M.Schmeelke Zeppelin-Lindau Aircraft of WW1 (A Centennial Perspective on Great War Airplanes 42)

Zeppelin-Werke-Lindau GS.I

  In mid-1917, the RMA asked ZWL for a design of a two-engine armed reconnaissance aircraft, called a G-type. Marinebaurat Schmedding arrived in Reutin in the fall of 1917 to discuss this project personally with Claude Dornier. Dornier later wrote:
  “[...] I received a visit from Marinebaurat Schmedding, with whom I discussed the Navy’s demands for the boat to be designed, and the fulfillment of the same. On my drawing board I had an early draft with all of the components of the later “Wal”. I had covered this with a piece of paper because I thought it was too early to subject it to governmental criticism. In the course of the discussion, Mr. Schmedding approached my drawing board and took away the piece of paper that I had affixed to protect my project. What could I do? Mr. Schmedding did not hold back on his criticism. He had nothing positive to say about it and strongly suggested I stop working on it. He especially hated the way the engine and the sponsons were placed. He wanted them replaced with the side floats. [...] I apparently defended my draft so well that the official criticism was so shaken, so that we agreed to take my revolutionary design to underlie the offer. It led to the order of three boats which would be designated “Gs.l” [...]”
  This unusual and modern design (for 1917) had nothing to do with the common G-type versions from Gotha or Friedrichshafen. Therefore, this modern flying boat was received with everything from open criticism to complete rejection by the very conservative-thinking leaders of the RMA. In the end, though, Dornier's ingenious design won over the RMA, and in early 1918 it placed an order for three Gs.I large flying boats (sea). They were designated navy numbers 8805-8807.
  In the waters of the North and Baltic Seas, the threat of enemy submarines was rising. The Rs- and G-types were designed to recognize and fight these U-Boats. The lighter G-aircraft were surely at an advantage due to their manoeverability in direct combat. In addition to the standard armament of the G-aircraft, with MG and light bombs, it also would carry a 2-cm Becker-gun. An effective strategy against the U-boats, meaning sinking them, could not be achieved with the MG 7.9-millimeter caliber guns alone. This was drastically proven when on July 8th, 1918, Hansa Brandenburg W12s and W29s stationed at the base in Zeebrugge, attacked the British submarines C25 and E51 in the English Channel. Although the W29s shot 5,000 rounds of ammunition and threw numerous 5-kilogram bombs, neither of the submarines was sunk. C25 was damaged, but was able to return safely to an English harbor.
  In December 1916, the first tests with the fixed-mounted 2-centimeter Becker gun began at the SVK in Warnemunde. These tests, using a Gotha WD7, Naval number 676, were successfully completed in November 1917. Tests with a 3.7 centimeter aircraft gun from the Deutsche-Waffen- und Munitionsfabriken on a Gotha WD7, however, were not as positive. Often, the munitions feed failed, so that the project was ended on October 17th, 1917.
  The head of the material and structural calculation department Ernst Rothenburg was responsible for the initial drafts of the Gs.I in 1917. After he moved to the Hansa-Brandenburg Werke, where he took charge of the development of metal fuselages as chief engineer, Lindau engineer Richard Vogt continued the work.
  Construction commenced on the first Gs airplane, designated navy number 8805, as soon as the orders were placed. It was also customary that the RMA submitted a down payment along with the order. Based upon Vogt's drawings, blueprints for the completion of parts were prepared. All of the critical parts would be made of steel. To build the 15.3 meter-long and 2.5 meter-wide hull, as well as the non-critical parts of the wings, duraluminum would be used. The wingspan would be 21 meters. As in the Rs.IV, sponsons would also be used. Two Maybach Mb IVa engines in a tandem configuration would power the craft. The radiator for the front engine was conceived as a front closure for the entire engine system. For the back engine, the radiator was set upon the nacelle. The central placement of the engines had many advantages. If one failed, there would be no yaw moment to either the port or starboard sides. As a result, the vertical stabilizer could be kept relatively small because it only served for directional stability. This gave the Gs.I a great advantage in that it was very maneuverable, far better than all of the other G-types in the navy. The engine mechanic's spot was in the hull directly under the nacelle. The four fuel tanks, made by Luftschiffbau-Zeppelin, each held 215 liters and could easily be reached by the mechanic. Two oil tanks made of brass sheets held 35 liters each and they were placed in the nacelle.
  The square rudder was, like the wings, double-sparred and covered in fabric.
  The vertical and horizontal fins were balanced. The trimmable horizontal stabilizer was a conventional tail attached to the vertical stabilizer and supported by a spar on the fuselage. The trim was carried out through the rear spar and displayed visually for the pilot.
  In the late summer of 1918, the construction of the Gs.I was further delayed. In addition to the lack of materials, the end of the war created unrest amongst the employees. Heinrich Triller wrote:
  “[...] We were instructed to take over 200 soldier-prisoners from Munich to support our skilled workers in Lindau. These people did not have a productive time and therefore the completion of the parts was slow. Instead of a help, these people hindered our manufacturing process and also soiled our good employees with their radical thoughts. Deliveries of dural, steel, and further materials were delayed, sometimes for months. Under normal circumstances, our flying boat would have been ready to fly by the end of the summer 1918, since the Rs.II, an R-craft, at the time took just four months go from design to the water [...]”
  Construction of the flying boat continued in Reutin after the war ended in November 1918. When the facility in Lindau closed, Triller took all Gs.I parts by ship to Seemoos, where the aircraft was completed. It was here that it also received the cabin structure for passenger operations at the front of the hull. After the Treaty of Versailles was signed, and all military aircraft construction was banned, Claude Dornier wanted to launch the Gs.I as a civilian aircraft. But time was racing. The ban took effect on January 10th, 1920, and the Gs.I had to find neutral customers outside of the country by that date. Eventually, the ban would be extended to the civilian sector, and lasted until 1926.
  On July 31st, 1919, the Gs.I took off on its maiden flight, with naval aviator Weiss at the controls. Shortly thereafter, potential customers from Switzerland showed significant interest - Dornier's friendly contacts to the neighbor to the south surely helped. In August and September, 1919, Swiss Flight Lieutenant Ernst Frick tested the Gs.I several times in Seemoos. Frick was an experienced pilot, who had received his license in Johannisthal before the First World War. He spent the war years in Germany, working as a flight instructor and test pilot, and joined the Swiss Fliegertruppe (Air Force) after the end of the conflict. On September 20th, 1919, he founded the Gesellschaft Frick et Cie, Zurich. He offered sightseeing flights and flight displays. On October 2nd 1919, the Gs.I was lent to Frick & Cie and received the Swiss civil aviation identifier CH-8. It is unclear whether Frick used it solely for his own company or if he was a middleman for the "Schweizer Luftverkehrs Gesellschaft Ad Astra" ("Swiss aviation corporation Ad Astra"). According to a newspaper article in "Het Vliegveld" in December 1919, the company Ad Astra advertised the Gs.I for the route: Geneva - Lausanne - Zurich - Romanshorn - Friedrichshafen, with a connection to the airship "Bodensee" and further travel to Munich - Berlin - Stockholm.
  The Gs.I (CH-8) was extensively tested in Switzerland for seven weeks, from October 17th until December 9th. During this time, the flying boat was never stored in a hangar, but rather between the flights it was moored on various Swiss lakes. Despite terrible weather with snow, rain, and storms, only the engines and the cockpit openings were covered with tarps. Maintenance was also kept to a minimum. Still, Gs.I remained operational throughout. Also, the inside of the hull remained mostly dry, as the Swiss test reports pointed out.
  On December 10th, the Gs.I began a journey to Holland, designed to be a roadshow, now once again with a crew comprising ZWL employees. The aircraft still carried the Swiss designation. The crew stopped over in Norderney. It was there that Pilot Lesch received the first word that the allied forces were looking for Gs.I.
  At the naval air base something happened that put the stable construction of the flying boat to the test. Heinrich Triller wrote:
  “[...] At low tide, a strong gust of wind lifted the solidly anchored boat, raised it several meters in the air, and tossed it about 30 meters onto the beach without it sustaining any damage at all. This is proof that the aircraft is robust and stable [...]”
  In the Dutch town of Schellingwoude near Amsterdam, Gs.I was scrutinized and then flown by civilian and military observers. It was here that the crew learned that the Naval Interallied Commission of Control (NIACC) was searching for the Gs.I. The planned continuation of the flight to Sweden was cut short in Kiel-Holtenau, in order to await instructions from Seemoos. A NIACC delegation had inspected the facilities in Lindau Reutin and Seemoos, and they took particular interest in the Gs.I. Therefore, company leadership decided to destroy the Gs.I, so that they would not have to deliver her to the victorious powers. The operations manager Schulte-Frohlinde wrote a telegram to the crew Karl Lesch and Adolf Marquard on April 24th, instructing them to dismantle the engines and the instruments. Following that, they were to prepare to secretly sink the boat. They were in danger not only from the Commission officers but also the members of the soldiers' councils, members of which were still at the naval bases and in the barracks. Karl Lesch wrote in the aircraft's logbook:
  “[...] During the night of April 24th to 25th the front engine was disassembled and the airplane was prepared to be brought into the water. There was no one at the base that night. At about 5am a French warship dropped anchor near the base. We called to see which ships would be sent through the locks. Among those scheduled to pass was also the French ship. So, we had nothing to worry about and waited to open the hangar doors until after it had left. At 7 in the morning, with the help of some people we had told that the craft would be towed to Warnemunde, we brought it into the water. In the Kiel Bay there was light fog and rain. In addition, a relatively strong southwest wind. The weather allowed Marquard and I to tow the boat alone. I had to inform the duty officer and three duty NCOs of our plans. To tow the craft, we took the steam-powered pinnace. We first left the Kiel Bay completely. As we departed, the harbor police showed some interest. However, they let us pass when we told them that we were going to do some testing and would soon return. During the tow we prepared the aircraft for sinking. We destroyed all of the bulkhead walls. We cut through all of the lower sides of the fabric covering the wings once we were fairly far out of the bay. We had cut open the upper sides in the hangar already. Outside of the bay we experienced sea swells of 3-4. When we reached the Kiel I buoy, we turned from the channel toward the northwest. The water here had a depth of 18 meters. We turned the boat into the wind and the pinnace led the way. This is where the real work began. Three men, each armed with an ax, were also on board. They wrecked as much as they could in each section of the boat. The fuel tanks were also made unusable. The floats, which we opened, were the last pieces to be destroyed. After we did this, the boat was already sinking. We made sure that everything was filling with water, and left the boat. [...] At first the boat sank lengthwise, but after the fuselage filled with water, the tail sank faster than the bow. The aircraft disappeared at a 45 degree angle to the rear.
  The construction of flying boats in Germany ended with the loss of Gs.I. Officially, the Gs.I was lost during towing testing outside of the Kaiser-Wilhelm Canal. The successor model, Gs.II, had to be scrapped in 1921 when it was only partially completed because NIACC had categorized it as a military aircraft. Claude Dornier had, in the meantime, rented production facilities in Marine di Pisa. Here, another Gs.I keel, which had all of the characteristics of the later Dornier Wal, was laid. The Wal, which was built in several versions, would become Dornier's most successful aircraft.



Specifications of Zeppelin-Lindau Aircraft

Type Length, m Span, m Height, m Chord, m Propeller Manufact. Armament
(guns) Weight, kg Motor Crew
Gs.I 15.28 21.00 4.7 4.30 Garuda 3.00 2 flex or 1 Becker 2 cm 3,000 Maybach Mb IVa 260 hp 3



Military Numbers of Dornier-ZWL Aircraft
Military Designation Manufact. Type Class Engine Notes
M.N.8805 ZWL (Do) Gs.I G Mb IVa Flying boat, completed
M.N.8806 ZWL (Do) Gs.I G Mb IVa
M.N.8807 ZWL (Do) Gs.I G Mb IVa