A.Jackson Avro Aircraft since 1908 (Putnam)
Avro Type G
A. V. Roe's second cabin aeroplane was a two seat biplane designed specifically for the Military Aeroplane Competition of August 1912, and today historically important as the world's first cabin biplane. Very similar structurally to the Type F, the fuselage filled the whole mainplane gap and was again very narrow with a maximum beam of 2 ft. 3 in. tapering to only 15 in. at the front end. This was made possible by the use of a slim in-line engine mounted on steel bearers and enclosed in louvred cowlings with the main exhaust taken over the roof. As on the Type E prototype, cooling was by means of spiral tube radiators on each side of the cabin, entry to which was through triangular doors hinged to slanting struts in the sides of the fuselage. Mainplanes, undercarriage and tail unit were identical with those of the Avro 500. Once again there was no vertical fin and the steel shod rudder also acted as tail skid. Lateral control was by wing warping with a maximum warp at the tip of 18 in.
Two Type G biplanes were laid down. One with a 60 h.p. Green engine to be flown by Wilfred Parke with competition number 6 and a second, numbered 7, for R. L. Charteris of the All-British Engine Co. Ltd. with a 60 h.p. A.B.C. eight cylinder engine. Unfortunately this A.B.C. engine was not ready in time and as a matter of expediency No. 7 was completed with the Green engine in place of No. 6.
There was no time for test flying and the aeroplane was delivered in a crate direct to the competition ground at Larkhill on Salisbury Plain and there flown for the first time by Wilfred Parke. On August 7, 1912 he took off at the start of the 3 hours endurance test but after half an hour turbulent conditions compelled him to give up. Hurriedly landing down wind, he overturned and so damaged the machine that it had to be sent back to Manchester for repair. Exactly a week later on August 14, the machine returned, no doubt incorporating many components of the unfortunate No. 6. During the resumed trials Parke demonstrated the machine's all-weather qualities by flying in a rainstorm for 37 minutes and for half an hour in a wind of 40 m.p.h.
At 6.04 a.m. on Sunday August 25, 1912 Parke again started on the endurance test carrying Lt. Le Breton as passenger. Just after 9 a.m. he commenced a series of steep dives to relieve the monotony and in so doing spun off a turn, but Parke's cool head and analytical mind were equal to the situation and he soon discovered that if the stick were central, recovery was possible by applying full opposite rudder. He was the second pilot to survive a spin but the first to do so before competent observers. In the ensuing discussions he gave a lucid account of what had taken place and today 'Parke's Dive' is recognised as an important milestone in the development of flying techniques. Later in that eventful day H. V. Roe flew as passenger to Upavon and became the first person to type a letter in an aircraft in flight.
The Type G cabin biplane was an easy winner in the assembly test in a time of 14 1/2 minutes compared with the 9 hours 29 minutes of the Farman biplane and although the accident left insufficient time for the compilation of all the required data, the Avro company was awarded ?100 for attempting all the tests. The Type G failed to secure a major award because the initial rate of climb was poor (9 min. 30 sec. to reach 1,000 ft.).
F. P. Raynham flew the machine home to Shoreham on October 11 but it had been in the open for so long that both engine and rigging needed attention. He therefore took the machine to Brooklands for adjustments on October 21 in 45 minutes and next day made an attempt to win the British Empire Michelin endurance prize. A broken water connection ended the flight after 3 1/2 hours but on October 24 he established a duration record for all-British aeroplanes with a time of 7 hours 31 minutes. Competing against Harry Hawker in the Sopwith Wright biplane, Raynham flew round Brooklands all day with the Green engine throttled right back to conserve fuel until forced to land through shortage of oil. His record stood for only an hour as Hawker went on to establish a new record of 8 hours 23 minutes and win the ?500 prize. The Type G biplane was afterwards flown back to Shoreham where it was last heard of in February 1913 hangared with the Type D biplanes of the Avro School.
SPECIFICATION AND DATA
Manufacturers: A. V. Roe and Company, Brownsfield Mills, Great Ancoats Street, Manchester; and Shoreham Aerodrome, Sussex
Power Plant: One 60 h.p. Green
Span 35 ft. 3 in. Length 28 ft. 6 in.
Height 9 ft. 9 in. Wing area 335 sq. ft.
Weights: Tare weight 1,191 lb. All-up weight 1,792 lb.
Maximum speed 61.8 m.p.h. Initial climb 105 ft./min.
Range 345 miles
Production: One aircraft only, second machine not completed
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)
The 1912 Military Trials on Salisbury Plain brought forth diverse designs in two-seat aeroplanes for Army use. The Avro G Biplane was unique among them as the only one with an enclosed cabin. Two examples were built: No. 6 with a four-cylinder 60 h.p. Green engine, and No. 7, which was to have had an eight-cylinder 60 h.p. A.B.C. fitted. Lt. Wilfred Parke, R.N., was selected to fly No. 6 in the Trials, and R. L, Charteris, of the All-British Engine Company, was the pilot chosen for No. 7. When the time came the A.B.C. engine of Charteris's machine was not ready, and Parke's Green-engined aircraft was the only one of the pair of Avros to take the field. Its Trials No. 6 was replaced by its companion's No. 7.
The Avro G featured a slender 2 ft. 3 ins. wide fuselage which was deep enough at the cabin section to support both upper and lower wings without needing centre-section struts. The wings themselves were of unstaggered two-bay type with 18 ins. warping movement at the tips for lateral control. The Green-engined G was fitted with radiators on each side of the cabin, the pair of which comprised 600 ft. of 3/16 in. tubing, and the engine itself was fully cowled. The lower part of the rudder was shod with iron and was used as a tailskid, an idea which imparted undesirable loads to the hinges of the control surface although a vertical spring movement was incorporated.
In the Trials the machine won the quick assembly test in 14.5 minutes and came first also in that for fuel consumption. Simple, speedy assembly by means of unit construction was incorporated in Avro aircraft from the beginning. On 25th August, after completing his 3 hrs. qualifying flight, Parke found himself in a spin and managed to recover when only 50 ft. from the ground. He was the second British pilot lucky enough to extricate himself from a spin, about which little was then known, being preceded by F. P. Raynham on an older type of Avro biplane. Parke was unfortunate in crashing the machine while landing downwind during one of the tests. Despite rebuilding during one week, the G Biplane was without sufficient power to prove a success in the Trials. During the competition H. V. Roe became the first to use a typewriter in the air, typing on a Monarch machine while Parke flew him in the G from Salisbury Plain to Upavon.
The Green-engined machine was afterwards put to good use at the Avro School at Shoreham from October onwards. Raynham used it for an attempt on the British Michelin Cup No. 1 and stayed aloft for 3 hrs. 50 mins., but this time was bettered during a second attempt on 24th October, 1912, when the G Biplane set up a new British endurance record of 7 hrs. 31.5 mins.
Description: Two-seat tractor biplane. Wooden structure, fabric covered.
Manufacturers: A. V. Roe & Co., Brownsfield Mills, Manchester.
Power Plant: 60 h.p. Green, 60 h.p. A.B.C.
Dimensions: Span, 35 ft. 3 ins. Length, 28 ft. 6 ins. Wing area, 310 sq. ft.
Weights: Empty, 1,191 lb. Loaded, 1,700 lb.
Maximum speed: 62 m.p.h.
Jane's All The World Aircraft 1913
AVRO. Aeroplanes. A.V. Roe & Co., Clifton Street, Miles Platting, Manchester; also Shoreham, Sussex. A.V. Roe designed his first machine, a biplane, in 1906. It was the first British machine to leave the ground. He then experimented with triplanes in Lea Marshes, where he managed to fly with only 9 h.p. in 1908-9. In August, 1910, built Roe III, and in September, Roe IV, also triplanes (see 1911 edition for full details). In 1911 he abandoned triplanes for the Avro biplane. School: Shoreham.
D 1911-12. E 1912. F 1912. G 1912-13. E 1912-13.
Model. 2-seater 2-seater Totally Totally Hydro-biplane.
biplane. biplane. enclosed enclosed
Length.....feet(m.) 31 (9.45) 29 (8.84) 23 (7) 29 (8.84) 33 (10)
Span.......feet(m.) 31 (9.45) 30 (11) 28 (8.50) 36 (11) 47-1/2 (14.50)
Area....sq.ft.(m^2.) 279 (26) 335 (32) 158 (14-1/2) 335 (32) 478 (34-1/2)
Weight, empty lbs.(kgs.) 800 (363) 900 (482) 550 (249) 1191 (540) 1740 (789)
Weight, fully loaded, lbs. (kgs.) ... 1300 (589) 800 (363) 1700 (771) 2700 (1224)
Motor...........h.p. 35, any 50 Gnome 40 Viale 60 Green 100 Gnome
Speed....m.p.h. (km.) 48 (78) 61 (97) 65 (105) 61.8 (100) 55 (90)
during 1912....... several 6 1 1 1
Remarks.--Of the above, 4 of the 50 Gnome E type were purchased by the British Royal Flying Corps, and one by the Portuguese Government; the other went to Windermere on January, 1913, for hydro experiments. Climbing speed of this type is 440 feet per min. (134 m.) Dual control fitted. D type are no longer being built. Climbing speed of F type, 300 feet per min. (91.5 m.) Gliding angle, 1 in 6. G has a gliding angle 1 in 6.5. On October 24th, 1912, made British record to date, 7'31-1/2" (=450 miles). The hydro. was delivered to the British R.F.C. naval wing early in 1913.
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, August 31, 1912.
Salisbury Plain, Sunday, August 25th.
HERE is the true story of one of the worst experiences in mid-air from which any pilot has extricated his machine in absolute safety, and as the circumstances precisely represent the hypothesis of the most debated problem among pilots at the present time, the following particulars should be studied with the closest attention by all.
At four minutes past six this morning Lieut. Parke, R.N., accompanied by Lieut. Le Breton, R.F.C., as observer, started on the Avro biplane (60-h.p. Green engine) from Salisbury Plain for the three hours' qualifying flight in the Military Trials. At ten minutes past nine, having more than completed the required duration, he was returning from the direction of Upavon for the express purpose of alighting in front of the sheds.
The direction of flight was practically towards due south; the wind was blowing approximately from the south-west, with a tendency to back southwards. He was, therefore, flying virtually up wind. The speed of the wind was estimated about 10-15 m.p.h. by the pilot, and the maximum air speed of the machine with the present propeller is about 60 m.p.h., as tested over the measured distance yesterday. The engine was pulling well, and the machine in perfect trim. There was bright sunshine and some clouds.
Throughout the flight an altitude of between 600 and 700 ft. was maintained, and the pilot, observing that he was still at this height, decided that he had sufficient room for a spiral glide. At the point A, in the diagram, he closed the throttle without switching off (which kept the engine just turning) and immediately proceeded to glide round down wind. At the point B, having completed a half spiral, Parke thought the machine was in an unnecessarily steep attitude, and was insufficiently banked for the turn he was making. He therefore elevated, and believes that he may also have given a momentary touch to the warp, which two operations were for the purpose of reducing the steepness of the descent and increasing the bank respectively.
The machine at once started a spiral nose-dive.
At the point C, Parke opened the throttle full out, in the hope that the propeller might pull the nose up, for he was aware (and had also confirmed the fact during this flight) that the machine was slightly nose-heavy with the throttle closed. The engine responded instantly, but failed to produce the desired effect on the machine; it may or may not have accelerated the descent, but the fall was already so rapid that the maximum engine speed was unlikely even to be equal to it.
Also at the point C, he drew the elevator lever hard back against his chest and put the rudder hard over to the left with his foot so as to turn the machine inwards, this latter being the principle of action that is accepted as proper in cases of incipient side-slip, and, therefore, naturally to be tried in an emergency such as this. The warp was normal, i.e., balanced with the control wheel neutral. These operations failed utterly to improve the conditions.
From C to D the machine was completely out of control, diving headlong at such a steep angle that all spectators described it as vertical and stood, horror stricken, waiting for the end. According to Parke, the angle was very steep, but certainly not vertical; he noticed no particular strain on his legs, with which he still kept the rudder about half over to the left (about as much as is ordinarily used for a turn), nor on his chest, across which he was strapped by a wide belt to his seat. His right hand he had already removed from the control wheel in order to steady himself by grasping the body strut forming an upright between the windows of the enclosed body. This he did, not for support against the steepness of the descent, but because he felt himself being thrown outwards by the spiral motion of the machine, which he describes as "violent." The absence of pressure on the legs and arms appears to me, however, to be evidence that the machine was falling as fast as the pilot, who was, therefore, unstable on his seat, and without a fulcrum until he fastened himself to the framework by the grip of his hand.
It was his recognition, through this forcible effect, of the predominating influence of the spiral motion, as distinct from the dive, that caused him to ease off the rudder and finally push it hard over to the right (i.e., to turn machine outwards from the circle), as a last resource, when about 50 feet from the ground.
Instantly, but without any jerkiness, the machine straightened and flattened out - came at once under control and, without sinking appreciably, flew off in perfect attitude. Parke made a circuit of the sheds in order to get into position for landing in a good place up wind, and proceeded to alight in the usual way without the least mishap. Thus did he and his observer, who, having no belt and rather cramped accommodation, was thrown up against the front wall of the cabin, escape at the last moment from what looked like certain death and effect a perfect landing with the machine none the worse for its severe straining save for a slight stretching of some of the lift-wires under the main planes.
Like the majority, I was at breakfast when the dive occurred; for, having watched the Avro during the earlier part of its flight and up to the end of its second hour, its uniform behaviour inspired a confidence that one was not loathe to translate into an excuse for leave. Very soon afterwards, however, I saw Lieut. Parke on the field, and, together with G. de Havilland and F. Short, of the R.A.F., adjourned to the competitors' mess, where we held an informal, but extremely close, enquiry into the whole affair. It was so obvious to all that the problems of the accident were so near to having to be discussed under the shadow of the pilot's absence, that the opportunity of recording on the spot the essential facts and impressions as he understood them was not only unique, but of the utmost consequence to aviation. His own anxiety to facilitate this work for the benefit of others, and the fact that he retained his presence of mind from first to last in the emergency - although admittedly terribly alarmed - so that he was conscious of each operation and the effect produced serves to give to the aviation world at least one definite experience of an extreme character for its guidance.
The seriousness of the situation there is no denying. Parke himself stared death in the face; most of the spectators sickened for the crash, and among them were those who were also furious in the belief that he had attempted a "stunt" and failed. There was some reason for this belief, because the machine behaved throughout in a perfectly smooth, normal manner, despite its extremely exaggerated attitude, and when it flattened out so nicely at the last moment even those who had been convinced they were witnessing an accident were left in doubt, whether, after all, it had not been intentional.
If disaster had followed, all manner of "explanations" would have been forthcoming, and, among them, de Havilland would have given it as his opinion that the control had become jammed, having regard to the fact that there was no excuse otherwise for a pilot of such experience to get himself into that position. With this latter observation Parke himself heartily agrees; but it happened all the same. He was not tired after his flight, but he was naturally pleased at its successful termination after all the previous misfortunes that the Avro firm had borne in such good spirit, and had in mind merely the finishing of the flight safely, but in good style.
Of the many important and interesting aspects of the case, one is obviously related to the value of flying high. But for the room available for the fall, disaster was unavoidable. For the first 100 ft. the descent was normal, but, afterwards, acceleration to something in the order of 90 m.p.h. (speed suggested by de Havilland) took place, and the machine fell about 450 ft. whilst more or less out of control - which is a lesson those who have not yet learnt would do well to bear in mind.
The next and most important point is that affecting the popular discussion on the proper method of recovering from side-slip in the air, particularly with reference to ruddering inwards and ruddering outwards in emergency. In the first place it is necessary to differentiate between the present circumstances and a side-slip in the incipient stage as ordinarily understood. A side-slip (which means the machine slips inwards), is caused, fundamentally, by over banking, insufficient speed and a cabre attitude (tail down), may be incidental to the occurrence. Ruddering inwards in such an emergency, brings the machine on to its accidental line of motion in a flying attitude (instead of sideways), and promotes a dive, from which the pilot obtains both the position and the velocity necessary to recovery.
In Parke's dive, the machine was not side slipping in the above sense (even supposing that the term could properly be applied to any phase of the occurrence) when ruddering outwards proved so marvellously effective. It was flying on a true helix of an excessively steep pitch, and to obtain a proper understanding of the effects produced it is necessary to have a clear mental picture of the tail in its line of flight. It is illustrated diagrammatically in the sketch. The elevator is hard up and the rudder hard over to the pilot's left. In common with the rest of the machine the tail as a whole has a spiral motion downwards through space, but leans inwards somewhat towards the centre of the vertical path in such a way as might produce a side-slip if the machine lacked velocity.
The present position of the rudder (to the pilot's left) supports the tail, and as the speed increases tends to make it cruise round outwards after the nose of the machine, thus turning the machine still more about its vertical pivot, increasing the steepness of the dive, and also, by maintaining the outer wing at its high velocity, accentuating the bank.
By throwing the rudder over to the right, this accentuation of the centrifugal action of the tail is checked, and a virtual acceleration of the inside main wing tip takes place in consequence, so that the machine tends to change its spiral direction of motion into a straight line, and at the same time to recover its lateral trim. These conditions at once release the elevator from the neutralising influences that have rendered it inoperative, and being already hard up it brings the machine on to an even keel at that high speed with extreme rapidity. The warp was not used consciously at this time; the wheel could have been turned with one hand, but Parke thinks he did not do so; i.e., the entire phenomenon is related to elevator and rudder action only.
Such is the gist of the explanation as we argued it on this occasion, and I believe the others who were party to the discussion are in agreement therewith, unless I have misunderstood their meaning on any point. There was a question as to whether the draught off the rudder being directed on to one half of the divided elevator could have exercised an appreciable torque through the backbone of the machine, first to increase the bank and afterwards to reduce it, but there seemed absolutely no evidence one way or the other on the subject. Later, it was suggested that the machine might have made an automatic recovery, such as models do when launched vertically from the hand, but here it seems necessary to remember that a model is in the process of picking up its flying speed, whereas in this case the phenomenon is related to an occurrence that took place when the flying speed had been far exceeded. If it were it would have been a most extraordinary coincidence, for the response of this machine to the right-hand swing of the rudder was instantaneous and indeed with only 50 ft. to go, it would have been quite useless otherwise.
Yes, on the whole I think we may consider it a genuine practical lesson in aeroplane control, and one, moreover, of the most important order. There has been endless discussion on this very subject and much conflicting opinion, but no one is voluntarily going to risk losing control of his machine in mid-air for the sake of demonstrating the facts. Now that it has happened to Lieut. Parke by accident, and he is safely through it to tell the tale, let no one forget the rule to "rudder outwards from a spiral dive that has already acquired a high velocity."
In conclusion, a word to the credit of the Avro biplane and Green engine. That the machine withstood the strain of flattening out at 90 m.p.h., or thereabouts, is no more than any pilot has a right to expect of any machine. Nothing must break in midair, and nothing did break. That it recovered in the long run is at least evidence in support of the design. The tail is the same on Parke's machine as on the Avro biplanes supplied to the Army, which are fitted with Gnome engines; but two of those machines have been refitted, by instruction, with larger tails than the designers and pilot consider necessary, although they see no objection to their use. One of the Army Avros still has the original tail.
By the courtesy of the firm, a scale drawing of the machine is reproduced on another page.
From this drawing the general lines of the machine and proportions of the surfaces are self-evident. The fuselage at backbone is entirely surfaced and rectangular; its sides narrow to a knife edge at the rudder-post, and present a considerable vertical surface to the wind. It appears, however, that this fin effect is balanced on either side of the vertical pivot about which the machine naturally swings in space, because Lieut. Parke has found no tendency for it to be slewed off its course either into or out of the wind.
This is an important consideration, because the large extent of the surface thus presented by the backbone, which is most easily arranged this way as a natural extension of the cabin-body, was thought to be a possible source of trouble in windy weather. Under normal conditions the machine takes a natural bank when turning; its wings have a large dihedral angle and are quite rigid in the ribs. Equal-sized spars are used.
In winds the machine appears to be very steady and weatherly.
Flight, February 8, 1913.
WHAT THERE WILL BE TO SEE AT OLYMPIA.
Messrs. A. V. Roe and Co., Ltd.,
Will be exhibiting on their stand one of the 50-h.p. Gnome-engined passenger-carrying biplanes that have given the War Office such satisfaction. It is interesting to recall, too, that a similar machine was recently supplied to the Portuguese Republic. Light, but strongly-constructed, fast, able to carry weight well, the 50-h.p. Avro biplane has proved itself one of the most successful machines of the day. And it reflects great credit on its designer, Mr. A. V. Roe who, having tasted the bitter sweetness of the pioneer, has gone doggedly ahead to such success. Mr. Roe has the distinction of being the only constructor, we believe, in the world who has designed and constructed successful monoplanes, biplanes, and triplanes.
Flight, April 26, 1917.
THE "TOTALLY ENCLOSED" AEROPLANE.
Probably the Avro enclosed biplane is best remembered, and will go down to history, as the machine on which the late Lieut. Wilfred Parke, R.N., had the nasty experience that became known to all the aviation world as "Parke's Dive." That the machine came out of this bad spin without breaking anything is not only an outstanding testimony to Avro design, but is of far greater significance in showing that, even with such a great amount of side area, a machine need not be uncontrollable in a bad spin, provided the pilot knows what to do. This Lieut. Parke only discovered at the last moment, but when he put her to it the machine answered the controls at once.
Except for the fact that it had two pairs of wings the enclosed Avro biplane was very similar to the monoplane already described. The main planes were attached to the upper and lower longitudinals of the body respectively, and pilot and passenger were seated tandem fashion inside. Entrance to the body was through a triangular door in the side, this being shown in our illustration. The engine, a 60 h.p. Green, was mounted in the nose of the body, which had here a width of only 15 inches, this being made possible by the fact that the engine was of the vertical type. The radiators were mounted on the side of the body in front of the door. Forming a partition between what may be termed the "engine room" and the occupants' cockpit was a large dashboard with all the instruments. These were therefore, as the passenger sat in front, some distance away from the pilot, who had to look over the passenger's shoulders in order to read the instruments.
The number of windows had been reduced, in this machine, to a long rectangular opening in each side of the body, but the interesting fact was disclosed after a few flights, that during straight flying no draught was felt by the occupants. When the machine was turning and banking a slight wind from the side was noticed, but not sufficient to be in the slightest degree uncomfortable. Although the Avro enclosed biplane was undoubtedly very promising in many respects the authorities did not encourage the production of this type, otherwise the totally enclosed aeroplane might have been very considerably more advanced than is now the case. When the war is over and this type will once more have to be studied seriously, it is to be hoped that the Avro firm, who pioneered the type, will be among the first to take it up again.