Sunday, March 16, 2008

Weekend Wings #11: A Legend Is Born

Here's a quiz.

Which aircraft achieved ALL of the following milestones:

  • Was in production and in operational front-line service from the first to the last day of World War II?
  • Was the most-produced fighter aircraft of any of the Allied powers in World War II and the third-most-produced military aircraft in history?
  • Served in every theater of combat in World War II, from land bases and/or in naval operations from aircraft-carriers?
  • Served in the Air Forces of every major Allied power?
  • Achieved such fame that its very name was enough to scatter enemy formations in panic, and led to a senior enemy officer demanding that his unit be equipped with them?
  • Revolutionized air reconnaissance and was responsible for taking the photographs that led to some of the most daring and successful operations of World War II?
  • Attained the highest altitude ever achieved by a single-engined propeller-driven aircraft?
  • Attained the highest speed ever reached by any propeller-driven aircraft?

This aircraft is so well-known, even sixty-three years after the end of World War II, that I'm sure you'll recognize it immediately. (Click this and all other photographs for a larger view.)

This is the first instalment of a three-part Weekend Wings series about the Supermarine Spitfire and its superb operational record, probably unsurpassed by any other aircraft in history. This first part will examine the genesis, design and early versions of the Spitfire, up to and including the Battle of Britain in 1940. The second part will explore its development over the rest of World War II. The final part will examine the Seafire naval variant, the Spiteful, Seafang and jet-powered Attacker developments and post-World-War-II Spitfire models, and assess the enormous impact of this aircraft on aviation history.

The Spitfire had its genesis in the Schneider Trophy races for seaplanes.

R. J. Mitchell, the brilliant designer for the Supermarine Aviation Works (a subsidiary of the Vickers conglomerate), developed a series of fast monoplane seaplanes that won the Trophy in 1927, 1929 and 1931. These triple victories won the Trophy permanently for Britain, and today it's displayed in the Science Museum in London. The Supermarine S.6B, which won the Trophy in 1931, is illustrated below.

Seventeen days after winning the Schneider Trophy the S.6B set a new world speed record of 407.5 mph. This was a major embarrassment to the Royal Air Force (RAF), whose fastest fighter of the day, the Hawker Fury biplane, could manage only 207 mph.

Previously, the Air Ministry had issued Specification F.7/30 for a new fighter. Mitchell designed the Supermarine Type 224 to meet it. This was a gull-wing monoplane with a fixed undercarriage powered by a Rolls-Royce Goshawk engine producing 660hp.

Neither Mitchell nor the RAF liked it very much. It lost the competition when the Air Ministry selected the Gloster Gladiator, which would be the last biplane fighter developed for the RAF.

Mitchell now began to combine elements of the Type 224 and the S.6B seaplane. A new Air Ministry Specification F.5/34 led to the Supermarine Type 300 design, still using the Goshawk engine but for the first time featuring elliptical wings similar to those developed for the S.6B, which were to become the Spitfire's most recognizable feature. However, the aircraft was still woefully underpowered. Only when Rolls-Royce introduced their Merlin engine (destined to be as famous as the Spitfire and powering many of the finest aircraft of World War II) did the new fighter design really show promise. The Air Ministry agreed, and wrote Specification F.37/34 around Mitchell's design (at the same time that they wrote F.36/34 around the design of the Hawker Hurricane).

The Spitfire was to have far more serious production problems than the Hurricane due to its all-metal construction. Mitchell reasoned that high speed was vital, and because this would place greater stress on the wings and airframe he discarded biplane manufacturing techniques. The Spitfire would be of all-metal monocoque construction. Only the rudder, elevator and aileron surfaces would be fabric-covered, and that only in the earliest models - metal replaced fabric in those parts by 1941. However, until the mid-1930's the entire British aircraft industry had worked with wood frames and cloth coverings for wings and fuselage. Most aircraft component manufacturers were too small and too poorly funded to afford the transition to all-metal fabrication. This caused very serious production delays for the Spitfire at first, leading the Air Ministry to consider abandoning its production after the initial contract. Fortunately its performance was so superb that abandoning it became out of the question, and the teething problems in production were overcome by 1940.

The Spitfire's contemporary, the Hurricane, had no such production problems. Sydney Camm designed the Hurricane along the same lines as existing biplane fighters, using wood covered with fabric for much of its structure. He wanted it to be highly maneuverable with a tight turning circle, regarding high speed as a less important factor. Due to adopting the same methods as biplane construction, already widely known and used in the aircraft industry of the day, it could be produced quickly and easily. Largely for this reason, Hurricanes would make up about two-thirds of the RAF's fighter force during the Battle of Britain. A Hurricane Mk. 1 is shown below.

Unfortunately, the Hurricane's old-fashioned construction meant that it could not be improved to any great extent. It was effectively obsolescent for first-line interception duties (particularly against later German fighters) from 1941 onwards. It was relegated to ground-attack and sea strike duties and second-line air defense until it finally went out of production in 1944. It was succeeded by the all-metal Typhoon and Tempest.

However, the Spitfire's all-metal construction proved suitable for growth and development throughout the war, resulting in no less than 54 different versions (Marks and sub-Marks) of this aircraft. From the earliest standard production model to the last the Spitfire's loaded (i.e. combat) weight would increase by 67%, from 5,935 to 9,900 pounds; its engine power by 131%, from 1,030 to 2,375 horsepower; its maximum speed by 25%, from 367 to 457 mph; its rate of climb by 124%, from 2,175 to 4,880 feet per minute; and its combat range (on internal fuel alone) by 36%, from 425 to 580 miles. Specialized versions such as photographic reconnaissance models would exceed some of these figures very considerably.

Sadly, R. J. Mitchell would not live to see the extraordinary success of his brainchild. He died of cancer in 1937.

At first the Spitfire's all-metal construction caused amazement among service personnel. As Jeffrey Quill, Supermarine's chief test pilot, observed in 1936:

. . . I had to land [the prototype Spitfire] at Tangmere, which was the home of 1 and 43 Squadrons equipped with the Hawker Fury - a lovely little biplane fighter. I taxied in to the tarmac and shut down the engine, and a crowd of pilots and airmen immediately gathered round to examine this strange new beast. I took off my helmet and had begun to shed my Sutton harness and parachute straps when a strange sound came from the rear fuselage. It was a sort of high-frequency hammering noise, as sometimes produced by ancient domestic hot-water systems, and it considerably startled me. I leant out of the cockpit and looked towards the tail in some alarm, and there I saw a crowd of airmen all tapping on the metal fuselage with their knuckles. It was the first time they had ever encountered a metal-skinned aeroplane!

The prototype Spitfire, registration K5054, is shown below. It first flew on March 6th, 1936, and would be followed by well over 22,000 siblings and descendants.

While on the subject of construction, the fabric-covered ailerons and elevators in early versions of the Spitfire would lead to some interesting problems. A former apprentice at the Supermarine Works, Peter Weston, was involved with the production testing of aircraft before delivery to squadrons during the Battle of Britain. He remarked:

The pilots would taxi out from the apron onto the grass and take off in almost any direction regardless of the wind factor. The duration of the tests were normally about 20 minutes. Meanwhile I would be standing about 50 feet or so from the apron, on the grass area with a pot of dope and paint brush in hand along with fabric patches. A Spitfire would land and taxi to me and the pilot point to the ailerons or to the elevators and . . . often to both. During the tests the aircraft [were] dived to around 400 mph and this sometimes cause[d] the fabric on the ailerons and elevators to be ripped, so I, while [the] engine was running would have to dash around, put dope over the area of the rip, put a patch of fabric on and dope over it again, the dope dried almost immediately. I would give the thumbs up sign and off they would go at full throttle, tail up almost immediately, and airborne.

Such problems were overcome with the introduction of metal-skinned ailerons and elevators during 1941, which also considerably improved the aircraft's handling at high speeds.

The first production model of the Spitfire was the Mark IA. This had a Merlin II or III engine producing 1,030 horsepower and was armed with eight .303-inch (7.62mm.) Browning machine-guns, four in each wing. Initially a two-blade wooden fixed-pitch propeller was fitted (as seen on the prototype above), but a three-bladed variable-pitch unit was rapidly developed to better use the power of the engine. The Mark IB had a slightly modified wing, initially fitted with two 20mm. cannon and later with two cannon and four Browning .303 machine-guns.

The Mark II Spitfire was essentially the same as the Mark I - the designation referred to a slightly modified design to be manufactured at the brand-new Castle Bromwich factory (interior view shown below) erected to mass-produce the Spitfire.

The first Mark II's were produced there in June 1940. It had a Merlin XII engine producing 1,175 horsepower. The Mark IIA (shown below) had eight machine-guns, and the Mark IIB two cannon and four machine-guns. Up to and during the Battle of Britain virtually all Spitfires were armed with eight machine-guns: only after the Battle did cannon-armed Spitfires become common. The cannon were a huge improvement over the small-caliber machine-guns, offering greater effective range and a much greater impact on target. Eventually the later Marks of Spitfires would dispense with machine-guns altogether and be armed with four 20mm. cannon.

The first production Spitfires entered service with 19 Squadron on August 4th, 1938. By the outbreak of World War II on September 3rd, 1939, the RAF had 306 Spitfires in service, equipping ten squadrons. A further 71 were in reserve and 2,000 more had been ordered. Very few Spitfires were sent to France during the first months of World War II, simply because there were so few of them in service. They were retained for home defense while the more numerous Hurricanes were despatched to France.

During the so-called "Phoney War" between September 1939 and the Blitzkrieg of May 1940, a remarkable Australian, Sidney Cotton (who qualifies for a full Weekend Wings article in his own right - I'll write it in due course), managed to wheedle two of the very scarce Spitfires from Air Chief Marshal Dowding, Commander-in-Chief of Fighter Command. At the time Cotton was establishing the first professional Photographic Reconnaissance unit in the RAF. He noted:

We took out the guns and gun fittings and got rid of all excess weight, we filled in the gun holes with metal plates, we stopped up all cracks with plaster of Paris and we polished the external surfaces into a hard, sleek gloss. In this way we increased the speed of these two Spitfires from 360 to 396 mph . . . [He also installed a 29-gallon auxiliary fuel tank.] . . . by the end of October [1939] I had two aircraft capable of a cruising speed of close on 400 mph with a range of 1,250 miles at 30,000 feet, fitted with the best photographic equipment I could get.

These two reconnaissance Spitfires performed very well, taking photographs of enemy positions that could not be obtained by any other aircraft (those that tried suffered severe losses). They flew too high and too fast to be easily intercepted, and had the speed to run away from any pursuing fighter of the day. They were the precursors of many PR (Photographic Reconnaissance) models of the Spitfire, both converted from fighters and factory-produced, that would total in excess of a thousand aircraft by the end of World War II. I'll cover the PR variants in more detail in the next part of this series on the Spitfire.

When the Blitzkrieg exploded in May 1940, the RAF squadrons in France found themselves overwhelmed by massive German superiority in aircraft numbers - and, all too often, in aircraft performance as well. The Hurricane could barely hold its own against the faster Messerschmitt Bf 109E.

This Bf 109E flew in the Battle of Britain. It landed
at a RAF airfield in November 1940 and was captured.
It is today on display at RAF Hendon in England.

As the Allied armies retreated before the German onslaught the British Expeditionary Force congregated at Dunkirk in northern France, from where a famous and remarkably successful evacuation was conducted. Spitfire squadrons were thrown into battle to keep the German Air Force, the Luftwaffe, at a distance from Dunkirk. They achieved considerable success: but enough German aircraft got through and bombed the evacuation site to cause considerable resentment among the troops, who could not see the RAF fighting many miles away. The RAF lost 474 aircraft in this endeavour compared to only 132 for the Luftwaffe.

The Battle of Britain followed from July to October 1940. The story is so well-known that I won't repeat it here in any detail. Suffice it to say that the RAF fighter pilots fought the Luftwaffe to a standstill in one of the most pivotal and crucial battles ever fought in any war at any time. If the Luftwaffe had succeeded in gaining air superiority, Germany would have invaded England and the subsequent course of World War II would have been very different. However, the RAF held the line and the invasion was first postponed, then cancelled. As Winston Churchill said of the RAF fighter pilots, "Never in the field of human conflict has so much been owed by so many to so few."

The Spitfire played a crucial role in the Battle of Britain. Tactics were developed so that whenever possible the faster Spitfires took on the German escorting fighters, while the slower, more maneuverable Hurricanes attacked the German bombers. Famously, Luftwaffe fighter commander Adolf Galland was so enraged by Hermann Goering's poor tactics and strategy that he demanded that his squadrons be equipped with Spitfires. RAF losses were heavy, but aircraft were quickly replaced by the rapidly-expanding factories. Aircraft never ran short during the Battle. However, the loss of skilled, experienced pilots was another matter. Many replacement pilots entered line squadrons only to be shot down within days (sometimes within hours) because their training and experience were woefully inadequate for a combat environment. It would take the RAF a year or more after the Battle to rebuild a cadre of sufficiently experienced pilots, particularly in leadership positions.

The video below shows the only Spitfire still in flying condition that fought in the Battle of Britain. It's a Mark IIA from the Castle Bromwich factory, accepted into RAF service in August 1940, and is today part of the RAF's Battle Of Britain Memorial Flight. The music in the first part of the video, before the flying demonstration, is from the film "Battle Of Britain".

The Battle of Britain marked the end of the beginning for the Spitfire. It had proven itself to be one of the finest combat aircraft in existence: but more advanced enemy aircraft were on the horizon, and it would have to grow to meet the new challenges ahead. The story of how it did so (with enormous success) will be told in the next Weekend Wings.



fastbike said...

Not to quibble, but are you sure about the "Attained the highest speed ever reached by any propeller-driven aircraft?" claim. Even for WWII combat aircraft, I have never heard this claim for the Spitfire. I know that some claim that a P-47J was the fastest during WWII (~505MPH). I do know that the speed record for sinlge piston engined aircraft is the Rare Bear (a modified Grumman Bearcat)> Just curious because I love the Spitfire, but have never seen this particular claim.

Peter said...

Fastbike, yes, all the sources agree that a Spitfire did, indeed, attain the highest-ever speed for a piston-engined aircraft. It wasn't in level flight, though - we're talking maximum overall speed attained, which was in a dive, where the Spitfire was superior to every other prop-driven aircraft in terms of attainable Mach number. Details will be provided in the third instalment.

As for the fastest in level flight, I'm not sure which standard production-model propeller-driven aircraft could claim that crown: but I know that a PR Spitfire Mark XIX, "Cottonized" as per the technique discussed in the article above, did attain a speed of about 515 mph in level flight at high altitude in 1945. Whether or not this is a record I couldn't say - but, of course, this wasn't a standard production model: rather, it had been specially prepared to obtain maximum speed.

Hope this clarifies the situation.

Larry said...

I would add that during the Battle of France, the lack of self-sealing fuel tanks led to Spitfires and Hurricanes being as flammable as Japanese Zeroes later in the war. The additional weight (resisted by the pilots) and expense (resisted by the bean counters) turned out to be more than worth the cost. I can't find the source now, but IIRC, by the time of the Battle of Britain, serious efforts were being made to rectify this. Especially since one fuel tank was located directly between the pilot and the engine where if penetrated, it could and often did pour high-octane fuel practically into the pilot's lap.