plus cockpit and rear gun position armour plating.
It seemed evident during 1941 that the initial delivery date would not be met, but the attack on Pearl Harbor in December 1941 provided the impetus to give the building programme top priority. Production flight testing began on June 30,1942 some six months behind schedule. The first four pro¬duction SB2C 1s were ‘hand built’ for further testing, with subcontractors being used to help accomplish the task in hand. New radar, IFF and radio installations were tested and approved, and in May 1942 1000 Helldivers were ordered from the Canadian Car and Foundry Company of Fort William, Ontario, Canada, 450 of which were ear¬marked for the Royal Navy in the UK. Armour, self-sealing tanks, protected fuel and oil lines, increased armament, a lengthened fuselage and a completely new tail unit with greatly enlarged fixed and moveable surfaces were incorporated in the production SB2C-1. The SB2C-1 (A-25) production version, 978 of which were built by Curtiss, was powered by a 1,267kW Wright R-2600-8 engine driving a three-bladed Curtiss Electric constant-speed propeller.

Between June 30, 1942 (the first flight of the first production SB2C 1) and December 1942, when the first aircraft were delivered to VS 9 Squadron, more testing for structural stabil¬ity and safe diving techniques had been carried out. Basic armament on initial pro¬duction SB2C-1s comprised two fixed, for¬ward firing 20 mm (0.79 in) cannon in the wings, a 0.50 in (12.7 mm) gun on a power-¬operated mounting in the rear cockpit, and a maximum internal bombload of 454 kg (1000 lb); powerplant was the 1700 hp Wright R-2600 8 radial.
In December 1942, the first squadrons went aboard the new Essex class carriers but the aircraft were so deficient that they were declared non operational.
Truman’s committee found the Helldiver “hopelessly behind schedule and that [by April 1943] Curtiss had not succeeded in producing a single SB2C usable as a combat airplane despite expensive self praise in advertising”.
Curtiss lobbyists managed to secure further contracts and Curtiss engineers made constant redesigns.
Two hundred Helldivers were built to this standard, but were still prone to arrester gear troubles, tailwheel collapse and other structural problems. After further stages in the modification programme, production of a further 778 aircraft took place under the designation SB2C-1C, with two 0.30 in (7.62¬mm) guns (on an improved mounting) in the rear cockpit, hydraulically operated wing flaps, and most of the earlier problems over¬come. This batch were fitted with non-retractable tailwheels and self sealing fuel tanks.
On October 21, 1943, Squadron VB 17 aboard the USS Bunker Hill finally took the Helldiver into action when this carrier sailed to join the Essex and Independence in action against the Japanese at Rabaul harbour, New Guinea. Here, on November 11, with the loss of very few Helldivers, a considerable amount of damage was inflicted upon the enemy’s land based Zero squadrons and on shipping in the harbour.
Up to November 1943, (when the Helldiver first went into action in the Pacific theatre of war) more than 880 design changes were made. Some were part of the Army-Navy standardisation programme to permit the production of an Army version of the Helldiver as the A-25, which later served with the Marine Corps.
By the end of 1944 every large American carrier was equipped with a Helldiver bombing squadron.
By the end of March 1944 the factory at Columbus, Ohio, had built 978 SB2C-1/-1Cs, and this included the XSB2C 2 which was fitted with huge Edo floats and intended for the Marines, delivered in 1943. The USAAF did not want the aircraft, and used them only as target tugs and for other mundane tasks.
The next production version was the SB2C 3, of which 1112 were built with an uprated 1,416kW / 1900 hp R 2600 20 Cyclone engine and four blade propeller, deliveries starting in January 1944, and 1,112 examples of the SB2C-3 were produced
This was followed by the SB2C-4, with the same powerplant, but capable of carrying eight 5 in (127 mm) rockets or another 454 kg (1000 lb) bombload under the wings. Some were equipped with radar and designated SB2C-4E, and a total of 2045 of the -4/4E versions were built. The subsequent 970 SB2C-5s had increased fuel capacity and were basically a long range variant of the -4E.
During production, Curtiss and the USN strove to eliminate problems and improve the design. The ultimate production variant was the SB2C 5 (970 delivered, US Navy Bureau Numbers 83128 83751, 89120 89465), which had greatly improved combat effectiveness and APS 4 radar. Wing racks could carry an additional 1,000 lb of bombs or eight 5in high velocity aerial rockets. Handling characteristics were massively improved by perforating the dive brakes, while increased fuel capacity extended the type’s range.

Nine hundred Helldivers built by Curtiss were purchased by the USAAF and given the Army designation A 25A Shrike. They were, however, used only for second line duties such as training and target towing, and 410 of them were transferred to the US Marine Corps in 1943 as SB2C 1As. Ten others were supplied to the Royal Australian Air Force.

Canadian Car and Foundry was awarded a contract for 1,000 Curtiss SB2C Helldivers, designed to replace the Douglas SBD Dauntless. Iinitial development of this, the third Curtiss design to bear the name Helldiver, had begun in the US in 1939 and it was claimed that it would be capable of carrying a bigger bomb load, faster and farther than any other single engined dive bomber, but the aircraft was plagued by stability and structural problems. Both the prototype and the first production model suffered in flight structural failure and the first machines to go into service encountered so many problems that at least three major modification programmes were required before the type became acceptable. At Fort William one aircraft was destroyed and one damaged beyond repair during test flights. The first of the CanCar Helldivers, designated SBW, flew in July 1943 to be followed in August of that year by the first flight from an order of 300 Helldivers, designated SBF, which had been placed with Fairchild Aircraft in Quebec.
The SBW was identical to those produced by Curtiss in the US being a single engined, two seat, monoplane dive bomber, capable of delivering a 1,0001b bomb load (the ‘dash numbers’ signifying similarity to the SB2C 1, 3, 4 and 5). It mounted two cannon in the wings and .50 machine gun in the aft cockpit. Apart from the fabric covered control surfaces, it was of all metal construction, with folding wings for aircraft carrier stowage and with dimensions designed to allow it to fit the standard carrier deck lifts. The SBW 1 was powered by a Wright R 2800 8 engine, but later variants were fitted with the R 2800 20 and had wing racks installed to bring the bomb load up to 2,0001b. The wings were also fitted with jettisonable fuel tanks and from the SBW 4 onwards had improved wing flaps and dive brakes installed.
By the end of the war, when production was cancelled, CanCar had produced 833 of the original 1,000 ordered. This compares with a total of over 5,000 Helldivers produced in the United States. Almost all of the SBWs were delivered to the US Navy, but of the 450 original earmarked for the UK, 26 SBW 1s actually reached the Fleet Air Arm under Lend Lease in 1944, and these were never used operationally. There is some doubt as to whether these were actually taken into service, however. In addition to complete aircraft, CCF also provided a large number of components such as oleo legs and propeller blades for the Curtiss company.
The Canadian Fairchild Company produced 300 SBF 1, 3 and 4 Helldivers (also corresponding to Curtiss built 1, 3 and 4 models), bringing the total production of the SB2C series to 7200 aircraft.
The Helldiver’s main theatres of operation were the Philippines and the Pacific, where they replaced the SBD Dauntless as the standard USN scout/bomber during the second half of the war. They served in many naval air actions during the remainder of the Second World War and, in the case of the later models, for a while after. Two experi¬mental versions were the XSB2C 2 (an SB2C-1 (fitted with twin floats) and the XSB2C 6 (with a 2100 hp Wright R 2600 22 engine installed), but neither was considered suitable for series production.
The RAAF enjoyed considerable success with the Vultee A 35 Vengeance in the dive bombing role against the Japanese. Wanting to enlarge its air force, Australia placed an order for 150 A 25A Shrikes. However, Gen George Kennedy was strongly critical of the A 35 mission despite excellent results, and stated that the Australians did not have enough pilots to fly the Shrikes, even though the RAAF denied this. Kennedy got his way and the A 35 Wing was withdrawn from New Guinea.
In order to replace their Dauntlesses, worn out from combat in Indo China, France obtained an initial batch of SB2C 5s in 1950. They saw heavy action against communist forces and introduced napalm to the field of combat, operating from the carrier Arromanches and land bases and the final Helldivers were withdrawn from Aeronavale service in 1955.
In view of the communist threat to Greece 42 SB2C 5s were delivered, starting in 1949, which formed a training unit and the 336th Light Bombing Squadron at Larisa, replacing the Supermarine Spitfire. The Helldivers saw considerable action in the civil war, attacking communist forces backed by the Soviets and Yugoslavs. The type was effectively retired in 1954, replaced by F 84s.
Worried about communist threat, the USA supplied 25 SB2C 5s to Italy. However, the 1943 surrender agreement specified that Italy could not operate bombers so, in a bureaucratic move, the designation was changed to S2C 5. Some examples were used for anti submarine patrols and participated in NATO exercises. Further Helldivers were supplied to the Italian Air Force and two were gifted to the Italian Navy in the USA where a couple of Italian Navy pilots were trained on them, the only Italian S2C5 fitted with tailhooks. In 1953 the USA supplied the Italian Navy with 46 examples; they were never used, and by the early 1960s these aircraft were scrapped.
The USA supplied Portugal with 24 SB2C 55 in 1950; they were operated by the Navy until 1952, then transferred to the Air Force. All were out of service by 1956.
The Royal Thai Air Force received six SB2C 5s during 1951, and these aircraft were flown on combat missions against communist forces until 1957.
In all, 5105 Helldivers were built at Columbus, 900 A 25As at St Louis, Missouri, 300 SBFs a Fairchild Canada and 834 SBWs at Canadian Car and Foundry. The last Helldivers soldiered on until June 1949.
Production: a total of 5516 of all variants.

Gallery

Model 84 SB2C
Engine: 1700 hp Wright R 2600 Cyclone 14 cylinder two row radial

XSB2C-1
Engine: Wright R 2600 8, 1,700 hp
Wing area: up to 39.2 sq m (422 sq ft)

SB2C-1 / SBF-1
Engine: 1700 hp Wright R¬2600 8 radial.
Armament first 200 aircraft: 4 x 0.5in wing guns, 2 x 0.3in guns for the observer
Armament: 2 x 20 mm (0.79 in) cannon, 1 x 0.50 in (12.7 mm) gun
Internal bombload: 454 kg (1000 lb)

A 25A Shrike / SB2C 1A
Engine: 1,267kW Wright R-2600-8
Propeller: three-bladed Curtiss Electric constant-speed

SB2C 1C Helldiver
Engine: Wright R 2600
Span: 15.15 m (49 ft 8.5 in)
Length: 11.18 m (36ft 8 in)
Gross weight: 7533 kg (16607 lb)
Maximum speed: 452 km/h (281 mph)
Armament: 4 x 12.7mm heavy machine guns, 2 x 7.62mm M1919 Browning machine guns

XSB2C 2
Undecarriage: Edo floats

XSB2C 2
Engine: Wright R 2600
Span: 15.15 m (49 ft 8.5 in)
Length: 11.18 m (36ft 8 in)
Armament: 4 x 12.7mm heavy machine guns, 2 x 7.62mm M1919 Browning machine guns
Undercarriage: twin float

SB2C 3 / SBF-3
Engine: 1,416kW / 1900 hp R 2600 20 Cyclone engine
Propeller: four blade
Span: 15.15 m (49 ft 8.5 in)
Length: 11.18 m (36 ft 8 in)
Gross weight: 7471 kg (16471 lb)
Maximum speed: 473 km/h (294 mph)

SB2C-4 / SBF-4
Engine: 1,416kW / 1900 hp R 2600 20 Cyclone engine
Propeller: four blade
Armament: eight 5 in (127 mm) rockets or 454 kg (1000 lb) bombload

SB2C-4E
Engine: 1,416kW / 1900 hp R 2600 20 Cyclone engine
Propeller: four blade
Radar equipped

SB2C 5
Engine: 1 x Wright Cyclone R 2600 20, 1,900 hp (1417 kW) at 2,1300 rpm at sea level.
Wing span: 49 ft 8 5/8 in. (15.15m)
Length: 36ft 8in. (11.17m)
Height: 13ft 1.5 in.
Wing area: 422 sq.ft.
Empty Weight: 10,580lbs (4,799kg)
Maximum Take-Off Weight: 16,288lbs (7,388kg)
Cruising speed: 148 mph.
Maximum speed: 260 mph (418kmh; 226kts) at 16,100ft.
Maximum Range: 1,165miles (1,875km)
Climb to 10,000 ft: 8.9min.
Service Ceiling: 26,401ft (8,047m)
Armament:
2 x 20mm cannons in the wings
2 x 7.62mm Browning M1919 machine guns on a flexible mount in the rear cockpit.
Up to 2,000lbs of ordnance in the internal bomb bay including 1 x Mark 13-2 torpedo.
Up to 500lbs of ordnance across two underwing hardpoints.
Crew: 2
Hardpoints: 2
Radar: APS 4

XSB2C 6
Engine: 2100 hp Wright R 2600 22

CanCar SBW-1 Helldiver
Engine: Wright R 2800 8, later R 2800 20
Armament: 2 x cannon and 1 x .50 machine gun
Bomb load: 1,0001b, later 2,0001b

In 1937 the United States Navy was looking for a replacement aircraft for its Curtiss SOC Seagull series of biplane floatplane aircraft. The USN wanted a more modern, monoplane that could fulfill the same floatplane reconnaissance role but also include better performance and could operate from both land and water bases as needed. The undercarriage wasmrequired to be interchangeable. Curtiss and Vought were invited to produce prototypes through a May 1938 contract. The Curtiss prototype designated XSO3C-1 and the Vought XSO2U-1. The XSO3C-1 first flew on October 6th, 1939 and Curtiss receiced an order for production after some design revisions were ordered by the USN (including larger tail surfaces and upturned wingtips to aid in stability). The revised Curtiss Model 82A became the USN SO3C-1 for production under the early nickname of “Seagull”. The chosen powerplant became the 388kW Ranger V-770-6 series engine.

The SO3C fuselage sat atop a large centralized float running nearly the length of the aircraft while each wing underside was supported by smaller stabilizing floats fitted to struts. The pilot sat immediately behind the engine and the second crewmember, the designated observer (seated facing forward), was in a separate cockpit towards the rear of the aircraft, his position at the base of the vertical tail fin. Wings were mid-mounted and straight along the leading edge and tapered at the trailing edge, clipped at their tips (with a noticeable upturn to each tip end, needed to counter some initial instability problems in the prototype design). The empennage was dominated by a large vertical tail fin curved to provide the SO3C a most identifiable appearance. Horizontal stabilizers were fitted to either side of the vertical tail fin base. Construction was of all-metal, with the exception being the fabric-covered control surfaces.
Power was a Ranger XV-770-8 inverted V12 engine of 600 horsepower. The engine provided a listed top speed of 172 miles per hour though cruising was limited to around 123 miles per hour. Range was roughly 1,150 miles (or about eight hours of flight time) and the service ceiling was limited to 15,800 feet. The SO3C held an empty weight of 4,284lbs with a maximum take-off weight equal to 5,729lbs.

The SO3C carried a single 0.30 caliber fixed, forward-firing M1919 Browning machine gun (operated by the
pilot) and a 0.50 caliber Browning M2 heavy machine gun in the rear cockpit (operated by the observer). The SO3C could make use of a pair of 100lb general purpose bombs or 325lb depth charges, held externally underwing or on a central bomb rack. If fitted, the central bomb rack could field a single 500lb general purpose bomb.

The SO3C first flew in 1939 and was officially introduced for service in 1942. Users were limited to the United States Navy and the British Royal Navy (RN) Fleet Air Arm (FAA).
The first SO3C-1 “Seagull” production models were received by the USN in July of 1942 and served aboard the USS Cleveland with their V-770-6 series engines. The performance of these was never truly up to the expected USN performance standards and the type was subsequently generally converted to radio-controlled target drones under the designation SO3C-1K. All SO3C-1s were removed as front-line service, by the USN, by the time the SO3C-2C production models became available.

The SO3C-2 was based on the Curtiss Model 82B and was perceived as a more “navalized” form complete with arrestor gear and an under fuselage bomb rack on the landplane version to mount a 227kg bomb. 456 SO3C-2s were ultimately produced though 250 of these were sent to the UK under Lend-Lease under the designation of SO3C-1B (Curtiss Model 82C), although British records would seem to suggest that only 100 were received. However, these were ultimately delivered as SO3C-2C models featuring an uprated powerplant, hydraulic brakes for aircraft with wheeled landing gear and other improvements.
The Royal Navy Fleet Air Arm utilized the SO3C as the Seamew Mk.I. When the newer SO3C-2C versions came online with the Royal Navy, these were simply designated as the “Seamew 1”. All of the British Seamews were relegated to general training elements and specific air gunnery/radio training groups.
First Seamews were delivered to the Royal Navy in March of 1943. The first squadron fielding the Seamew became training 755 Squadron at Worthy Down (FN459), Hampshire, UK, in August of 1943. This squadron operated up until 1945. Two other training squadrons existed as the 744 and the 745 Squadrons based out of Nova Scotia, Canada.
In all, 250 Seamew aircraft were received by the British. Later deliveries were cancelled after the availability of the American Vought OS2U “Kingfisher” floatplanes increased by January of 1944. Once the Kingfisher gained more ground, the Seamew quickly disappeared from the Royal Navy by the beginning of 1945.
The “Queen Seamew” was the FAA designation for the SO3C-1K target drone production variant of the SO3C series. Thirty such examples were ordered under Lend-Lease but the order was cancelled before delivery.

Curtiss attempted to revive the aircraft by introducing the SO3C-3 (Curtiss Model 82C). The SO3C-3 boasted a lighter operating weight with a more powerful engine in the form of the SGV-770-8 series. While promising, only 39 examples were completed before production ended in January 1944. Any existing orders were cancelled outright.
Plans to introduce an SO3C-3 variant with arrester gear, and production by the Ryan Aeronautical Corporation of SO3C-1s under the designation SOR-1, were cancelled. Some 795 SO3C were ultimately produced. The SO3C was deemed more-or-less obsolete by 1944 and retired completely from service by 1945.

Curtiss SO3C-2 Seamew
Engine: 1 x Ranger VX-770-8 inverted V12, 600 hp
Length: 36.84ft (11.23m)
Wingspan: 37.99ft (11.58m)
Wing area: 289.982 sq.ft / 26.94 sq.m
Wing loading: 19.68 lb/sq.ft / 96.0 kg/sq.m
Height: 14.99ft (4.57m)
Maximum Speed: 172mph (277kmh; 150kts)
Cruising speed : 109 kt / 201 km/h
Maximum Range: 1,150miles (1,851km)
Service Ceiling: 15,797ft (4,815m)
Armament:
1 x 0.30 (7.62mm) caliber M1919 Browning machine gun in fixed, forward-firing position.
1 x 0.50 (12.7mm) caliber M2 Browning heavy machine gun in rear cockpit position.
2 x 100lb bombs OR 2 x 325lb depth charges underwing.
1 x 500lb on centerline bomb rack (land-based Seamews).
Accommodation: 2
Hardpoints: 2
Empty Weight: 4,284lbs (1,943kg)
Maximum Take-Off Weight: 5,730lbs (2,599kg)

Curtiss SO3C-2C
Engine: 1 x 447kW Ranger SGV-770-8 inline
Take-off weight: 2599 kg / 5730 lb
Empty weight: 1943 kg / 4284 lb
Wingspan: 11.58 m / 37 ft 12 in
Length: 11.23 m / 36 ft 10 in
Height: 4.57 m / 14 ft 12 in
Wing area: 26.94 sq.m / 289.98 sq ft
Max. speed: 277 km/h / 172 mph
Cruise speed: 201 km/h / 125 mph
Ceiling: 4815 m / 15800 ft
Range: 1851 km / 1150 miles
Armament: 1 x 7.62mm + 1 x 12.7mm machine-guns, 2 x 45kg bombs

The 1938 Owl was designed as an observation aircraft. First flown in 1940 the US Army Air Corp ordered 203 but performance was lacking and they were redesignated as coastal sub hunter and liaison aircraft.

The 1938 Owl was designed as an observation aircraft. First flown in 1941 the US Army Air Corp ordered 203 but performance was lacking and they were redesignated as coastal sub hunter and liaison aircraft.

Of all-metal construction, slots extend over the full span of the wing, and when the slots are opened flaps are automatically lowered.

Engine: Pratt & Whitney R 1340-51 Wasp, 592 hp
Length: 26.345 ft / 8.03 m
Height: 9.285 ft / 2.83 m
Wingspan: 40.781 ft / 12.43 m
Wing area: 210.436 sq.ft / 19.55 sq.m
Max take off weight: 5364.8 lb / 2433.0 kg
Weight empty: 4231.4 lb / 1919.0 kg
Max. speed: 191 kts / 354 km/h
Cruising speed: 167 kts / 309 km/h
Service ceiling: 20997 ft / 6400 m
Wing load: 25.42 lb/sq.ft / 124.0 kg/sq.m
Range: 609 nm / 1127 km
Crew: 2
Armament: 2x cal.30 MG (7,62mm)

In July 1937 Curtiss installed an 1160 hp supercharged Allison V 1710 19 V type engine in the 10th production P 36A, designated XP 40 (Model 75P).

Curtiss P-40 Article

The XP 40, flown for the first time on October 14, 1938, and evaluated by the USAAC in the spring of 1939, brought Curtiss a $13 million contract for 524 produc¬tion aircraft, fitted with 1040 hp Allison V-1710 33 engines, in April of that year. The first three of these were used as prototypes, the first flight by a production P 40 (Curtiss Model 81 A) being made on April 4, 1940.

In April 1939 the US Army Air Corps awarded what was at that time the service’s largest ever fighter contract, covering 524 examples of the P-40. Deliveries of the P 40 order, which had meanwhile been reduced to 200, began in May 1940. Two 0.30 in (7.62 mm) guns were installed above the nose, in the upper engine cowling. The USAAC (or USAAF, as it became in June 1941) gave the name Warhawk to all variants of the P 40.

France, already a major customer for the radial engined Hawk 75A, ordered 140 Model 81 Als (similar to the P 40), but France had fallen before these could be delivered. They went instead to the RAF, operational with No 2 Squadron in August 1941. These aircraft were given the RAF name of Tomahawk I/IA/IB, equipped with four 0.303 in (7.7mm) Browning machine guns (two in the cowling, one in each wing), and used for low-level tactical reconnaissance. The next US production version was the P 40B, of which 131 were built for the USAAF, having the same powerplant as the P 40 but with an additional 0.30 in (7.62 mm) gun in each wing, the calibre of the two nose guns increased to 0.3 in (12.7 mm), and armour protection for the pilot. The RAF received the 110 similar Model 81 A2s of this type intended for France, naming them Tomahawk IIAs. Variant P 40C followed, being similar to the P 40B but with a further 0.30 in (7.62 mm) gun in each wing and improved self sealing fuel tanks. The first flight took place on April 10, 1941, and 193 were built for the USAAF. Again an order intended for France, for 635 similar Model 81 A3s, went instead to the RAF, these becoming the Tomahawk IIB. A further 295 of this version, supplied to the RAF, were passed on to China (100) and the USSR (195) under the Lend Lease programme.

Curtiss P-40 China Article

In 1941 Curtiss introduced major design changes which earned the Warhawk the new Curtiss Model number 87. The new model was powered by an 1150 hp Allison V 1710-39 engine, equipped with a modified propeller reduction gear which permitted the fuselage, to be shortened by 152 mm (6 in). The undercarriage main wheel legs were also shortened; the rear fuselage was redesigned, and a deeper nose radiator was fitted. Provision was made for carrying one 227 kg (500 lb) bomb or a 197 litre (43 Imp gal) drop tank under the fuselage, and smaller bombs could be carried under the wings. Armament was reduced to two 0.5 in (12.7 mm) machine guns in each wing, the over nose guns being removed. Most examples of this new fighter-bomber version went to the RAF, which received 560 Model 87 Als as the Kittyhawk 1. Twenty three similar Model 87 A2s were built for the USAAF as the P 40D, and two were retained by Curtiss for further development. An increase in armament to six 0.5in (12.7 mm) wing guns led to the Model 87 A3, of which the RAF allocation was 1500 as Kittyhawk 1As, under Lend Lease, while 820 were delivered to the USAAF as the P 40E.

Meanwhile, one of the two P 40Ds retained by Curtiss became the XP 40F (or Model 87D) with the installation of a Rolls Royce Merlin 28 V type engine; this made its first flight on June 30, 1941. The Rolls engine offered a far better performance at altitude than the Allison, as a result of which a total of 1311 Merlin engined P 40Fs were built for the USAAF. Approximately the first 260 of these had the old style P 40 fuselage, but later models had a 53 cm (20 in) longer, redesigned rear fuselage, which improved low speed stability. They had the American (Packard) built version of the Merlin engine, designated V 1650 1 and developing 1300 hp; the air intakes were removed from the top of the engine cowling. These Warhawks were able to carry a 644 litre (142 Imp gal) drop-tank under the fuselage. A consignment of 250 aircraft for the RAF, to have been called Kittyhawk II, were not delivered.
US designations continued with the P40G, allocated to 60 of the original P 40s brought up to six wing gun standard in late 1940. The P 40H and J were experimental projects, which never left the drawing board the latter was to have utilized a turbocharged Allison powerplant, but was deemed unnecessary after the Merlin engined version appeared.
The next Warhawk to go into production, and the heaviest, was the P 40K. Built in parallel with the P 40F, it had a 1325hp Allison V 1710 73 engine, the longer fuselage of the later F models, and a small dorsal fin. With an all up weight of 4540 kg (10000 lb), it was nevertheless capable of 579 km/h (360 mph). Twenty one were delivered to the RAF as Kittyhawk IIIs, and the USAAF received a total of 1279. The K series P-40s were produced by the Curtiss plant at Buffalo to a total of 1300 units during the latter part of 1942.

The first sub type, the K 1, appeared in August 1942 and replaced the “E” model on the production line. However the Merlin engined “F” series was also in full production by this time so the “F” and “K” continued until they were supplanted by the “L” and ‘V’ models respectively in late 1942. Early “F” and “K” examples had the original “short” fuselage of all previous P 40 models but, from the P-40F 5 onwards and the K 10 onwards a new one foot eight inch section was introduced aft of the existing fuselage. This additional section supported the fin and rudder but the tailplane and tailwheel were left in their original positions.
The “K’s” were very similar to the preceeding “E’s” (and succeeding M’s” for that matter) with the primary difference being the engine; the V 1710 73 (or V-1710 F4R to use the GM Allison designation) of preceeding P 40E.
The main external differences from the P 40E were the addition to the P 40K-1 and K 5s of a curved dorsal fin (some late “E’s” had this) and the introduction of flared or “fishtail” exhaust ports (round on E, F and L). On the P 40K 10 and K-15s the differences were the lengthened rear fuselage with fin and rudder moved aft of tail plane, a strenthened windscreen assembly with extra bracing strut incorporated in port side only of curved side panel, and a radio mast introduced aft of the cockpit.
This version was followed by the P 40L, a lighter weight, ‘stripped’ development of the P 40F, often known for that reason as the ‘Gipsy Rose Lee’. It had two fewer wing guns, a lower fuel capacity, and no armour protection, but this resulted in only about 113 kg (250 lb) of weight being saved, and production was therefore limited to the 700 delivered to the USAAF. These were a mixture of long and short fuselage models, all powered by V¬1650 1 Packard Merlins. Similar to the K, but with the 1200 hp Allison V 1710 81 engine, the P 40M went in the main to the RAF (595 aircraft, also known as Kittyhawk IIIs), only five being delivered to the USAAF.
Other major external changes which followed were the revised cockpit canopy on P 40N 5 and subsequent models and the fitting of smaller diameter mainwheels (from 30 inch down to 27 inch) except on the P 40N 40 CU. On the “N” model also, the old “ring and bead” type gunsight atop the fuselage nose gave way to a single “bead” just aft of the engine; undercarriage position pins (introduced on the P 40M) protruded above the wing just aft of the undercarriage housing billets when the undercarriage was down; and the large external rear view mirror fitted to most P 40E, F, K, L and M on the support port edge of the windscreen rim was replaced by a smaller interior mirror centrally placed.

Numerically, the major production version in the Warhawk series, and the last, was the P 40N of 1943 after an extensive programme of structural weight saving to provide a higher performance. The USAAF received 4634 of this variant, and the RAF 586 as the Kittyhawk IV. They were powered mainly by the 1200 hp Allison V 1710 81 or 99 engine, but the final 220 of the batch had a 1360 hp V¬1710 115 powerplant. Armament comprised four 0.5 in (12.7 mm) wing guns on early models, and six of the same calibre on the later ones, which were also equipped to carry a 680 kg (1500 lb) bombload. The aircraft also featured a lengthened fuselage and redesigned canopy. Thirty P 40Ns were converted to two seat advanced train¬ers; two Ks and one N were converted (two of them with ‘bubble’ canopies) to XP 40Q to test engine cooling equipment, wing radiators and a four blade propeller.

Three hundred P¬40Fs and Ls were redesignated P 40R1 and R2 respectively when they were refitted with V 1710 81 engines.

Prior to the final termination of P-40 development, some effort was expended in combining aerodynamic refinement with increased power to produce a higher-performance model. A P-40K airframe was fitted with an Allison V-1710-121 engine rated at 1,425hp for take-off and 1,100hp at 7620m. Semi-flush low-drag radiators were incorporated in the wing centre section and a four-bladed propeller was fitted, the designation XP-40Q being assigned. A second, similarly re-engined P-40K for the P-40Q programme reintroduced the nose radiator scoop, but featured an all-round vision bubble-type canopy (previously tested on a P-40N). The definitive XP-40Q (converted from a P-40N-25 airframe) had clipped wing tips, the cut-down aft fuselage with bubble canopy and coolant radiators faired into the wing leading edges. Four 12.7mm guns were carried but proposed production models were to have carried, either six 12.7mm or four 20mm weapons. No production was undertaken.

When Warhawk production ended in November 1944, Curtiss had built, in addition to the XP 40, a total of 1704 Model 81s and 12 034 Model 87s; annual output being at its highest in 1942 (4453 built) and 1943 (4258), with the greatest number in any one month occurring in August 1943, when 463 were delivered. In addition to widespread use by the USAAF in Europe, North Africa and the Pacific theatres of war, aircraft from the Lend Lease and ex French allocations to the RAF (1180 Tomahawks and 3262 Kittyhawks) were also employed by the Royal Canadian, South African, Australian and New Zealand Air Forces; these too served in the Far East, the Western Desert and Italy as well as in the European theatre. China and the USSR also received P 40s under Lend Lease, the USSR receiving a total of 2097 aircraft. Their chief role was as close support low level attack aircraft.

Flying the Curtiss P-40

The principal versions were P-40 and, in British service, Tomahawk Mk 1(339 aircraft with the 1,160-hp/865-kW V-1710-19 engine), P-40B and Tomahawk Mk IIA (241 aircraft with heavier armament), P-40C and Tomahawk Mk IIB (1,123 aircraft with a revised fuel system), P-40D and Kittyhawk Mk 1(582 aircraft of a P-40C version with 1,150-hp/857-kW V-1710-39, shorter fuselage and shorter landing gear legs), and P-40E and Kittyhawk Mk IA (3,820 aircraft with two additional wing guns).

A total of 301 P-40 were allocated to the RNZAF. Thirteen squadrons covered the Pacific region. The P-40 was the only fighter used by the RNZAF in air-to-air combat, claiming 99 victories.

A total of 13,783 were built, making it the third most numerous American fighter of the war. The final delivery, P-40N-40 and P-40R, was in December 1944.

Curtiss P-40 Restorations

Curtiss P-40 Pilot’s Check List

Gallery

Replicas:
Loehle P-40
Jurca MJ-12 P-40
Rowley P-40
Grady Curtiss P-40

XP 40 / Model 75P
Engine: 1160 hp supercharged Allison V 1710 19

P 40 Warhawk / Model 81 A
Engine: 1040 hp Allison V¬1710 33
Armament: Two 0.30 in (7.62 mm) guns

Model 81 Al / Tomahawk I/IA/IB
Engine: 1,160-hp/865-kW V-1710-19
Armament: four 0.303 in (7.7¬mm) Browning machine guns

P 40B / Model 81 A2 / Tomahawk IIA
Engine: 1040 hp Allison V¬1710 33
Armament: 4 x 0.30 in (7.62 mm) guns

P40C / Model 81 A3 / Tomahawk IIB
Engine: Allison V-1710-33, 1040 hp
Wingspan: 37 ft 3.5 in / 11.36 m
Length: 31 ft 8.5 in / 9.7 m
Height: 12 ft 4 in / 3.75 m
Empty weight: 5812 lb / 2636 kg
Loaded weight: 7459 lb / 3393 kg
Max speed: 345 mph / 555 kph
ROC: 2650 fpm / 807 m/min
Service ceiling: 30,000 ft
Range int.fuel: 730 mi / 1175 km
Armament: 6 x 0.303in
Bombload: nil
Seats: 1

Model 87 / P-40D
Engine: 1150 hp/857-kW Allison V 1710-¬39
External load: one 227 kg (500 lb) bomb or 197 litre (43 Imp gal) drop tank + small bombs
Hardpoints: 3
Armament: 4 x 0.5 in (12.7 mm) machine¬guns

Model 87 Al / Kittyhawk 1
Engine: 1150 hp/857-kW Allison V 1710-¬39
External load: one 227 kg (500 lb) bomb or 197 litre (43 Imp gal) drop tank + small bombs
Hardpoints: 3
Armament: 4 x 0.5 in (12.7 mm) machine¬guns

Model 87 A2 / P 40D
Engine: 1150 hp Allison V 1710¬39
External load: one 227 kg (500 lb) bomb or 197 litre (43 Imp gal) drop tank + small bombs
Hardpoints: 3
Armament: 4 x 0.5 in (12.7 mm) machine¬guns

Model 87 A3 / Kittyhawk 1A / P-40E Warhawk
Engine: one Allison V-1710-39, 1,150-hp (857-kW).
Maximum speed 335 mph (539 kp h) at 5,000 ft (1,525 m)
Climb to 10,000 ft (3,050 m) in 4 minutes 48 seconds
Service ceiling 29,000 ft (8,840 m)
Range 850 miles (1,368 km).
Empty weight: 6,350 lb (2,880 kg)
Maximum take-off weight: 9,200 lb (4,173 kg).
Wing span 37 ft 4 in (11.38 m)
Length 31 ft 2 in (9.50 m)
Height 10 ft 7 in (3.22 m)
Wing area: 236.0 sq ft (21.92 sq.m).
Armament: six 0.5-in (12.7-mm) machine guns, up to 700 lb (318 kg) of bombs.

Model 87D / XP 40F
Engine: Rolls Royce Merlin 28 V type

Hawk 87D / P 40F Warhawk / Kittyhawk II
Engine: Packard V-1650-1 Merlin, 1300 hp
Wingspan: 37 ft 3.5 in / 11.36 m
Length: 31 ft 2 in / 9.55 m or 33 ft 4 in / 10.14 m
Height: 12 ft 4 in / 3.75 m
Empty weight: 6550 lb / 2974 kg
Loaded weight: 8720 lb / 3960 kg
Max speed: 364 mph / 582 kph
ROC: 2400 fpm / 732 m/min
Service ceiling: 30,000 ft
Range int.fuel: 610 mi / 976 km
Drop-tank capacity: 644 litre (142 Imp gal)
Armament: 6 x 0.50in, 281 rds each
Bombload: 1000 lb
Seats: 1

P40G Warhawk
Armament: six wing gun

P 40K / Kittyhawk III
Engine: 1325¬hp Allison V 1710-73 / V-1710 F4R
All up weight: 4540 kg (10000 lb)
Max speed: 579 km/h (360 mph)
Vne: 478 mph (415 kt)

P 40K-1
Engine: 1325¬hp Allison V 1710-73 / V-1710 F4R

P 40K-10
Engine: 1325¬hp Allison V 1710-73 / V-1710 F4R

P 40L
Engine: V¬1650 1 Packard Merlins

P 40M / Kittyhawk III
Engine: 1200 hp Allison V 1710 81

Hawk 87M / Curtiss P-40N / Kittyhawk IV
Engine: 1 x Allison V-1710-81 or –99, 1,360hp / or 1360 hp V¬1710 115
Length: 33 ft 4 in (10.2m)
Wingspan: 37 ft 4 i n (11.42m)
Wing area: 235.947 sq.ft / 21.92 sq.m
Height: 12.37ft (3.77m)
Empty Weight: 6,005lbs (2,724kg)
Maximum Take-Off Weight: 8,858lbs (4,018kg)
Wing load: 37.52 lb/sq.ft / 183.0 kg/sq.m
Maximum Speed: 378mph (609kmh; 329kts) at 3210m
Range: 240miles (386km)
Maximum range: 938 nm / 1738 km
Rate-of-Climb: 2,143ft/min (653m/min)
Service Ceiling: 38,156ft (11,630m)
Armament:
6 x 12.7mm M2 Browning air-cooled machine guns
2,000lbs of external ordnance
Accommodation: 1
Hardpoints: 3 (centre fuselage and two underwing)

P 40N-1-15
Engine: 1200 hp Allison V1710 81.
Span: 37 ft 4in (11.42m).
Length: 33 ft 4in (10.2m).
Max wt: 8850 lbs (4018 kg).
Max speed: 378mph (609 kph).

P-40N-20-35
Engine: Allison V-1710-99
Wingspan: 37 ft 4 in
Length: 33 ft 4 in
Height: 12 ft 2 in
Empty weight: 6550 lb
Loaded weight: 8850 lb
Max speed: 375 mph
Cruise: 300 mph
Normal range: 610 mi

P-40N-40
Engine: Allison V-1710-115, 1200 hp

XP-40Q
Engine: Allison V-1710-121, 1,425hp take-off /1,100hp at 7620m
Propeller: four-bladed
Armament: Four 12.7mm guns

P-40Q
Wingspan: 10.75 m / 35 ft 3 in
Length: 10.16 m / 33 ft 4 in
Max. speed: 679 km/h / 422 mph

P 40R1
Engine: V 1710 81

P 40R2
Engine: V 1710 81