The Flying-off Platform- an Evolutionary Dead End?

Welcome to Matt Willis, who is joining the BritishNavalHistory team and will be contributing on a number of topics, including the Fleet Air Arm and 20th century Royal Navy history. In this blog, Matt examines one effort by the Royal Navy to incorporate aircraft into the fleet.

Aircraft that took off and landed directly on water were an important part of the infancy of naval aviation, but possibly the most significant development made in this field by the Royal Navy during the First World War was the ability to fly landplanes off warships. While by the end of the conflict the concept of the dedicated aircraft carrying ship had become established, the idea of creating tiny flight decks fitted to fixed or revolving platforms to allow battleships and cruiser to carry one or two aircraft also seemed worthwhile. The early success of these platforms even when better alternatives were available arguably lead to a dead-end in naval aviation, which provided a detrimental influence into design of naval aircraft well into the post-First World War period.

Experiments in launching aircraft from warships had begun in the years before the First World War, almost as soon as aeroplanes became a practical means of transport. Eugene Ely took off and landed a Curtiss pusher from anchored USN warships in October 1910. Just over a year later, in January 1912, Lieutenant C.R. Samson flew a Short S.38 from a ramp mounted to the bow of HMS Africa. The Royal Navy’s experiments were somewhat more sustained than those of the US Navy, and included the first take-off from a ship at sea, in May 1912.

In 1912 the armoured cruiser HMS Hermes was modified with a hangar, and a launching ramp fitted on the bow. She was recommissioned the following year as the parent vessel for the Aeroplane and Airship section. That development was relatively short-lived, but persuaded the RN that there was merit in ships that could carry aircraft. A collier under construction at the Blyth Shipbuilding Company was selected and became the second HMS Ark Royal. When construction finished in 1914, the Ark Royal became the first ship in the world to be completed as an aircraft-carrying ship. It was also the largest seaplane carrier of the war, at 7,020 tons displacement. Ark Royal was designed to carry both float planes and land planes, though once launched the latter would be required to return to land.

Fairey IIIF Floatplane on a catapult.

By the time Ark Royal commissioned in 1915, the value of shipborne seaplanes had been proven. The daring raid on Cuxhaven did little damage to the dockyards, but it panicked German authorities and caused the High Seas Fleet to withdraw ships to more distant anchorages. Rather than operating with the Home Fleet, Ark Royal was dispatched to the Mediterranean and was quickly on hand when the Dardanelles campaign began. The ship reached Tenedos, 15 miles from the Dardanelles, on 17 February. Within two hours of its arrival, one of Ark Royal’s aircraft was dispatched on a combat reconnaissance flight, demonstrating the potential for rapid power projection that even this rudimentary form of aircraft carrier could provide. The Ark Royal’s aircraft took part in reconnaissance and gunnery spotting for British ships during the campaign and the subsequent landings at Gallipoli.

Experiments in the launching of landplanes from cruisers and battleships initially continued in parallel with the development of dedicated seaplane carriers. In the early part of the First World War four cruisers had fixed ramps fitted, but the practical difficulties proved too great and, from August 1915, the experiment was curtailed.

Nevertheless, the value of flying aircraft directly from warships at sea was recognised, and trials with launching ramps took place aboard the battlecruisers HMS Renown and HMAS Australia in 1917. German naval zeppelins posed an increasing threat to naval operations. The zeppelins had excellent range and ability to loiter, and combined an early strategic bombing role with an ability to reconnoitre for the German navy. Royal Navy operations could lose the element of surprise at a single stroke. It had become important for the Royal Navy to find ways of launching high-performance aircraft that could intercept the Zeppelins.

During the Battle of Jutland, no fewer than five German naval Zeppelins were deployed to locate the British ships. They had been unable to due to poor visibility, but more were deployed the following morning and at first light, L-11 located the main British force. By then, the battle was over, but the sighting of the Grand Fleet prevented further sweeps that might have located some of the damaged German vessels attempting to limp home.

It was around this time that the idea of fitting launching ramps to cruiser was once again raised. HMS Caledon and HMS Cassandra were among the first vessels so fitted. These ramps were built on the foredeck, and extended from the bridge structure out over the bow gun in such a way that its movement was not impaired. The flying-off decks added relatively little topweight, and it was ordered that one ship in each of the light cruiser squadrons should be so fitted. A number of light cruisers had platforms fitted in 1917-18, to accommodate aircraft such as the Sopwith 2F.1 ‘Camel’ single-seat scout aircraft. Although much smaller than capital ships such as battleships and battle cruisers, light cruisers had the advantage of speed and manoeuvrability, with their powerful steam-turbine machinery promising speeds of over 30 knots, meaning that an aircraft would need very little take-off roll to become airborne.

The potential of the arrangement could be seen in the flight by Flight Sub Lieutenant B.A. Smart on 21 August 1917. Smart was the pilot of a Sopwith Pup carried by HMS Yarmouth of the 3^rd Light Cruiser Squadron. At 0530, the ‘Q-Class’ zeppelin L23 was spotted. This airship was a veteran of 51 reconnaissance missions and three bombing raids. Yarmouth turned into wind and Smart used the Pup’s excellent climbing capability to put his aircraft above the zeppelin, and was able to take advantage of the lightly loaded biplane’s manoeuvrability to keep himself out of the defensive machine guns’ fields of fire. Making his final attack from around 100 yards, Smart saw incendiary bullets enter the airship’s stern, and L23 quickly caught fire and crashed.

A further development was the adaptation of the Admiralty Seaplane Lighter as an alternative to the cruiser-mounted platform. The lighter was initially developed to carry large flying boats, were supposed to be towed by destroyers to an offshore location to extend their patrol range. It was soon realised that by fitting a small platform to the lighter, it could be used in exactly the same way as the cruiser platforms.

The Seaplane Lighter was a carefully-designed, sophisticated vessel that had to perform a number of potentially conflicting tasks. They were relatively large, at around 60ft long and almost half as wide, dwarfing launches and other small vessels. The hull form was a shallow ‘vee’ at the stern with a hard chine and slab sides. At the bow, the chine swept upwards and the ‘vee’ became progressively deeper. The overall shape was not far removed from later high-speed launches, as the lighter had to be towed at speeds of up to 30 knots. Even with a large Felixstowe F2A flying boat aboard, the lighter would ride up on its own bow-wave in a semi-planing condition. The lighter could not be steered, but two large fins were attached to the underside at the stern to keep the lighter tracking at high speeds. These Lighters were arguably the first purpose-designed ‘aircraft carriers’.

In 1917 and 1918, the Royal Naval Air Service (and later the RAF) developed the ability to fly scout and reconnaissance aircraft from platforms placed on top of battleship turrets. The turrets could be traversed so the ship did not even need to steam directly into the wind for the platform to be correctly aligned. A lengthways trestle carried the aircraft’s tailskid, maintaining the aircraft at the correct attitude. The engine was run up while the aircraft was restrained, and following release the aeroplane would reach flying speed by the end of the platform.

Sopwith Strutter and Battleship launch platform

Light cruiser turrets were too small, but a purpose-built rotating platform for launching was fitted to more than 30 light cruisers in place of the fixed foredeck ramp previously used. This structure no longer required the vessel to steam directly into wind to launch the aircraft.

The use of revolving platforms as mini flying-off decks was still continued in the mid 1920s when the Fairey Flycatcher and Parnall Plover – the first properly new postwar naval fighter designs – entered service, although the increasing weight and size of military aircraft was making the application less and less practical. The Flycatcher is today considered a small and lightly-loaded aircraft, but its full service weight was more than double that of the Sopwith Pup. Despite this, flying-off platforms continued to be used for this new fighter. The Royal Aircraft Establishment’s work on aircraft catapults was beginning to bear fruit by this time – the first ‘live’ aircraft launch from a catapult fitted to an operational warship, HMS Vindictive, took place in October 1923. The potential for launching aircraft at much higher loadings must have been apparent, yet the RN continued to develop some aircraft with the ability to take off from cruisers and battleships entirely under their own power. Experimentation at the National Physical Laboratory’s wind-tunnel, and later ‘live’ tests from HMS Caledon seemed to prove that the use of platforms was still valid despite the rapid growth in size and weight of naval fighters. The philosophy briefly held sway that aircraft carriers should be restricted to reconnaissance and offensive aircraft, while fighters should be carried on gun-armed warships.

In 1924, a number of comparative deck landing took place aboard HMS Argus, the first flush-decked aircraft carrier. The Parnall Plover and Fairey Flycatcher competed in order to decide which should equip the Fleet Air Arm’s fighter units. These tests included operation both from aircraft carrier decks and cruiser/battleship platforms. In July, a 17 foot long structure was fitted to the after end of the carrier’s flight deck to replicate a flying-off platform. A number of take-offs and landings were carried out, and it was concluded that both the Flycatcher and the Plover powered by the Bristol Jupiter would be able to operate from battleships with 20 knots of wind over the deck, and from cruisers with 28 knots of wind. It was decided that the standard Jaguar III-powered Flycatcher, already in limited service, did not have sufficient performance to be deployed aboard either type. The need to conclude the protracted trial period put considerable pressure on the RN. It was noted that the platform trials continued through difficult weather and conditions that “put a considerable strain on the endurance of the pilots taking part, particularly when launchings had to be repeated by the same pilots at short intervals.”ⁱ

The continued insistence on using turret platforms revealed the difficulties in designing aircraft to take advantage of new, more powerful engines, increase performance, retain sufficient robustness to operate at sea, and take off in as short a distance as a platform afforded. The Admiralty and the Air Ministry were presented with a dilemma. The improved Plover, powered by the more powerful Jupiter engine, had a significantly better performance than the standard Flycatcher, which was important for operation from warship platforms. However the construction, structural strength and service life of the Plover were in doubt. In July 1924, Plover N9704 of 405 Flight crashed in the river Eden when its upper wing centre-section partially collapsed. Less serious but still worrying structural issues had come to light during the ongoing trials.

A conference on the situation regarding the Flycatcher and Plover was held on 1 August 1924. ⁱⁱ At the August 1924 meeting, the Air Staff, RAF, RN and Admiralty thrashed out the arguments. The Flycatcher, it was felt, had proved itself to be perfectly robust during limited operational service, and its handling and performance although slightly inferior to the improved Plover, were still found praiseworthy by pilots in their own right. Although the Flycatcher was felt to be unsuitable for cruisers and battleship flying with the standard Jaguar III engine, the powerful Jupiter engine degraded the Flycatcher’s fine deck landing characteristics and its general suitability. The RN did not want to introduce two types into service, and the representatives went so far as to consider replacing the Flycatchers in service with Plovers, or retaining the existing Flycatchers alongside a smaller number of Plovers which would be used exclusively for flying off ship platforms. This latter suggestion seemed to be a non-starter, as the Chief of the Air Staff had declared in June 1924 that “The Air Staff Policy is that for types of which comparatively few [aircraft] will be required, such as Fleet Fighters, Fleet Spotters, Army Co-operation Aeroplanes, only one type of aeroplane and engine is to be used in the service.”ⁱⁱⁱ

Fears about the Plover’s structural weakness proved hard to overcome. The Chief of the Air Staff noted widespread fears that the Plover “would not stand the strain imposed upon it” and later that he “frankly would not trust to the Plover”.^iv Nevertheless, it was considered that for the Flycatcher to use the Jupiter, it would have to be completely redesigned, and there was no guarantee that the redesign would be successful. The factor that did most to tip the balance finally in favour of the Flycatcher was the availability of the improved Jaguar powerplant. Armstrong Siddeley had increased the available power from 325 hp to 360hp and then to 385 hp, with a variant that would become the Jaguar IV.

It was a gamble on the part of the Air Staff and Admiralty, as the improved Jaguar was unproven at the time of the August 1924 conference and had not passed its type tests. In fact, during the later trials aboard Argus, the officer in charge of the programme sanctioned the inclusion of a 385 hp Jaguar-powered Flycatcher, even though the Air Staff and Admiralty had asked for trials only on the Jupiter-powered machines. The experiences there, and earlier in the year at Northolt, persuaded most of the service pilots that the Flycatcher had a performance that was, in most regimes, equal to or only slightly poorer than that of the Plover, but with the benefit of much greater robustness and practicality.

In August, the 385 hp Jaguar IV passed its service tests and the decision was therefore made that the Flycatcher with this engine would be the Fleet Air Arm’s main fighter “definitely until 1926”. (Oneone factor in the decision not to proceed with the Plover was the feeling that a substantially better aircraft would be available in a few years and in those circumstances it was not worth changing from the Flycatcher).^v

Fairey Flycatcher aboard HMS Enterprise

Orders for over 100 further Flycatchers were placed in 1924, and subsequent orders brought the total number of Flycatchers, including prototypes, to 193.

By the mid-1920s, however, Fairey’s insistence on prioritising structural strength was borne out when the RN started to switch to catapults powered by compressed air, and subsequently by cordite charges, developed at the RAE at Farnborough. Flycatcher floatplane N9913 was trialled from HMS Vindictive’s catapult in 1925, which proved the aircraft’s suitability and detachments of Flycatchers later served aboard catapult-equipped ships from 1926.

As naval aircraft became ever larger and heavier, it also became necessary to find ways to accelerate take-off in calm conditions. Flycatchers (including N9947) were used to test the RAE’s compressed-air powered accelerator (‘accelerators’ differed from catapults in the Royal Navy’s view as they assisted the take-off of an aircraft along a runway or flight deck, as opposed to catapults, which required a crane for the aircraft to be mounted) between 1928 and 1933, and their robust construction again proving ideal. This formed the basis of the systems which would be used on British aircraft carriers until the jet age. The Flycatchers of the final production batch, S1409 to S1418, were distinguished as ‘catapult type’ in the order of March 1930.^vi

By 1925, it was clear that the generation of naval fighters coming after the Flycatcher would have serious difficulty in operating from platforms, and that catapults the solution. Moreover, by the late 1920s, the use of ‘accelerators’ to increase the flexibility of aircraft carrier operations, meant that structural strength was paramount in naval aircraft, and striving for low enough weight for platform take-off was impractical – as shown by the Plover.

In 1926, when the Air Ministry issued a specification for the Flycatcher’s replacement, the requirement for platform launching had been dropped – just two years after such considerable effort had been made to ensure the Fleet Air Arm’s fighter aircraft could operate from them. The fitting of catapults to warships was slow, and many retained their platforms until the early 1930s. The initial development of the platform had afforded a relatively easy way to provide air cover and additional reconnaissance to the Fleet in the First World War, but its success potentially encouraged the RN to persist with it longer than any other air arm, to the detriment of the further development of the Royal Navy and Fleet Air Arm.

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