Seahawks Over the Fleet
In 1939 the US Navy (USN) selected a new fighter to replace their Grumman F3Fs. This would be the Brewster F2A Buffalo. After losing out to Brewster, their competitor, Grumman, completely rebuilt their competing design. This would lead to the US Navy also placing orders for the resulting Grumman F4F-3 after the F2A was found to be disappointing in service. This change in plans and thus the loss of production time resulted in the Bureau of Aeronautics (BuAer) becoming concerned about the ability of the USN to update its capability in time for the war that was already brewing in Europe. This was becoming a point of concern as the likes of the the Anglo-French Purchasing Board were already making efforts to purchase American types to bolster their own production. BuAer was worried that foreign orders would take precedence and delay the introduction of the more more modern types into the fleet. As such the Secretary of the Navy, Charles Edison, was lobbied to act. This would result in both Brewster and Grumman (and Douglas) being directed to prioritise production towards domestic needs.
The result of this was immediately felt by both the British and French who had recently placed orders with Grumman for their new type. A solution was quickly needed. The French were the first to move, approaching Curtiss-Wright to develop a carrier capable version of their H75 fighter that had recently entered Armée de l'air (AdlA) service. This new variant was a minimal design change variant introducing just enough changes to allow operation from the Marine Nationale’s existing carrier Béarn, and in construction Joffre class. A follow on more refined version was also in design with this introducing more significant changes such as manually folding wings and a more powerful Pratt & Whitney R-1830 engine (1,200 hp vs the existing 1,050 hp version). This improved version also increased the armament from four (two in each wing) 7.5mm FN-Browning machine guns of the earlier variant to six of the same by way of the addition of two more in the upper fuselage firing through the propeller. Unfortunately for France, neither type would see service as the country fell to the Axis powers before they could be delivered. The aircraft went instead to the British Royal Navy Fleet Air Arm (RN FAA) who christened the new fighter the Seahawk I in line with the related P-40 Tomahawk that was also on order from Curtiss-Wright. Although limited in capability, the new type was still an improvement on the Fairey Fulmar.
The type’s combat victory was on Christmas Day 1940, when a land-based Seahawk destroyed a Junkers Ju 88 bomber over the Scapa Flow naval base. This was the first combat victory by a US-built fighter in British service in World War II. The Seahawk I also also pioneered combat operations from the smaller escort carriers. The non-folding wings were not an impediment for these due to there being no hanger and the air fact stored on deck. The British re-gunned them with the standard British .303 in (7.7 mm) Browning machine guns though. Six Seahawks went to sea aboard the converted former German merchant vessel HMS Audacity in September 1941 and shot down several Luftwaffe Fw 200 Condor bombers during highly effective convoy escort operations.
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Top: A 'Sea Mohawk', one of four RAF Mohawk IVs - all ex-Norwegian H-75A-8s - loaned to the Fleet Air Arm for for training purposes. These 'Sea Mohawks' were navalised only in the sense of having ad hoc arrestor hooks fitted for deck landing practice. This aircraft has been repainted in an early variant of the FAA's Dark Grey and Green over Sky scheme.
'Sea Mohawk' AR634 ('Red X') was assigned to the Marine Aircraft Experimental Establishment. The MAEE had a slipway at RAF Helensburgh but lacked a runway. Fortunately, in June 1940, an RN Air Section was granted lodger status at nearby RAF Abbotsinch. [1] So, MAEE Mohawks operated from Abbotsinch where a dummy aircraft carrier landing area was marked out.
Bottom: The first production Curtiss Seahawk Mk.I (AL231) in its factory-applied Dark Grey and Green scheme. This aircraft - acting as a prototype and designated H75A-3N by Curtiss - lacked roundels and had been given a temporary British civil registration. This was required for the Seahawk's 60 mile delivery flight from Curtiss Wright Plant 1 at Tonawanda, NY, to RCAF Aerodrome Hamilton near Mount Hope, ON.
Upon arrival at Hamilton, a Canadian pilot flew this aircraft on to RN Air Section Dartmouth in Nova Scotia. There, AL231 was test-flown by FAA pilots before being boxed for shipping to the UK from the Port of Halifax. All further Seahawks went from Curtiss Plant 1 or - after the Fall of 1941 - Plant 2 directly to the Port of Buffalo for delivery by sea to Britain.
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[1] No. 602 Squadron RAuxAF had taken its Spitfires south in 1939, leaving only a Coastal Command torpedo training group at Abbotsinch. This field just outside of Glasgow passed into official RN/FAA control as RNAS Abbotsinch in 1943.
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Top: A Curtiss Seahawk Mk.I (AX824) in full Fleet Air Arm service markings in mid-1941. Seahawk M2-K served with 768 Naval Air Squadron - the FAA's Deck Landing Training Squadron. Advanced, shipboard landing was aboard HMS Argus (I49) but the unit's aircraft formed a detachment at HMS Landrail, RNAS Machrihanish near Campbeltown in Scotland.
Initially, the Fleet Air Arm fielded two nearly identical Seahawk variants. The Seahawk Mk.I was based upon airframes of the Curtiss H75A-3 begun for export to France. The slightly later Seahawk Mk.IA was based upon Hawk 75A-8 airframes for Norway but, in internal equipment, differed not at all from the Mk.I.
Bottom: A Curtiss Seahawk Mk.IA of the temporary RN Fighter Squadron in the Western Desert. A camouflage scheme of Middle Stone and Dark Earth over Sky was applied to all 12 x Seahawks based at Dekheila. However, this anonymous Mk.IA was assigned to RNAS Dekheila (HMS Grebe) to provide nocturnal protection for the city of Alexandria - hence the under surfaces being repainted in black.
In March 1941, the first of the improved Seahawk II was introduced. These were the improved design with more powerful engine and foldable wings that the French had originally ordered. A total of 100 of the type would enter service replacing the Seahawk Is which were now relegated to training units.
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Bottom: A Curtiss Seahawk Mk.II [2] of 801 NAS embarked aboard HMS Victorious (R38) in 1942. Seahawk 7H wears the new Duck Egg fuselage stripe introduced for FAA aircraft operating in the Med as well as the yellow fin tips identifying British aircraft on Malta convoy duty.
The Seahawk Mk.II introduced folding wings but was otherwise largely similar to the 'interim' fixed-wing Seahawk Mk.I. A discrete difference was the Mk.II's new aerial mast - indicating the introduction of British wireless transmitters. [3]
Top: Curtiss Seahawk Mk.IIA. Other than minor equipment changes, the Mk.IIA was essentially similar to the earlier SeahawkMk.II. Seahawk 7-C served with 800 NAS aboard HMS Indomitable (92) during the August 1942 Malta run under Operation Pedestal.
Although outwardly indistinguishable from a Seahawk Mk.II, some late Seahawk Mk.IIAs sported blown Malcolm hoods. (These bulged, clear-view canopies did add some drag but greatly improved pilot visibility when landing-on.) A less obvious change was the elimination of the the previous retractable tailwheel in favour of a more robust fixed unit.
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[2] The internal Curtiss designation for the Seahawk Mk.II series was H75-10N. The FAA requested the removal of exhaust shrouds as part of a weight-reduction campaign. Added drag showed this to be a false economy and shrouds were quickly reinstated.
[3] British VHF TR1133 or lower frequency TR-9D types replaced the original US RCA sets. To counter growing drag, ring-and-bead gun sights were eliminated (the rate of reflector gun sight failure being greatly reduced by this period).
While the initial Seahawks utilised the air-cooled Pratt & Whitney R-1830 radial engine, the RN FAA was interested in a more capable type. Such was the rapidity of developments in the war, upon introduction the new Seahawk version was already seen as lacking, especially at altitude. At the same time the Royal Air Force (RAF) was introducing the Curtiss P-40F Kittyhawk II. This introduced the 1300 hp British-built Rolls-Royce Merlin 28 engine with a single-stage two-speed supercharger thus dramatically improving performance at altitude. The RN FAA approached Curtiss-Wright to see if they could develop a version of this for the fleet. The result would be the Seahawk III (although a new type based on the P-40 rather than the earlier, though related, P-36, the Navy decided to stick with the basic Seahawk name).
The Seahawk III not only introduced the Merlin engine and the longer fuselage of the P-40F but also the folding wings mechanism of the Seahawk II and other carrier related equipment. Although a larger, heavier platform the new Seahawk III was an altogether better performer being over 100km/h faster; capable of much longer range and altitude and much better armed with six 0.50 (12.7mm) machine guns (three in each wing). 250 of the type would eventually be purchased by the RN FAA. The USN also purchased a pair for trials – these were designated as the Curtiss F14C1 – but beyond these the type did not serve further with the USN or USMC.
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Top: A Merlin-powered Curtiss Seahawk Mk.III of 766 Naval Air Squadron. Based at HMS Nightjar (RNAS Inskip) in Lancashire, 766 NAS was part of No.1 NOTU (Naval Operational Training Unit). This unit also some rather worn radial-engined Seahawk IIs but hands-on experience with the livelier Seahawk III was essential for future carrier fighter pilots.
Packard-built engine shortages occurred due to Merlin 29s already being earmarked for Kittyhawk IIs as well as CCF-built Hurricanes and Sea Hurricanes. As an interim, engineless Mk.III airframes were delivered to Britain for fitting with locally-made Rolls-Royce Merlin 30s (RM 2M). Driving Rotol props, these engines produced 1,300 hp @ 3,000 rpm. The FAA was already allocated supplies of Merlin 30s and, since Fulmar II production was winding down, the engine type was readily available for installation in Seahawk IIIAs.
Bottom: A Seahawk Mk.IIIA of 768 NAS operating from a forward airfield - RAF Heathfield - for advanced deck landing training in early 1944. [4] This aircraft was lost on 23 Feb 1944 during an attempted deck-landing aboard escort carrier HMS Ravager underway in the Irish Sea. (FN134 lost its arrestor hook before being stopped by the barrier. Pilot Sub-Lt I.C. Falconer, RNVR was unharmed in the crash but the Seahawk was a write-off.)
Inset: A detail of the cannon armament of the Seahawk Mk.IV. These aircraft were fitted with a quartet of International Harvester-built 20mm Hispano M2 guns. This proved an unhappy combination. The US-made cannons were prone to jams and other stoppages. Some delivered aircraft had their guns replaced with British Hispanos - resulting in the ad hoc but more successful Seahawk Mk.IVA model. However, the bulk of Mk.IV orders would be converted into resumed Mk.III production. [5]
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[4] 768 NAS was home-based at HMS Sanderling (RNAS Abbotsinch) but placing a detachment at RAF Heathfield greatly reduced flying time to reach practice carriers decks in the Firth of Clyde.
[5] Seahawk IIIBs were Mk.IV airframes converted on the production line to have a quartet of .5-inch Brownings. The Seahawk IIIC returned the type to full six-gun wing armament, being all but identical to the original Mk.III.
The Seahawk IV was introduced in late 1942. This was basically the same as the Seahawk III but replaced the machine guns with a pair of 20 mm Hispano cannon in each wing. Only 50 of the type were acquired.
In early 1944 Curtiss-Wright tried to interest the RN FAA in the Seahawk V. This was a significantly redesigned variant based on the company's similar P-40Q. The interest was not there though as the RN FAA had already started to introduce the F6F Hellcat (acquired under Lend-Lease) and the home-grown Hawker Sea Typhoon.
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Top: The Seahawk Mk.V was originally put forward as a navalised P-40Q variant. This concept featured the leading edge coolant radiators of the XP-40K with oil cooler retained under the nose. [6] The tailplane stretch of the Seahawk III and A-frame arrestor hook were both replaced by a new fuselage rear section and 'sting' hook (inspired by the larger Curtiss SB2C dive bomber).
The Seahawk V was to be powered by a Lend-Lease Packard V-1650-3 featuring a two-speed, two-stage supercharger and driving a 4-bladed Aeroproducts propeller (until a Curtiss Electric equivalent was available). Performance gains - especially at altitude - were claimed to be impressive. Unfortunately, Curtiss-Wright design staff were, at the time, distracted by the license-production of Republic P-47G Thunderbolt fighters for the USAAF.
On initial inspection of the proposed Seahawk Mk.V, the FAA found the cockpit to be inadequate. The lower cockpit of the P-40Q had obvious visibility implications. And Curtiss' beautifully-rounded 'bubble' canopy also prompted some negative comments. Firstly, a flat clear-view windscreen was thought essential. Secondly, the sliding hood was far too shallow for the pilot to raise his seat while landing-on.
Bottom: The Sea Typhoon that would ultimately replace the Seahawk.
The Seahawk would see out the war though with the last air raid of the war in Europe was carried out by RN FAA aircraft in Operation Judgement on 5 May 1945. Twenty-eight Seahawk IV aircraft, flying from escort carriers, took part in an attack on a U-boat depot near Harstad, Norway. Two ships and a U-boat were sunk with the loss of one Seahawk and one Grumman Avenger torpedo bomber.