by Guy Warner
(c)
She should have an endurance at full speed of about eight hours, carrying a crew of two.
(d)
She should carry a wireless telegraphy outfit with a range of 30 to 40 miles (19 to 25km).
(e)
She should take up about 160lbs (72kg) weight of explosives in the form of bombs.
(f)
She should normally fly at about 750 feet (238m) altitude, but be capable of flying up to 5,000 feet (1524m).
(g)
The design was to be as simple as possible in order that large numbers of these ships should be produced without undue delay.
(h)
An ample allowance of lift to be made for gas deterioration, so that each ship should remain in commission on one charge of gas as long as possible.24
The unsuccessful SS-1. (Via Patrick Abbott)
In the words of the by then, Rear Admiral Murray Sueter, CB, MP, RN (Ret’d), in a deposition written in 1925 to the Post War Royal Commission of Awards to Inventors in respect of a claim made jointly with the Executors of the late Commander Neville Usborne, RN:
‘Lord Fisher summoned an important conference to consider the proposal of Mr Holt Thomas to build a large number of small airships for antisubmarine patrols. Until then the Admiralty Airship Officers could get practically no support. But with Lord Fisher’s powerful interest, airship work was given a new lease of life. Holt Thomas was given an order for a small airship of Willows design, and to compete with this, Commander Usborne was given instructions to develop a small envelope of 60,000 cubic feet (1,703 cubic metres) capacity. Captain Sueter consulted Commander Usborne and Commander Masterman, and suggested that as he had some BE2c aeroplanes that the pilots did not like because Commander Samson had sent in an adverse report about these machines, that the chassis of one of them should be tried with one of the old envelopes of the army airships. This was done with No 2 envelope I believe. The result of tests with this machine promised well and a two-ply envelope of 60,000 cubic feet (1,703 cubic metres) capacity was ordered from Messrs Shorts. As Shorts had expertise in balloons, Commander Usborne had to develop the whole of this envelope work. At first we had considerable trouble with the dope, because of very small holes in it, but Commander Usborne had developed Ioco dope for the first rigid and brought his great experience into play, and gradually the dope became so good that he managed in later airships to save much weight by using single ply fabrics, which were lighter than rubber proofed fabrics.
‘When the new Shorts envelope was fitted to a BE2c chassis it was christened SS-3 – Submarine Searcher No 3. The first experiment was SS-1, which was a failure due to the fact that the envelope was a poor holder of hydrogen. The Holt Thomas airship was SS-2 and comparative trials were carried out between SS-2 and SS-3. SS-3 – after some difficulty in determining the best position for slinging the car and the best position for fins and rudder – was an undoubted success. The government supplied airships of this type to France, Italy and the United States.’25
SS-2 at RNAS Capel in 1915. (Ces Mowthorpe Collection)
The Royal Commission of Awards to Inventors had been set up in 1919 and would sit for the next fifteen years reviewing 1,834 claims from those who considered that their ingenuity had contributed to the war effort in such a way as to be worthy of monetary recompense. A brief report in The Times26 notes that Sueter’s claim in this case was not successful. It is interesting to note that Vivian Usborne had been paid £6000 from the commission in 1920 for his work on mine defence equipment for ships, additional to £4800 from Messrs Vickers Ltd in respect of patent rights.
SS-3 on trials.. (Ces Mowthorpe Collection)
It is possible that Sueter may have been in error as regards some of the details. The airship authority, the late Ces Mowthorpe, stated in a conversation with the author that the competition was between the RN’s SS-1, which was indeed a BE2c fuselage attached to the envelope of HMA No 2, and the Holt Thomas SS-2. He adds that SS-3 was a production model which came later and served in the Dardanelles campaign. Be that as it may, the general points made by Sueter are not in doubt and are supported in an article written in 1934 by Air Commodore Masterman. He wrote:
‘The Airship Branch was threatened with disintegration, but revived when Fisher became First Sea Lord – Usborne came into his own. He devised, in conjunction with others, the SS Class. Kingsnorth became a factory or assembly place for small non-rigids under Usborne’s direction. In all, his influence was apparent, difficulties were overcome in a Napoleonic way, nothing was allowed to delay progress and many ingenious devices were adopted. Here, his driving force had full sway and an ideal outlet.’27
The official historian is succinct and to the point:
‘The idea seems to have been struck out during a conversation in the mess at Farnborough at which there were present the late Wing Commander N.F. Usborne, Flight Lieutenant T.R. Cave-Browne-Cave, and Mr F.M. Green of the Royal Aircraft Factory.’28
This statement is corroborated by one of Usborne’s contemporaries, who wrote that he went straight down to Farnborough after leaving the Admiralty to talk over the requirement with Cave-Brown-Cave and Green.29 According to another renowned airship historian it was a, ‘splendid improvisation.’30 Certainly Usborne had a very major role to play in sorting out what could have become a very serious problem. There was considerable difficulty in obtaining a sufficient supply of envelopes, as all the regular manufacturers were much too busy with aeroplane orders to accept any new orders. He made personal visits to six manufacturers specialising in waterproof clothing or rubber goods, described the exact requirement, placed the orders directly and arranged for experts from each of the companies to come to Kingsnorth for intensive tuition on the correct preparation of the material. There is no doubt that his efforts were appreciated by Murray Sueter, who wrote that he was placed in charge of all the envelope work, as he had done such good service with the Mayfly’s gasbags and outer cover.31
The peril in which the Airship Branch then stood is highlighted by a minute from the First Lord of the Admiralty dated 18 January 1915:
AIRSHIPS AND AEROPLANES.
Secretary.
First Sea Lord.
Fourth Sea Lord.
Director of the Air Division.
18 January 1915.
The general condition of our airship service, and the fact that so little progress has been made by Vickers in the construction of the rigid airship now due, makes it necessary to suspend the purely experimental work in connection with airships during the war, and to concentrate our attention on the more practical aeroplane, in which we have been so successful.
1. The Director of Contracts should, in conjunction with the Director of the Air Division, make proposals for suspending altogether the construction of the Vickers rigid airship. The material which has been accumulated should be stored, and the shed in which it is being constructed should be thus set free.
2. The repairing staff of the airships, which is now at Farnborough, should be moved with the utmost despatch to Barrow, and should be accommodated in the neighbourhood of the new rigid airship shed and make the shed their repairing shop. Arrangements should be made to this effect with Vickers, so that we take over this shed completely from them during the war.
3. The Farnborough sheds are to be handed back to the army as soon as possible, thus meeting their urgent demands.
4. Messrs Vickers are to be urged to expedite as much as possible the two non-rigid airships they are building in the old Admiralty shed at Barrow. These, when completed, will give us five airships – three Parsevals and two Astra-Torres, besides the small military ones. These five airships will be accommodated, three in the wooden shed at Kingsnorth and two in the old Admiralty shed at Barrow. The iron shed at Kingsnorth will thus become available for the large numbers of aeroplanes which are now being delivered. All necessary steps must be taken to enable aeroplanes, in skilful hands, to alight or ascend from the neighbourhood of Kingsnorth.
5. Temporary housing accommodation for the aeroplane staff is to be at once provided near Kingsnorth, which is to become an aeroplane as well as an airship base.
6. The personnel of the Royal Naval Airship Service are to be reduced to the minimum required to man and handle the five airships. The balance, including especially the younger naval officers, is to be transferred to the aeroplane section. The military officers are to remain with the airships. I am not at all convinced of the utility of keeping this detachment at Dunkirk, and unless they are able to show some good reason for their existence they should be withdrawn.
W.S.C.32
The success of the RNAS blimps later caused him to change his mind when he wrote his four volume history of the war:
‘Had I had my way, no airships would have been built by Great Britain during the war (except the little blimps for teasing submarines).’33
The SS Class was a fairly simple and basic design, but it had several merits. The production model met the specification as regards speed, 40–50mph, and endurance, 8–12 hours. It could climb with its crew of two to a height of more than 5000 feet. It was also cheap – with a unit cost of £2500. The shape was reasonably streamlined, being blunt at the nose but tapering towards the tail. The gasbag had a capacity of 60,000 cubic feet and was 143 feet 6 inches in length, with a maximum diameter of 27 feet 9 inches. [As a comparison this is about twice the length of a Short 360.] The two internal ballonets mounted fore and aft not only ensured that the envelope kept its shape, but could also be used by the pilot to adjust the airship’s trim. They were inflated by means of a metal scoop mounted to catch the slipstream of the propeller. Two non-return valves made from fabric, the ‘crab-pots’, controlled the flow of air into and out of the ballonets. The gross weight which the airship could lift – including its own structure – was 4180lb, which gave a net lift available for crew, fuel, ballast and armament of 1434lb. The disposable lift with a crew of two on board and full fuel tanks was 659lb. The envelope was made of rubber-proofed fabric, reminiscent of an old-fashioned mackintosh. It consisted of four layers, two of fabric, with a layer of rubber in-between and on the inner surface. At the tail of the gasbag a single vertical fin and rudder were fitted ventrally, while horizontal fins and elevators were affixed to port and starboard.
To make them completely gastight and protected from the ravages of weather, saltwater and sun, four coats of dope were applied to the outer surface, with a top coat being of aluminium varnish. The BE2c fuselage was retained, stripped of its wings, rudders, elevators and eventually wheels, axles and suspension.
Propulsion was by means of a 75 hp air-cooled Renault engine driving a large four-bladed propeller. The observer, who also operated the wireless set, sat in the front seat, with the pilot behind him. It was powered by two four-volt accumulator batteries rather than by fitting a generator driven by the engine. This had two advantages; it was lighter and would still operate in the event of an engine failure. Communication was by means of Morse code. The wireless telegraphy receiver and Type 52 transmitter had a range of between 50 and 60 miles, when flying at not less than 800 feet. A long trailing aerial, some 200 feet in length, with a lead weight on the end to keep it from fouling any part of the airship, was wound down from a reel fitted to the side of the car. Small bombs, eight 16lb or two 65lb and a Lewis machine gun, could be carried by way of armament. A lever bombsight was fitted and the release was operated by Bowden wire control. It was considered to be capable of being flown by a young midshipman with small-boat training. To this end, junior officers were brought in from the Grand Fleet by means of ships’ captains being asked to select one of his midshipmen who was willing to volunteer for special temporary and hazardous service. One of these was Thomas Elmhirst, from the battlecruiser HMS Indomitable, whom we shall meet shortly. Enthusiastic, young, direct entry civilians were also induced to join up – specifically for this purpose. An intensive training course at Wormwood Scrubs, lasting about a month, was given in the theory of aerostatics (aeronautics, navigation, meteorology, engineering, rigging and engine overhaul), practical balloon flying and mastering the controls of a small airship. The training balloons all had girls’ names such as Joan, Alice, May and Hazel. Normally their baskets could carry up to five trainees and an instructor. The young officers greatly enjoyed the balloon flying, eight qualifying flights – six under instruction (including a night flight), one trip as second in command and finally, a solo. Elmhirst’s solo was in Suffolk, when the only difficulty encountered was after landing in a thorn hedge and an inquisitive local with a smoking pipe in his mouth began to closely examine the gas valve aperture. He was dissuaded from this dangerous practice very quickly.
Admiral Fisher demanded that forty more of these small airships should be produced as expeditiously as possible. Neither the First Sea Lord nor the First Lord were to remain at the Admiralty long enough to see the SS Class into operation. In May, following the tragedy of the Dardanelles Campaign, Winston Churchill resigned and Jackie Fisher also departed. They were succeeded by the former Prime Minister, Arthur Balfour and Admiral Sir Henry Jackson, respectively.
It is hard to imagine now just what it would have been like for the crews of the Submarine Scout airships, suspended in an open cockpit, between a few hundred and a few thousand feet above the cold, grey sea, making slow headway against the wind. Luckily two such pilots recorded their impressions. Air Marshal Sir Thomas Elmhirst recalled his experiences as a young pilot of only nineteen years of age:
‘I controlled height by means of a wheel in my right hand linked by wires to elevator planes stuck on the after end of the gasbag, and direction by foot pedals, again connected by wires to a rudder at the after end of the gasbag. My other controls, to be operated by the left hand, were the engine, the gas valve, two ballonet air valves and an air pressure control cable. I had a red cord to rip the top off the gasbag in case of a forced landing and a handpump to top up the main fuel tank under my seat from the gravity feed tank for the engine. I had made a wooden bombsight – quite simply two nails as foresight and backsight, the foresight being moveable to a scale marked with the speed of approach, 20 to 50 knots. My other instruments were mounted on a board to the front of the cockpit – a watch, airspeed and height indicators, an engine revolution counter, an inclinometer, gas, oil and petrol pressure gauges, and a glass petrol level indicator. These all had to be monitored closely. Provision was made for illuminating the instruments by four small bulbs. Navigation was by means of chart and floor-mounted compass. A map case with a celluloid front formed the door to a small cupboard.’34
Whilst doing all of this, he also had to pass messages back and forth to his wireless operator, read his maps, take compass bearings, plot his course, and at the same time keep a constant watch on the sea below. It should be noted that conditions were cramped and confined on board, exposed to the cold and at the mercy of the elements – the speed through the air of these craft could be reduced to only a few knots when flying into a headwind. This would not be a pleasant experience when returning from a long patrol – tired, hungry and cold. Another airship pilot of the period, T.B. Williams, wrote:
‘As the pilot could not leave his little bucket seat during a flight of often many hours duration, he just didn’t get a meal. It was also difficult to answer the call of nature. I evolved an arrangement made up from a petrol funnel to which was attached a piece of rubber hose passing to a watertight junction in the hull under my seat. The petrol funnel was hung on a brass cup hook near my elbow. I had some difficulty in inventing a purpose for this gadget when explaining the instruments and controls to the wife of a VIP on one occasion.’35
There is no doubt that Neville Usborne’s drive, imagination and technical knowledge were of considerable importance in the rapid design and production of this exceptionally useful weapon which helped to win the first U-boat war. His estate later made two specific claims regarding the design of the SS Class – the rigid umbrella nose frame, which
helped maintain the shape of the gasbag, and the ‘crab pot’ system, which diverted air from the propeller’s slipstream through a non-return valve to keep the internal ballonets charged, and so retain the shape and trim of the airship.36
The intent with the SS Class airships was to guard the eastern entrance to the English Channel with stations at Capel, near Folkestone, and Polegate, near Eastbourne, and the Irish Sea to the north and the south from bases at Luce Bay in Wigtownshire and the Isle of Anglesey. Bases were then added at Mullion in Cornwall and Pembroke in Wales. They operated from four locations in Ireland; Ballyliffin, Co Donegal; Bentra, Co Antrim; Johnstown Castle, Co Wexford and Malahide Castle, Co Dublin. Bentra and Ballyliffin were sub-stations of Luce Bay; an airship shed and supporting huts were erected at Bentra. Johnstown and Malahide were sub-stations of Pembroke and Anglesey respectively, neither had a hangar.
SS-23 approaching to make a landing at Luce Bay. (Via Donnie Nelson)
The SS Class were simple to fly and easy to produce in the numbers required at short notice. They were fairly crude designs and the engines were somewhat unreliable, but they provided the air cover needed when no other type of aircraft could have done so within the necessary timescale. An experienced airshipman of the period wrote:
‘At that time no aeroplane could carry out flights of eight, ten or more hours, as we did regularly – nor did we need a prepared aerodrome. Flights were possible in all but the very worst weather conditions. Fog did not stop us flying. In favourable weather we could land gently into the hands of a few men comprising a landing party. In unfavourable weather we could land by trail rope. Night flying was a little more difficult than by day and no elaborate landing lights were needed. I once landed in a flat calm, by the light of matches, and at best we only had a few oil flares to guide us.’37