A.Jackson Avro Aircraft since 1908 (Putnam)
The Duigan Biplane
John R. Duigan was an Australian who designed and built a Farman-type biplane at Mia Mia, Victoria in 1910 and flew it before a very large crowd at Bendigo Racecourse, Melbourne on May 3, 1911. A series of accidents convinced Duigan that he needed proper flying instruction and later in the year he sailed for England, arriving in October 1911. He went at once to Brooklands, joined the Avro School, placed an order for a private Avro aeroplane and in the following month went off to Manchester to see it built.
The machine was a two seat, dual control biplane, similar to Type D but fitted with a square rudder, steel framed tailplane and square instead of triangular section fuselage. The seats were arranged so that the occupants' heads were raised just above the padded rim of an elliptical opening and celluloid windows were provided in the floor to give downward view. Following current Continental practice, Roe tried a newer wing section having 'Phillips entry' whereby the chord line of the wing was horizontal in level flight. Wing warping was employed for lateral control and wing spars were of English ash with poplar ribs, rounded wingtips being formed from rattan cane. As usual, the whole machine was built in sections, easily dismantled for transport, the fuselage consisting of two halves bolted together behind the rear cockpit. The engine was a 40 h.p. horizontally opposed Alvaston driving an Avro airscrew of Kauri pine and cooled by large spiral tube radiators on each side of the front cockpit.
The undercarriage was a complete departure from normal Avro practice, incorporating a Nieuport-type leaf-spring axle and centre skid with bracing wires to flatten long grass and prevent nosing over. This type of undercarriage proved so successful that in modified form it was used on Avro aeroplanes for a generation.
First straight hops were made by Duigan at Huntingdon Racecourse flying ground early in February 1912 but in spite of experiments with different airscrews the machine was very loath to leave terra firma. Considering it advisable to return to the Avro fold, Duigan took the machine to Brooklands where a 35 h.p. E.N.V. engine was fitted and he met with more success. On March 10 several long straight flights were made but the aircraft was sadly underpowered and only flyable in good weather. Duigan then made and fitted an airscrew of his own design and working as his own mechanic, tuned the E.N.V. engine to such good effect that on April 12 he succeeded in flying several times round Brooklands track. On April 19 he flew figure eights at 300 ft. and on April 27 successfully completed tests for his Aviator's Certificate, the aircraft having completed four hours in the air up to that date entirely without damage. Passenger flights, not so successful on low power, were confined to straights within Brooklands track. Duigan's best and final solo flight in his machine, consisting of an hour's circuits over Addlestone at an altitude of 400-600 ft., was made on April 30.
Having achieved his objectives, Duigan returned home. There he built a very similar machine to the Avro which crashed on its first flight on February 17, 1913. His British aeroplane was put up for sale with engine for ?380 but was almost immediately reduced to ?180, no doubt because the engine had been sold separately. The airframe was purchased by the Lakes Flying Company who rebuilt it at Windermere as the centre float seaplane Sea Bird which H. Stanley-Adams flew off the lake for the first time on August 28, 1912. The company entirely redesigned the front end of the fuselage to accept a 50 h.p. Gnome rotary, the upper half of which was cowled and gave a cocked-up appearance to the nose. New three bay, warping mainplanes of Eiffel 12 section and 8-5 aspect ratio were also fitted. The machine proved much faster than the old Avro-built Water Bird and after it had been fitted with an improved twin float undercarriage, carried large numbers of holidaymakers during 1912-13. Dual control was fitted in 1915 but Sea Bird was destroyed in June of that year when pupil R. Buck spun in from 300 ft.
SPECIFICATION AND DATA
Manufacturers: A. V. Roe and Company, Brownsfield Mills, Great Ancoats Street, Manchester; and Brooklands Aerodrome, Byfleet, Surrey. Rebuilt by The Lakes Flying Company, Cockshott, Lake Windermere, Westmorland
One 40 h.p. Alvaston
One 35 h.p. E.N.V. Type D
(Sea Bird) One 50 h.p. Gnome
(Duigan) Span 34 ft. 0 in. Chord 4 ft. 6 in.
(Sea Bird) Span 39 ft. 4 in. Length 29 ft. 4 in.
Height 10 ft. 6 in. Wing area 350 sq. ft.
(Duigan) Speed 40 m.p.h.
(Sea Bird) Maximum speed 62 m.p.h.
Production: One aircraft only, first flown 2.12; converted into the Lakes Sea Bird 10.12, crashed at Windermere 6.15
Avro 500 (Type E)
The first War Office military aircraft specification, issued in 1911, called for a two seater to carry a 350 lb. load in addition to essential equipment and have an endurance of 4 1/2 hours, initial rate of climb of 200 ft./min., maximum speed 55 m.p.h., ability to maintain 4,500 ft. for one hour, and be capable of delivery to Salisbury Plain in a crate. Competing firms had only nine months in which to design, build and test.
A. V. Roe and Company met this specification by building a new two-seat biplane, very similar in design and construction to the previous year's Duigan machine. The built-up box-girder fuselage was again of square section, fabric covered in the rear and metal clad forward. It was more streamlined than the Duigan with pilot and passenger seated at the widest part with their heads protruding through padded openings in the top. Small celluloid panels were again provided in the floor to give downward vision. The mainplanes used ash spars and an improved, double-surfaced section covered with Pegamoid fabric. They were detachable in three sections for ground transport. The undercarriage was of the Duigan type with centre skid and leaf-spring axle, the tail being carried on a rubber-sprung skid.
A 60 h.p. E.N.V. watercooled engine was mounted on the top longerons and drove a 10 ft. Avro airscrew. The main fuel tank was in front of the passenger and twin gravity tanks were fixed to the centre section struts. Known originally as the 'Military Biplane', but in later years as the Type E prototype, the machine was first flown at Brooklands by Wilfred Parke on March 3,1912. It was obvious from the outset that this was no ordinary aircraft but one with that rare quality, a reserve of power. This encouraged its entry for the Mortimer Singer prize. Test flying took but a few days, during which it was promptly dubbed "Elinor Glyn" (after a well-known novelist of the period) and on March 23 Parke climbed to 1,000 ft. in under six minutes and to 2,000 ft. in 13 minutes with a heavy passenger (R. L. Charteris).
Cooling was by spiral tube radiators on each side of the front fuselage, augmented by two smaller units on the centre section struts on each side of the passenger's head. On April 20 Parke suffered partial engine failure when taking off for Hendon to compete for the prize. The hurried landing ripped off undercarriage and mainplanes and when the aircraft rolled on its side the auxiliary radiators folded over the front cockpit and engineer W. H. Sayers had to be extricated through a hole cut in the side. In the interest of future passengers the machine was rebuilt with only the lower radiators fitted. Parke successfully piloted the machine through Farnborough trials in June 1912 after which it returned to Brooklands to become a flying testbed for the new 60 h.p. A.B.C. engine. First straight hops with this power unit were made by F. P. Raynham on August 31 but it was not until October 18, when several engine and airframe adjustments had been made, that it flew strongly in the hands of the A.B.C. representative R. L. Charteris. In 1913 the E.N.V. engine was reinstalled and the aircraft sent to Shoreham and there flown by experienced pilots of the Avro School, such as H. R. Simms and H. S. Powell. On June 29, 1913 pupils were allowed to fly it for the first time but in the afternoon it stalled on a turn, crashed and was destroyed by fire. Pilot R. N. Wight received fatal injuries, the first ever in an Avro aircraft.
SPECIFICATION AND DATA
Manufacturers: A. V. Roe and Company (reconstituted as A. V. Roe and Co. Ltd., 11.1.13), Brownsfield Mills, Great Ancoats Street, Manchester (moved to Clifton Street, Miles Platting, Manchester, 4.13); and at Shoreham Aerodrome, Sussex
(Type E prototype) One 60 h.p. E.N.V. Type F
One 60 h.p. A.B.C.
Span 36 ft. 0 in. Height 9 ft. 9 in.
(Type E prototype) 30 ft. 6 in.
Wing area 330 sq. ft.
(Type E prototype) Tare weight 1,100 lb. All-up weight 1,650 lb.
(Type E prototype)
Maximum speed 50 m.p.h.
Initial climb 170 ft./min. Endurance 6 hours
Prototype only, first flown at Brooklands 3.3.12, destroyed by fire at Shoreham 29.6.13
M.Goodall, A.Tagg British Aircraft before the Great War (Schiffer)
Deleted by request of (c)Schiffer Publishing
P.Lewis British Aircraft 1809-1914 (Putnam)
Avro E 500
The development of the Avro biplane was carried a step further with the delivery of a single-seater in September, 1911, to S. R. Duigan, an Australian pilot staying in England. An Alvaston engine was fitted to the machine, which was flying at Huntingdon in the following December. The triangular-section fuselage of the earlier Avro products was replaced by one of rectangular section and which was fully covered. The new machine represented a great improvement over the D Biplane, and a slightly larger two-seater version with dual control appeared shortly afterwards at the beginning of 1912. This was fitted with a 60 h.p. E.N.V. "F" for power, and after testing at Brooklands was intended to be used by Lt. W. Parke, R.N., to compete for the Mortimer Singer Naval Prize.
The tandem cockpits were set several feet apart, the front one being just behind the leading-edge and the rear one at the trailing-edge. A pair of radiators were disposed one on each outer side of the front cockpit, and the comparatively heavy four-wheeled, twin-skid undercarriage of the D type was replaced by a simple form with a pair of wheels on an axle braced to the fuselage by a vee-strut, and incorporating a central skid supported similarly fore and aft.
Description: Two-seat tractor biplane. Wooden structure, fabric covered.
Manufacturers: A. V. Roe & Co., Brownsfield Mills, Manchester.
Power Plant: 60 h.p. E.N.V. "F"
Dimensions: Span, 36 ft. Length, 30 ft. 6 ins. Wing area, 330 sq. ft.
Weights: Empty, 1,100 lb. Loaded, 1,650 lb.
Performance: Maximum speed, 61 m.p.h. Climb, 440 ft./min. Endurance, 2.5 hrs.
Flight, March 30, 1912.
THE NEW AVRO BIPLANE.
EXCEPTING that the general disposition of its respective parts is the same, the new Avro biplane can hardly be recognised as a modification of the little machine on which Pixton attained his early successes and demonstrated the practicability of carrying a passenger cross-country with an engine of as low horse-power as 35.
Although it is in effect an original model to most of those who keenly follow the trend of design in this country, it is, in reality, several months old, for it was an almost identical machine that the Avro firm supplied to Mr. J. Duigan in September last. The only points of difference in the two machines are that, this present machine being a two-seater, a more powerful motor is installed, and dimensions are slightly increased throughout.
The triangular section body of the early machine has been superseded by one of rectangular section, built to an approximate streamline form, and so deep in the region of the cockpit that much head resistance and much personal discomfort of the pilot and passenger are avoided by virtue of the fact that only their heads emerge from its depths through the well-padded openings on top. Other advantages does this deep form of fuselage possess. The lower plane may be attached to it in a manner very similar to the attachment of monoplane wings; the chassis struts may be considerably shortened, thus making for more robustness in the landing gear. To facilitate transport the body may be dismantled into two sections. The crossbracing of the fuselage - it is of the ordinary girder type - is the same standard Avro system that has already been explained and illustrated in these columns.
A point worth mentioning in connection with the body is that its top surface is flat, and when the machine is in level flight is, theoretically, horizontal. To preserve its lines it is covered in by metal sheeting in the front, and by fabric to the rear.
The undercarriage needs little description, for it must be admitted that except for the central skid, and the front pair of struts fashioned from wood, and the steel disc wheels employed, it is identical with the Nieuport chassis. Rubber cushions are introduced between the struts and the central skid to further assist in deadening landing shocks.
When the machine first appeared at Brooklands there were some doubts as to whether this type of chassis would "stand up to its work" fitted to a passenger-carrying biplane. However, as far as the tests have gone it has proved eminently satisfactory. So doubts may, for the time being, be dispelled.
The main planes are rectangular, and have an aspect ratio of over 7 1/2, a feature which, coupled with the modified form of Phillips' cross-section employed, must have a most beneficial effect on their efficiency. In their bracing only eight struts are employed, these being fitted and riveted into welded steel sockets. Warping is employed for the maintenance of lateral balance.
In cross-section the planes have little curvature on the under surface, and have the peculiarity that the underside of the trailing-edge is horizontal in flight. Provisions have been made so that in quite a short space of time the machine may be turned into a monoplane. Virtually a double-purpose machine, it will be able to serve either as a weight carrier or a speedy scout. And speed it does exhibit - it must average at least 60 m.p.h.
Steel tubing is solely employed in the construction of the skeleton of the tail. This organ is purely directional, while elevation and depression is regulated by a pair of hinged flaps, operated through levers made from sheet steel.
Control is maintained by universal levers by either pilot or his passenger, the latter of whom is seated well forward in the body at the centre of gravity, so that his extra weight need not interfere with the balance of the machine.
Two little celluloid windows have been let into the floor boards in order that both will be able to see what is directly beneath them.
A 60-80 h.p. E.N.V. motor direct coupled to a 10-ft. Avro propeller provides the forward thrust.
Altogether the new Avro biplane is a decided advance on anything their works have hitherto produced. As for its efficiency it is only necessary to mention that on test on Saturday last it attained an altitude of 1,000 feet, in a little over live minutes. 2,000 feet was reached, with a heavy passenger aboard, in 13 minutes.
Flight, August 10, 1912.
THE MILITARY AEROPLANE COMPETITION - THE MACHINES.
THE AVRO BIPLANE.
THIS machine is one of the most remarkable of those flying at Salisbury, for the fact that it is the only one of the competition machines that allows the pilot and passenger to be totally enclosed and so completely protected from the rush of air. It is an interesting fact with this new Avro biplane that, with the side windows open the only wind felt is one which comes from the side when turning and banking. As will be seen by the photographs we publish this week, the fuselage completely fills the gap between the main planes. It is approximately streamline in side elevation, and its section may be represented by a tall vertical panel. The body is surprisingly narrow. Where the pilot and passenger sit it is only sufficiently wide to give them free movement. At the extreme front it is only 15 inches wide, a dimension which is obtainable by the use of a 60-h.p. vertical Green engine. The planes are identical with those fitted to the machine already supplied to the War Office. On the "all enclosed" biplane one deck is fitted to the extreme top of the fuselage, and the other to a point near the bottom. The warping wires pass from the top plane through slots in the lower, round a phosphor bronze four-grooved pulley attached to the end of the skid. It has been so arranged that a warp of eighteen inches at the wing tip is possible.
The landing gear is admittedly of Nieuport pattern, but it has the refinements that rubber blocks are interposed between the skid and the chassis struts, and that the transverse leaf springs are fitted to the wheels in an improved manner. The military authorities, recognising this latter improvement, are, by the way, now fitting this type of spring attachment to their Nieuport monoplanes.
Access to the interior of the body is obtained through triangular doors. A dashboard, on which are fitted all the instruments necessary for cross-country flying, is arranged to fill the whole space between the planes in front of the occupants. The latter are provided with safety belts.
The rudder serves a double purpose. By being shod with iron and by being arranged to slide vertically up and down the rudder post against the action of a spring, it is made to serve as a rear skid, as well as to perform its usual function of directing the course of the machine.
Overall length 30 ft.
Weight without complement or fuel 1,250 lbs.
Span 35 ft. 8 ins.
Speed 65 m.p.h.
Flight, November 2, 1912.
AVIATION IN PORTUGAL.
FROM some particulars which have been sent us by Mr. H. V. Roe, it is evident that Portugal is now taking aviation very seriously. Several of the prominent newspapers are collecting for the national subscription, and the shops prominently display aviation books and postcards. Out of the National Fund the Avro biplane and Maurice Farman biplane, and a Voisin hydro-aeroplane have already been bought, while some Brazilian officers have presented a Deperdussin to the Government. The Avro was officially handed over to the Minister of War on October 16th, when a crowd of about 20,000 people assembled to witness Mr. Copland Perry make some exhibition flights before the President. The flying ground is at Pedroucos, some 4 miles or so from Lisbon, between Belem and Algers, but it makes a very difficult aerodrome, as it is only about 300 yards long by 200 yards wide and is bounded on two sides by trees, on the third by some gas-holders, while the fourth is more or less open, as it adjoins one of the military rifle ranges. It is in that direction that Mr. Perry nearly always steered, and his favourite trip was up the river to Lisbon, over the town and the Avenida returning over the River Tagus, the round taking between 10 and 15 mins. The day after the machine had been handed over to the Portuguese Government Mr. Perry started off with a passenger intending to survey the country with a view to finding a permanent aerodrome. They disappeared in the direction of the town and were away for about an hour after which they continued flying in the opposite direction. Unfortunately when coming back the engine showed signs of giving up and the pilot decided, as it would be impossible to get back to the aerodrome, to bring the machine down into shallow water, about 50 yards from the shore, that being the only suitable place. Row boats were quickly to the rescue and the machine was hauled ashore little the worse for its bath. It is now called "Republica" the name being painted in red on both sides of the body and al;o in green underneath the wings, while a couple of little Republican flags are mounted on the outside struts. A good many flights have also been made by M. Trescarte on the Maurice Farman biplane. The Voisin machine is rapidly being erected, but the Deperduisin monoplane has not yet arrived, although it is expected shortly.
Flight, January 8, 1915.
The next step in the evolution of the Avro biplane was another tractor biplane in which numerous alterations as regards component parts were carried out, but which was fundamentally a logical development of the machine already described. With a view to provide more comfort for the pilot than was afforded by the comparatively shallow body of the Green-engined biplane, the fuselage of the next one in the series was made of rectangular section and was very deep so as to leave only the pilot's head projecting above the top covering. As regards the main planes and tail planes no radical alterations were made, but the under-carriage, which was hitherto of the wheel and skid type, was superseded by one resembling that of the Nieuport monoplanes. A short central skid was carried on three pairs of V-struts, and served as an anchorage for the leaf spring axle that formed the shock-absorbing device. The great amount of flexibility of this type of under-carriage caused considerable controversy, some critics maintaining that it was too "squashy" to stand up to its work, others being of opinion that its flexibility was just its greatest advantage, as it saved the remainder of the machine from receiving any severe shocks in case of a rough landing. Passenger's and pilot's seats were arranged as before in tandem, with the passenger in front. The engine fitted was a 60 h.p. E.N.V.