Japanese Military Airships
(Editors Note: This article recently appeared in an edition of the JAS Jottings as is being reprinted with the permission of the author. Our thanks to Peter for allowing us to reprint this article here. -Dave)
Whilst the Navy made the first Japanese manned ascent in a captive balloon in spring 1876 they soon lost interest in the idea. However, the Army was more enthusiastic and after many experiments, even using them for reconnaissance in the 1904 Russo-Japanese War, they established a balloon unit near Tokyo in 1907, followed by formation of the Provisional Military Balloon Research Association (PMBRA) two years later.
Despite it name, PMBRA was intended to investigate all forms of manned flight and included representatives from the Army, Navy, Tokyo University and Central Meteorological Observatory, 14 in all. An outline of subsequent Army and Navy airship developments follows.
In the month previous to formation of PMBRA the first airship to be flown in Japan was demonstrated in a Tokyo Park, brought there by an Englishman named Hamilton. It was a small non-rigid type of unknown origin (although possibly built to his design), some 60ft long and 17ft maximum diameter with a hydrogen capacity of just over 8,000 ft 3 and un-laden weight 180kg. Power was provided by a small petrol engine mounted in the centre of the suspended gondola, driving a tractor propeller. How much this demonstration influenced PMBRA is unknown, but one of its first actions was to arrange for the building of an indigenous non-rigid airship.
A lifeboat manufacturing company owned by Isaburo Yamada was given the order to fabricate the envelope, designed for carrying a gondola to be built by the Hirokoa Ironworks. Yamada had been interested in balloons since 1897, building kite type, which had interested the Army, and others of cylindrical shape. His first airship was based on this experience, also on what he had learnt from studying the Hamilton model, and was called:
Yamada-shiki No.1. This was also non-rigid type, approximately 60ft long and said to have had a hydrogen capacity of 56,500ft 3 , which seems high when compared to similar figures for its larger successor (see below). An open tubular gondola of upright triangular cross-section and almost as long as the envelope was suspended below it, in the centre of which was a small platform for the helmsman and a 12hp motor car engine driving a pusher propeller. There was a rudder at the rear (stern?) proudly displaying a hinomaru on each side and a small elevator between the platform and the front (bow?) of the gondola for flight control.
The airship was flown for the first time in early September 1910 from Osaka, but soon lost a considerable amount of hydrogen and had to land for refilling on the ground to enable it to fly back to Osaka. Its ultimate fate is unknown, but a few months later it was followed by:
Yamada-shiki No.2. This was a larger version of airship No.1, approximately 108ft long with a hydrogen capacity of 53,000ft 3 . The gondola suspended below it was of similar construction to that on airship No. 1, but of bigger cross-section and perhaps only half the length of the envelope. The centre platform now carried a 50hp four cylinder in-line water-cooled engine petrol engine, again driving a pusher propeller, whilst both rudder and elevator were slightly larger.
There are conflicting accounts regarding the fate of this airship. One *2 suggests that it was blown away during mooring tests in early February 1911, without any mention of subsequent recovery. Another *3 suggests that it was destroyed in a ground explosion on 23 rd March 1911, just before its second flight. Yet a third *5 is quite different and suggests that it did not make its first flight until early May 1911 and was then later damaged during an emergency landing near Osaka in early February 1912 when the engine failed. In between these conflicting dates came:
Yamada-shiki No.3 . How this differed from airship No. 2 is unclear as no details of it are available. It might even have been just the repaired or rebuilt No. 2 re-designated No. 3. It is reported as having first flown at the beginning of June 1911 and later making a successful trip from Osaka to Tokyo and back in mid September that same year, although there are no details of staging arrangements. It is possible that there is confusion between the activities of airships Nos. 2 & 3, also over eventual disposal of the latter. One source *3 suggests that it was eventually sold to China where it was flown over the Hankow-Wuchang area, but see also the fate of the next airship:
Yamada-shiki No.4. There are few details to be found for this airship, other than it was an improved version of its predecessor and fitted with a 75hp engine. One source *5 suggests it was this airship which was eventually sold to China in 1913, making its first flight there (also the first airship flight in China) in August of that year and then being destroyed soon after in its hangar during a storm.
Notwithstanding the trials and tribulations of Yamada's first two airships, PMBRA were sufficiently impressed with their potential to design their own in 1911. Plans and specification were completed by August that year and once again orders were given to Yamada for the envelope and to Hirokoa Ironworks for the gondola. Interestingly, planning was co-ordinated by a joint Army and Navy team, resulting in:
Kai-shiki I-go (Association type model 1). Whilst still of non-rigid type, this airship was larger than Yamada-shiki No.2, namely almost 159ft long, maximum diameter 38ft and with a hydrogen capacity of 103,500ft 3 . The gondola suspended below it was again of open tubular type construction, but now rectangular in cross-section. The centre platform carried a cockpit with side panels for the crew of three at the rear, whilst at the front was a Wolseley 60hp four cylinder in-line water-cooled engine petrol engine driving a tractor propeller. A dorsal rudder was fitted to the envelope rear and an elevator above the gondola forward section for flight control.
The airship made its first flight from Tokorozawa early on the morning of 25 th October 1911 under the joint command of 1 st Lt Ito (Army) and 2 nd Lt Nakajima (Navy), the latter subsequently starting his own famous aircraft company of that name in 1917. According to one source *1 it covered just under 3 miles in 10 mins at an altitude of 132ft, whilst another *2 states 5 miles in 15 mins at 550ft. Details of subsequent flight trials are scant, other than it made of one of some 20 miles in 1hr 41mins and had a maximum endurance of 5 hrs. It was dismantled in 1914.
Not only did PMBRA design their own airship in 1911 as just recounted, they were further impressed by airship progress in Germany and also ordered one from there that same year, namely:
Parseval Pl-13: Again of the non-rigid type, this airship was the 13 th Parseval design, manufactured at the Deutsche-Luftfahrzeug-Gesellschaft works near Berlin. It was almost 252ft long, with a maximum diameter of 50ft, hydrogen capacity of 310,950ft 3 and an un-laden weight of 7,150kg. It was powered by two Maybach 150hp six cylinder in-line water-cooled petrol engines, each chain driving a four bladed pusher propeller, mounted in line with each other either side of the gondola rear. The gondola itself resembled a short, flat bottom, square nose boat and was designed to carry a crew of 7/12. Horizontal stabilisers, a large dorsal rudder and a small ventral fin were fitted to the envelope rear for flight control.
This airship was far bigger and more powerful than anything the Japanese had experienced, with an anticipated cruising speed of 40mph and endurance of 20 hrs. Hence during the period of manufacture a team of Army officers was sent to Germany to study construction methods and be trained in handling it to qualify for a Public Airship Conducting Licence. The completed airship was transported to Japan by sea in mid 1912 and assembled under supervision of a German engineer in a hanger built specially for it at Tokorozawa. The first flight of 25 mins duration was made on 31 st August 1912 by a joint German and Japanese crew of four.
Thereafter it gained remarkable popularity with crowds of sightseers after flights over Tokyo, and during November that year it participated in a Naval Review at Yokohama, and in major Army manoeuvres. In response to its popularity, arrangements were made for flights by it to form part of a public event on the Yoyigi Army drill ground at the beginning of February 1913. However, a prior demonstration was planned at Aoyama training ground a few days earlier, when disaster struck. Whilst preparing to land at Aoyama the airship collided with a monument to the Japanese Emperor Meiji, seriously injuring members of the crew and badly damaging the stern. It was subsequently transported back to Tokorozawa and stored in the hanger there.
After some 12 months in storage PMBRA decided to carry out repairs and modifications to the airship, on completion of which it was named:
Yuhi-go (Majestic Flight): The envelope was enlarged and its fabric completely replaced, the elevator lengthened and the gondola rebuilt, but still utilising the Maybach engines. As a result the length was increased to 279ft, the hydrogen capacity to 353,360ft 3 and the weight by 100kg, although the cruising speed and range were both slightly reduced in consequence. The rebuilt airship made its first flight on 21 st April 1915, followed by a succession of flights up to seven hours duration over the rest of the year. During this time night flights were made, also experiments with air to ground wireless telegraphy. Whilst the airship's actual flight performance was satisfactory, engine reliability became a problem.
The problem arose from increasing maintenance difficulties due to lack of engine spare parts from Germany, Japan having joined the Allies in the war against her. It came to a head in January 1916 when three attempts to fly from Tokorozawa to Osaka were interrupted by engine failure. A fourth attempt on 21 st January was successful after a flight of over 11 hrs duration, but the engines could not sustain a return flight the following day and the airship was transported ignominiously back to Tokorozawa by train.
Thereafter desultory flights plagued by engine failure were made up to the time of completing aerial compass tests in July 1917. By then the Army were becoming far more encouraged by advances in their parallel development of aircraft and by 1918 they had finally given up all thoughts of furthering their interest in airships. The Yuhi-go was duly scrapped.
Ironically, it was not long after that time when the Navy started to take a serious interest in them! Dissatisfaction with increasing Army dominance of PMBRA led to creation of its own Naval Aeronautics Research Association in 1912. This new organisation concentrated on aeroplane design, but kept a watching brief on the Army lighter than air developments described above. Then, towards the end of WWI, the effectiveness of German Zeppelins encouraged the British and American navies to expend considerable effort in developing their own airships. In view of this the Japanese Navy began investigating their use in its own tactical and strategic schemes, establishing an airship unit in 1920 at Yokosuka and starting to acquire airship technology from abroad.
At the end of WWI Japan was awarded the German Navy's L37 Zeppelin as part of its war reparations. This overweight airship had only been flown for about a year on wartime operations in the Baltic area and had not received modifications made to other class L30 Zeppelins as it was laid up in 1917. Japanese Navy representatives inspected the airship, but they were not really interested in acquiring it. They had it broken up in 1920 after removing components thought worthy of study back in Japan, which included gas valves, instruments, control equipment and engines. Also in 1920 Lt Cmdr Onishi (later Vice Admiral Onishi, better known for his instigation of Kamikaze operations in WWII) undertook airship flight training with USN personnel in America.
Then in 1921 the Navy decided to order their first airship from England, namely:
#1.Vickers SS (Sea Scout) 3: This non-rigid type airship was in service with the British Royal Navy and used for submarine spotting in WWI. It was almost 171ft long with a maximum diameter of 36ft and hydrogen capacity of 100,000ft 3 , powered by two Rolls-Royce 90hp six cylinder in-line water-cooled engines. Each drove a four bladed pusher propeller, mounted outboard and in line with each other either side of and towards the gondola rear. The gondola itself was a streamlined enclosed unit housing a crew of five and which could also carry two machine guns plus four 5.5kg bombs. Horizontal stabilisers, also both dorsal and ventral rudders, were fitted to the envelope rear for flight control, and it had a maximum speed of 60mph with a range of almost 800 miles. The SS3 and mooring mast arrived in Japan during early 1922 for assembly at Yokosuka Naval Air Station. It made a successful maiden flight from there on 11 th May, but never saw operational service. On 11 th July 1922 it was destroyed in an explosion believed to have been caused by an electrostatic discharge whilst it was in a makeshift hangar at Yokosuka. Around four months after the disaster the Navy ordered their second foreign airship, this time from France:
#2.Nieuport AT-2: This non-rigid airship, much larger than the SS-3, was of the Astra-Torres (AT) type (which had a trefoil instead of circular section envelope), almost 263ft long, maximum diameter 54ft and with a hydrogen capacity of 363,950ft 3 . It was powered by two Sunbeam 300hp twelve cylinder V water-cooled engines each driving a two bladed tractor propeller, mounted outboard and in line with each other either side of the gondola centre. The gondola had a raised, enclosed cockpit at the front housing a crew of 7/12; it also carried one 75mm cannon and one machine gun, plus four 45kg or two 90kg bombs. Horizontal stabilisers and dorsal/ventral rudders were fitted to the envelope rear for flight control and it had a range of 970 miles at a cruising speed of 29 mph.
The AT-2 arrived in Japan during early 1923 and was assembled in the Army airship hangar at Tokorozawa (!). It made a successful maiden flight on 10th July that year, but further flights had to be restricted after an earthquake on 1 st September damaged the plant generating hydrogen for it. However, in the meantime a 787ft long Zepplin hangar from near Berlin, also part of WW1 reparations, had been transported to Japan and was being assembled at the Kasumigaura naval base. After it was completed the airship was transferred this new abode to form half of the Navy's first airship fleet, established there in December 1923. There are no details of the airship's subsequent operational history other than it took part in the Grand Naval Review of October 1924 and was dismantled shortly thereafter.
The other half of the first airship fleet mentioned above was Japanese built, namely:
#3.Vickers SS3 (Replica): When the Navy ordered airship #2 after the airship #1 disaster, they also decided to build a virtual replica of the latter at Yokosuka, but with 100hp engines. Completed in 1923, it is recorded as having flown the round trip from Yokosuka to Osaka in June that year, then transferred to Kasumigaura in December. Again there are no details of the airship's operational history other than it was as ill-fated as its progenitor, exploding in mid-air during a flight on 19 th March 1924, killing all the crew.
In 1925, despite the misfortunes of airships #1 and #3, the Navy gave an order to Fujikura Industrial Company for fabrication of an envelope to carry a gondola built by Mitsubishi, the whole design based on the non-rigid SS3, namely:
#4.Fujikura Navy Type 1-kai: Slightly larger than the SS-3, it was almost 182ft long, maximum diameter 40ft and with a hydrogen capacity of 111,490ft 3 . It was powered by two Sunbeam 100hp six cylinder in-line water-cooled engines each driving a four bladed pusher propeller mounted as for the SS3 on a slightly larger gondola housing a crew of six. However, the original aluminium doped envelope covering was replaced with a different fabric in an endeavour to minimise build up of static electricity, whilst the controls and internal equipment were modified.
The result was a successful airship first flying on 26 th May 1926, albeit slightly slower than the SS3, but with a longer range of 1,250 miles. After satisfactory operational trials it was accepted one year later as Navy Type 15 Airship. Although it appears to have remained as a prototype for operational trials, an order was given on acceptance to Fujikura for three more similar airships, starting with:
#5.Navy Type 15: The production model was slightly different in size to the Type 1-kai, namely 174ft long, maximum diameter 42ft and with a hydrogen capacity of 129,600ft 3 . It was also powered by two larger Benz Bz.III 130hp six cylinder in-line water-cooled engines. Armament was similar to the original SS3, but the ordnance was increased to two 45kg bombs. The net result of these changes was a longer range of 1,375 miles, but at a slower cruising speed of 30mph.
The first Type 15 had entered service by mid 1927, followed by two more (#7 & #9) later that year. They formed the core of the Navy Airship Fleet and remained in service until all were phased out in 1932. In February 1931 airship #9 made an endurance flight of 30hrs 52mins, all the more remarkable because much of it was in a blizzard during which the temperature dropped to -14°C.
In addition to ordering the three Type 15 airships in 1926, the Navy also ordered a much larger and more powerful one from Italy:
#6. Nobile N-3: The Navy's first semi-rigid type, the N-3 was almost 263ft long with a maximum diameter of 49ft and a hydrogen capacity of 274,700ft 3 . It was powered by two Maybach 245hp six cylinder in-line water-cooled engines, each driving a two bladed pusher propeller, mounted in streamlined nacelles abreast of each other below, close to and about half way along the envelope. A well glazed enclosed cabin for the crew of 7/12 was fixed direct to and almost at the front of the envelope keel, with horizontal stabilisers and dorsal/ventral rudders at the envelope rear for flight control. It had a range of 1250 miles at a cruising speed of about 60mph.
The N-3 arrived in Japan during January 1927 and was assembled in the Zeppelin shed at Kasumigaura by Maj.Gen.Umberto Nobile and a team of Italian technicians. It made a successful first flight on 6 th April with a crew of six Japanese and six Italians, after which it operated satisfactorily and joined naval manoeuvres south of Tokyo on 22 nd October 1927. Unfortunately strong winds resulted in an emergency landing on Kozu-shima Island, where all the crew managed to disembark. After they had done so a sudden gust of wind carried the airship out to sea, where it exploded and was totally destroyed. Its one claim to fame was in being the fastest Japanese airship.
#8.Navy Type 3: Ordered in 1928, this airship was built by Fujikura/Mitsubishi as a successor to the ill-fated #6, but still followed the Nobile N-3 basic design. However, the keel was strengthened whilst envelope skin and engines were similar to those on the Type 15 airships. It had slightly different dimensions and capacity to #6 and was now powered by two Benz Bz.III engines modified by Gasuden to give an increased output of 150hp. The net result of these changes was a marginal 25 miles less range at a 2mph slower cruising speed.
The Type 3 made a successful first flight on 23 rd July 1929 and soon joined the three Type 15s in the Navy Airship Fleet. Between 14 th and 17 th March 1931, carrying a crew of nine, she made a flight of 60hrs 1min to establish a new national duration record, but it was also the last significant flight of a Japanese airship. That same year the Navy decided that airships were too expensive to build, too vulnerable to damage and of questionable use in operational service, long after the Army had reached the same conclusion. They realised at last that the future of naval aviation lay entirely with the aeroplane and so the airship unit was abolished. The four remaining airships were used by the Fleet until all were phased out in 1932.
There is an interesting tail piece regarding the Zeppelin shed at Kasumigaura. It was used in August 1929 to house Graf Zeppelin LZ127 for maintenance when it visited Japan in August 1929 during an epic 21 day round the world flight.
1. Fifty Years of Japanese Aviation 1910-1960, Aireview
1. Dimensions to nearest foot, capacity to nearest 50ft 3 . NB. Most
of the figures given vary in different sources and those given here are
the most consistent