Flight, November 1926

THE SUPERMARINE "SOUTHAMPTON”
Two Napier "Lion" Engines

   THE Supermarine Aviation Works, Limited, occupy a somewhat unique position inside the British aircraft industry. Founded by Mr. Noel Pemberton Billing in 1913 (Mr. Billing, by the way, has had no connection with the company for a number of years) this firm concentrated from the first upon the design and construction of seaplanes of the flying-boat type. Machines of other types have been produced, it is true, such as the Pemberton Billing "seven day 'bus" (so called from the fact that it was built in a week), and the "Night Hawk" triplane built during the war, while of more recent years the firm has built a few light 'planes and last year the Supermarine S.4 for the Schneider Cup seaplane race, the latter machine being, of course, a twin-float seaplane of the monoplane type. In the main, however, the firm has specialised in flying boats even for fast machines, and it will be recollected that it was on a machine of this type that Captain Biard won the Schneider Cup Race at Naples in 1922. After the 1923 Schneider Cup Race at Cowes, however, it was decided that the flying-boat type was no longer fast enough for the speeds demanded, and Mr. R. J. Mitchell, the firm's chief designer, set to work and produced the S.4, to which reference has been made above.
   Another respect in which the Supermarine Aviation Works have differed from most other firms, apart from concentrating on the production of flying-boats, has been that of further specialising on the type of flying-boat hull which has now come to be known as the "Linton Hope" type, consisting of a main hull of approximately circular cross-section, built on to which, as a separate structure, are the two steps. In this connection it is rather interesting to recall that even the very first Supermarine flying-boat was more or less of this type. This machine, the P.B.1 had a cigar-shaped hull, built, if we remember right, with a ply skin of spruce planking running fore and aft, and having a single step. This machine, which was exhibited at the Olympia Aero Show in 1914, was not a success, it is true, but the main idea of the circular flexible hull was undoubtedly there in a somewhat crude and incompletely understood form, and all Supermarine flying-boats built since those early days have retained this feature of the circular flexible hull. In modern times this type has come to be looked upon almost as the standard type, but it is worth keeping in mind that when Supermarines first started producing hulls of this type the general practice was to design hulls with straight "V" bottoms and flat sides.
   Having specialised for thirteen years on the design and construction of flying-boats, it is not to be wondered at that the Supermarine Aviation Works have secured a leading position in this branch of aircraft work, and within the last year or so the firm has produced a boat which proved an instant success and large orders for which have been placed by the British Air Ministry. This type has become known as the "Southampton," and the machine having gone into quantity production it has now become possible to give a detailed description of it, unfettered by the rules of secrecy which surround all aircraft built for the British Air Ministry until the restrictions are raised upon the machine being ordered in quantities. The Supermarine "Southampton," among its many other excellent features, incorporates the somewhat unusual one of being able definitely to fly and manoeuvre with one of its two Napier "Lion" engines stopped. There are probably very few types of twin-engined aircraft in the world able to do this, and the fact that the "Southampton" will do it with comparative ease speaks well for the design of the machine.
   It will not be unknown to readers of FLIGHT that during the years immediately following the war the flying-boat type of machine received somewhat step-motherly treatment by the authorities, a fact upon which we have commented frequently in FLIGHT, pleading for greater support for this type of machine which, in our view, is the logical type to develop for British Empire aviation. For a number of years but little was done, and one should not blame the Air Ministry unduly for this, since war-time experience with flying-boats had not been altogether satisfactory, the war-time hulls being somewhat frail and the percentage of useful load carried rather small in comparison with aeroplanes of the same power. The idea rather gained currency that the flying-boat as a type was necessarily less efficient than a land machine. This view has never been held by the Supermarine Aviation Works, and certainly recent developments seem to indicate that a well-designed flying-boat of medium size is at least as efficient as the land machine of about the same weight and power, while it seems very probable that the future will show that in really large machines the flying-boat may be far and away more efficient than its counterpart on wheels. Moreover, so far as can be seen at present, it seems probable that a practical limit in size is likely to be reached much sooner with land machines than with flying-boats, so that if we look to the really large aircraft of the future, the flying-boat type appears to hold very considerable claims on our attention.
   However, to return to the history of the Supermarine "Southampton." During the slump to which we have referred, the Supermarine Aviation Works produced a civil flying-boat, the "Swan," which was a really remarkable machine in many ways, and which appeared to put a somewhat different aspect on the flying-boat question. On the strength of the results obtained with the "Swan," the Air Ministry decided to give the Supermarine Aviation Works a chance to retrieve the reputation of the flying-boat, and a contract for six machines was placed in 1924. The placing of such a contract was, incidentally, significant of the trust which the Air Ministry placed in this firm, since it was an unusual procedure to order six machines of an experimental type. Needless to say, the confidence of the Air Ministry proved to be not misplaced, and the direct outcome was the "Southampton" flying-boat, which forms the subject of this article. Work was commenced in August, 1924, and the first machine was flying on March 14, 1925. The machine was found to provide one of those somewhat rare instances in which a machine is absolutely "right" straight away. No modifications of any kind were found to be necessary, and the machine was delivered by air to the Experimental Air Station at Felixstowe on the following day. This feat of designing and constructing a large twin-engined flying-boat in a period of only 7 1/2 months must be regarded as a remarkable achievement. The machine then went through its type tests at Felixstowe, and everything went "without a hitch," with the result that the trials were completed in record time. The "Southampton" was then adopted as the standard twin-engined reconnaissance flying-boat of the R.A.F., and by now a large number of "Southamptons" have been delivered, while many more are still on order.
   Hardly had a flight of these machines been handed over to the Service, than it was announced that they would undertake an extended cruise, in conjunction with the Fleet, around the British Isles. This cruise, which commenced on September 3, 1925, was accomplished without incident, and the success, from the Service point of view, was such that, on October 8, 1925, the Air Ministry issued a special communique praising the boats. This communique was published in FLIGHT at the time, and there is thus no need to repeat it here, beyond recalling that the cruise was one of some 10,000 miles in very bad weather.
   On July 1, 1926, commenced the first long-distance foreign cruise by R.A.F. flying-boats to Egypt and back. Like the previous one, this cruise was a complete success, and again an announcement was issued by the Air Ministry (on August 2, 1926) concerning the flight of two "Southamptons" from Plymouth to Aboukir and back, a total distance of some 7,000 miles. This flight was carried out to a pre-arranged schedule, and with one exception the programme was strictly adhered to, the exception being that, owing to a northerly gale at Marseilles, it was considered advisable to postpone the departure for Plymouth until the following day. No trouble whatsoever was experienced, either with the machine or with its Napier "Lion" engines, and a special feature of the cruise was that constant wireless communication was maintained throughout, with R.A.F. and other wireless stations.
   To appreciate to the full these two cruises, it should be kept in mind that they were in no way stunt flights with an elaborate detail organisation, but ordinary Service exercises with standard machines, carrying throughout a crew of four and full Service load.
   Owing to the fact that the "Southampton" has, until comparatively recently, been on the Air Ministry's "Secret List," it has been prevented from attempting to beat some of the existing word's records, although there is very little doubt that it could do so. In point of fact, it is believed that the "Southampton" could beat no less than 15 existing records, and establish four new ones not hitherto attempted. It would scarcely be fair to the firm to state at the moment the exact nature of these records, but it is to be hoped that it will now be found possible to make arrangements for the carrying out of a number of flights with this object in view.
   The Supermarine "Southampton" has been designed as a Naval Patrol and Reconnaissance flying-boat, possessing very long range, being very effectively armed, and capable of carrying out bombing operations.
   The "Southampton" is a twin-engined flying-boat with a two-stepped circular-section hull of the flexible "Linton Hope" type, the steps being built on as a separate structure. Apart from the generally "clean" lines of the hull, the machine is mainly remarkable on account of its somewhat unusual wing structure.
   The whole machine has been designed with a view to eliminate "blind spots," i.e., areas blanketing the gunners' view and field of fire. As a result the "Southampton" is well able to defend itself, and the manner in which the usual "blind spot" behind the tail has been avoided is extremely interesting. To begin with, the tail has been designed as a semi-cantilever, the supporting struts projecting but a very short way out from the tail root. Secondly, the cockpits for the aft guns are placed as far out as possible laterally, and staggered in relation to one another, so that from one or other of the two cockpits there is no blind area beyond a distance of about 50 ft. from the tail.
   The hull has been given plenty of freeboard and buoyancy, so that the cockpits and propellers are well clear of the water, and the lines of the hull and planing bottom are such that the machine is exceptionally "clean" when manoeuvring on the sea. Very complete marine gear is provided, such as towing bollards, mooring slings, boathooks, sea anchor, etc., so that the machine can be very efficiently handled while on the sea. The forward cockpit is well situated for the purpose of picking up moorings and generally attending to the various operations on the water.
   Another feature of the "Southampton" is that no petrol is carried inside the hull, the main petrol tanks being supported under the top plane. In consequence the hull itself is particularly free of obstructions, and in fact it is possible for members of the crew to walk about freely anywhere from bow to stern. There is even ample space in which to sling hammocks for the crew, who can, and do, thus sleep on board. In fact, except for refuelling, the machine is independent altogether, and is a self-contained unit.
   The accommodation for the crew is as follows : In the bows is the forward gunner's cockpit, fitted with mounting for Lewis gun. A comfortable hinged seat is provided, which can be swung out of the way and stowed when the gun is being operated. Aft of this is the pilot's cockpit, while behind that again is the cockpit for the navigator. Inside the hull, aft of the navigator's cockpit, is a roomy compartment with chair and table for the navigator, the wireless compartment being still farther aft. Finally, the two rear gunners' cockpits are situated quite a long way aft of the wings, where the field of fire is exceptionally clear.
   The total loaded weight of the "Southampton" is 14,300 lbs. (6,500 kgs.), and clearly the disposable load can be arranged in any way suitable to the purpose of the machine. When used as a bomber the "Southampton" carries the following load: Crew of four, 720 lbs. (327 kgs.); armament and military equipment, 2,130 lbs. (968 kgs.); 300 gallons of petrol, 2,220 lbs. (1,000 kgs.); 22 gallons of oil, 220 lbs. (100 kgs.). Total load, 5,290 lbs. (2,405 kgs.). When the machine is used for reconnaissance the load is composed as follows: Crew of five, 900 lbs. (410 kgs.); armament, etc., 1,130 lbs. (514 kgs.); 400 gallons of petrol, 2,960 lbs. (1,345 kgs.); 30 gallons of oil, 300 lbs. (136 kgs.); total load, 5,290 lbs. (2,405 kgs.). For bombing the range has been reduced to enable 1,000 lbs. (455 kgs.) of bombs to be carried. Fitted with two Napier "Lion" engines, using 0-65 pints of petrol per horse-power per hour, the "Southampton" has the following officially observed performance: Maximum speed at sea level, 107-7 m.p.h. (173 km./h.); rate of climb at sea level, 610 ft./min.; ceiling, 14,000 ft. (4,260 m.); minimum speed, 56 m.p.h. (90 km./h.); optimum cruising speed, 85 m.p.h. (137 km./h.); range at cruising speed (400 gallons of petrol), 680 miles (1,100 kms.).
   The Supermarine "Southampton" could, of course, be converted into a commercial machine, when, by allowing for a crew of two, wireless instruments, marine gear, seating, etc., 800 lbs. (364 kgs.), there would be a disposable load of 4,490 lbs. (2,040 kgs.) that could be arranged in any combination desired; as, for instance, 400 gallons of petrol, range 680 miles (1,100 kms.); duration, 8 hrs.; number of passengers with luggage, 6. Or, petrol, 300 gallons; range, 510 miles (820 kms.); duration 6 hrs.; and 10 passengers. Or, 200 gallons of petrol, range 340 miles (550 kms.); duration, 4 hrs.; and 14 passengers. These figures are all based upon a cruising speed of 85 m.p.h. (137 km./h.). This is for a total loaded weight of 14,300 lbs. (6,500 kgs.). For long-range work it would be permissible to "overload" the machine up to a total loaded weight of 15,700 lbs. (7,140 kgs.), when, by reducing the weight of crew, armament, etc., the range would be greatly extended.

Flight, July 1928

THE SUPERMARINE "SOUTHAMPTON”
Two Napier "Lion" Engines

   ONE of the most successful British flying-boats of modern times is the "Southampton" designed and built by the Supermarine Aviation Works, Ltd., of Southampton. A flight of these machines, manned by British Royal Air Force personnel, is now on a protracted cruise to Australia. The machine is produced both with wooden hull and with metal hull. The latter is considerably lighter than the former, and has the additional advantage of absence of water soakage.
   The normal "Southampton" is designed for a total useful load of 5,290 lb. (2,400 kg.), the composition of which can be varied within the total according to whether the machine is intended for bombing or for reconnaissance. If it is desired to use the machine for long-distance flights, carrying but a crew of two or three, with the rest of the disposable lo'ad in the form of fuel, a very great range is provided.
   The Boat Hull. - The metal hull is built entirely of Duralumin, with the exception of fittings made of stainless steel. All Duralumin parts are given the anodic treatment to enable them to resist corrosion. The hull is of the two-step type, and is so located and proportioned as to prevent "porpoising." Lateral stability on the water is by Duralumin wing-tip floats. When the machine is used for bombing, a crew of four can be carried, while for reconnaissance this may be increased to five. The hull construction is such that there are no obstructions inside, and as the tanks are mounted under the top plane, the whole hull is clear for stowing the load carried, moving about, &c.
   Wings. - Of biplane arrangement, the wings are of equal span and chord, with the gap between them equal to the wing chord. The centre section of the wing structure is built up in the form of a Warren girder, an arrangement which lends itself admirably to the installation of the power units.
   Engine Installation. - The engine mountings are separate units carried on the lower centre-section plane. They can be removed without interfering with the main wing structure. The radiators and oil tanks are removed with the engine units, and all engine instruments are mounted on the engine bearers. The petrol system is by gravity feed only, the two petrol tanks being hung under the top centre-section.


THE SUPERMARINE "SOLENT”
Three Armstrong-Siddeley "Jaguar" Engines

   To the Supermarine Aviation Works, Woolston, Southampton, belongs the credit of being the first British firm to produce a three-engined torpedo-carrying flying-boat capable of carrying a 1,500-lb. (682-kg.) torpedo slung on each side of the hull. The machine, which has been christened the "Solent," has recently completed its tests, and no difficulty was experienced in dropping the torpedoes one at a time, the aileron control being sufficiently powerful to overcome the weight of one torpedo mounted some way out from the centre.
   The Boat Hull. - Of all-wood construction, the hull of the "Solent" is of the type which has become known as a "Linton Hope," i.e. with a main structure approximately circular in cross-section, and the steps and chines built-on. As in all modern British flying boats, there are two steps, and the planing bottom has the form of a rounded Vee. The internal framework consists of light frames and timbers, with numerous light stringers running fore and aft. The planking is laid on in a fore-and-aft direction, and is of mahogany.
   The two torpedoes, supported under the lower centre section, are provided with gear for winding, so that they can be wheeled under the wings while the machine is on a slipway, or taken out in a launch and hauled up on to the racks without the use of any extraneous equipment.
   When carrying the two torpedoes the "Solent" carries fuel for 3 1/2 hours' flight, but by leaving off the torpedoes and completely filling the tanks the endurance is increased to 11-2 hours and the range to 950 miles (1,530 kms.).
   Wings. - Arranged as an equal-span, equal-chord biplane, with a back-sweep of several degrees. Of wood construction, fabric covered, with the normal two-spar arrangement. Ailerons fitted to both top and bottom planes. Lateral stability on the water is provided by two wing-tip floats.
   Tail. - Large monoplane horizontal tail plane, with smaller one between rudders, used for trimming. There are three fins and rudders, with horn balances.
   Engine Installation. - The three "Jaguar" engines are mounted in the gap, and are carefully streamlined. The two large petrol tanks are in the top plane, slightly off the centre line, and provide direct gravity feed, so that there is no petrol in the hull.

Flight, July 1929

BRITISH AIRCRAFT AT OLYMPIA

SUPERMARINE AVIATION WORKS, LTD.

   As a result of the purchase, some months ago, of the Supermarine Aviation Works by Vickers (Aviation), Ltd., the two firms are now practically one, with Supermarine's looking after the maritime side and Vickers after the aeroplane side. This division is probably not intended to be an absolutely rigid and unalterable one, but with the accumulated experience of 15 or 16 years of specialising on marine aircraft, it may be assumed that in the great majority of cases the Southampton designing office will deal with marine types. It is logical that, on the other hand, Vickers (Aviation), Ltd., should devote their energies to aeroplanes of all types and classes, their experience of which dates back to the early days of flying in Great Britain. The two firms thus united are both among the pioneer aircraft companies of Great Britain, and the combination should be a very powerful one. At Olympia the two firms will naturally exhibit their aircraft together, but for the sake of easy reference we have thought it preferable to deal with the exhibits separately.
   Supermarine's will, it is hoped, exhibit two complete marine aircraft: One of the metal "Southampton" flying-boats with Napier "Lion" engines which made the 27,000 miles' R.A.F. Far East Flight, and the other the Supermarine S.5 with Napier racing engine which won the Schneider Trophy for Great Britain in 1927, and which, in 1928, gained the British high-speed record of 319-57 m.p.h. .

   The Supermarine "Southampton" is a twin-engined five-seater reconnaissance flying-boat, and is the standard machine of this type used by the Royal Air Force. Similar machines have been supplied to the Royal Australian Air Force, the Imperial Japanese Navy, and the Argentine Navy. In 1927-28 four metal-hulled "Southamptons" of the Royal Air Force flew from Plymouth to Singapore, thence around the continent of Australia, and back to Singapore, a distance of some 27,000 miles. This formation flight was carried out without serious trouble of any description.
   The hull of the metal "Southampton" is built almost entirely of duralumin, the only exception being certain highly-stressed fittings, which are made from stainless steel. As regards hydrodynamic design, the "Southampton" metal hull differs slightly from the older type wooden hull in its lines. This applies mainly to the sides of the hull, which have a less pronounced curvature between deck and chines than had the wooden hulls. Although the effect (which is probably relatively small) is hydrodynamic and aerodynamic, the cause must be sought in structural considerations. The more flat-sided form is necessarily a good deal easier to produce in metal, and as far as we have been informed, the metal hull is certainly not less good either on the water or in the air than was the wooden hull. The step arrangements and disposition and the up-swept stern portion remain practically identical. One very great advantage of the metal hull is, of course, the total absence of water soakage, which in a hull of this size may easily amount to some 300 lbs. or even more. Apart from this, the weight of the duralumin hull is, in itself, smaller than the dry weight of the wooden hull, so that one way and another it will be realised that the use of metal hulls on the "Southamptons" has been very well worth while. One difficulty of duralumin hulls, that of corrosion, appears to have been successfully overcome in the "Southampton" type of hull. Anodic treatment is some protection, but a good paint is probably at least as good, and possibly better. On the Far East Flight surprisingly little corrosion took place, as visitors to Olympia will be able to see for themselves, the hull of the "Southampton” exhibited being one of the actual four machines which made the flight.
   Structurally, the metal "Southampton" hull is of interest on account of the form of construction employed. The fore and aft members, or stringers, run through from bows to stern, the frames being cut to accommodate them. The duralumin skin or planking is riveted to both frames and stringers. With this form of construction the planking is not called upon to resist longitudinal bending loads to as great an extent as in hulls where the stringers stop short at the frames. On the other hand, presumably, the frames themselves must be slightly weakened by being cut, although this can fairly easily be made up by local strengthening.
   As exhibited at Olympia, the "Southampton" will have an all-metal superstructure, whereas on the Far East Flight it was fitted with the older type composite construction wings. The metal wings have spars and ribs of duralumin, but are, of course, fabric covered. In arrangement, the wings are of equal span and chord, and without stagger. Top and bottom centre-sections are of equal span, interconnected by vertical struts at their ends, and with four sets of struts in the form of a letter "W" when viewed from the front, in between which are mounted the engines.
   The tail unit consists of a monoplane tail plane and elevator, with three vertical fins mounted on top of the tail plane and carrying three balanced rudders.
   The standard "Southamptons" are fitted with two Napier "Lion" engines, supported on steel strut mountings, which are complete units independent of the wing bracing members. A large variety of other engines can be fitted if desired. Bristol "Jupiters" and French Lorraine Dietrich engines have already been so fitted, while a design is now in progress in which Armstrong Siddeley "Jaguars" are employed. The Rolls-Royce "F" type engines can also be used.
   Fuel is carried in two main tanks slung under the top centre-section, the capacity being 500 gallons. Subsidiary petrol tanks each of 50 gallons capacity can be fitted under the wing roots if the machine is required for long-distance work.
   The accommodation in the "Southampton" is as follows: In the bows is the cockpit for gunner and bomber. This is provided with a Scarff ring for machine guns. Behind are two cockpits for the pilots, arranged in tandem, with dual controls. The after pilot also has a complete navigation equipment. Below the wings is the wireless compartment, which communicates with two staggered cockpits, aft of the wings, each equipped with Scarff gun ring.
   Main dimensions of the "Southampton" are :- Length o.a., 49 ft. 8 in.; wing span, 75 ft.; wing area, 1,426 sq. ft.; overall height, 18 ft. 7 in.
   The tare weight is 8,760 lbs., and the gross weight (normal load) 14,600 lbs., giving a wing loading of 10-25 lb./sq. ft and a power loading (with Napier "Lion" engines) of 15-5 lb./h.p.
   Brief performance figures are :- Full speed, 108 m.p.h. landing speed, 52 m.p.h.; climb to 5,000 ft. in 10 mins. Ceiling, 14,000 ft. Range, 800 miles with normal quantity of fuel.
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Flight, November 1932

British Aircraft

The Supermarine Aviation Works, Ltd.
Woolston, Southampton

   FOUNDED in 1913 by Mr. Noel Pemberton Billing, the Supermarine works are now a part of the Vickers (Aviation) group, but its traditions as seaplane designers and constructors are being maintained, and marine aircraft form the bulk of the firm's productions. Flying-boats have always been Supermarine's speciality, but it must not be overlooked that the firm has shown its ability to produce fast racing craft as well by designing and building no less than four Schneider Trophy winners! That, surely, is a unique record. The last of the Schneider winners, the S.6B with Rolls-Royce "R" engine, in addition to winning that classic race, also established, piloted by Flt. Lt. Stainforth, a world's speed record of 655 km./h. (407 m.p.h.).
   The Supermarine "Southampton" flying-boats have seen long and useful service, not only in British home waters, but also abroad. The latest version, the "Southampton" Mark II, is fitted with two Rolls-Royce Kestrel engines, and evaporative cooling is employed, so that this machine is in every way up to date.
   Principal particulars of the "Southampton" Mark II are :-
   Tare weight 9,014 lb. (4 088 kg.)
   Crew (5) 1,000 lb. (454 kg.)
   Fuel 3,496 lb. (1 586 kg.)
   Oil 213 lb. (97 kg.)
   Military load 1,127 lb. (511 kg.)
   Gross weight 14,850 lb. (6 735 kg.)
   Maximum speed 117-5 m.p.h. (189 km./h.)
   Cruising speed 90 m.p.h. (145 km./h.)
   Alighting speed 54 m.p.h. (87 km./h.)
   Service ceiling 13.300 ft. (4 053 m.)
   Duration 10 1/2 hours
   Range 945 miles (1 521 km.)
   The Supermarine Aviation Works are at present constructing an attractive private venture marine aircraft which will be available in both service and civil form. At present the firm prefers not to disclose any particulars.