“It was inevitable that the FAA had to have the Seafire. It was the only fighter available that would fit into the new, low-hangar-roofed Implacable and Indefatigable. There were no other British aircraft. Hawker’s Hurricane replacement — the Typhoon — was too large, the Martin-Baker MB5 was not being built and the Blackburn Firebrand had yet to fly properly. The Hurricane itself was not available in sufficient quantity and it was unlikely to be fitted with the Griffon engine or be modified to allow wing folding.”
““When the batsman says: ‘Lower’. I always go higher. I drift off to starboard and prang my Seafire. The blokes in the ‘goofers’ all think I am green, but I get my commission from Supermarine. Cracking show, I’m alive, but I’ve still got to render my A25.””
Seafire Operational Notes
The Seafire would prove to be an excellent fighter in the hands of above-average flyers, but threatened to be a coffin for those who were not.
Deck Landing: A successful Seafire deck capture needed a “three-point” landing. If the fighter hit the deck on just its main wheels, it would bounce over the arrester wires and go into the crash barrier.
But the Seafire had also proven it possessed excellent carrier-deck take-off characteristics, needing as little as 5mph of “over-deck” wind to get into the air.
And in spite of its evil deck-landing reputation, Seafire squadrons also proved to be capable of catching an arrester-wire at 40-second intervals.
Nevertheless, ongoing attempts were made to mitigate its landing weaknesses: In March 1943 all Seafire Mk IB and IIC aircraft received modifications to their arrester hook to increase its load from 7000lbs to 10,500lbs. In August that year the strengthening of the arrester “A” frame and fittings was initiated.
A Supermarine Seafire hits the barrier on HMS INDEFATIGABLE after returning from a strike on the Japanese oil refinery at Pangkalan Brandan, Sumatra..
But the Seafire’s high crash rate on small escort carriers in the windless skies over Salerno was to inflame concern over the type’s suitability as a naval fighter.
Three aircraft and the escort carrier HMS Ravager were allocated to an urgent program of testing in an effort to identify problems and develop improved landing techniques. In November 1943, test pilot Lieutenant Eric Brown again found himself behind the stick of a Seafire.
His orders: Put the Seafires through a rigorous program of testing “until something broke”.
This he did: He wrote-off two of the machines. His testing program involved landing at incrementally lower speeds and heights, as well as experimenting with different approach techniques.
The main undercarriage legs were strengthened and extensive landing trials conducted aboard HMS Pretoria Castile in February 1944 and HMS Indefatigable in March to find ways to eliminate Seafire’s tendency for arrester-hook bounce.
A major discovery of these trials was that arrester wires needed to be correctly tensioned to avoid the tail of the Seafire rising after capture, which – in turn – caused the propeller to make contact with the deck.
HMS Implacable’s Seafire pilots in 1945 would consider the Seafire’s landing problems significantly reduced by the time they were deployed to Japan. The aerodynamics of the US 89gal drop tanks pressed into use on their LF IIIs actually improved the little fighter’s deck approach characteristics. Combined with improved training, this fleet carrier’s Seafire attrition rate fell to acceptable levels.
“When the decklanding trials unit in the UK got to hear of the Seafires’ efforts at Salerno, it carried out its own trials in Ravager. However, the test pilots, keen to break new frontiers of science, used their own private techniques — not the curved approach but a ‘crab’ approach — so that their results were of no interest to the squadrons, who would not use such a dangerous method. So that, even if Admiral Vian had asked for advice on how to avoid Seafire troubles in the future, he would have received nothing useful in reply from the carrier trials unit.”
“As regards the speed of the (early) Seafire, the added weight of strengthening the fuselage to take the heavy arrester hook had reduced this quite considerably and indeed it was far from being the famous fast Spitfire from which it was derived. ”
Performance: Many Seafire pilots would say the IB model was the overall best of the Merlin-engined machines as it was the closest to the original Spitfire. The penalty on weight and aerodynamics through the strengthening of the arrester hook, catapult spool and folding wings ranged from reductions in speed to poorer handling.
Performance concerns were raised shortly after Operation Torch in 1942 when Seafires proved unable to overhaul fleeing Ju88s.
The first instance, when a Ju88 bombed HMS Furious, caught the Seafires landing-on. One pilot broke off his approach but was unable to jettison his 30gal ventral tank – reducing his top speed to only 310mph. Later that same day a patrol of two Seafires - one IB and one IIC – failed to overhaul another Ju88. The IB proved to be the faster machine in the chase.
Ongoing improvements saw the LF III become the fastest Seafire of World War II.
All marks retained the Spitfire’s outstanding rate of climb and exhilarating flight characteristics. Pilots knew they could extricate themselves from virtually any trouble by pulling the nose up and letting the Merlin haul the light fighter away.
The Rock of Gibraltar viewed between two Supermarine Seafire aircraft of No 885 Squadron Fleet Air Arm on board HMS FORMIDABLE.
But the Merlin’s operational life was much shorter at sea than the 500 flying hours touted for its land-based sisters. Hard wear from the boost used in take-offs and the jolts from landings saw engine exchanges being conducted after every 200 hours.
A maintenance crew at work on a Supermarine Seafire at RNAS Lee-on Solent.
Maintenance, however, was regarded particularly difficult. Unlike the US-built naval fighters, the Seafire’s internal workings were difficult to access. These access panels would also often distort, and jamb, after heavy deck landings.
It is worth noting that the Spitfire airframe was capable of sustaining extraordinary dive speeds before pilots lost control or the aircraft began to break-up. Tests with a photo-reconnaissance version of the Spitfire achieved Mach 0.86 before controlled flight was put in peril. In comparison, the Me 109 and Fw 190 could handle up to Mach 0.75. The Lightning, howerver, could only handle up to Mach 0.68 and the Thunderbolt 0.71. This is one of the reasons the Mustang became the standard US escort fighter over Europe: It could achieve Mach 0.78
One of the Seafire’s particular quirks was evident in Cunliffe-Owen built machines. These were put together with flush-fitting rivets instead of the pop-head variety used in Westland’s 1023 builds. Pilots said the difference was obvious when it came to handling characteristics. The 250 Cunliffe-Owen built Seafires became prized possessions.
Flight deck hands about to free the arrester wire from a Supermarine Seafire which has just landed on HMS ILLUSTRIOUS in the Clyde. It is carrying a distinctive conformal "slipper" drop tank.
“From the operational point of view, the Seafire most significantly had an entirely inadequate flying range and endurance. A Carrier aircraft should have at the very least two and a half hours of flying endurance for its work on combat patrols and much longer endurance than that for long-distance strike actions. But the Seafire could be airborne only for little more than an hour and twenty minutes before having to return to land. This could adversely affect the whole operation of the Aircraft Carrier itself, which would have to adapt to the limitations of its aircraft.”
Endurance: The Seafire's low endurance is the subject of much debate and discussion. Certainly, it limited the usefulness of the interceptor on fleet carriers where mutli-role aircraft were rapidly becoming the norm.
As a land-based interceptor, the Spitfire needed enough fuel to respond to sightings of hostile aircraft, take-off and climb madly to engagement height, engage in combat – and then return to the home airfield below.
Carrier based aircraft generally had a different set of requirements. In order to respond fast enough to incoming raids, fighters needed to already be in the air. This involved participation in fleet Carrier Air Patrols (CAP), generally split into three sections – high, medium and low.
To be an effective contributor to the CAP, the Seafire needed good endurance - the ability to loiter in the air for a useful time or cruise steadily over great distances in company with bombers.
Initially, it did not have that.
But the Seafire remained in production during and after the war due to the Royal Navy's unique requirement for a rapid-response fighter to counter fast moving, land-based aircraft.
Early Seafires could remain on station for only 45 minutes under combat conditions. The Sea Hurricane was barely better, offering only one hour CAP patrols. The Martlet could stay on station for 2 hours 15 minutes, while the Fulmar averaged 2 hours.
As a result, the Seafire was initially reserved for defensive missions: The longer-ranged Martlets and Fulmars maintained the CAP, while the Seafire filled its sibling’s interceptor role – sitting on the deck ready to leap into action once the first radar reports started rolling in.
Commander 'Mike' Crosley gave this account of the RAF-style "slipper" drop tank fitted to Seafires:
Amongst the piles of ammunition, wireless sets, pilot’s seats, propeller spinners, tail steering arms, wing mats, sweating bodies and noise, we could see several huge slipper-shaped petrol tanks. Some of these were being offered up to the underside of the Spitfire’s fuselage — where a bomb might ordinarily be — and the fuel lines were being connected by an invisible, sliding fit. There was only a half-inch gap between the underside of the fuselage and the top surface of the tank, which was all of six feet long by two feet wide. We found that it could hold 90 gallons of 100 octane fuel. This was more than the Spitfire carried in its internal tanks. A closer study of the jettison arrangements showed that a Bowden cable release in the cockpit let go the lifting ring — stressed to three tons breaking strain — in the top surface of the tank. The tank then slid backwards onto two lugs sticking out two inches from the fuselage underside. The nose of the tank then dropped and the airflow forced it downwards and clear of the fuselage underside. The slightest skid, we thought, and the whole thing would come clear of the two lugs, slide back and hit the tail. However , the Spits would now have a range of 400 miles and would allow a fly-off to Malta well before we got to ‘bomb alley’.
An original Seafire L-IIC performance data sheet. CLICK HERE
Seafire L-IIC endurance: The figures for the LIIC were typical of the Merlin models and are an accurate indicator for other low-rated variants. The most economical cruising speed was 188mph, loiter speed was 167mph, at 5000ft.
Clean: Total fuel 85 gallons. Range 493 miles. Total endurance 2.75 hours. Operational endurance* 0.95 hours (57 minutes).
30gal Drop Tank: Total Fuel 115 gallons. Range 682 miles. Total endurance 3.8 hours. Operational endurance* 2.05 hours.
45gal Drop Tank: Total fuel 130 gallons. Range 755 miles. Total endurance 4.25 hours. Operational endurance* 2.5 hours.
* Makes accommodation for 5 minute take-off climb to 5000ft, 15 minutes of combat at 5000ft, 20 minutes of holding pattern at 2000ft.
“During this time (October/November 1944) the UK had sent out a Supermarine Seafire for the (US Naval) Patuxent Test Centre, and others, to fly. I had the job of test flying it after assembly and also briefing a number of pilots to fly it. Without exception all were amazed at the small size of this fighter, which had been the backbone of the Battle of Britain. They all loved its flying characteristics, but wondered if it was beefy enough in its operations. Its performance over the years and many theatres of war, spoke for itself.”
COMBAT NOTES
Henry "Hank" Adlam: The Disastrous Fall and `Triumphant Rise of the Fleet Air Arm from 1912 to 1945
I would like to record that a fellow pilot and friend of mine from a Seafire squadron, Bruce Clark, arranged to have a race and a dog-fight against me and my Wildcat, just for the fun and interest of it. Both our squadrons were serving in Illustrious but, at the time (1943), were working up at Hatston Air Station in Scotland. For the race, we flew alongside and level at a steady 130 knots and then, at a signal , we both opened the throttles wide. As expected the Seafire was faster and gradually moved ahead but not all that swiftly. We reckoned and agreed afterwards that the Seafire was no more than 7 or 9 knots faster than the Wildcat. For the dog-fight, my Wildcat and I were at a disadvantage because Bruce was an exceptional pilot and always had been even while training, whereas I was never in that category. It was interesting to find that the Seafire had a much better rate of climb but the Wildcat was steady and gained speed faster in a steep dive. It was surprising to find that the Wildcat with its stubby little wings could sustain a steep turn inside the Seafire and this was all the more surprising and gratifying too bearing in mind that Bruce was by far the better pilot. In a real fight, the formidable fire power of the Wildcat, with 0.5 calibre shells from six Browning machine guns would have been at a very considerable advantage over the Seafire with its much smaller 0.3 calibre machine gun bullets. A two-second burst of fire from the Wildcat guns on the Seafire would have been sufficient to smash it out of the sky, whereas two seconds of fire from the Seafire probably would have no more than peppered the Wildcat with little bullet holes. This was the Seafire Mark (F) 2c we are considering… (Editor's note: From the Scotland location, the Martlet may have been from a training squadron of older model Martlets, or a freshly forming 'line' squadron of new aircraft. Only a handful of original RAF conversion Spitfires, the Seafire IB, appear to have carried six 0.303 machine guns, and none of the Spitfire IIC)
Commander R 'Mike' Crosley DSC RN. They Gave me a Seafire
We had several interesting dogfights with the much larger and more powerful F4U Corsair. In turning dogfights, the Corsairs were unable to get a bead on us if we saw them first. However, they could, like the Fw 190, out-dive us (both starting together) because of their much higher density (weight/ frontal area). Also, above 15,000 feet, they were faster than Seafire LIIIs. However, the FIII with its two speed, uncropped supercharger, could easily keep up with the Corsair at 20,000 feet and above. The Corsair could not out-turn a Seafire I, II or III as has been claimed. However, if the Corsair slowed down to about 90 knots and then the pilot selected half flap — provided it was down to its last 50 gallons of fuel — it could hold a Seafire LIII in a turning match at this speed and configuration at heights above 10,000 feet. Below this height, the Seafire, if it did not overheat (Seafire IIIs all had additional thermostatically controlled engine cooling radiators under the port wing), could outclimb the Corsair while making the turn and ‘spin it off’. Each type and mark of fighter aircraft ever built has its ‘best’ height for various performance aspects and where it can out -perform most of the others over a narrow height band . For the Seafire LIII, this height band was 0 — 12,000 feet .
A Seafire IB
Seafire Mk IB:
A batch of 48 ex-RAF Spifire Mk VB s entered the workshops for adaptation to naval use in mid 1942. This was roughly half the number requested and the conversion was incomplete – relegating the aircraft to the training role.
The modifications, which proceeded slowly, were carried out by RAF repair centres.
A second batch-order was placed and 118 more “second-hand” Spitfire Mk VB s were earmarked for Seafire Mk IB status. This time RAF Maintenance Unites were given the task. However, due to the demands on their time for repairing damaged RAF aircraft, these Seafire conversions also were given a low priority and many did not enter service until the RN had started receiving the purpose-built Seafire IIC.
The F IB had the Spifire’s “B” category wing with four 0.303in Browning machineguns (with 350rpg) and two Hispano Mk 2 No. 5 20mm cannon (60-120rpg).
It was engined with a Rolls-Royce Merlin 45 or 46 producing 1415hp, and was plumbed to allow the fitting of a 30 gallon jettisonable fuel tank. But the IB was to prove to have poor take-off performance/ This limited the type to the fleet carriers, with Sea Hurricane IIs and Martlets filling the gap on escort carriers.
Such was the urgent need for high-performance interceptors that six IBs were assigned as permanent deck parks on outriggers to Illustrious, Formidable and Victorious in June 1942.
For the cameras ... A publicity shoot aboard HMS Indomitable.
FAA Pilot Hugh Popham's view:
From "Sea Flight: The Wartime Memoirs of a Fleet Air Arm Pilot"
Once again we found ourselves at the mercy of the haphazardness of the Fleet Air Arm’s development, for the Seafire, like the Hurricane before it, had fixed wings of too great a span to go down the lifts; and so we were consigned to outriggers, of which there were three only, and a permanent deck park. This arrangement had the abstract disadvantage of making us feel as if we didn’t quite belong, and the more concrete one of always being in someone’s way… There were practical disadvantages as well: the difficulty of maintenance in the open air, and of perpetual handling of aircraft up and down the deck. These would have been quite acceptable if they had not coincided with our first experience of the Seafire’s special faults as a deck-landing aircraft. Minor damage was frequent, for apparently faultless landings often buckled an oleo-leg or bent a propeller tip: major prangs were not unknown: and what with one thing and another, Commander Flying quickly acquired a strong aversion to using us if he could possibly use the Wildcats. And so we struggled to keep the aeroplanes serviceable, or to make them so … and watched the Wildcats, of which there were two squadrons aboard, come bouncing in from absurd height with complete impunity.
Seafire Mk IIC:
The first “real” Seafire rolled off the production lines was the Mk IIC and began to enter service in September 1942. This was a variant of the Spitfire Mk VC.
Some 40,000 man-hours was spent redesigning the Spitfire fuselage to seamlessly integrate the arrester hook and the necessary strengthening to accommodate carrier launches and landings.
Yet it did not yet possess a folding wing.
Instead, the “C” designation declares this model as carrying the Spitfire’s “Universal” wing, with provision to carry up to four upgraded 20mm Hispano cannon (120 rpg). But the navalised fighters never carried this configuration because of the extra weight which lengthened the take-off run.
The Seafire IIC, therefore, usually retained the two-cannon, four machine-gun configuration.
The capacity to fit a 250lb bomb under the fuselage would also be rarely used, also due to weight and range issues.
A few extra modifications were based on the experience of the Mk IB, mainly extra strengthening around the catapult spool points.
The landing gear also was redesigned and strengthened – along with being angled forward in the hope of reducing the fighter’s tendency to topple on its nose.
The Seafire’s low profile made it difficult to launch via catapult, with the propeller barely clearing the raised accelerator housing aboard the armoured carriers. This proved to be of little concern: Seafires required very little deck to get airborne unassisted.
The provision of RATOG (Rocket Assisted Take Off) hard points also proved of little value.
Combat experienced prompted the addition of extra armour under the pilot’s seat to protect him from ground-or-sea based anti-aircraft fire.
A Supermarine Seafire Mk IIc of No. 885 Naval Air Squadron on the flight deck of HMS FORMIDABLE in the Mediterranean, December 1942.
But the most significant change was the addition of a structural-strength fishplate, which ran along the mid-fuselage longeron between the forward cockpit bulkhead and the radio bay.
In all, 53 modifications had been made over the original Spitfire airframe.
The resulting aircraft retained most of the Spitfire's advantages - and disadvantages. The Seafire IIC climbed twice as fast as the F6F-5 Hellcat at 2980ft per minute. But the Hellcat had a combat radius of 340nm against the 140nm of the IIC.
The Royal Navy, however, regarded the interception capability of the Seafire to be of equal importance to that of the loiter capacity of its American counterpart (supplies of which were regarded as suspect).
Two main versions of the Mk IIC were built.
Mk F IIC
Built by Supermarine, this mid-altitude fighter was generally fitted with a Merlin 45 (maximum power at 13,000ft) or 46 (maximum power at 20,000ft) with a three-blade propeller. There were 262 examples built.
This model had an empty weight of 5322lb (2419kg), increasing to 69781b (3172kg) for a normal operational weight. The 30gal extended range fuel tank lifted the full weight to 7272lb (3305kg).
Trial flights produced a maximum speed of 363mph (581km/h) at 7300ft (2200m). This increased to 398mph (641km/h) at 2l,000ft (6400m). Rate of climb was 4900ft (l500m) per min at 4800ft (l500m). This fell to 4050ft (l250m) per min at 18,000ft (5500m).
The main concern was that the IIC was six per cent heavier than the Seafire IB - but retained the same Merlin 45/46 engine. This meant the IIC was 15mph slower than its predecessor.
Captain Brown commented:
“Nevertheless, there was some concern over performance shortcomings, initial climb rate and low-altitude speed particularly leaving something to be desired. The Seafire IIC was some 13-15 knots slower than the Mk Ib at all altitudes owing to the heavier “C” wing and the added weight of local strengthening coupled with the greater drag of the wing to which could be added that of the catapult spools”
A Supermarine Seafire taking off from the carrier HMS FURIOUS.
“My enthusiasm for this new Seafire variant was such that, one afternoon, in sheer exhilaration, I looped it around both spans of the Forth Bridge in succession – court-martial stuff nowadays, but during a war nobody has the time to bother with such formalities.””
Mk LF IIC
Built by Westland Aircraft in a configuration optimised for low-altitude operations, this model mostly had a Merlin 32 engine with a four-bladed propeller.
The switch from the medium-altitude focus of the IIC to a low-altitude configuration was based on studies which showed most naval interceptions were made below 10,000ft. This is where a carrier-based interceptor needed its top performance.
The Merlin 32 was capable of putting out 1645hp at 1759ft, and 1640hp at 3000ft. At full emergency boost, the L Mk IIC could bound upward at 4600ft per minute to a height of 6000ft. This was 1500ft per minute better than the Hellcat and Corsair. The 'low-rated' LF IIC could even reach 20,000ft some two minutes ahead of the earlier F IIC, though its performance at height was lacking.
Seafires fitted with the Merlin 32 produced a maximum sea-level speed of 316mph (506km/h, rising to 335mph (536km/h) at 6000ft (l850m). On the surface this may look worse than the F-IIC, but the heights quoted are not direct comparisons. What the data represents was a significant boost in low-level speed, acceleration and responsiveness.
The LF Mk IIC production run totalled 372 machines.
Such was the turnaround in performance experienced by the LF IIC that the decision was made in late 1942 to convert all Merlin 46 F Mk IIC's to the LF standard.
Captain Brown was very impressed with this Seafire:
“With this engine change, the fighter became the Seafire L Mk IIC… the most exciting aircraft that I had flown to that time.
Its initial climb rate and acceleration were little short of magnificent and at maximum boost it could maintain 4600ft/min up to 6000ft.
Another result of the installation of the Merlin 32 was a quite dramatic reduction in take-off distance and, in fact, the L Mk IIC without flap could get airborne in a shorter distance than the standard Mk IIC using full flap!
Later, some Seafire L IICs were to have their wingtips clipped to boost roll rate and incidentally, add another four knots to maximum speed, although these changes were to be obtained at some cost in take-off run and service ceiling.
My enthusiasm for this new Seafire variant was such that, one afternoon, in sheer exhilaration, I looped it around both spans of the Forth Bridge in succession – court-martial stuff nowadays, but during a war nobody has the time to bother with such formalities.”
The first Seafire fighters fly over Japan, 17 July 1945. The first plane to actually crass the coast (top) was piloted by Lieut (A) Norman Goodfellow, RNVR, of Southport, Lancs. These planes soon returned to their carrier as the strike was cancelled due to heavy fog.
“Once airborne , the Seafire responded with the sensitivity of a polo pony to nearly all our ignorant demands upon it. It behaved in its normal habitat with such unselfish grace and with such rapid response and power, that we knew we were being allowed to fly a thoroughbred. Once we were climbing away into the sky, all we had to do was keep our eyes open and the enemy could not touch us.”
Seafire Mk III
The eventual supply in April 1943 of a folding version of the Spitfire’s distinctive elliptical wing finally produced a naval fighter to be reckoned with.
Now workable numbers of the aircraft could be stowed within the Royal Navy’s fleet carriers’ hangars via their narrow lifts. No more would the Seafire be relegated to five-or-six deck-parked machines solely for the purpose of fleet protection patrols.
Instead of taking up 36ft 10in, the folded Seafire was just 13ft 6in wide.
It had been no easy task: The slender elliptical wing which gave the Spitfire both its scintillating performance and its distinctive looks was already tightly-engineered. The greatest challenge which faced the Supermarine team was limiting loss of structural integrity. It was not until October 1942 that they had began work of fitting prototypes to a test aircraft.
The wing was distinctive in it had two folding points: The first just outboard of the wheel well and the second at the wingtip. This was to guarantee the upward-folding wing would fit under the low, 14ft high, hangar ceilings of the likes of HMS Indomitable, Implacable and Indefatigable.
There simply was no space among the leading-edge fuel tanks, ammunition feeds and spars to accommodate a powered retraction system. Nor was there enough reserve weight.
As it was, the folding mechanics increased the weight of the Seafire by 125lbs. The rigidity of the wing was assessed to have been reduced by 10 per cent.
In active service, an experienced Seafire handling crew could fold the wings within 45 seconds. Spreading them took an extra five seconds. However, five men had to be dedicated to the process.
Seafire IIIs under construction in a Westland factory. Also evident are early versions of the twin-engine Welkin high-altitude fighter.
A Seafire III from HMS KHEDIVE carries a 500lb bomb during Operation Dragoon.
Mk III Armament: For weight reasons, the gun armament remained the same as previous marks – two cannon and four machineguns. These were, however, more efficiently designed into the folding wing. The drag-inducing spare cannon stub of the "universal" C wing was deleted (as can be seen in the photos of the MkIIIs on this page) - adding some 5mph to the fighter's top speed.
The cannon was a new Mk V model Hispano. This was given a new form of gun housing involving a small “blister” housing on the upper wing . This, combined with the gun's light weight, lifted the fighter’s top speed by another 5mph.
The Seafire III also was fitted with hard-points capable of holding a 500lb bomb under the main fuselage and two 250lb bombs under the wings. In service, the 250lb bombs were never carried for fear of damaging the wings. Instead, the under-wing hard points were used for six 60lb "zero length" rocket projectiles.
A Royal Navy Fleet Air Arm Seafire fighter being warmed up on board the aircraft carrier HMS Implacable while ratings hold chocks under the wheels. The 89 gallon ex P-40 Warhawk drop tank is prominent.
Mk III Endurance: Off Sakishima Gunto in the Pacific, the Seafire's loiter capability was found to be no longer good enough. Especially not in return for the little fighter’s high wastage rate .
It became essential to extend the Seafire’s range.
Fortunately, the fighter wings of HMS Indefatigable and HMS Implacable independently came up with solutions to this lingering problem.
Indefatigable’s pilots and maintenance teams snared a supply of the RAF’s troubled 90 gallon “slipper” conformal fuel tanks from the RAAF. The 45 gallon type provided for Indefatigable had proven insufficient. While these conformal tanks were notorious for splitting and leaking, and incredibly difficult to fit as the connector nozzles were out of sight once the tank was flush with the airframe, they did the job.
Implacable’s air wing – greatly disturbed by the disparaging reports they had been hearing of the Seafire as they made their way across the Indian Ocean to join the Pacific Fleet – were determined to save their beloved steed's reputation.
Pilots of 801 and 880 Squadrons used 'the rumour mill' to locate an abandoned stock of RAAF P-40 Warhawk 89 gallon drop tanks on Papua New Guinea. After a somewhat dubious trade involving an exchange rate of one case of Scotch whiskey for 100 tanks, the contraband was transferred to Implacable and the air fitters set about adapting them to suit the Seafire IIIs.
The end result was a great boost in the Seafire’s operational endurance to 3.5 hours. Suddenly, it was capable of engaging in RAMROD (offensive air superiority ) missions. However, it could still not match the performance of its US counterparts - a Corsair carrying a 1000lb bomb could still fly further.
"Drag did increase by as much as 10%, but when all aircraft in the Wing had been modified to carry the 89-gallon tank, it meant they could carry out offensive sweeps or strike escort duties to a useful radius of 185 miles - 225 miles was achieved by one 'Ramrod…” - The Seafire, David Brown
Some pilots reported the 89 gallon 'teardrop' tank as having another, unexpected benefit: It changed the aerodynamics of the Seafire in such a way as to actually improve the type's landing characteristics. Whether it was this 'beneficial' drag or simply better trained and less fatigued pilots, Implacabe's Seafire accident rate was considerably lower than previous operations.
Mk III Landing Equipment: This, the final Merlin engined Seafire, would incorporate a strengthened arrester hook and “A” frame assembly from the production line. But testing revealed the need for further modifications. Extra strengthening was added to counter the sideways load induced by the rolling of an aircraft carrier’s flight deck while at sea.
Under the bombed bastions of the entrance to Grand Harbour, Valletta, Malta, an escort carrier arrives with the deck loaded with Supermarine Seafire IIIs (recognisable by their detached wingtips).
“The Seafire, as opposed to the Spitfire, had the immense weight of an arrester hook added a long way aft of its centre of gravity , and the 28 pounds of solid lead added by the front engine bearers had not entirely corrected this tail heaviness. In the case of the Seafire III series, the aircraft was so unstable fore and aft that it should not have entered service in that condition.”
Stability: One of the first completed Seafire III machines was delivered for trials on June 8, 1943. It was found to be unstable due to an unexpected shifting of the centre of gravity. All Seafire F IIIs therefore received ballast weights, shifted radio equipment and modified elevator controls.
Disturbed airflow produced by the folding joints contributed to the unexpected instability. New seals along the wing fold points helped fill the gaps producing the disturbed airflow but never fully solved the problem.
Pilots also complained of trim problems, aileron stiffness and decreased rate-of-roll at speed. Fixes were found through plating over the outer machinegun bays to give the wing extra torsional stiffness and roll-rate was improved through aileron balance tabs and the optional removal of wingtips.
Remediating these stability issues considerably delayed the Seafire III program. Production of the new wing also was an issue. Delays in tooling and manufacturing resulted in significant delays in their delivery. The first 32 airframes earmarked as F III’s eventually received a fixed wing – and were therefore re-designated Seafire F IICs.
“The second thing he did on taking over the Wing was to get us a better low-level version of the Seafire III. This had the Merlin 55M engine, which gave more output at low level and less at high altitude . This was because the 55M engine had a ‘ cropped’ blower. It did not then absorb the engine power to no purpose at low altitudes. The energy saved was then available for going faster and farther on the same fuel.”
Mk III Variants: The Seafire III came in three versions: The F (original model) III, the LF (low-altitude optimised) III and the LR (low-altitude reconnaissance) III. The vast majority of the total Seafire III production run was the LF variant, with 870 built by Westland and Cunliffe-Owen 350. So successful was this, the last Merlin-powered Seafire, that it remained in service until 1947.
The F III. Only about 100 examples of this original version were completed with the Merlin 55 engine before production shifted towards the more powerful LF variant.
The Merlin 55 was very similar to the 45, but had automatic boost control and barometric governing to reduce the load on the pilot. These refinements, along with the aerodynamically "cleaned-up" wing and four-bladed propeller, boosted the IIIs top speed by some 20mph at all heights over the IIC
The F III was designed to fight between 8000ft and 15,000ft and proved to be 20mph faster than the IIC at all heights. In operational service it proved to be faster than the F6F-3 Hellcat between 3000ft and 14,000ft, and was evenly paced with the F4U-1A Corsair between 6000ft and 10,000ft.
The LF III was fitted with a Merlin 55M optimised for low-level performance. Its empty weight was about 54571b (2480kg) with an all-up weight of 71331b (3242kg). A cropped supercharger impeller helped this low-rated engine deliver 1585hp at 2750ft. This was slightly less than the Merlin 32 of the L Mk IIC, but the LF III was still the faster and steeper-climbing machine. It could achieve 358mph at 6000ft. More than 900 of this variant were produced.
The LR III. As with the reconnaissance variant of the Seafire LR IIC, this aircraft had provision for one vertical and one oblique camera in the rear fuselage. Some 129 were built.
“... the Chance Vought workforce and pilots were astounded at the small size of the Seafire. Nevertheless, their pilots were keen to fly the Seafire so, having given them cockpit checks, I left them to get on with it. I came back the next day to find their engineers and draftsmen had removed a number of hatches to see inside. This was fine but, when one of their pilots flew the aircraft, a large panel broke away which had not been replaced correctly. By the time I arrived, they had made and fitted a replacement hatch. The pilots carried on flying and were all equally impressed with the Seafire’s performance and manoeuvrability.”
“The Seafire LIII now had 200 more horsepower at 3000 feet than the Spitfire IX. Its fuselage was lighter by about 200 pounds. It was further lightened in 3 Wing by removing half the gun ammunition and taking away the two outboard .303s altogether. In this condition it could out-turn, out-roll and out-climb the Spitfire IX at all altitudes up to 10,000 feet, a feature which would come into urgent use on several occasions in the forthcoming operations. At last the Fleet Air Arm had an aircraft which could out perform, in a narrow heightband, its contemporary in the RAF.”
OVERVIEW
By the end of the war in 1945, the Seafire III retained the best climb rate of all allied carrier-borne aircraft. It's ability to attain high dive speeds without losing control, as well as maintaining competitive level-flight speeds, guaranteed its place aboard British carriers for years to come.
Surviving Supermarine Seafire LF III G-BUAR.
Despite the challenges of its light airframe, the Seafire's deck landing characteristics were eventually improved to acceptable levels.
Perhaps' the Seafire's lasting epitaph comes not from a British pilot, such as Captain Eric 'Winkle" Brown, but instead an American one.
US Navy test pilot 'Corky' Meyer got to fly a Seafire III at a Navy Fighter Conference in March, 1943, Florida. Meyer was a Grumman test pilot and lead project pilot for the F6F Hellcat, F7F Tigercat, F8F Bearcat, F9F Panther, F9F-6 Cougar, Jaguar, Tiger, and Mach II Super Tiger and eventual President and CEO of Grumman American:
In his own words (from his 2006 book: Corky Meyer's Flight Journal: A Test Pilot's Tales of Dodging Disasters - Just in Time):
Without argument, the Spitfire/Seafire configuration was probably the most beautiful fighter ever to emerge from a drawing board. Its elliptical wing and long, slim fuselage were visually most delightful, and its flight characteristics equalled its aerodynamic beauty.
The Seafire had such delightful upright flying qualities that, knowing it had an inverted fuel and oil system, I decided to try inverted 'figure-8s'. They were as easy as pie, even when hanging by the complicated, but comfortable, British pilot restraint harness.
Spins were like a training aircraft, with instant recovery as soon as the controls were released. Even if I couldn't find the trim tab controls handily, which I couldn't, I didn't need them. The stability about all three axes of the aircraft was low enough to be a fighter pilots dream and high enough to fly hands-off in mildly turbulent air, it was a great combination, acrobatics were a pleasure, the aircraft responded right after the thought came to the pilots mind, seemingly without effort.
I was surprised to hear myself laughing as if I were crazy.
I have never enjoyed a flight in a fighter as much before or since, or felt so comfortable in an aeroplane at any flight attitude. It was clear to see how so few exhausted, hastily trained, Battle of Britain pilots were able to fight off Hitler's hordes for so long, and so successfully, with it.
The Lend-Lease Royal Navy Wildcats, Hellcats and Corsair fighters were only workhorses. The Seafire III was a dashing stallion!
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