Sunday, March 30, 2008

Weekend Wings #13: The Spitfire - The Legend Lives On

In the first part of this three-part series we examined the initial development of the Spitfire and its operational service through the Battle of Britain in 1940. In the second part we looked at its further development and operational service through the rest of World War II. In this final part we'll examine the maritime version of the Spitfire; the Spiteful, Seafang and Attacker developments; and the final versions of this classic fighter to see service.

1. The Seafire.

The Fleet Air Arm (FAA) of the Royal Navy expressed interest in the Spitfire very early in its development, but the urgent need for operational aircraft for the Royal Air Force (RAF) meant that no attention could be spared to develop a more specialized version suitable for aircraft-carrier operation. In one sense this was a blessing, because by the time such attention could be given the Spitfire was already in its Mark V version with a more powerful engine and armament. The "Sea Spitfire" was quickly renamed the Seafire by collapsing the two words into one.

The Seafire Ib, the first production variant, was a converted Spitfire Mark Vb equipped with an arrestor hook. It soon exhibited very serious problems in the carrier environment. The aircraft had never been designed for the hard landings encountered on an aircraft-carrier (which are essentially a controlled crash onto the deck), and the relatively narrow undercarriage wasn't strong enough to stand up to repeated landings of this sort. The fuselage was also too weak to take the strain of such abuse, for which it had never been designed.

The Seafire II was soon introduced, with reinforcing strips riveted around weak areas, catapult spools and other equipment making the aircraft more suitable for the maritime environment. Unfortunately this had the effect of moving its center of gravity further back, making it more difficult to control in low-speed flight. The aircraft also lacked the large landing flaps found on other carrier-dedicated aircraft such as the Grumman F4F Wildcat and F6F Hellcat and Chance-Vought Corsair F4U. These problems led to many landing accidents. Furthermore, neither the Ib or II had folding wings, which made it difficult to store the aircraft aboard carriers.

The Seafire F.III was the most developed Merlin-engined Seafire variant. It incorporated double-folding wings (folding at the tips and near the roots in a reversed Z shape) and addressed many of the shortcomings of earlier versions. It proved to be a little slower than its Spitfire progenitor due to the added drag of the tailhook and additional maritime equipment, but still satisfactory in overall performance.

The Seafire saw its first major operational service during Operation Torch, the invasion of North-West Africa during late 1942. It flew from HMS Furious, a full-size aircraft carrier, and from smaller escort carriers whose confined decks weren't really suitable for the combat operations of high-performance aircraft. Several aircraft were lost to operational accidents due to the relatively light, low-strength airframe - a perennial problem with early Marks of Seafire. This would be even more in evidence during the Salerno landings in southern Italy in 1943. Out of over a hundred Seafires covering the landings from escort carriers, more than 40% were lost due to operational accidents and still more required an excessive amount of maintenance and/or repair.

The Seafire F.III design tried to address these problems, but the FAA wanted a more significant improvement. Jeffrey Quill, Supermarine's Chief Test Pilot, was given a temporary commission as a Lieutenant-Commander and spent five months at sea on Royal Navy carriers, flying Seafires in all weather conditions and sea states and getting a clear idea of what was needed to make the Seafire as superb a performer at sea as the Spitfire was on land. When he returned to Supermarine he was able to inform designers of his experiences and pass on lessons learned.

This would bear fruit in the Seafire F Mark XV, a Griffon-engined variant which entered service in 1944. Its more powerful engine gave it significantly better performance, and its fuselage and undercarriage were further strengthened. This version would see combat against Japanese aircraft in the Pacific theater. It was basically similar to the Spitfire Mark XIV. Just as the latter was was developed into a flush-fuselage version with bubble canopy, the Mark XVIII, so the Seafire was developed into the Mark XVII, shown below. Note the unique double-folding wings, at the tip and near the root.

Four aircraft-carriers plus a supporting fleet of battleships, cruisers, destroyers and a Fleet Train moved into the Indian Ocean during 1944, carrying out air strikes against Japanese installations in Malaysia en route to Australia where they would be based. In 1945 they joined the US Navy in operations against Iwo Jima and Okinawa. The British carriers were tasked with interrupting the flow of Japanese aircraft replacements through minor islands, freeing the larger US carriers to support the landings and resist kamikaze attacks.

British carriers could accommodate fewer aircraft than their US counterparts because of their heavily-armored decks, which weighed far more than the wooden decks of US carriers and took up much more internal space. On the other hand, during kamikaze attacks the British armored decks withstood the impact of enemy aircraft and bombs far better than their US counterparts. In one famous incident a kamikaze crashed abreast the island on a British carrier, making a large dent in the armored deck. It was promptly filled with quick-drying cement, and within ninety minutes the carrier was in full operation once more. US Navy officers observing the incident were amazed, saying that any US carrier suffering such an impact would be out of operation for months and require major shipyard repairs.

The FAA and Royal Navy Carriers also operated with the US Navy carrier task forces against mainland Japan. The Seafires still had the same limited range of their Spitfire forebears and couldn't carry as much ordnance as the larger, more powerful US aircraft, so they were usually assigned to Combat Air Patrol over the carriers to protect the ships. They performed very well in this role.

After World War II a final version of the Seafire, the Mark 47, was produced. This was the highest-performance variant of the entire Spitfire/Seafire family. It had a Griffon 87 or 88 engine driving a contra-rotating propeller with six blades. It carried 152 gallons of internal fuel, giving it a greatly extended range compared to earlier versions. This version saw action from a Royal Navy carrier early in the Korean War.

2. The Spiteful.

The elliptical Spitfire wing was very effective, but as aircraft speeds increased with more powerful engines it became clear that it produced too much drag. Supermarine engineers designed a new laminar-flow wing similar to that of the P-51 Mustang to overcome this problem. They took the opportunity to widen the track of the undercarriage. The new wing was tested on a Spitfire Mark XIV in 1944.

While the new wing was being developed the Griffon-engined Spitfires were experiencing directional stability problems. To overcome these a larger tail unit was designed. The opportunity was taken to mate this with the new wing and a flush fuselage with bubble canopy, similar to that on the Spitfire Mark XVIII. This effectively produced a completely new aircraft, which was named the Spiteful. The Air Ministry ordered 150 of the new design, but due to the higher performance of jet-powered aircraft only a few were built in 1945. They were never taken into service.

3. The Seafang.

The Spiteful design was not adopted for service, but the FAA wanted a faster, more powerful fighter for carrier operation. The Spiteful was redesigned with an arrestor hook and folding wings. It was also fitted with a contra-rotating six-bladed propeller. In this naval version it was renamed the Seafang. Eighteen prototypes and initial production aircraft were completed, but its low-speed handling was not as good as the competing Hawker Sea Fury. Also, its performance was essentially the same as the Seafire Mark 47. Further production was therefore cancelled and the Seafang never entered operational service.

4. The Attacker.

The advanced laminar wing design of the Spiteful and Seafang was adopted by Supermarine for its Attacker jet fighter design for the FAA. This first flew in 1946 and entered service in 1951. 183 were built, but its tail-wheel design led to numerous problems in service and it never saw combat.

5. The Last Versions Of The Spitfire.

Towards the end of World War II the Spitfire Mark 21 was produced. This had severe handling problems, so much so that the RAF's test pilots recommended that no further development of the Spitfire family be undertaken. However, Supermarine still had faith in its aircraft and worked hard to eliminate the problems. Meanwhile, the Mark 21 entered service in 1945. Only 120 were completed before the end of the war terminated production.

A later development with a flush fuselage and bubble canopy, the Mark 22, was produced in larger numbers after the war.

As mentioned above, an enlarged tail unit was designed for the Spiteful to provide greater longitudinal control. This was adopted for the Spitfire, along with a larger fuel capacity and provision for launching rockets. The final Spitfire version, the Mark 24, incorporated all these improvements. Only 84 were built and it served with only one squadron (plus reserve units).

Spitfires continued to serve in the Royal Air Force and many other countries after World War II. They saw combat in the 1947 Indo-Pakistani War and the 1948 Arab-Israeli War. The last combat flight of the Spitfire in the Royal Air Force occurred in 1954 in Malaysia, an air strike against Communist guerillas. The last RAF Spitfires were withdrawn from service in 1957, but some air forces continued to operate them into the 1960's.

In conclusion, what can we say about this magnificent aircraft? It saw service from the first to the last day of World War II and in every theater of operations: Britain, Africa, Sicily, Italy, the Normandy invasion and assault on Germany, the Russian Front, Australia and the South-Western Pacific, the assault on Iwo Jima, Okinawa and Japan, and operations in the China-Burma-India theater. Including the Seafire variants, well over 22,000 were produced in total. That makes the Spitfire family the third-most-produced fighter aircraft in history, behind the Soviet Ilyushin Il-2 and German Messerschmitt Bf-109.

Unlike most other aircraft companies which produced new aircraft designs at frequent intervals (e.g the Hawker Hurricane-Tornado-Typhoon-Tempest-Fury/Sea Fury range), Supermarine chose to keep developing the Spitfire. I think this may be due to the premature death of its designer, R. J. Mitchell, in 1937. His successors actively sought ways to continue to improve his design rather than replace it with something new. Furthermore, Mitchell's basic design was so advanced, so superb, that it allowed for such development.

It should also be noted that the Spitfire achieved the highest speed ever attained by a propeller-driven aircraft. In high-speed diving trials conducted at Farnborough in England during late 1943 and 1944 a Spitfire Mark XI achieved a true air speed of 606 mph. Another Spitfire, a Mark XIX, reached an altitude of 51,550 feet in 1951, which is reportedly the highest altitude ever attained by a single-engined propeller-driven aircraft. In descending, this aircraft entered an uncontrollable dive during which it is calculated that a true air speed of no less than 690 mph was achieved. The aircraft landed safely. The Spitfire's ability to achieve such speeds in a dive was due to its wing, which had a Mach limiting number of 0.9 - the highest of any Allied aircraft in World War II.

Overall there has never been a more successful fighter aircraft than the Spitfire in operational service in any country. It established a record that is unparalleled and unsurpassed, and to this day remains iconic of the Royal Air Force in World War II. The surviving Spitfires draw huge crowds at air shows to this day, and an Australian company is even producing a kit version of the Spitfire to 80% and 90% scale for home-building!

In closing, let's remind ourselves that the Spitfire can still surprise people. The following video clip illustrates this perfectly. Warning - the reporter's language is Not Safe For Work.



Anonymous said...

Peter, I've enjoyed your blog (and your moderating at THR) especially the aviation posts.

I thought you might be interested in this article regarding Armoured Vs Non Armoured flight decks for carries in WWII.

I am not a naval architect or damage control specialist so I have no clue as to the relative merits of the arguments.

Best wishes keep blogging.


I discovered the site while looking up B

Anonymous said...

Thanks for the info for mine and my friends science project.

Anonymous said...

There are a group of twenty guys at the Enstone Flying Club near Oxford (UK) who are building a squadron of 12 replica, 90% full size, Supermarine Spitfire Mk 26Bs.
They hope to have them all flying by the end of 2012.