Lighter Than Air

by Guy Warner

  The first entirely post-war rigid was the ill-starred R38, which at the time of its construction was the largest airship in the world, being 699 feet long (213 metres), with a diameter of 86 feet (26 metres) and a capacity of 2,750,000 cubic feet (77,825 cubic metres). She was built by the Royal Airship Works at Cardington in response to an order from the US Navy and made her maiden flight on 23/24 June 1921, being re-registered in American markings as the ZR-2 in August. On 23 August she broke up in mid-air over the Humber; among the forty-four British and Americans on board was Air Commodore E.M. Maitland, CMG, DSO, AFC, whom it will be remembered, Usborne had rubbed up the wrong way slightly some seven years before. The R38 was badly designed and poorly stressed, so was unable to cope with the forces experienced during low-level manoeuvring. Much had been riding on the project; if it had been a success and had pleased the Americans, it was hoped that this would lead to an airship industry in Britain exporting its products around the world.

  R38 leaving her shed at Cardington for the first time on 23 June 1921. (Ces Mowthorpe Collection)

  Barnes Wallis, who had worked on airships for Vickers since 1913, designed the beautifully streamlined R80, which had considerably reduced drag compared to any of her predecessors; ‘There is little doubt that she would have proved the finest British airship.’5 Her maiden flight was on 19 July 1920, but before being scrapped in 1924, the R80 accumulated only seventy-five hours flying time:

  ‘This was a decision taken by a Labour Government to avoid a challenge from private enterprise, as R80 was costing less to maintain than the bigger ships designed by the official constructors’ team. Politically, the evidence was inconvenient.’6

  The final two British rigids could not have had more contrasting stories. The Cardington-built R101, G-FAAW, had a length of 777 feet (237 metres), a diameter of 131 feet (40 metres) and a capacity of 5,500,00 cubic feet (160,000 cubic metres), regaining for Britain the title of world’s largest aircraft. She was too heavy, lacking in engine power, and had leaking gasbags. The design was at the very edge of the technology then available. It was an experimental craft rushed – for reasons of political expediency – into a major and challenging flight before she was either ready or fully tested. The R101 was wrecked at Beauvais on her way to India on 5 October 1930 with a large loss of life, forty-eight of the fifty-four on board. The victims included the Secretary of State for Air, Lord Thomson, the Director of Civil Aviation, Sir Sefton Brancker and Major G.H. Scott, one of the most renowned airshipmen of the period.

  The ‘government ship’, R101, approached the mooring mast at Cardington.

  Air Vice-Marshal Sir W.S. Brancker, KCB, FRAeS, (1877–1930) a regular army officer, made his first flight in India in 1910 and from that time devoted the whole of his considerable talents to the furtherance of British aviation. During the First World War he held a succession of staff appointments in the RFC and then the RAF. In 1919 he left the service to become one of the great advocates of civil air transport, becoming Director of Civil Aviation in 1922. He was a very well known and popular figure of boundless energy and enthusiasm. His death in the R101 disaster of 5 October 1930 was a severe blow to the cause of aviation in the United Kingdom and beyond.

  The R100, G-FAAV, was another creation of Barnes Wallis and was built at Howden, which was reactivated for the purpose in 1925–26. The chief calculator assisting Wallis was N.S. Norway, who later gained fame as the novelist Neville Shute, and whose autobiographical book, Slide Rule, includes the story of the two competing designs.

  Also, seen here at Cardington, the ‘private’ contract, R100.

  The R100 was 719 feet in length (219 metres), with a diameter of 133 feet (41 metres) and a capacity of 5,156,000 cubic feet (146,000 cubic metres). She is a strong contender with the R80 for the title of Britain’s finest airship; she was certainly the fastest, with a top speed in excess of 80mph (128kph). Her maiden flight was on 16 December 1929. In 1930, commanded by Squadron Leader R. Booth, she flew successfully to Canada and back. In the aftermath of the R101 disaster, there was a complete collapse of confidence in official circles in Britain as regards airships and, through no fault of its own, the R100 was grounded and scrapped, with less than £600 being raised by the sale of this. No British rigid has been built since then.

  Squadron Leader R.S. Booth, AFC, (born 1895) was originally in the Royal Navy, transferring to the RNAS in 1915 to become an airship pilot, firstly of the SS and Coastal classes. He was appointed first officer of the rigid airship R24 in 1917; from 1924–26 he was the first officer and then captain of the R33, and in 1929–30 he captained R100, during which time the airship made its successful double crossing of the Atlantic.

  Rigid Airships in the USA

  The American experience post-war was different in that it was the only country to have sufficient supplies of helium to make using this much safer gas a viable proposition. Their only large post-war airship using hydrogen was the semirigid Roma, purchased from Italy in 1921. It crashed at Langley Field, Virginia, in 1922 with the loss of thirty-four lives. The first of three rigid, helium-filled, airships was the USS Shenandoah, ZR-1, which was 680 feet (207 metres) long, 78 feet (24 metres) in diameter and had a capacity of 2,235,000 cubic feet (63,295 cubic metres). On 3 September 1925 she broke in two during a violent storm over Ohio; there were twenty-nine survivors from the crew of forty-three, who were saved by riding buoyant sections of the airship which fell to the ground like free balloons. On 4 April 1933, the USS Akron, ZRS-4, was forced down into the sea off the coast of New Jersey with the loss of seventy-four crew members out of seventy-seven, the world’s worst airship accident. Her sister ship, the USS Macon, ZRS-5, encountered a storm off Point Sur, California, on 12 February 1935 and suffered a similar fate, fortunately with a very much lower loss of life. These last two airships were among the largest ever built, being 785 feet (239 metres) in length, with a diameter of 132 feet (40 metres) and a capacity of 6,497,960 cubic feet (184,000 cubic metres). It is an odd fact that all three succumbed to adverse weather conditions. The USA joined Britain in abandoning the rigid airship. This left the field to Germany.

  USS Shenandoah.

  The USS Akron moored inside the Goodyear air dock.

  Zeppelins

  In the aftermath of the First World War, Germany had been greatly restricted by the terms of the Treaty of Versailles with regard to the further development of airships.

  Article 198

  The armed forces of Germany must not include any military or naval air forces. No dirigible shall be kept.

  Article 202

  On the coming into force of the present treaty, all military and naval aeronautical material must be delivered to the governments of the Principal Allied and Associated Powers. In particular, this material will include all items under the following heads which are, or have been, in use, or were designed for warlike purposes:

  Dirigibles able to take to the air, being manufactured, repaired or assembled.

  Plant for the manufacture of hydrogen.

  Dirigible sheds and shelters of every kind for aircraft.

  Pending their delivery, dirigibles will, at the expense of Germany, be maintained inflated with hydrogen; the plant for the manufacture of hydrogen, as well as the sheds for dirigibles, may, at the discretion of the said powers, be left to Germany until the time when the dirigibles are handed over.

  A brief resumption of commercial services in 1919, during which 103 flights were made and 2450 passengers carried, terminated when the Zeppelins LZ121 Nordstern and LZ120 Bodensee had to be handed over to France and Italy respectively as reparations. The Zeppelin works was saved by the order of an airship from the USA; this was the LZ126/ZR-3 USS Los Angeles, which was completed in 1924. While the Zeppelin workforce was happy, the Berlin Morning Post was not, commenting unfavourably on a ship, ‘built in Germany by German workers and engineers, paid for with German money, but which belongs to America.’7 Her delivery flight on 13–15 October 1924, commanded by Dr Hugo E
ckener, was the third airship crossing of the Atlantic, after R34’s double run in 1919. In US service the hydrogen originally used was replaced with helium. She was the most successful rigid airship ever operated by the US Navy and had an unblemished eight year flying career of nearly 5000 hours.

  The greatest rigid airship of all time first took to the skies on 18 September 1928. This was LZ127, the Graf Zeppelin. She was 775 feet long (236 metres), 100 feet in diameter (30 metres) and with a capacity of 3,700,000 cubic feet (104,784 cubic metres). Her five Maybach engines of 550 hp (410kW) each, gave her a top speed of 80mph (129kph) and a cruising speed of 68mph (109kph). For the next decade she was one of the most famous aircraft in the world, regularly making the headlines and newsreels with spectaculars, including a round-the-world flight in August 1929, with a research trip to the Arctic in 1931, and multiple crossings of the North and South Atlantic. The Graf Zeppelin’s engines ran on ‘Blau Gas’, which had several advantages over liquid fuels such as petrol. It was non-explosive, and because it was only slightly heavier than air, burning it and replacing its volume with air did not lighten the airship – eliminating the need to adjust buoyancy or ballast in flight.8 She was followed by the largest flying machine ever built, the LZ129, Hindenburg, which measured 800 feet (245 metres) in length, had a diameter of 135 feet (41 metres) and a capacity of 7,000,000 cubic feet (198,240 cubic metres). The Hindenburg was destroyed by fire as she arrived at Lakehurst, New Jersey, on her first commercial flight to the USA on 6 May 1937. A sister ship, the LZ130, Graf Zeppelin II, flew briefly in 1939 and carried out some electronic intelligence gathering missions probing British radar defences, but in 1940, both LZ127 and LZ130 were broken up for scrap. So ended the rigid airship era which had lasted for some forty years.

  LZ129 Hindenburg.

  Proof of concept with regard to intercontinental flights had been established by the exploits of LZ104, the Afrikaschiff, in November 1917. She took off from Yambol in Bulgaria to fly to German East Africa with supplies to relieve the hard-pressed force of General von Lettow-Vorbeck. While the airship was enroute, erroneous reports arrived that von Lettow-Vorbeck had been defeated and it was not until the Afrikaschiff had overflown Khartoum that a recall message was received on board. She returned to base some four days after her departure, having flown a record breaking ninetyfive hours and covering 4200 miles (6800 kilometres) in challenging and changing climatic conditions.

  A mechanic crosses to the Hindenburg’s port forward engine gondola.

  It was in the end a technological cul-de-sac, rigid airships were too slow and unwieldy to compete with fixed-wing aircraft, and, along with the flying-boat, are now icons of a time when air travel had glamour and style. They were not big enough to make their speed advantage over surface shipping commercially viable. The construction techniques and materials available at the time could not make craft (apart from a few notable exceptions) which were able to survive stormy weather. (It is of interest that Lord Rayleigh was of the opinion that there was nothing more difficult than calculating the stresses, particularly the torsional stresses of a rigid.)9 The contemporary naval fixed-wing airman, Richard Bell Davies, had some interesting comments to make with regard to airships and safety:

  ‘I have never been a great believer in the future of airships, but I think one of the reasons that they failed to do better than they did was due to the difficulty of giving long enough training to their captains. The master of a merchant ship has usually spent ten years or more in a subordinate position before he is given command. He has seen the ship berthed literally hundreds of times and has seen her handled in all sorts of weather. I suppose in the whole world there has only been one man who had experience with airships comparable to the ship experience of the average British Master Mariner. This was Dr Eckener when he commanded the Graf Zeppelin. She had no accidents and made trips all round the world.’10

  The Graf Zeppelin lands at Los Angeles, note the Goodyear blimp in the background.

  There is much food for thought in this statement, as there also is in remarks made by Murray Sueter:

  ‘The tide tables, laws of storms, etc, as applying to surface vessels, have been built up by years and years of patient labour by experts all over the world. Surely, then, it is not unreasonable to suppose that the same study of the conditions in the lower strata of the atmosphere in the England, Egypt, India, Australia, South Africa and Canadian air routes will have to be considered for the use of airmen navigating all types of aircraft, so that they can be guided in the same way as the seaman is in the normal conditions expected. The meteorological staff are not fools; they and the airship staff realize the importance of wind currents, both permanent and otherwise, and that is why they are analysing the lower strata of the atmosphere in the area of the England-Egypt-India route for every day of the year, in order to discover what are the normal conditions to be expected.’11

  It remains a question, could a niche still be found for a rigid airship equipped with advanced avionics and engines, built from strong but light composite materials? Could it be used to deliver heavy plant and machinery to remote and inaccessible areas, or as an aerial cruise liner?

  Non-Rigid Patrol Airships

  In all, 147 Submarine-Scout type airships were constructed, twenty-nine with the BE2c fuselage, twenty-six Maurice Farman types, ten with an Armstrong-Whitworth car, six SS-Pushers (which had rubberized fabric petrol tanks, which were not a success and were soon replaced by aluminium ones) and seventy-six improved model SS Zeros. The SSZ was built to the design of three RNAS officers, Commander A.D. Cunningham, Lieutenant F.M. Rope and Warrant Officer Righton, at RNAS Capel, near Folkestone. Work started on building the prototype in June 1916. The car was specifically designed to be streamlined in shape and was constructed almost like a boat, with a keel and ribs of wood with curved longitudinal members. The whole frame was braced with piano wire and then floored from end to end. It was enclosed with eight-ply wood covered with aluminium. The crew of three consisted of the wireless telegraphist/observer/gunner in the front, with the pilot in the middle and the engineer in his own compartment to the rear. A machine gun could be mounted either to port or starboard, operated from the front seat, and two 110lb bombs could be carried. The car, as well as being boat-shaped, was watertight, so the airship could land on calm water. The engine was a great improvement. It is said that the engineering officer at Kingsnorth, Lieutenant T.R. Cave-Browne-Cave, had complained time and again about the adapted aero engines used in the SS Class, which because they were not designed for use in airships, were unsuitable for slow, sustained flight and were always giving trouble. His commanding officer, tiring of this, ordered him to go and do something about it. So, taking him at his word, Cave-Browne-Cave took the train to Derby and requested a meeting with Henry Royce. After only a few hours of discussion an engine specification was agreed. This became the 75 hp Rolls-Royce Hawk six-cylinder, vertical inline, water-cooled engine driving a four-bladed pusher propeller; 200 of these were manufactured under licence by Brazil Straker of Bristol, which was the only company entrusted by Henry Royce to build complete engines. It was a superb creation and was test run for the first time at the end of 1915. The words of an airship pilot tell it all; ‘The sweetest engine ever run – it only stops when switched off or out of petrol.’12 It gave the airship a top speed of 53mph and a rate of climb of 1200 feet per minute. Slung on either side of the gasbag were two petrol tanks made from aluminium. The gasbag had a capacity of 70,000 cubic feet. It was of the same length as the SS Class gasbag, but was of a slightly greater diameter. The nose of the gasbag was reinforced by radially positioned canes to prevent it buckling at speed. As with the SS Class it was attached to the car with cables secured to the envelope by kidney-shaped Eta adhesive patches, which were also sown on, so spreading the load evenly. The SSZs, or Zeros as they were known, which first flew in September 1916, were more stable in flight than the SS Class and had much greater endurance. They were able to fly in weather condition
s that would have prevented the earlier type from operating. Its unit cost was about £5000. It rapidly gained the approval of its pilots:

  ‘The SSZs were dreams come true. I fell for them almost at once. At last we had a trouble-free engine and our engineers were able to get some sleep at nights.’13

  An SSZ Class airship, looking over the pilot’s head to the engineer’s station at the rear of the car. (via Tom Jamison)

  The larger and longer range Coastal Class were the workhorses of the airship service, seeing more action than any other type; in all thirty-five of these were produced, flying from bases in Kent, Cornwall, Sussex, Norfolk, Wales and Scotland. The most famous of these was C9, which entered service at Mullion in Cornwall on 1 July 1915 and flew a record 2500 hours (averaging three hours six minutes per day flying time) and more than 68,000 miles (108,800 kilometres) before being retired from active service on 1 October 1918. She attacked several U-boats successfully. In 1917 the indefatigable Wing Captain Maitland made an experimental parachute jump from C17. It is believed that two, and possibly three, of this class were lost due to enemy action, two in duels with German seaplane fighters and one in an action with a U-boat, with the result that the order was given that their top gun, mounted on the envelope, should be manned at all times. It is thought that the two which were shot down by aircraft had strayed too close to enemy-occupied territory. They were the only airships destroyed by hostile fire.