Snippets of History: The Avro 504L Seaplane Experiment

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By 1913 the Royal Australian Navy realised the significance of naval aviation for reconnaissance and defence purposes, and a plan to form a Naval Air Service was under serious consideration. Kim Dunstan briefly outlines the early stages of naval aviation in the RAN and its first tentative steps post WW1.  
 

Left: An Avro 504 seaplane being hoisted aboard the heavy cruiser HMAS Australia in 1920 (ADF Serials)

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The early days

In May 1917, HMAS Brisbane (1) used a Sopwith Baby floatplane to search for the German raider SMS ‘Wolf’ at large in the Indian Ocean (see ‘Brisbane’s Baby‘). In 1918, when operating with the Royal Navy in the North Sea, HMAS Australia (1), Sydney (1) and Melbourne (1) successfully launched Sopwith aircraft from platforms mounted on gun turrets to attack Zeppelins and enemy aircraft. All of which provided valuable experience for the RAN.

Captain Claude Cumberlege RN, following his experience in 1917 with the Sopwith Baby on Brisbane became an aviation enthusiast, making numerous recommendations urging the Australian Naval Board to acquire seaplanes for RAN ships. Captain John Dumaresq RN who took command of HMAS Sydney (1) in February 1917, also supported naval aviation and devised a rotating platform for launching aircraft from light cruisers. Later he used his influence with the Australian Naval Board to obtain aircraft for trials on RAN ships.

In March 1919 Dumaresq was promoted Commodore First Class, in charge of the RAN fleet, where he continued to advance the case for naval aviation. Aware of the benefits of aviation, both the RAN and the Australian Naval Board sought to capitalise on his experience with aircraft in order to establish a Naval Air Service. But this was frustrated as following the Armistice, the Sopwith aircraft on RAN ships were returned (to the Royal Flying Corps or RNAS) prior to the ships sailing for Australia in April 1919.  

In Australia the lack of suitable aircraft for use on RAN ships caused a delay. However, early in 1920 twenty Avro 504 aircraft, no longer needed in the UK, were shipped to Australia in crates ready to be assembled. These ‘Imperial Gift’ aircraft were taken on charge by the Australian Air Corps for the Central Flying School. Most of these aircraft were 504Ks, the wheeled version, but two were Avro 504L twin-seat seaplanes that Dumaresq requested for trials on RAN ships.

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Above:  An Avro 504L being hoisted aboard HMAS Australia to be stowed on the upper deck.  The size of the aircraft and the fact it did not have folding wings made it very susceptible to damage (RAN Sea Power Centre).

The Avro 504L was similar to the Avro 504K except the landing wheels were replaced by floats. Early in WW1 the Avro 504s were front-line aircraft, but in 1915 they were moved to second-line employment. Like most biplanes of the time they had timber airframes covered with fabric and braced with wire. 

The Avro 504 in a Nutshell

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The 504 was designed and built by the Avro Aircraft company from 1913 until production ended in 1932.  Over this period over 10,000 were manufactured, making it the most produced aircraft of any kind that served in the First World War, in any military capacity.  Many other companies were licensed to build the aircraft including Harland and Wolff in Belfast (better known for shipbuilding), the Sunbeam Motor Car Co. Ltd. in Wolverhampton, and Brush Electrical Engineering Co.Ltd in Loughborough, UK to name just a few.

The first 504 undertook its maiden flight in September 1913.  It was powered by an 80hp Gnome Lambada seven cylinder rotary engine driving a two bladed wooden propeller.   Like most of the aircraft of the time it was constructed of wood with a square-section fuselage covered by fabric. 

Although it soon became obsolete as a front line fighter (it had the dubious distinction of being the first British aircraft shot down in combat), the 504 was principally used as a two-seater training aircraft in the “K” model, which could accommodate two seats. Virtually every British pilot of WW1 was taught how to fly on this machine. The 504K had a universal engine mount to accommodate a variety of engines including the 130hp Clerget 9, the 100hp Gnome Monosoupape or the 110hp Le Rhone 9J, but otherwise its design did not differ markedly from earlier derivatives.   

training-avro-ad-248x344With the wheels removed and floats fitted, the aircraft became the “L” model, which could also be fitted with a number of different engines.   It was one of these that did the trials aboard HMAS Australia/Melbourne, fitted with a nine cylinder 130 hp Clerget 9B air-cooled rotary engine. This gave the aircraft a  maximum speed of 78 knots and an endurance of three hours, but scant performance margins particularly in high density-altitude operations (e.g.hot and humid). 

Avro was a British aircraft manufacturer founded in 1910 whose later designs included the Avro Lancaster – a famous four engined bomber of the second World War, and the Avro Vulcan, a stalwart of the Cold War and arguably one of the most beautiful aircraft of that era.  The company also had success in the 50s and 60s its twin-engine turboprop Avro 748, powered by Rolls-Royce Dart engines. It sold widely across the world including to the Royal Navy and the Royal Flight. The company disbanded in 1963 when it became part of Hawker-Siddeley aviation.   

The Avro 504 L trials

In July 1920, following a request by Commodore Dumaresq, an Avro 504L seaplane was transferred to the battle-cruiser HMAS Australia (1) for trials in home waters. (The pilot, Captain De La Rue from the Australian Air Corps was a former RNAS pilot and highly experienced with seaplanes). The first trials conducted over several weeks were successful, but defence cuts meant Australia was moved to Flinders Naval Depot in Western Port as a training ship. In September 1920 the 504L, now with starting gear and wingtip floats fitted, was transferred to the light-cruiser HMAS Melbourne (1), which began a five-week cruise to Woodlark Island and the former German colonies at Rabaul, New Ireland and New Guinea, returning via Cairns.

Due to the success of the 504L seaplane trials on HMAS Australia the RAN was keen to proceed with the tropical trials, confident that the Avro 504 series had a good record of reliability; in fact it was the most produced allied military aircraft of World War 1. Unfortunately the tropical trials were a failure. In the first instance the Avro 504L was not suited to a light-cruiser as it was too large and heavy. Nevertheless because HMAS Melbourne was now ‘flag ship’ and the only vessel available the trials went ahead.

Another reason for the cruise, beyond inspecting harbours, anchorages and consulting with local Administrators was that Australian defence planners were considering establishing seaplane stations in the islands to the north of Australia for early warning surveillance and to detect enemy activity. The idea was to have stations at Bynoe Harbour west of Darwin, New Guinea, Rabaul and others on the Solomon Islands, Santa Cruz and Fiji. But the plan did not proceed as in 1921 the newly formed RAAF assume responsibility for air defence.

Commodore Dumaresq produced a ‘Report of Proceedings’ for the Commonwealth Naval Board dated 6 November 1920 and titled “HMAS Melbourne Cruise to Mandate Islands. Failure of Seaplane Allotted by Air Board for Cruise”. It provides a commentary on the problems encountered by the Avro 504L during the cruise to the tropical north. Difficulty with access to coal supplies also created problems and shortened the planned cruise – an important part of which was ‘showing the flag’ and public relations.  

HMAS Melbourne departed Sydney on 29 September 1920 with the Avro 504L on board. The pilot was Captain Fryer-Smith, with an observer, mechanics and spare parts. The ship made several calls along the east coast including to Shoalwater Bay on the Queensland central coast, but the seaplane was unable to fly due to the wind and rough seas. Further north at Woodlark Island (in the Solomon Sea) Dumaresq records: “At Woodlark the seaplane actually rose about 200 feet into the air, greatly impressing the natives, but did not get sufficient revolutions and was obliged to alight. The air was very hot and damp apparently affecting the reserve of power necessary in the tropics.

New engine installed

Dumaresq’s report continued: “I arrived at Rabaul on 14th October and left on the 20th, in accordance with the programme. During this time continued efforts were made to get sufficient revolutions from the seaplane engine, without success, and finally the engine was taken out and a spare one put in. The aircraft was left behind at Rabaul to use this new engine and if possible to carry out a survey of Mioko Harbour, etc. I then proceeded to New Ireland in accordance with the approved programme.”

Despite the engine change the Avro 504L failed to lift of the water of Simpson Harbour at Rabaul and the Mioko Harbour survey was not done. HMAS Melbourne returned to Rabaul on 25th October for two days to embark the seaplane and for conferences with the local Administration about the problems experienced with receiving wireless signals and the difficulty of getting supplies of coal at Rabaul. However, Dumaresq said the visit to the ex-German Colonies “unquestionably did much good and supported the Administration considerably; but more good would have been done if the coal at Rabaul could have been used.”

Dumaresq was disappointed the Avro 504L did not fly at Rabaul saying: “The affect on the natives of the inability of the seaplane to fly was bad, as the German’s will put it about that a German machine would have done so”. [Note: the FF.30e on the German raider SMS Wolf was able to fly in the tropics – see the ‘Brisbane’s Baby’ story.] Dumaresq continued: “I endeavoured to initiate a propaganda that the machine was not a real seaplane, but a land machine experimentally converted with an unsuitable engine lacking in reserve power necessary for flying in damp tropical air,” he said, “I hope that if possible machines that will fly will be sent up next year.”

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Above left: The Avro at Cairns, where successful flight trials were conducted. Note the wing-tip floats on the underside of the lower wing, a feature not seen in other 504Ls. (Sea Power Centre) Above right. Beached at Rabul, PNG, the Avro awaits an engine change in an attempt to gain more power (Australian War Memorial image).

Melbourne arrived at Port Moresby on 30 October. Again the Avro 504L did not fly owing to a stiff prevailing south-east wind and rough seas. Arriving at Cairns on 5 November, the seaplane took off from the water and obtained a height of about 2000 feet. But, according to Dumaresq, “The revolutions were not satisfactory and the flying tentatively arranged for the following day as a public display was cancelled.”

He said: “I do not consider the life of the pilot and observer should be risked by flying the machine without obtaining sufficient number of revolutions and all this was explained to the Mayor. Flight Lieutenant [sic] Fryer-Smith and his mechanics have worked unceasingly and the former in whom I have every confidence is naturally very keen not to disappoint the public.” At this point Dumaresq’s ‘Report of Proceedings’ ends.

The Cairns flight 

By contrast, an article in the ‘Cairns Post’ of 6 November 1920, page 8, headed “Up In The Air, Seaplane Flight Over Cairns” gives a glowing account of the flight which lasted just under one hour. It said: “The mechanic set the propeller spinning and the plane began gliding over the smooth waters of the inlet, gathering speed as it came along. About 8.30 the plane gracefully rose from the water like a big seagull and as the pilot raised the elevators, the plane rose higher and higher. The noise of the engine attracted a large number of people to the wharf and the excitement especially amongst the younger generation was intense”.

At Cairns, the pilot said the Avro skidded over a mud bank helping it to become airborne, but the engine overheated and lost power. A report in the ‘Sydney Morning Herald’ of 29 November 1920, says: “Whilst in the tropics Melbourne’s seaplane was unable to rise, and it was ascertained that due to the warmth of the climate, the engine did not develop the same number of revolutions as it did in cooler climes, and consequently was unable to raise sufficient power to lift itself from the water. The same effect of tropical heat was also experienced by Sir Ross Smith in his flight from England to Australia, but the Vickers-Vimy had powerful dual engines enabling it to overcome the difficulty”.  

Avro504L-6HMAS AUSTRALSuezCanal%201919[1]The battle-cruiser HMAS Australia (1) which had room to carry one Avro 504 on deck.

 

Avro504L-4HMAS_AustraliaAbove: An Avro 504L aboard HMAS Australia (1). The aircraft would be hoisted to/from the water for take off and landing, a tricky operation in all but the smoothest of seas.  Right: HMAS Melbourne (1) in 1920.  Considerably smaller than Australia, the light cruiser had difficulty accommodating the aircraft.

Imagery Scanned from Navy Historic Archive

The Avro problems

After leaving Cairns no further flights were made during the ship’s return to Sydney. The Avro 504 L trials on HMAS Melbourne identified a number of problems. The main issue was the dangerous lack of engine power in the tropics. Secondly, without folding wings the Avro was too big and unwieldy and easily damaged, striking the ship’s side when hoisted to or from the water; and it lacked tie-down points. Saltwater spray and tropical humidity degraded the wooden airframe and its canvas covering; and petrol tins stowed in the open rusted and leaked. Also, operating in all but calm conditions was impossible. Although the experiment proved the Avro 504 L was unsuitable, the idea of naval aviation was not diminished and the search for a better aircraft began.      

With the experience gained during the HMAS Melbourne cruise, Commodore Dumaresq advised the Naval Board that to cope with tropical conditions a purpose-built seaplane with a more powerful engine was necessary. The RAN subsequently ordered six Fairey 111D seaplanes with the 375 hp Rolls Royce Eagle V11 engine, the first of which arrived in August 1921. Unfortunately the idea of an RAN Air Service had been shelved by then, so the aircraft went to the newly formed RAAF, established on 31 March 1921.

The way ahead

This was not the end of aviation for the RAN’s aviation capability as Fairey 111D seaplanes, now flown by the RAAF Fleet Cooperation Unit, assisted HMAS Geranium to survey the Great Barrier Reef.  (See The Geranium Story).

Following the 1923 Imperial Conference, and growing defence concerns, the Australian government ordered two heavy cruisers, both capable of carrying a seaplane. Then, in June 1925, the government announced that a seaplane carrier, HMAS Albatross, would be built at Cockatoo Dock in Sydney; leading to the purchase of the Supermarine Seagull 111 & V amphibians. From this point onwards aircraft became an integral part of RAN operations.  

Below:  The Avro on a jetty at RAAF Point Cook after being returned from the RAN.  Although the experiment had not been successful it was still an important step for Naval Aviation as it led to the acquisition of more powerful, purpose designed seaplanes.  (RAAF Museum)  Right:  Avro 504K drawings, courtesy of Wikipedia.Avro504L-1


doc_imageGraphic.  A copy of HMAS Melbourne’s report of her visit to the Mandate Islands in 1920, courtesy National Archives), which contained the Avro report.  It also contained a note from CDRE Dumaresq that he had called in to Dunk Island and spoken to a Mr Banfield, a resident of that island, who reported a conversation he had had with the captain of a Japanese lugger operating in the Great Barrier Reef area.  Dumaresq asked him to send a detailed report to Naval HQ on the matter. The Australian government of the time was very concerned with the number of Japanese boats operating in Australian waters, and that they were charting the GBR. (Click image to expand).

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doc_imageGraphic: Minute 597/A.F.1250 from the Commodore Commanding, HM Australian Fleet to the Secretary of the Department of Navy dated 15 June 1920,  in which he requests the attachment of a AVRO Aeroplane for the forthcoming ‘cruise to the Islands’.  The Minute also requests suitable crew, equipment and modifications to the aircraft, noting that although it is an unsuitable type it is urgent to make some start in seaplane reconnaissance experience in the Fleet.  Interestingly, it also raises the point that the Australian Air Corps was not liable for service outside the Continent of Australia – a policy incompatible with Naval requirements.

doc_imageGraphic: During the embarkation, the Avro’s pilot, Captain Fryer-Smith, submitted weekly reports to his Captain, setting out the work of each week, the difficulties they had experienced with the aircraft and their attempts to overcome them, and the damage to the aircraft due to weather and exposure.  Of particular interest was his observation that whilst the engine revolutions during deck testing were satisfactory, they dropped significantly as soon as the aircraft was on the water.  These reports were forwarded to Navy Office on 29 October 1920 by the Captain, as per the last page.

doc_imageGraphic: Reasonable records still exist of the logistics of requesting the Avro and the process of getting it, the flight and maintenance crews, and spares.  The documents left reflect some of the process which, aside from the fact that is was done by letter and telegram, probably haven’t changed a great deal since then.  Of note is that the Avro required a starter motor (the alternative was for someone to ‘swing’ the propeller, which is obviously difficult when the aircraft was on water), and wing-tip floats to try and improve its stability in rougher seas. 

doc_imageGraphic:  Operating aircraft at sea revealed a number of unforeseen problems. One was the provision of petrol for the aircraft, which in Melbourne was stowed in tins on the upper deck.  They deteriorated quickly in the weather resulting in a request from Captain Cumberledge for a dedicated fuel tank to be fitted.  Navy Office responded early in January 1921 denying the request as the Admiralty had decided not to fit any Australian Light Cruisers with aircraft again.  The more general question of aircraft at sea was to be discussed at the Imperial Naval Conference later that year. 

doc_imageGraphic:  A copy of an excerpt from Petty Officer Joseph Kemp RAN, who kept a meticulous diary on events he observed during his time in service. He served on HMAS Sydney (1) in the North Sea, on which he commented on a Sopwith Pup launching to chase German aircraft; and in various other theatres.  In this entry he is aboard HMAS Melbourne (1) during the Mandate Island cruise, and he remarks on the inability of the Avro 504L to fly despite an engine change.  (Image courtesy of the Australian War Memorial).


Snippets of History Index

 

Acknowledgement citations:

Title: Seaplanes for ‘Australia’ and ‘Melbourne’ provision of flying personnel
Series number: MP 1049/1
Citation: NAA: MP 1049/1, 1020/0204
Item barcode: 406754
Location: Melbourne

Title: Seaplane of ‘Melbourne’ Petrol storage interim decision 
Series number: MP 1049/1
Citation: NAA MP 1049/1, 1921/032
Item barcode: 406168
Location: Melbourne


References:

National Archives of Australia, Cruise to Mandate Islands. Ref: MP1049/1

Naval Historical Society

ADF Serials

RAN Sea Power Centre

Australian War Memorial photos

Cairns Post, 6 Nov 1920

SMH 29 November 1920

‘Seagulls, Cruisers & Catapults,’ by R. Jones

‘The Forgotten Cruiser – HMAS Melbourne 1913-1928,’ by A. Kilsby & G. Swinden