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Rotary Run-Around

Rotary Run-Around

During more than 50 years of painstaking research, historian Keith Meggs has been slaving away to preserve something of this country’s rich aviation history. This month, Keith takes a look at Australia’s embryonic rotary industry with the Fortescue Helicopter, a design created in the early twentieth century by Albert John Fortescue.   

Albert John Fortescue was born in Yackandandah (Vic) on 31 July 1870, and eventually became Managing Director of Geo E. Fortescue & Sons Limited, IXL Manufacturing Company, (an engineering firm founded by his father) after its move to the present location in Loftus St Arncliffe, (Sydney) — it later became Federal Machinery Ltd. With his engineering background and an inventive outlook, Fortescue became a man of talent in engineering development, being responsible for, amongst many other things, an automatic pest fumigator, windmills of advanced design, variable gearing, concrete mixers, and harvesters. However he also did considerable aerodynamic research, with his main interest centred on the field of rotary-wing flight, although he had no previous aeronautical knowledge as a basis. He commenced work on this problem as far back as 1909 and built numerous models to various scales and configurations, in an effort to confirm his theories on vertical take-off and landing, and on transition to horizontal flight. Initial patents were taken out in the 1909-12 period, with the Sydney firm of Waters & Sons, and full patents were taken out in Great Britain, France, and the United States, as well as Australia, in 1914.

Development had reached the stage where a full-size vehicle, fitted with an eight-cylinder ENV engine of 40hp, was completed in 1916. This work was not the concern of the engineering company, but was a private venture, undertaken by Fortescue in his own time, at his home address of 12 Loftus St, next to the company factory, although a syndicate was formed to finance its development. A series of ground tests was carried out on the Bonnie Doon golf course and, although its performance did not quite meet requirements, it apparently lifted off the ground for a few feet. Details of the experiments and the results to that stage were sent to the British Government, and also to the United States Government.

The New South Wales Chamber of Commerce passed advice to the Dept of Defence regarding Fortescue’s efforts on 12 February 1917, and a request for Capt Eric C. Harrison to inspect it was made two days later. In turn, the Prime Minister’s Department wanted to know, on 1 March, what was being done about the matter.

Testing was carried out in the early hours of the morning, to maintain a measure of secrecy, well away from any built-up areas, until eventually the British Government instructed that the machine be kept out of sight and, accordingly, it was officially sealed in its shed at Loftus St until the end of the war. Although it was anticipated that some official investigation and possible development would take place, nothing was done about making use of it. However, and unfortunately, an offer from the United States Government was refused on patriotic grounds, although publicity for

Fortescue’s effort was later afforded in the United States press in 1924.

(In retrospect, it is probable that the official embargo was imposed because of the parallel work underway on the Brennan helicopter at the RAE Farnborough. Further patents were taken out in 1917 -18 -20 and -22, and the 1917 one, which was dated in London on 20 April, and was numbered 106,092, described the stage of development reached as follows:-

“This invention relates to improvements in aerial machines of the heavier than air type and has for its main object the construction of a machine which will be capable of ascending or descending under control at a steeper angle than machines heretofore constructed. A further object is to enable the machine to be changed from a high speed to a low speed or vice versa when desired without manipulating the engine throttle, the low speed if necessary approximating to poising of the machine.”

Although the full sequence is difficult to assess, it seems that there were four basic models and that first postwar piloted flight attempts were made by Delfosse Badgery during 1919-20, with the 1916 patent vehicle — with this he made two hops to a height of six or eight feet, one of which was recorded as 30-35 yards in length, at 25mph, and after a take-off run of 20 yards. A date of 5 May is associated with this hop, but the year is unknown.

The rotor speed was gradually built up through a clutch and gearbox while the take-off run was started, but, as the rotor load came onto the engine, the latter would stagger, through inability to cope with the added power requirement. Although the principle was satisfactory, a lot more work was required to perfect it, and it went back to the workshop.

In 1921, an Anzani-engined tandem biplane without a rotor was completed and tested, and this had variable incidence on its eight outer-wing sections, which were altered for ascent, horizontal flight, or volplaning (a contemporary term for gliding, ie. descending with the engine throttled off).

The engine was mounted amidships and drove two propellers in tandem, although they were on slightly different vertical centrelines and appeared (from photographs) to have a gearbox of some kind between them. The front one was known as a retarder and was mounted as a pusher behind the short forward nacelle, in order to provide braking facilities.

A nosewheel undercarriage, plus a large sprung tail skid, was fitted, and the fin and rudder were similar in shape to that of the Avro 504K.

Either during the development of this aircraft, or as a successor, a three-winged arrangement was built, with the single lower wing placed at the apex of an inverted triangle of wings, each of which had ailerons. Overall length was slightly reduced, and the retarding propeller was not used in this model, which also had a shorter tailskid. Common to both was the nacelle, nosewheel unit, main undercarriage (except for additional struts on the 1921 biplane), rudder, engine and propeller, and petrol tank.

Photos are available of a tandem monoplane configuration in this basic line, with the variable-incidence wing and the two propellers, but in large model form. One of these photos is annotated as the ‘Modification Machine-model’ and is shown without a rotor, whereas the others showed a short-span, wide-chord rotor like that on the 1916 aircraft, and obviously demountable as required. Without the rotor, a pair of vertical posts were fitted to take the bracing wires from the main spar bracing points.

It is therefore obvious that Fortescue’s work on reasonably orthodox fixed-wing layouts was only a means to an end, and that his aim was set on helicopter operation.

After submitting details and a copy of his Patent Specification 14203/20 during January 1922 to Air Ministry (London), Fortescue wrote to the Secretary of the Air Investigation Committee on 14 September 1922 to advise that neither of his two machines were able to be present at the Air Ministry competition, (a prize of £50,000 for a practical helicopter), but that they had features not possessed by other flying machines, and which he believed overcame all the difficulties and defects of aeroplanes. He enclosed a further Specification and photos of models of the designs, with the news that full-sized machines were about to be built, and should be ready in a few months.

Following examination of this material it was considered in London that their design was of no practical utility for RAF use and that no further action should be taken on that Service’s behalf, although results of any tests were requested. At the same time Louis Brennan was developing his helicopter at Farnborough, under the auspices of the RAE.

On 21 July 1923, Fortescue advised the CCA that one of his machines had flown for about 75 yards, and on one occasion had reached a height of six to eight feet. Experiments were proceeding satisfactorily and he was soon to commence construction of a full-size helicopter-combination machine, a powered model of which was then underway. Because of the lack of room, he requested the use of Mascot for test work, together with accommodation in the new shed then nearing completion, and such approval was given.

A progress report on what he called the Commercial Machine was passed to the CCA on 12 October. This was apparently powered with a 40hp Anzani, was easily converted to or from a gyroplane, and valuable and satisfactory results had been obtained with it, although no move had then been made to Mascot. Work on it was deferred following the initial assessment, in favour of another design to meet the Air Ministry Prize requirement, and which had then been underway for some months. The program called for tethered tests, and then the installation of variable incidence planes. A 130hp Clerget from liquidation stocks at the AA&ECo was to be used.

Over the 12 to 14 years of experimentation with helicopters and gyroplanes, Fortescue claimed to have collected valuable data.

A considerable amount of aircraft material was bought very cheaply from the AA&ECo at the time of its liquidation in 1923 and, while a lot of it was Avro 504K parts and components, its use in the gyroplanes generally required a reduction in size and weight, which latter was considered, but not sufficiently, as most of the models and full-size aircraft were far too heavy for the power available. Fortescue also bought a few unserviceable engines, plus propellers, dope, and general aircraft parts, and in some categories of small parts, built up sufficient stocks that he was able to meet requests from many aircraft owners and operators for spares and replacements — his home became a supply centre over the next few years.

The rotors were all fabric-covered wooden frames, braced with piano wire, and were fixed at their roots, whereas later work by others showed the need for flapping hinges.

The variable-incidence parasol upper mainplane was supplemented by small stabilising planes mounted on the lower longerons, and operation as a seaplane was advised as possible, either with or without the revolving top. Empty weight (without the revolving top apparently) was 700 pounds, while all-up-weight in the same configuration was 900-925 pounds, and maximum speed was 65-70mph.

Bob Burton was employed at the factory and was also involved in the development work of the gyroplane, and he stated in 1959 that Fortescue was attempting to find some means of providing lift and forward motion in one transmission system, but was unable to overcome the problems involved, nor the troubles encountered with his systems. A tractor propeller was provided in the meantime for forward thrust, and it was ultimately found that lift was sufficient for take-off, after a run of 30 to 40 yards, but that stability was insufficient for flight. Naturally, no wind-tunnel research was possible, nor was there any serious stress-analysis work undertaken, although extensive testing of propellers and rotors was undertaken at Fortescue’s workshop. A continual process of change and evolution in rotor design was required, and pitch changes, to ensure adequate rpm and lighter engine loads, was one of the avenues of exploration undertaken.

Fortescue had never had any flying experience himself and in fact never even left the ground as a passenger in his lifetime — his interest was purely in the design and engineering development of his idea. Syd Marshall was asked to undertake part of the testing program, but declined to do so unless ropes were attached to the aircraft so that ground parties could control it. Ex-NO4 Sqn Lt R.C. Nelson was then engaged, and made the first hops, to a height of about four feet, but was reputedly not keen to try it again because of the lack of stability.

First flight as a conventional monoplane without the stabilising planes was attempted at Mascot in about mid-October 1924, with Nelson reported as putting it through its paces on about 19 October. Power was insufficient, and it was intended to fit a Clerget of 110hp, possibly before the Aerial Derby at Richmond on 8 December, for which it was listed as an entry, with the entry-number Nine. However, it did not reach the competitions because of instability and the lack of power, and, as far as is known, was not developed any further.

Dud Wright (later a senior engineer and Queensland manager for QANTAS) was at Mascot as a Larkin employee working on the AAS Sopwith Wallaby engine in November 1924, and saw the Fortescue aircraft’s attempts to fly. An Avro 504K fuselage had upper-wings installed in a variable-incidence parasol configuration, wire braced to the cabane, and adjusted by a screw-jack system ahead of the cockpit. He never saw it get into the air, and was concerned about the result if it had.

When Juan de la Cierva first flew his Autogiro in Spain in 1922, Fortescue felt that his patents had been infringed, as there was so much similarity in the designs. Cierva’s rights were queried, and it was found that Fortescue’s basic patents had lapsed 14 days previous to Cierva’s application. Although he had not overcome stability and control problems, Fortescue was possibly ahead of Cierva in having had a gyroplane airborne, but, as his had powered rotors, and Cierva’s had free-rotating ones, the difference was obvious by today’s definitions, but not so clearly defined in principle at the time. As it was, Cierva was later awarded £80,000 by the British Government in recognition of his achievement.

A receipt from Badgery was made out to the ‘Secretary A.F. Flying Machine’ on 7 September 1928, covering the payment of £20 for an Anzani engine and sundries.

On the occasion of the opening of the Sydney Harbour Bridge on 19 March 1932, the Executive Committee which organised the ceremonial parade invited Fortescue to display one of his aircraft, and, accordingly one of his early models joined the parade across the bridge, mounted on a truck. Illustrations of his various developments were at one time displayed on the walls of Science House in Sydney, and Fortescue was made an Associate Fellow of the Royal Aeronautical Society for his achievements.

After his death on 25 October 1936, the property was sold, and most of the work was disposed of, except that the final version was taken to Wollongong in about 1938 by Victor Fortescue, a nephew who had intentions of fitting the Clerget, and finishing the aircraft off again. However, he joined one of the services after the outbreak of war and during his period away the aircraft was moved out onto a rubbish tip, although the Clerget was still there, supposedly in running order, in 1961 or thereabouts.

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