H.King Sopwith Aircraft 1912-1920 (Putnam)
Type 860
The primary points to note concerning this big production-type torpedo-dropping float plane of late 1914 are the following:
(1) It bore a near relationship to the experimental Type C, and, especially when provided (as it was in some instances) with strut-braced overhang on the top wings, resembled that aircraft very closely.
(2) It was more or less contemporary with the Short Admiralty Type 184 and the Wight Admiralty Type 840, and was intended to meet similar requirements.
(3) Like the Short and Wight types just named, it was designed specifically for the new 225 hp Sunbeam engine - a powerplant so important in the development of British Naval aircraft that the Short Type 184, upon which it was decided to standardise (especially after the torpedo-dropping requirement became secondary, following initial successes by Shorts during the Dardanelles campaign of 1915) was familiarly known as the 'Short 225’.
(4) An installation of a Sunbeam engine, though one of lower output (150 hp) was made in the Admiralty Type 806 Gun Bus, as noted in a preceding chapter.
(5) The wings - initially at least - were arranged to fold.
The earliest Service numbers known to have been allocated to Type 860 seaplanes were 851 -860 (ten aircraft), and of these No.854 was being tested, by Victor Mahl, over the Solent at the beginning of 1915. Twelve more (Nos.927- 938) were also ordered, and - except for numbers 933, 934, 936 and 937 - duly delivered, thus giving the RNAS a known total of eighteen Type 860 seaplanes - all Sopwith-built. Beyond the facts that the type was used in the Dardanelles and was flown from the Isle of Grain, however, little is known of its Service history. Thus it is worth noting that - in particular for Short Type 184s - demands for 225 hp Sunbeam engines (later named Mohawk) must have been heavy; and here too it is especially relevant to note the following recollection by Rear-Admiral Murray Sueter, who, as Captain Sueter, had been Director of the Air Department of the Admiralty before the 1914 war. This officer said:
'After the war broke out, we required all Mr. Sopwith's efforts and those of his factory to produce high performance machines, then just beginning to show some promise. But Hyde-Thomson and myself [the name Hyde-Thomson will be remembered from the chapter on the Type C] were quite determined to succeed with a torpedo machine. So I sent for that fine pioneer seaplane constructor, the late Mr. Horace Short. When I explained my requirements to him and the great weight that had to be lifted with a 225-h.p. Sunbeam engine ...'
But the successful outcome of that meeting - the historic 'Short 225' - is well enough known; and having now re-emphasised the Navy's special interest in Sunbeam engines we may proceed with our study of the Sopwith Type 860 torpedo-dropping seaplane, which appears to have continued in service (in however lowly a role) until 1916.
Here, once again, we are involved with the Sunbeam story, for one of the most arresting visible features of this big Sopwith was the immense solid-looking block, towering not only above the engine but the top wing also. This was not, in fact, the radiator - in the familiar Short-style location - but the exhaust manifold. The Sopwith's radiator was positioned in the nose, just behind the propeller (sometimes two-bladed, sometimes four-bladed).
Although existing photographs show clearly that Nos.851 and 859 had wings of unequal span - the strut-braced upper-wing extensions having additional top-surface bracing from kingposts - and although these particular machines were characterised also by the elegant 'Sopwith' tail surfaces (much as on the production Tabloids and Folder Seaplane) No.928 or 938, here depicted on the water, had wings of equal span and a much larger fin, no longer triangular, but curved.
In the Sopwith tradition by this time established, the two main floats were sprung, and like the tail float (seen well-nigh submerged) were carried on struts of great height. Being attached to the fuselage, and not to the wings, the main alighting gear, in the form depicted, would appear to have been less favourable to torpedo dropping than that of the Type C; though the point is by no means conclusive, having regard to the astonishingly low-slung torpedo stowage on the Short Type 184. Aiming the torpedo must, in any case, have been a truly hit-or-miss business, for the pilot occupied the rear cockpit. Defensive armament could well have been intended or improvised, jointly with the top-wing aperture over the front cockpit (especially so as Owen Thetford's Putnam book British Naval Aircraft since 1912 records that the Type 860 was used on patrols in home waters during 1915 and 1916); but as with many other points concerning this Sopwith type - there is no certainty in this regard. More positively it can be recorded that Nos.851 and 852 were not written off (in the clerical sense) until March 1917, and that Nos.931 and 932 were at the same time reduced to spares in the Supermarine works (successor to Pemberton Billing) at Woolston, Southampton.
The name Pemberton Billing having now been mentioned twice (formerly in the context of the Type 137) it is interesting - though not necessarily significant that those well-known Sopwith characters Howard Pixton and Victor Mahl were both present at early tests of the P.B.9 - the "seven day 'bus' - concerning which aeroplane some mysteries persist. Mahl, in fact, made the first flight shortly whereafter the little single-seater was seen at Brooklands.
F.Manson British Bomber Since 1914 (Putnam)
Sopwith Admiralty Type 860
Experience with the early torpedo-carrying seaplanes had demonstrated to two of the three main Admiralty contractors that the smaller Salmson and Sunbeam engines were inadequate to enable torpedo-carriers to lift off the water when carrying full fuel load. After the unsuccessful attempts by the Sopwith Special No 170 to lift a torpedo into the air in August 1914, its manufacturers decided to produce a smaller aircraft, powered by the 225hp Sunbeam (later named the Mohawk). In the meantime Sopwith persevered with another of its seaplanes, No 138 (also powered by a 200hp Canton Unne engine), and on 29 August 1914, flown by Longmore, this machine succeeded in lifting and launching an 810 lb torpedo at Calshot.
Continuing frustration with the recalcitrant Canton Unne engine encouraged Sopwith to adopt the 225hp Sunbeam, at the time the most powerful engine available to the RNAS; no prototype of the new aircraft was built as such, a total of 22 examples of this aircraft being ordered during the autumn of 1914. All but four were completed between December that year and early in 1915. The first ten examples were numbered 851-860, and were referred to as Admiralty Type 860s (although confusion was compounded when the RNAS equipment list erroneously referred to them as Type 157s, suggesting that they were a production batch of Sopwith Type Cs). The first flight by a Type 860 with a torpedo was made by Victor Mahl, a Sopwith pilot, at Calshot on 27 January 1915.
The big Sunbeam engine, driving either a two- or four-blade propeller, featured a frontal radiator and a prominent stack of twelve vertical exhaust pipes extending upwards immediately forward of the upper wing. The single-step main pontoon floats were attached by long struts to the lower fuselage longerons, the 14in torpedo being carried on crutches at the centre of the cross-bars between the floats (when the aircraft was at rest on the water the torpedo was partly submerged). A single tail float was provided, as well as stabilizing wingtip floats.
Folding wings of at least three alternative designs appeared on the production aircraft; the original three-bay wings of equal span were fitted with double-acting ailerons on upper and lower surfaces. Some aircraft were fitted with two-bay wings of unequal span with ailerons on the upper wing only; the outboard upper wing extensions were wire-braced with kingposts, but some aircraft featured outwardly raked struts in place of interplane wire bracing. At an early stage in production the fin, originally a small triangular structure, was enlarged to incorporate a curved leading edge. Further redesign resulted in a rectangular fin being fitted.
The Sopwith Type 860 was flown from the rear cockpit, a surprising feature of this aircraft having regard for its torpedo-dropping role. The observer's cockpit was located beneath a large aperture in the upper wing centresection, suggesting that it was intended to mount an upward firing Lewis gun though no evidence has been found to suggest that this was ever fitted, despite being called for in the original Admiralty purchase order.
Production Type 860s are said to have been test flown from the Solent and subsequently served briefly with the RNAS at Grain, though without much distinction. The greater experience gained by Short Bros in numerous aspects of naval seaplane design inclined the Admiralty to favour that company's parallel project, the Type 184, which was to become one of the outstanding British seaplane bombers of the First World War. Certainly the Sopwith aircraft never launched a torpedo in anger.
Type: Single-engine, two-seat, two- or three-bay biplane, torpedo-carrying twin-float seaplane.
Manufacturer: The Sopwith Aviation Co Ltd, Kingston-upon-Thames, Surrey.
Powerplant: One 225hp Sunbeam Mohawk twelve-cylinder, water-cooled, in-line engine driving a two- or four-blade propeller.
Dimensions, Weights and Performance: No records traced.
Armament: Provision to carry one 810 lb 14in Whitehead torpedo. Provision may have been made to mount a Lewis gun above the observer's cockpit.
Prototypes and Production: Total of 22 aircraft ordered, Nos 851 -860 and 927-938, but four (Nos 833, 834, 836 and 837) not completed. No 851, possibly regarded as the prototype, is believed to have first flown in December 1914.
Summary of Service: At least three Sopwith Type 860s were flown at the RNAS Station, Isle of Grain, in 1915, and two may have been present during the Dardanelles campaign that year.
P.Lewis British Bomber since 1914 (Putnam)
A 1915 design which was produced for R.N.A.S. service in small numbers was the Sopwith Admiralty Type 860, a two-seat tractor seaplane capable of carrying the 810 lb. 14 in. torpedo. Powered by the 225 h.p. Sunbeam engine cooled by a frontal radiator, the Type 860 had equal-span, three-bay, folding wings incorporating cable-connected ailerons on each surface. The machine’s pilot occupied the rear cockpit. Pontoon main floats, each with a single step and sprung, were accompanied by a tail float and one at each wingtip. A version of the Type 860 was constructed with wings of unequal span, kingposts and wire supporting the upper overhanging tips; ailerons were in the top wings only.
M.Goodall, A.Tagg British Aircraft before the Great War (Schiffer)
Deleted by request of (c)Schiffer Publishing
SOPWITH seaplane Type FTS.200 (Admiralty Type C)
The three aircraft ordered on Contract CP37385/14/X7331, costing ?3,122 each, were not a good investment for the Admiralty, for they failed badly in their early trials, and it was the rival Short 184 which entered production.
The naval specification included folding wings, carriage of wireless, a gun and bomb gear. Instructions for the three machines were issued to the works on 15 April 1914, and they were completed in September and October and taken to Calshot in November. After abortive attempts at flight with load aboard the machines were accepted but the engines were removed and development was abandoned. All three were deleted in 1915. No photographs of Nos.157-159 can be traced, but the design bridged the period between the types numbered 137-138 and 170 and the later machine, known as Admiralty Type 860.
An unnumbered Sopwith drawing for a machine of this general specification exists, Type FTS.200, and may represent the type at some stage of its design. It was a side by side two-seater with the pilot in the starboard seat, a note indicated there was an earlier version with tandem seating. The machine was similar in general layout to No. 138, being a three bay biplane of unequal span with twin pontoon type main floats, sprung by leaf springs at the rear attachments only and without steps. A box like tail float with water rudder was fitted.
The wings were not staggered and consideration seems to have been given to moving the folding joint further outboard, at the same time folding down the top wing extensions by 'breaking' the bracing struts. The radiator was apparently to be hung on the front cabane struts which were in the form of an inverted vee, to which the radiator shape would conform. The chassis was shown with crossbars, but sketches show a triangulated structure raising the center for the carnage of a bomb or torpedo. For this role the floats would be increased in buoyancy by increasing their length and beam, at the same time bringing their centerlines inboard.
Power: 200hp Salmson 2M7 (Canton-Unne) fourteen-cylinder two-row water-cooled radial driving a 9ft 6in diameter propeller.
Data
Span top 58ft 6in
Span bottom 41ft
Gap 6ft 3in
Area 630 sq. ft
Length 38ft 6in
Height 13ft
Chord 6ft 3in
Area tailplane 39 sq. ft
Area elevators 28 sq. ft
Area fin 6 sq. ft
Area rudder 13 sq. ft
Main floats 14ft long 2ft 9in beam 2ft 1in deep spaced at 10ft centers
Later amended 15ft 3in long 3ft beam 2ft 1in deep spaced at 9ft. centres
Endurance 5hr (90 gal)
SOPWITH tractor biplane (Admiralty Type D)
This single seater aircraft remains something of a mystery for, although ordered by the Admiralty on Contract CP37385/14/X7331 and allocated Serial No. 160 it was apparently canceled and there is no evidence of completion. The suggestion has been made that it was retained by the firm for Hawker to use as a means of transport to naval bases. It had been promised for delivery to Eastchurch on 14 September 1914 at a price of ?1,473.
The Order Book shows an alteration of engine from 80hp Gnome to one of 100hp from the Schneider machine.
SOPWITH tractor seaplane (Admiralty Type 860)
An initial Contract CP02140/14/X13443 for ten 'Torpedo Carrying Seaplanes' appeared in the Order Book on 21 August 1914, with a further entry on 13 October 1914 for another twelve on Contract CP02165/14/X20893. The first batch carried serial Nos.851-860, the second Nos.927-938, of which six machines Nos.927,932,934 and 936-938 were not delivered, being either retained at Woolston by the firm for trials, or were not complete when the contract was closed in September 1916. The extent of completion of these aircraft is uncertain, although there is photographic evidence that the last machine, No.938, was completed. Deliveries were made between December 1914 and June 1915. A further batch of 24 aircraft ordered on 7 December 1914, Serial Nos. 1280-1299 and 1347-1350 were costed at ?53,322, but were canceled well before completion. The Short 184 with the same engine, built to the same requirement, was more successful and entered large scale production. The Sopwith Type 860 had a short service life and was being discarded in the second half of 1915.
Victor Mahl carried out much of the seaplane flying at Woolston, and on 1 November 1914 he took off in 851 with Reg Alston, a senior Sopwith designer as passenger, only to crash soon after. Alston was drowned, but Mahl was thrown clear, only to die himself on 1 April 1915 after an operation.
The fuselage of the Type 860 was of conventional wooden braced girder type, with the pilot in the rear cockpit. The engine was cooled by a front mounted radiator and had a tall exhaust manifold combining the pipes from between the cylinder blocks of the vee-twelve engine On No.852, tall side mounted radiators were fitted, with a cylindrical shaped header tank below the top center section; this latter system became the standard fitment and replaced a box section tank on an earlier machine.
The tail unit was conventional with a divided elevator and a triangular fin with an unbalanced rudder. The fin was later considerably enlarged, No.852 having an ugly rectangular unit, which was later rounded off at the front.
The machine was mounted on twin sprung floats of pontoon type, with a chassis of inverted W-form struts with crossbars, the latter carrying torpedo crutches, a role which was tested but not proceeded with. Wing tip and tail floats, the latter with water rudder, were of pontoon type and hung on four struts well below their mounting points under the wings and rear fuselage. No.855 was initially tested as a landplane at Brooklands.
The wings were first of unequal span, two bay type with Nstrut and kingpost bracing of the overhang on No.851. The struts were subsequently changed to wire bracing. Pairs of interplane struts at the wing roots, adjacent to the center section, were provided as part of the arrangement for wing folding. A large cutout in the center section was provided to enable a gun to be fitted and to permit an easier exit from the front cockpit in an emergency.
The need for more wing area caused the lower wings to be increased by 100 sq. ft to the same span as the top wing making the aircraft into a three bay biplane. A drawing proposing the new wings and a revised tail unit, provides the following data, although the tail surfaces fitted to the final version of the aircraft were quite different.
Power: 225hp Sunbeam Mohawk twelve-cylinder water-cooled vee driving a two-bladed propeller. No.851 was tested with a four-bladed propeller.
Data
Span 62ft 11 in
Chord 6ft 10in
Area 790 sq. ft
Area tailplane 65.4 sq. ft
Area elevators 25.6 sq. ft
Area fin 16.8 sq. ft
Area rudder 12 sq. ft
J.Bruce British Aeroplanes 1914-1918 (Putnam)
Sopwith Seaplane, Admiralty Type 860
THIS little-known Sopwith seaplane was contemporary with the Short 184 and Wight 840; like them it was powered by the 225 h.p. Sunbeam engine and was designed to carry a torpedo. In common with its contemporaries it was given a designation derived from the serial number of an aircraft of the first production batch, and was known as the Sopwith Seaplane Type 860. It was not the first torpedo-carrying seaplane of Sopwith design, for it was preceded by the Type C seaplane of 1913, which had flown successfully with a 14-inch torpedo late in that year.
The Sopwith 860 was a two-seater which, in its standard form, had three-bay wings of equal span arranged to fold on the Short principle. The engine had a frontal radiator, and a massive central exhaust stack was fitted. The sprung floats were single-step pontoon structures, and torpedo crutches were fitted at the centre of each of the two cross-bars. There was a single tail-float, and stabilising floats on unusually long struts were mounted under each lower wing-tip. The fin and rudder were an ill-assorted combination: it appeared that a rudder similar to those of earlier Sopwith seaplanes was used, together with a new fin which, in order to provide the necessary area, had a humped leading edge.
An unequal-span version of the type also existed, as the second illustration shows. The extensions of the upper wing were braced from king-post structures; and longer ailerons were fitted to the upper main-plane only.
The aircraft was flown from the rear cockpit. There was an aperture in the centre-section directly above the observer’s cockpit, and it seems probable that he would be provided with a gun-mounting above the upper mainplane.
The Sopwith 860 was built in small numbers, but no large-scale production was undertaken; four of the machines of the second batch were not delivered. No doubt the lack of further orders for Sopwith 860s was attributable to the decision to standardise the Short 184, but the Sopwith type remained in service until 1916 at least.
SPECIFICATION
Manufacturers: The Sopwith Aviation Co., Ltd., Canbury Park Road, Kingston-on-Thames.
Power: 225 h.p. Sunbeam.
Armament: One 14-inch torpedo, weighing 810 lb. It is probable that a single Lewis machine-gun could be fitted to a mounting above the upper centre-section.
Service Use: Flown at R.N.A.S. Station, Isle of Grain.
Production: Serial numbers were allocated for at least twenty-two Sopwith 860s, but four were not delivered.
Serial Numbers: 851-860; 927-938, of which 933, 934, 936 and 937 were not delivered.
O.Thetford British Naval Aircraft since 1912 (Putnam)
SOPWITH ADMIRALTY TYPE 860 SEAPLANE
Used by the RNAS on patrols in home waters during 1915 and 1916, the Type 860 was designed to carry an 810 lb 14 in torpedo. Twenty-four were delivered to the RNAS, numbered 851 to 860, 880, 897 to 899 and 927 to 938. The engine was a 225 hp Sunbeam or 220 hp Canton-Unne.
H.King Armament of British Aircraft (Putnam)
Type 860. Like its contemporary, the Short Type 184, this tractor seaplane of 1915 was designed to carry a 14-in torpedo. The crutches were attached to the two cross-ties joining the floats. There was a cut-out in the top centre-section, but whether this was associated with a gun mounting has not been established.