Hawker Hurricane variants

The Hawker Hurricane was a British single-seat fighter aircraft designed and predominantly built by Hawker Aircraft Ltd. Some versions were built in Canada by the Canada Car and Foundry Co Ltd

British Variants

Hurricane Mk I

As expected, the first Mk I production machines were ready fairly quickly, with deliveries starting in December 1937. These early aircraft were simple, with fabric-covered wings, a wooden two-bladed, fixed-pitch propeller, and lacking armour or self-sealing tanks. Powered by the 1,030 hp (768 kW) Rolls-Royce Merlin Mk II or III engine, the Mk I proved to be a stable gun platform and was armed with eight .303 inch Browning machine guns.

Although the use of this number of guns sounds impressive, the fact is that this relatively small calibre armament was more suited to shooting down the wood/canvas machines of the First World War. It was relatively common during the Battle of Britain for the (metal) German planes to be struck by a surprisingly high numbers of .303 bullets but still return safely to base. The use of a smaller number of larger calibre guns would have been far more effective and this was rectified in later versions of the Hurricane. Hurricanes built under license by SABCA in Belgium featured four 12.7mm FN-Browning guns instead of the .303 inch armament.

In 1939, a revised Mk I series utilized a de Havilland or Rotol constant speed metal propeller, ejector exhaust stacks for added thrust, metal-covered wings, armour and other improvements. In 1939, the RAF had taken on about 500 of this later design to form the backbone of the fighter squadrons during the Battle of France and into the Battle of Britain. The first RAF ace of the war, a young New Zealander known as "Cobber" Kain, flew a Hurricane with No. 73 Squadron. In June 1940, another inspirational wartime ace, Douglas Bader, was promoted to Squadron Leader and took command of No. 242 (Canadian) Squadron flying Hurricane Mk Is.^[1] The famous children's author Roald Dahl also flew Hurricanes with No. 80 Squadron in Greece and later in Syria, against the Germans and Vichy France.^[2]

Although relying on older technology, the Hurricane proved to be a match, to an extent, for the Luftwaffe's Messerschmitt Bf 109. In his book, Duel of Eagles, British ace Peter Townsend, who flew Hurricanes with No. 85 Squadron RAF during the Battle of Britain, provides examples demonstrating how the Hurricane's superior turning ability could offset the Bf 109's higher speed. Another factor in the Hurricane's performance was the Merlin engine that also powered the Supermarine Spitfire, especially after the introduction of Miss Shilling's orifice. This was a simple device fitted to the engine's carburettors to reduce the effects of fuel starvation during negative-g manoeuvres and inverted flight – a problem which would be fully addressed during 1943 with the introduction of fuel injection. The Merlin, thanks to a different supercharger design, gave more power at low altitude than the Daimler-Benz DB 601 used in the Bf 109, however, above 15,000 feet, the DB601A-1 was better than the Merlin III and XII.

During the Battle of Britain, the Hurricane shot down the majority of the planes claimed by the RAF (1,593 out of 2,739 total claimed). Hurricane fighters were sometimes directed against slower bombers whilst the Spitfires attacked German fighters. By the close of the Battle of Britain in late 1940, production of the Spitfire had increased to the point where all squadrons could be supplied with them. Deliveries of the Spitfire outpaced the Hurricane because it turned out that all-metal construction allowed it to be produced even faster than the mixed-construction Hurricane.

Hurricane Mk II

The improved Merlin XX (Mk.20) engine appeared in 1940 featuring a new two-speed supercharger that could have its impeller speed changed by the pilot depending on the outside air pressure (altitude). At about 18,000 ft (effective), it would be switched to a higher speed gearing ("FS ratio" – Full Supercharge) for added compression, while below that, at its lower speed gearing, ("MS ratio" – Moderate Supercharge), it "robbed" less power from the engine. The result was more power at both lower and higher altitudes, dramatically increasing the overall performance of the engine, peaking at 1,280 hp (954 kW).

Hurricane IIA Series 1

Although, by this time, production of the Spitfire had started to increase, a Merlin XX powered Hurricane Mk I was built and first flew on 11 June 1940. The initial Mark II, later known as the Mark IIA Series 1, went into squadron service in September 1940 at the peak of the Battle of Britain.

Hawker had long experimented with improving the armament of the fighter by fitting cannon. Their first experiments used two Oerlikon 20 mm anti-aircraft cannons in pods, one under each wing, (one aircraft was tested during 1940 with 151 squadron) but the limited amount of ammunition carried coupled with the frequent stoppages suffered by the drum-fed guns, meant the arrangement was unsatisfactory. A more reliable fit was made with four Hispano Mk II 20 mm cannons, two in each wing, but the weight was enough to seriously reduce performance. Fitting the cannons was not easy; feed based on a recoil system stopped when the recoil movement dropped, but changes to the Hispano cured this problem.

Hurricane IIA Series 2 (Hurricane IIB)

With the new Merlin XX, performance was good enough to keep the aging Hurricane in production. Hawker soon introduced the new Mark IIA Series 2 with either of two wings; one mounting 12 Brownings, the other four Hispano cannon. The first Series 2s arrived in October, also sporting a new and slightly longer propeller spinner and later become the Mark IIB in April 1941.

Hurricane IIB Trop.

For use in North Africa; the Hawker Hurricane IIB, (and other aircraft), were tropicalized, or "trop". They were given engine dust filters and the pilots were issued a desert survival kit.

Hurricane IIC

Hurricane IIA Series 2 become the Mark IIC in June 1941, using a slightly modified wing. The new wings also included a hardpoint for a 500 lb or 250 lb bomb, and later in 1941, fuel tanks. By then performance was inferior to the latest German fighters, and the Hurricane changed to the ground-attack role, sometimes referred to as the Hurribomber. The mark also served as a night fighter and "intruder."

Hurricane IID

Mk IIs were used in ground support where it was quickly learned that destroying German tanks was difficult, the cannons did not have the performance needed while bombing the tanks was almost impossible. The solution was to equip the aircraft with a 40 mm cannon in a pod under each wing, reducing the other armament to a single Browning in each wing loaded with tracers for aiming purposes. Hurricanes so equipped were quickly nicknamed "Flying Can Openers", perhaps a play on the No. 6 Squadron's logo which flew the Hurricane starting in 1941, and was equipped with the Hurricane II starting in December of 1942.

The layout was originally tested on a converted Mk IIB and flew on 18 September 1941. A new-build version of what was known as the Mk IID started in 1942, including additional armour for the pilot, radiator and engine. The aircraft were initially supplied with a Rolls-Royce gun and carried 12 rounds, but soon changed to the Vickers S 40mm gun with 15 rounds. The weight of guns and armour protection marginally impacted the aircraft's performance.

The IID undertook an anti-tank role in limited numbers during the North African campaign where, provided enemy flak and fighters were absent, they proved accurate and highly effective, not only against armoured vehicles but all motor transport.

Hurricane IIE

Another wing modification was introduced in the Mk IIE, but the changes soon became extensive enough that it was renamed the Mk IV after the first 250 had been delivered.

Hurricane T.IIC

The T Mk IIC was a two-seat training version of the Mk. IIC. Only two aircraft were built for the Persian Air Force.

Hurricane Mk III

The Mk III was a Mk II equipped with a Packard-built Merlin engine, intending to provide supplies of the British-built engines for other designs. By the time production was to have started, Merlin production had increased to the point where the idea was abandoned.

Hurricane Mk IV

The last major change to the Hurricane was to "rationalize" the wing, configuring it with a single design able to mount two bombs, two 40 mm Vickers S guns, or eight "60 pounder" RP-3 rockets. The new design also mounted the improved Merlin 24 or 27 engines of 1,620 hp (1,208 kW), equipped with dust filters for desert operations.

The Mk IV was used in ground-attack missions in the European theatre until the early days of 1944, before being replaced by the much more modern Hawker Typhoon. French ace Pierre Clostermann recalls in his book, The Big Show, that RP-3-equipped Hurricanes were limited to 330 km/h (205 mph) top speed due to the rockets' drag, and that Hurricane casualty rates against the lethal German flak were extremely high. In particular, Clostermann describes a rocket attack by Hurricanes from No. 184 Squadron RAF against a V-1 flying bomb launch-site on the French coast on 20 December 1943, in which three of the four aircraft were shot down before they could attack.

Hurricane Mk V

Two Hurricane Mark Vs were built as conversions of Mark IVs, and featured a Merlin 32 engine driving a four-bladed propeller. As the ground attack role moved to the more capable Hawker Typhoon, production of the Hurricane ended, and only a handful were delivered with the Merlin 32.

By this time, the Hurricane was no longer a frontline fighter in the United Kingdom. However, it still saw extensive service overseas as a fighter, playing a prominent role in the Middle East and Far East. It was also critical to the defence of Malta during 1941 and early 1942.

Canadian Variants

Canadian-built Hurricane XII painted to represent Hurricane IIB Z5140 of 126 Squadron RAF

Some production of the Hurricane was carried out in Canada by the Canada Car and Foundry Co Ltd.

Hurricane Mk X: Single-seat fighter and fighter-bomber. Powered by a 1,300-hp (969-kW) Packard Merlin 28. Eight 0.303-inch (7.7-mm) machine guns mounted in the wings. In total, 490 were built.

Hurricane Mk XI: 150 were built.

Hurricane Mk XII: Single-seat fighter and fighter-bomber. Powered by a 1,300-hp (969-kW) Packard Merlin 29. Initially armed with 12 0.303-inch (7.7-mm) machine guns, but this was later changed to four 20-mm cannons.

Hurricane Mk XIIA: Single-seat fighter and fighter-bomber. Powered by a 1,300-hp (969-kW) Packard Merlin 29, armed with eight 0.303-inch (7.7-mm) machine guns.

Sea Hurricanes

Sea Hurricane IA: The Sea Hurricane IA was a Hurricane Mk I modified by General Aircraft Limited. They were modified to be carried by CAM ships (catapult armed merchantman). These were cargo ships equipped with a catapult for launching an aircraft, but without facilities to recover them. Thus, if the aircraft were not in range of a land base, pilots were forced to bail out and be picked up by the ship. They were informally known as "Hurricats".; The majority of the aircraft modified had suffered wear-and-tear from serving with front line squadrons, so much so that at least one example used during trials broke-up under the stress of a catapult launching. 50 aircraft were converted from Hurricane Mk Is.

Sea Hurricane IB: Hurricane IIA Series 2 version equipped with catapult spools plus an arrester hook. From October 1941, they were used on Merchant aircraft carrier (MAC ships), which were large cargo vessels with a flight deck enabling aircraft to be launched and recovered. 340 aircraft were converted.

Sea Hurricane IC: Hurricane IIB and IIC version equipped with catapult spools, an arrester hook and the four-cannon wing. From February 1942 400 aircraft were converted.

Sea Hurricane IIC: Hurricane IIC version equipped with naval radio gear. 400 aircraft were converted and used on fleet carriers.

Sea Hurricane XIIA: Canadian-built Hurricane XIIA converted into Sea Hurricanes.

References

^ Bader 2004, p. 16.
^ Dahl, Roald. Going Solo. London: Puffin Books, 2001. ISBN 0-14131-142-8.