H.King Sopwith Aircraft 1912-1920 (Putnam)

From steam-cooling, direct fuel-injection and supercharging we must now pursue our essentially chronological narration; and in a technical context this is conveniently achieved by recalling that, in the present writer's earlier Putnam volume Armament of British Aircraft 1909-1939 it was shown that the Coventry Ordnance Works Ltd was best-known in the development of military aeronautics for its 37 mm guns. Yet this same company had an even earlier association with the design and construction of airframes - an association which had its beginnings in 1911, when the 'C.O.W.' absorbed the Warwick Wright concern, acquiring also the services of Howard T. Wright and W.O. Manning. The talents of these two men Manning in particular were evident in two biplanes that were built (under the Battersea railway-arches) for the Military Trials of August 1912; and in this Sopwith story these aeroplanes have a special place because T.O.M. Sopwith was the test-pilot for them both.
   Though entered in the Military Trials as No.10, the first of the pair was otherwise known as the Wombus, the first three letters connoting Manning's involvement. This involvement was, in fact, more than a purely technical one, for it was Manning who occupied one of the side-by-side seats when Sopwith made the first ground tests and short flights; but the technical feature calling for special attention here (and certainly for study on Sopwith's part) was the 14-cylinder 100 hp Gnome rotary engine which - after steam-cooling and direct fuel-injection - afforded him experience with a geared powerplant. True, the Gnome itself lacked any built-in gearing; but a 2:1 reduction ratio was afforded by a chain drive. The high thrust line thus resulting allowed a propeller diameter of no less than 11 ft 6 in - a figure appreciably greater than the 10-ft diameter that characterised the Sopwith B.1 bomber of 1917. On one occasion the big chain-driven propeller of 1912 enabled Sopwith to carry not one, but two passengers though these had to sit on the bottom wing.
   Sopwith's second C.O.W. responsibility was the testing and demonstration of another biplane - No.11 which had tandem seating and a Chenu water-cooled engine. There were frequent troubles with this aeroplane, as with its predecessor, and during August 1912 Sopwith set out for America on a second visit, to race not aeroplanes but motor-boats. He returned triumphantly in September.

M.Goodall, A.Tagg British Aircraft before the Great War (Schiffer)

P.Lewis British Aircraft 1809-1914 (Putnam)

Coventry Ordnance Works Biplanes

   During 1911, the Warwick Wright concern was absorbed by the Coventry Ordnance Works, Ltd., and its designers, Howard T. Wright and W. O. Manning, joined the new parent company. The decision was taken to enter the Military Trials scheduled for August, 1912, and two biplanes were designed by Wright and Manning and were constructed in the old Warwick Wright workshops under the railway bridge arches at Battersea.
   Most of the metal components were fabricated at the main Coventry Ordnance Works plant, and the first machine, nicknamed "The Wombus", entered as No. 10 in the Trials and fitted with the fourteen-cylinder 100 h.p. Gnome engine, was ready for testing at Brooklands at the end of April, 1912. It differed in several respects from No. 11, its 110 h.p. Chenu-powered counterpart. The Gnome-engined No. 10 was given a broad fuselage which seated two side-by-side and which was untapered in the plan view. The side elevation, however, was of good streamlined form. The large 11 ft. 6 ins. two-bladed propeller was driven at 600 r.p.m. through a 2 : 1 reduction gear and Hans Renold chain, resulting in a high thrust-line, with the boss incorporating the refinement of a spinner. The twin rudders were mounted on fairly small fins, and were given upper and lower horn balances, the same balancing being applied to the elevators. The lower wings were joined to the fuselage through the medium of two pairs of struts and of a streamlined fairing which embodied the petrol tank. No centre-section struts were used, and the upper wings were borne solely by the four pairs of interplane struts, the unusually large gap of 8 ft. appearing between upper and lower planes to bestow a remarkably good field of view from the cockpits. Warping was used for lateral control, the control pulleys were faired, and sliding aluminium panels facilitated inspection of the wings. King-posts and wire-bracing supported the considerable overhang of the upper wing-tips. No springing was incorporated in the undercarriage; all shock-absorbing was undertaken by the large, soft, 6 ins. thick tyres.
   The second machine, No. 11, carried its two occupants in tandem cockpits and consequently possessed a narrower fuselage than that of its companion. Between the rear cockpit head fairing and the tail, the fuselage was shortened by 2 ft. and it was set higher above the lower wings than that of No. 10, with a deeper support beneath it. The Chenu engine was water-cooled, its radiators being carried on each side of the cockpits. The tail unit differed also in having a single fin and rudder of unusual "shark's-fin" outline, and the main undercarriage was given extra vertical struts at the rear of each unit. No. 11's upper wings were 5 ft. shorter in span than those of No. 10, and the lower tips were fitted with skids. A four-bladed propeller was formed by superimposing a pair of two-bladed propellers.
   No. 10 was flying very successfully at Brooklands for about two months before the Trials, for the purpose of which T. O. M. Sopwith had been appointed as the pilot of both machines. In the event, neither aircraft distinguished itself. No. 10 suffered from trouble with its large propeller, and the Chenu engine in No. 11 proved refractory, the machine flying very little.
   After the fiasco of the Military Trials, the Gnome-engined No. 10 was rebuilt during the latter part of 1912. The original tapered wings were replaced by a new larger set with parallel chord and three bays provided by eight pairs of interplane struts. The unequal span was retained and, again, centre-section struts were not included. In its new form the C.O.W. biplane proved quite successful, and was flown at Brooklands during early 1913 by F. P. Raynham, who was able to land it at under 20 m.p.h.

SPECIFICATION

   Description: Two-seat tractor biplane. Wooden structure, fabric covered.
   Manufacturers: Coventry Ordnance Works, Ltd., Coventry, Warks., and at Battersea, S.W.II.
   Power Plant: 100 h.p. Gnome (No. 10); 110 h.p. Chenu (No. 11).
   Dimensions: Span, 40 ft. (No. 10); 35 ft. (No. 11). Length, 33 ft. 3 ins. (No. 10); 31 ft. 3 ins. (No. 11). Wing area, 350 sq. ft. (No. 10); 325 sq. ft. (No. 11).
   Weights: Empty, 1,200 lbs. (No. 10); 1,300 lbs. (No. 11). Loaded, 2,000 lbs. (No. 10); 2,100 lbs. (No. 11).
   Performance: Maximum speed, 60 m.p.h.

Jane's All The World Aircraft 1913

COVENTRY ORDNANCE. The Coventry Ordnance Works, Ltd., Coventry. London office: 28, Broadway, Westminster, S.W. Established 1912. Capacity: 50 machines a year without difficulty.

   1912.
   Model 10.
----------------------------------------------------
Length...............feet(m.) 29 (8.80)
Span.................feet(m.) 56 (17)
Area............sq. feet(m?.) 630 (58)
Weight, total......lbs.(kgs.) 1900 (861)
   useful.....lbs.(kgs.) 800 (362)
Motor....................h.p. 100 Gnome
Speed, max........m.p.h.(km.) 60 (97)
   min........m.p.h.(km.) ...
Endurance................hrs. ...
Number Built during 1912 .... 2

Remarks.--Experimental machines.

Журнал Flight

Flight, May 18, 1912.

THE COVENTRY ORDNANCE BIPLANE.

   THE first impressions one gets of the New Coventry Ordnance Biplane are its marked originality, its excellence of design and construction, and its businesslike - more than that - its warlike appearance. It has a certain atmosphere about it that brands it as a machine intended for harder and more serious service than mere aerodrome work.
   It was designed jointly by Mr. W. O. Manning and Mr. Howard Wright to fulfil War Office requirements. And from the tests that have already been carried out - it has lifted with perfect ease two passengers over its full complement, four persons in all, and that with the ignition of its 100-h.p. Gnome motor very much retarded, and with its extra passengers standing outside on the cellule, where they each were absorbing a considerable power in extra head resistance - we think we can safely predict that it will have no very great difficulty in showing itself to advantage in the military competitions.
   Second impressions single out for notice the large gap of 8 ft. between the main supporting surfaces, the hugeness of the propeller, it measures eleven and a half feet from tip to tip, and the neatness of the landing gear, unsprung except for the resiliency that its large six-inch tyres afford.
   A factor of safety of 12 has been worked to throughout, and probably it was the consideration of how to obtain that safety factor without having to resort to too much weight of material that influenced the designers in deciding to make their machine a double-decker.
   It was built throughout at Howard Wright's original works at Battersea, with the exception of most of the metal work. This was turned out at the Coventry works.
   The total area of supporting surface is, roughly, 350 square feet, this lifting its total load of about 2,000 lbs. all on, at its flying speed of 60 miles per hour - a loading of approximately 5 1/2 lbs. to the square foot. The upper and lower surfaces span 40 ft. and 20 ft. respectively, the chord in both cases diminishing from 6 ft. in the centre to 5 ft. at the tips. The extra span of the upper surface is made up by an extension on each side. These extensions are virtually complete monoplane wings braced to the rigid plane structure by king posts and steel cable on top, and by stranded steel cable below. They are arranged to warp for the correction of lateral balance. Both their tips and the tips of the lower plane are finished off like those of the Borel wing in order to obtain a very powerful warp. The warping is operated by stout stranded steel cables passing from the rear boom of one extension under stream-line pulleys on the lower plane, straight through to the pulley on the opposite side and up to the other extension. The operating-wires from the control-wheel are "tapped" on to this main cable, for by this arrangement the movements and jerkings that are produced in the main warping cable by the action of wind gusts on each warping surface, are communicated direct to the opposite wing-tip and not, as in many cases, via the control-wheel. This feature should also materially lessen the fatigue of the pilot when flying in anything of a strong wind. The warp-compensating wires on top pass over rocking king posts and down again under pulleys fixed just above the rear wing-spar.
   For a biplane, the spars, of ash, are of very generous dimensions. They are 3 inches in depth and over an inch thick in both cases. The ribs are of spruce, and solid, except for the drilling in each to allow the internally fitted drift cables to pass. These drift cables are, by the way, of the same size solid core stranded steel cables as are used for taking the main lift.
   The 8 ft. vertical struts separating the main planes are of silver spruce. Although they arc of a goodly size from front to back they are relatively quite thin. But this is compensated for by the fact that they are braced together in two sets of four. They fit into steel lugs where the cross-bracing cables are also assembled.
   The planes are built and attached in sections, the attachments being arranged internally where they are accessible, and where they may be systematically inspected through neat aluminium sliding doors. There are eight of these - one against each strut socket.
   The main body - wide enough to seat pilot and passenger side by side - is essentially a wedge-shaped box girder, flattening horizontally towards the rear. In its construction ash is employed for the main booms and spruce for the cross-members. Viewed from above its sides are parallel from stem to stern. Thus it is sufficiently wide at the tail to provide a good damping surface, a point which reduces the extra tail surface necessary. These surfaces are flat, and have a purely floating action in flight. In shape they are quarter elliptical. At the extreme rear, the sides of the fuselage extend above and below the top and bottom surfaces, forming small fins, to the back edge of which the vertical rudders are hinged. They, similarly to the elevators, are balanced in their action. A bent cane skid takes the weight of the after section of the machine when at rest on the ground. The main chassis wheels are so placed that there is only about 40 lbs. of weight at the extreme tail - a joy to its attendant mechanics - they most probably in their time have had to deal with machines tremendously tail-heavy when on the ground.
   The engine mounting is decidedly interesting. The four body booms in front are assembled in a pressed steel housing, which accommodates both the motor - a 100-h.p. 14-cylinder Gnome - and the propeller shaft. The Gnome is slung low down in the housing and, keyed to its nose is a chain wheel, from which the drive is taken by a Hans-Renold chain - this alone weighs something like 25 lbs. - to the propeller shaft above. There is a reduction of 2 to 1 in the transmission. The propeller shaft is mounted, together with the engine in ball bearings, and two ball thrust washers are fitted - the larger to accommodate the propeller thrust and the smaller to take the negative thrust caused by the head resistance on the slow running or stationary propeller during a vol plane.
   A peculiarity about the engine - we say peculiarity because we have never previously seen this system applied to a rotary motor - is that it is equipped with Bosch dual ignition, by which it may be started from the pilot's seat. Another refinement is the drip-catching funnel arranged beneath the carburettor, by which any overflow of petrol is collected and led through a copper pipe to the exterior of the body, where it is out of harm's way. A covering, similar to a Sizaire car bonnet cases in the motor and propeller-shaft housing. It is cut from sheet aluminium, and kept in place by ordinary car-hood fasteners.
   The propeller is a colossal structure of teak with nine laminations. It is 11 ft. 6 ins in diameter, and rotates at 600 revs, per minute. It is noteworthy that, from the boss to a point 18 ins. along the blade it is designed to give no thrust, but merely for that section to travel through the air, causing as little head resistance and absorbing as little power as possible. In defence of this notion the designers ask two questions. - Firstly, why should the pilots sit in more draught than can be avoided? and secondly, what is the use of projecting that 3 ft. diameter column of air rearwards to impinge directly on the fuselage where it would cause a drag equal to or in excess of the thrust obtained from projecting it?
   Regarding the landing gear we must certainly say that its simplicity appeals to us a great deal more than the weird and wonderful shock-absorbing devices that we occasionally see. It consists of a pair of 30-in. wheels - 6-in. tyres are employed - mounted on a common axle, which supports the machine through short struts of Honduras mahogany. No sideways movement of the machine on landing is provided for. Two wheels only are used. Three or more, if rigidly attached, would cause trouble, such as was experienced with the Astra triplane, if a landing were made on anything but the smoothest of grounds.
   A single skid of hickory proceeds forward, supported by two struts in V of Honduras mahogany, to protect the propeller and front section of the machine.
   From the cockpit the pilot and his passenger obtain a very clear view of the country directly beneath and all round them. The short span of the lower plane helped in this respect to a great extent.
   Before the pilot is a wheel, mounted at the top of a vertical column. Warping is operated by twisting the wheel laterally, and the altitude is varied by rocking the column to and fro. A foot lever commands the twin rudders; at present only single control is fitted, but this will be duplicated shortly se that the passenger as well can take charge.
   In front is a dashboard where are located the engine controls and the various gauges and instruments common to present-day aeroplanes.
   The oil tank, holding 22 gallons, and an auxiliary gravity feed petrol tank, holding 10 gallons, are arranged just in front of the dashboard. The main petrol tank, containing 40 gallons of fuel, is stored away in the streamline well beneath the cockpit.


Flight, July 13, 1912.

THE MILITARY COMPETITION - THE MACHINES.

THE COVENTRY ORDNANCE BIPLANE.

   As mentioned in our issue of last week, the Coventry Ordnance Works, Ltd., are entering a pair of machines for the War Office aeroplane competition. One of these has already been described in FLIGHT; the other is of the same type, but is fitted with a 110-h.p. Chenu motor in place of the 100-h.p. Gnome; it has 5 ft. less of wing span, and it is some 2 ft. shorter in overall length. Details and photographs of this latter machine we are not yet able to publish. In the meantime, however, let us briefly recapitulate the main characteristics of the 100-h.p. Gnome-engined machine that has been flying at Brooklands for some two months past. We print in this issue a series of photographs illustrating this highly interesting and original biplane. Its design is jointly due to Mr. Howard Wright and Mr. W. O. Manning, A.F.Ae.S. For its construction, most of the building was carried out at Mr. Howard Wright's works at Battersea, the metal work being done at the Coventry works.
   Incorporating the fuselage as a feature of construction, it is a biplane of the tractor type. The body, of lattice-girder construction, flattening toward the rear, is sufficiently wide to seat pilot and passenger side by side. Its sides are parallel. In front, the four longerons are assembled into a specially designed pressed-steel housing, in which both the motor and the propeller-shaft are mounted. The drive to the propeller-shaft is by a Hans Renold chain, it being so arranged that the speed of rotation of the propeller is half that of the engine. The propeller itself is strikingly large, for it measures 11 ft. 6 in. from tip to tip, while in its construction nine laminations of teak are employed. It has the peculiarity that, from the boss to a point some 18 ins. down the blade, it is designed to give no forward thrust, but merely to revolve in air, causing as little resistance and absorbing as little power as possible. For this and other reasons, when the machine is flying, those in the cockpit notice comparatively little rush of air. As an advance on accepted practice, particularly relating to Gnome engines, the motor on this machine has been equipped with Bosch dual ignition in order that it may, when necessary, be started from the pilot's seat.
   The main supporting surfaces are double surface, are unequal in span and are separated by a gap of 8 ft. The upper plane spans 40 feet, the lower 24 ft. 8 in. The chord in measurement diminishes from 6 ft. at the centre of the wings to 5 ft. near the tip. Both end sections of the top plane, each 10 ft. in length, are constructed so that they may be warped for the correction of lateral balance. As for the cross sections of the plane, the designers have made use of one that has been experimented with by M. Eiffel, for, data relating to its behaviour being available, it has been thought more advantageous to have something definite to work upon than to employ a section the virtues of which might be problematical. The landing gear is about as simple a conception as one could possibly cite. No shock absorbers have been introduced, all the shock absorbing necessary being done by large diameter 6 in. tyres. Protection is afforded against damage to the propeller by a turned up hickory skid, which proceeds forward and which is connected to the nose of the machine by a pair of struts of Honduras mahogany arranged V fashion.
   A good idea of the tail is conveyed by one of our photographs. Tanks for the storage of fuel and oil are located under the bonnet. Here there is a tank for oil holding 32 gallons and one for petrol holding 10; the main balk of the petrol, however, is carried in a large tank arranged in the streamline well below the fuselage. From there to the auxiliary tank under the bonnet it is fed by pressure.

Main characteristics:-

Motor 14-cyl. Gnome, 100-h.p. rotary
Overall length 33 ft. 3 in.
Span 40 ft., 24 ft. 8 in.
Area 350 sq.ft.
Average chord 5 ft. 6 in.
Weight, all on 2,000lbs.
Speed 60m.p.h.


Flight, August 10, 1912.

THE MILITARY AEROPLANE COMPETITION - THE MACHINES.

THE CHENU-ENGINED COVENTRY ORDNANCE BIPLANE.

   THIS machine differs very little from the 100-h.p. Gnome-engined biplane that we described in these columns quite recently. The main point of difference, besides the fact that a 110-h.p. water-cooled Chenu motor is fitted instead of a 100-h.p. Gnome, is that the fuselage is much narrower, being designed to accommodate the pilot and passenger in tandem. The main dimensions, too, are considerably smaller. A four-bladed propeller is employed.

Main characteristics:-
Overall length 32 ft.
Speed 68-70 m.p.h.
Span 32 ft.
Weight without complement or fuel 1,250 lbs.
Area 300 sq. ft.