Although firms like Siemens-Schuckert and Luftverkehrsgesellschaft (LVG) had made tremendous inroads into the development of long-range bombers during the First World War, the most successful company by far was Zeppelin-Werke Staaken. It was the Staaken R-planes that bombed Britain during the hostilities and they were the only large bombers to have carried out attacks on the Western Front.
The birth of the Staaken R-planes can be traced back to the dream of one man: Hellmuth Hirth. In 1915, he had planned to build an aircraft that would fly across the Atlantic and appear at the World’s Fair in San Francisco. The financial backing was assured by Gustav Klein, Director of the Robert Bosch Werke, but the arrival of the First World War put paid to his dream. But the concept had not been forgotten, and the airship manufacturer Graf Zeppelin took a long, hard look at the project and saw the potential for a terror weapon.
With the demise of the Naval Zeppelin LZ, the German Naval High Command started to take a long, hard look at Graf Zeppelin’s design of the airship and at Graf Zeppelin himself. Graf Zeppelin, whose relationship with the German Admiral von Tirpitz had never been good and was at this point in time almost non-existent, turned his attention to the building of long-range bombers. Zeppelin approached the Robert Bosch Werke and persuaded them to allow Gustav Klein, thirty of their engineers and assorted other workmen to join him in building bombers.
Large sheds were rented from Gothaer Waggonfabrik AG (Gotha) on the Gotha airfield and work started on the giant bomber. A corporation was set up by the name of Versuchsbau GmbH Gotha-Ost (VGO), which was financed by Bosch and Zeppelin. Among the engineers that were invited to join the company were Claude Dornier and Ernst Heinkel, but only Dornier accepted. Both were later to become famous aircraft manufacturers in their own right. Almost from day one it was decided to use two different types of material in the construction of these giant bombers: wood and metal. Claude Dornier was given a relatively small hangar on Lake Constance, where he carried out experiments in building an all-metal aircraft with considerable success. This section of the company was known as Zeppelin-Werke Lindau GmbH, and the aircraft built there were given the prefix Dornier.
Claude Dornier, working diligently on the side of Lake Constance, started constructing a giant flying boat at the beginning of 1915, the Zeppelin-Lindau (Dornier) Rs.I. Powered by three 240-hp Maybach Mb.IV engines, this gigantic aircraft had a wingspan of 142 ft 8 in, a fuselage length of 95 ft 2 in, and a height of 23 ft 7½ in. The engines were mounted within the fuselage and turned three pusher propellers. On 12 October 1915, the Rs.I was at anchor on Lake Constance, the taxiing trials having been completed; the 22 December was set as the date of the first of the flight trials, but during the night gale-force winds rose up and the aircraft broke its moorings and ran aground. Within hours, the aircraft had been battered into pieces by large waves. Fortunately, a second machine, Dornier Rs.II, was already in production and was powered in exactly the same way. The only main difference was that the wingspan was considerably shorter at 108 ft 11 in and the fuselage length was 78 ft 4 in. On 30 June 1916 the Rs. II took to the air and within weeks the flight test programme was completed, the aircraft was dismantled and the parts used to construct the Zeppelin-Lindau (Dornier) Rs.IIb. This aircraft’s engines were in a four-engined configuration and in a tandem arrangement; this was to become a characteristic of many of Claude Dornier’s designs in later years.
The Rs.III appeared in October 1917 and, after trials, was scheduled to be delivered to the Navy at Norderney on the North Sea. There was concern about the delivery of the aircraft, as no one had ever flown a seaplane such a distance, and about how it would stand up to the heavy seas of the North Sea. On 19 February 1918, the aircraft took off and seven hours later touched down in the sea off Norderney. The flight was uneventful and the aircraft’s response to the large waves of the North Sea was in the Navy’s report:
The aircraft passed the sea test with heavy seas – Beaufort 3 to 4; wind velocities between 33 and 36 feet per second and a payload of 4,400 lbs.
Work on the VGO.I-RML.1 (Versuchsbau-Gotha-Ost Reichs Marine Landflugzeug), as the aircraft was to be called, started in earnest in December 1914 and by the end of January 1915, work had to be halted as the engines were not ready. The 240-hp Maybach HS engines that had been chosen for the aircraft were a modified version of the HSLu airship engine. The aircraft was powered by three engines, one mounted in the nose driving a tractor propeller, the remaining two mounted in nacelles, supported between the wings by inverted struts, driving pusher propellers. The wings were fitted with unbalanced ailerons.
The rectangular fuselage was of the conventional slab-sided structure and constructed with a mixture of spruce longerons and welded steel tubing. With the exception of the plywood-covered top decking, the fuselage was covered in doped fabric. The fuselage narrowed down to a horizontal knife-edge at the biplane tail, which consisted of four small fins with unbalanced rudders along the top. The control cables from the cockpit to the tail rudders passed along the outside of the fuselage to large quadrants situated in the cockpit.
The aircraft had a flight crew of six: two pilots, a commander/observer and three mechanics, one for each engine. The cockpit was a large open one, with the observer in an enclosed section behind. Communications between the crew were relatively crude and were carried out by means of hand signals, blackboards and a series of bells. One wonders how, during a flight in an open cockpit or standing by one of the engines, anyone could have possibly heard any bells!
By the beginning of April 1915 the aircraft was completed, and on 11 April, piloted by Hellmuth Hirth, the VGO.I took to the air on its maiden flight. The success of its initial flight prompted the manufacturers to make plans for a long-distance cross-country flight from Gotha to the Maybach Werke, Friedrichshafen. The reason for the flight was firstly to see how the aircraft responded on long flights, and secondly to obtain improved and more reliable engines from Maybach.
It took almost six months for reliable engines to be installed in the aircraft, but then on the return flight, during a particularly bad snowstorm, disaster struck. Flying over the Thüringen Forest two of the three engines cut out, leaving just the one. It soon became obvious that the aircraft could not stay airborne on the one engine and with tremendous skill the two pilots, Hans Vollmöller and Flugmaat Willy Mann, put the giant aircraft down in a small clearing. The aircraft was severely damaged but the crew were uninjured.
Engineers collected the remains from the site and returned them to the factory at Gotha. There the aircraft was rebuilt, only this time with a number of modifications made. The VGO.I had cowled engines installed with gun positions for what was now the mechanic/gunner in the front of the nacelle. On the top of the centre-section cabane a large, streamlined gravity tank was fitted. The rebuilt VGO.I flew again on 16 February 1916, and after tests was accepted by the Navy and assigned to Navy Kommando LR.1, which was commanded by Leutnant zur See Ferdinand Rasch. On the side of the aircraft were painted the letters RML.1 (Reich Navy Landplane 1). On the trip from Gotha to Alt-Auz, normally a three-day trip, problems arose from day one. The undercarriage collapsed and the engines overheated and had to be replaced, with the end result that it took three months to complete the flight.
Over the next few months the RML.1, as it was now referred to, was involved in a number of raids against Russian troop installations and air stations. Then, in late 1916, it was involved in another crash. On 10 March 1917 the rebuilt VGO.I (RML.1) took off on a test flight with Hans Vollmöller and Leutnant der Reserve Carl Kuring at the controls, together with Gustav Klein acting as observer. Shortly after take-off there was an explosion in the port engine nacelle and the engine stopped. Circling the airfield and preparing to make an emergency landing, the rudder pedals jammed. Vollmöller cut the engines and prepared to land, but the jammed rudders forced the aircraft into a right-hand turn and the aircraft smashed into the doors of the airship shed. All three crew were killed instantly.
While the VGO.I was being rebuilt after its first accident, work had been continuing on the VGO.II. The aircraft was identical in construction and specifications to the VGO.I, although there were a number of modifications made in the tail area. The vertical tail surfaces were reduced to two but the rudder areas were increased.
The aircraft was accepted by Idflieg on 28 November 1915 and given the designation R.9/15. Again the VGO was dogged with problems; this time the aircraft ran out of fuel on one flight after encountering very strong headwinds. The aircraft, flown by Leutnant Lühr and Leutnant Freiherr von Buttlar, had to make an emergency landing in which the undercarriage was ripped off. One experiment to place a rear gunner in the tail failed miserably, when, after the test flight, the gunner was removed from the aircraft more dead than alive. The oscillations experienced in the tail were so violent that the gunner became violently ill soon after take-off and stayed that way throughout the flight. Tests on a gun mounted within the fuselage were carried out, but came to nothing as there were serious problems with its accuracy.
The third in the series of Staaken R-planes, the VGO.III was well under construction in 1915. It had been decided to replace the three 240-hp Maybach HS engines with six 160-hp Mercedes D.III engines. Although lower in individual output, the total horsepower was jumped from 720-hp to 960-hp. Two engines were mounted side-by-side in the nose of the aircraft, driving a twin-blade tractor propeller; the remaining four engines were mounted in pairs in outboard nacelles and drove twin-bladed pusher propellers.
The aircraft was given the designation R.10/15 by Idflieg and assigned to RFa 500. Carrying a crew of seven, including a wireless operator, the aircraft completed seven bombing missions, including the bombing of the railway station at Riga. Then on 24 January 1917, the aircraft was lost, along with five of the crew, when it crashed on landing and burst into flames.
A deviation from building bombers was made in November 1916, when the Zeppelin-Lindau V.1 took to the air. This was an attempt at a single-seat fighter constructed mainly of metal. It had an egg-shaped nacelle constructed of steel struts that were covered in aluminium sheet and attached to open steel tail booms and struts. The tail and wings were covered in doped fabric. Wingspan was 34 ft 5½ in, with a fuselage length of 20 ft 7 in. The aircraft was fitted with a 160-hp Maybach Mb.III pusher engine.
The Allied push meant that an Allied air attack on the Staaken factory became more and more of a possibility. The German High Command decided that the factory should be moved to a place of relative safety, so the whole outfit was moved to Staaken, near Berlin. The first of the Staaken types then came off the production line, the Staaken R.IV.
The aircraft was powered by two 160-hp Mercedes D.III tractor engines that turned twin-bladed propellers of 13 ft 9 in diameter, and four 220-hp Benz Bz.IV pusher engines that turned two four-bladed propellers of 14 ft 1 in diameter. This giant aircraft had a wingspan of 138 ft 5½ in, a fuselage length of 76 ft 1 in, and a height of 22 ft 3½ in. Machine gun positions were built into the upper wings, directly above the engine nacelles. These, together with one ventral, two forward and two dorsal machine gun positions, made it one of the most heavily protected aircraft in the world. The aircraft was involved in a number of bombing missions on the Eastern Front and survived the war only to be broken up in 1919.
The Staaken R.V followed soon after the first test flight of the R.IV. The main difference between the two aircraft was that the outboard engines were reversed, with the result that all the engines were tractors, turning four-bladed propellers. Solving the technical problems that were thrown up by the new positioning of the engines, but eventually the aircraft was assigned to RFa 501 at Ghent and during its eight-month career flew sixteen combat missions. It crashed in October 1918.
The best known of all the German R-planes was the Staaken R.VI. This was the largest aircraft ever to go into production during the First World War and nineteen models were built, including a seaplane version. The first six were built by Zeppelin-Werke Staaken; the remainder were built under licence by Luftschiffbau Schütte-Lanz, Zeeson, Ostdeutsche Alabatroswerke GmbH, Schneidemühl and Automobil & Aviatik AG, Leipzig-Heiterblick. The design was based on the earlier Staaken types, the main difference being that the positioning of the engines was changed to four 260-hp Mercedes D.IVa push-pull engines in tandem, installed in two nacelles in the wings. It had four radiators, two at the front and two at the rear, the rear radiators being mounted slightly higher than those in the front.
Eighteen of the aircraft were built; eleven were destroyed during the war, the remainder fought throughout the last part of the war. A couple of the aircraft were even used commercially after the war.
The Staaken R.VII was similar to the R.IV inasmuch as unlike the R.VI, two of the engines powering a four-bladed tractor propeller were mounted in the nose; the remaining four engines powered two four-bladed pusher propellers. The undercarriage was relatively short and consisted of two sets of four wheels on each side with a two-wheeled nose section.
After tests the aircraft was accepted by Idflieg and assigned to RFa 500 on 14 August 1917. On its way to the front, the aircraft stopped at the airfield of Flieger Ersatabteilung in Halberstadt for emergency repairs. With the repairs completed, the aircraft took off on 19 August 1917 and headed for the front. As the aircraft rose in the air it became obvious that something was not right. The aircraft was at around 70 metres from the ground when the starboard wing dropped and the aircraft was forced into a tight turn. As the R.VII 14/15 reached a wooded hill at the end of the field, the starboard wing lurched downwards suddenly and hooked into one of the trees. The aircraft somersaulted into a rocky ravine on the other side of the hill. Only three of the nine crew-members survived and they were all badly burned.
Claude Dornier’s attention was drawn to the development of a two-seat reconnaissance aircraft, the Zeppelin-Lindau C.I. The fuselage was of an all-metal construction covered in a sheet-metal skin; the wings, however, although constructed of aluminium, were covered in fabric. Powered by a 160-hp Mercedes D.III engine, which gave the aircraft a top speed of 93 mph, the C.I had a wingspan of 34 ft 5½ in, a fuselage length of 24 ft 4 in and a height of 9 ft. It was armed with a forward-firing, fixed, Spandau machine gun and a manually operated Parabellum machine gun. Tested by Idflieg, it failed to meet the requirements and was scrapped. The C.II was almost identical and only differed in the type of radiator used. Only a small number were built.
Another two-seater was constructed by the Zeppelin-Werke at the airship factory at Friedrichshafen. This model was designed by Paul Jarray, and was an entirely wooden machine, covered in doped fabric. The Zeppelin C.I and C.II were almost identical, with the exception of the tail surfaces on the C.II being removed and the tail frame being made of metal.
Powered by 240-hp Maybach Mb.IV engines which gave the aircraft a top speed of 125 mph, they had a wingspan of 39 ft 4½ in, a fuselage length of 26 ft and a height of 11 ft 9 in. Six C.Is and twenty C.IIs were built, none of which saw action. At the end of the war they were sold to the Swiss Air Force, who flew them until 1928.
Work was still continuing on the giant seaplanes, and the Rs.III, which arrived in October 1917, was a monoplane powered by four 245-hp Maybach Mb.IVa engines that gave the aircraft a top speed of 84 mph. It had a wingspan of 121 ft 8 in, a fuselage length of 74 ft 7½ in and a height of 26 ft 11 in. The tail booms that were so prominent in the Rs.II model were removed and were replaced by a fuselage made of steel longerons and alloy frames. The metal fuselage, with its biplane tail, was covered in fabric and mounted on top of the wing. The Rs.III had a short, wide hull that supported the two nacelles that contained the four tandem-mounted engines.
The first flight took place at Friedrichshafen on 21 October 1917 and was so successful that the aircraft was taken to Norderney, a flight of some seven hours. It underwent a series of tests but the Armistice occurred before it could be put into service. The last of the giant flying boats, the Zeppelin-Lindau Rs.IV, made its maiden flight in October 1918. The fuselage had a metal skin and a much-simplified cruciform tail section. It, like the previous model, was powered by four 245-hp Maybach Mb.IV engines which gave the aircraft a top speed of 90 mph.
The Rs.IV had one test flight and was then dismantled. Claude Dornier, who had been spearheading this programme, was able to use a great deal of the information he had gained from the test flights of these giant aircraft and incorporate them into the successful commercial flying boats he created after the war.
One of the most successful of all the Staaken giant bombers was the R.XIV. Three of the models were built: the R.XIV 43/17, 44/17 and 45/17. Four 12-cylinder, 350-hp Austro-Daimler engines initially powered the 43/17, but they proved to be too unreliable. These were replaced by four 300-hp Basse & Selve BuS.IVa, which also proved to be unreliable, so they were replaced by five 245-hp high-compression Maybach Mb.IVa engines. The reason for the sudden switch from four to five engines was that the increased weight of 2,000 kg required additional power. All three aircraft were ready by the early part of 1918.
Each of the aircraft was armed with six machine guns, two in the dorsal and ventral positions and one each in the engine nacelle positions. The cockpit was of the open type, while the bomb-aimer/observer/navigator’s position was in an enclosed cabin situated in the nose.
At beginning of December 1917, the German Navy ordered two Staaken seaplanes. They bore a strong resemblance to the Staaken R.XIV inasmuch as the cockpit area was completely enclosed for both the pilots and the navigator/observer. There were noticeable differences; the fuselage was raised five feet above the lower wing, which in turn raised the tail as well. The reason for this was to protect both the fuselage and tail from spray and rough seas while landing and taking off. The two models, numbered Type 8301 and 8303, carried a crew of five and were armed as the R.XIV with the addition of two 20 mm Becker cannons in the rear position. Powered by four 260-hp Mercedes D.IVa engines, the 8301 and 8303 had a maximum speed of 80 mph, a wingspan of 138 ft 5½ in, a fuselage length of 68 ft 10½ in and a height of 22 ft 3½ in. Neither aircraft ever saw active service.
An improved version of the R.XIV, the R.XIVa, appeared in the middle of 1918 and was the last of the R-planes to be built by Staaken. Four of the aircraft were ordered by Idflieg and given the designation R.69 to R.72. Only the first three were completed and were too late to see any active service. All three aircraft were used by the German Army to fly cargoes up to the end of the war, and afterwards by the Inter-Allied Control Commission.
Also in February 1918, there appeared another version of the Staaken R.VI, the Staaken L Seaplane. The undercarriage was replaced with 39 ft 4½ in duraluminium floats and slightly larger ailerons. During the last of the test flights (carried out by Leutnant Haller) the engines failed while flying over land, and the aircraft crashed, killing all the crew. However, earlier results had convinced the Navy that the aircraft had a great deal going for it, so the Navy placed an initial order for two, followed later by a further four Staaken R-seaplanes based on the design and construction of the Staaken L.
An experimental two-seater seaplane fighter was built in May 1918, the Zeppelin-Lindau CS.I. The aircraft was of an almost all-metal construction with the exception of the wings and tail surfaces, which were covered in doped fabric, and was powered by a V-8 195-hp Benz Bz.IIIb engine which gave the aircraft a top speed of 93 mph. It had a wingspan of 43 ft 3 in and a fuselage length of 36 ft. It was armed with one fixed, forward-firing Spandau machine gun and a manually operated Parabellum machine gun. Only one was built.
The specifications of the Staaken giant bombers only differed in the variety of engines used and some minor modifications. Their contribution to the bomber aspect of the First World War was modest to say the least, and although they had made some impact it was not as great as the German Army had hoped. Nevertheless, they opened a new page in the annals of aviation history.
