J.Herris Rumpler Aircraft of WWI (A Centennial Perspective on Great War Airplanes 11)

Rumpler Taubes

   On July 21 1910, Edmund Rumpler obtained an exclusive, five-year manufacturing license for Taube aircraft from Austrian inventor Igo Etrich. After a series of flight demonstrations, on Oct. 30, 1910, the Prussian army ordered five Taubes from Rumpler. However, the German patent office invalided Etrich's Taube patent in September 1911 and the Taube design became public domain. Immediately, many German companies started building aircraft to the Taube configuration due to its inherent stability and safety. Understandably, Rumpler then refused to honor the license agreement or pay license fees. Rumpler continued to build Taubes that were essentially the same as the Etrich design, and so Etrich successfully sued Rumpler. However, the amount of the damages awarded was small compared to the amount Rumpler was making from selling aircraft to the Fliegertruppe. The military was keen on the Taube due to its inherent stability and safety, a key advantage in these early days of aviation. As a result, the army purchased a wide variety of Taubes from different manufacturers, with the greatest number being purchased from Rumpler.
   The Taube’s limitations gradually became evident, and few were purchased after 1914, when the configuration was clearly obsolete. The Taube had high drag, so speed, climb, and ceiling were limited. And in combat, its inherent stability became a problem,- it was simply too stable and difficult to maneuver to dodge anti-aircraft fire or elude an attacking aircraft. Fortunately, there were few attacking aircraft during the war's early months.
   On September 4, 1913, a Rumpler Taube lost a wing during the annual army maneuvers and the two airmen were killed. This caused the German military authorities to perform their first serious structural tests on aircraft, with the result that the Rumpler Taube’s safety factor was found to be 3.42 at best. To express it differently, the Rumpler Taube could withstand a G-loading of 3.42 G's before its structure failed. To put that in perspective, a normal category light aircraft in the USA must sustain a load factor of 3.8 without damage, and 150% of that stress, or a load factor of 5.7 Gs, before structural failure occurs. To be certified as an acrobatic aircraft, the load factors would be 6.0 Gs without damage and 9.0 Gs before structural failure. To return to the Rumpler Taube, one aircraft (A.28/12) tested had a safety factor of 3.42, but another, A.46/13, had a safety factor of only 2.89! This was not strong enough to be safe for routine flight let alone the stress of combat missions.
   Recognizing the Taube configuration was obsolete, the army started purchasing biplanes before the war started and disposed of 55 older, worn out Taubes the end of June 1914, just before the war. Although the army had to purchase additional Taubes early in the war to make up losses, the Taube’s days were clearly over. Interestingly, Rumpler Taubes did not last long at the front after hostilities started; the Gotha Taubes were more robust and better able to withstand the rigors of operational service.

Rumpler Taubes Purchased by the Fliegertruppe (Prussian Army)
Year Quantity
1911 10
1912 48
1913 73
1914 3

M.Dusing German Aviation Industry in WWI. Volume 2 (A Centennial Perspective on Great War Airplanes 85)

Rumpler-Werke A.G. in Berlin-Johannisthal (Ru)

  In 1908, a small office and workshop were set up in Berlin on Gitschiner Strasse, where design parts for automobiles and aircraft were built; it was later moved to Reinickendorfer Strasse. In this office, among other things, the basic principles for the aircraft engine Aeolus were developed.
  Rumpler-Werke is the oldest aircraft factory in Germany after Euler-Werke. The first German aircraft factory had been founded a month earlier in October 1908 by August Euler in Frankfurt am Main.
  On November 24,1908, the "B.Z. am Mittag" published the following announcement:
  "Engineer Edmund Rumpler, Berlin SW, Gitschiner Strasse 5, has incorporated an aircraft construction institute (Luftfahrzeugbauanstalt) into his technical office. The company does not intend to manufacture specific types of aircraft, but rather to implement promising ideas in an appropriate manner at moderate prices. Small aircraft models are also to be manufactured there." Thus the company "Edmund Rumpler, Luftfahrzeugbau" was born. At first it was only a small department, which was attached to the already existing engineering office.
  Thus, in the founding period of the company, the main focus was initially on the advisory and expert evaluation of the countless existing ideas and conceptions in aircraft construction. The business idea led quite quickly to success. Engineer Rumpler, who had previously worked in automotive engineering at Daimler and Adler, where he designed the Adler engine and the Adler motor car, quickly made a respected name for himself.
  In 1909, particularly as a result of the heavy workload in the aircraft department, E. Rumpler saw fit to transform the company into a "Rumpler-Luftfahrzeugbau GmbH" with 90,000 Marks in capital and at the same time to move the factory to Lichtenberg. Gradually, the capital was increased to 700,000 Marks.
  In 1910, Rumpler rented a hangar in Johannisthal on the northern border of the airfield to have the opportunity to test flying machines on the airfield.
  In July 1915, Rumpler-Werke was renamed "Rumpler-Werke GmbH". After the GmbH was dissolved in September 1917 and registered as "E. Rumpler Luftfahrzeugbau in Liqu.", Rumpler-Werke transformed into a stock corporation (equity capital: 3.5 million Marks) as of January 1, 1918.


Aircraft Development:

  The origin of the Rumpler-Taube, whose construction period fell between October 1910 and December 1912, can be traced back to the research work of the Hamburg professor Ahlborn. Ahlborn pointed out to Rumpler that the Austrians Weis, Hiner and Etrich were already working on an aircraft project whose wings were being manufactured on the basis of his information concerning the stabilizing properties of the Zanonia seed. Shortly after, Rumpler-Werke signed a license agreement with Etrich. Shortly thereafter, however, it became apparent that, despite the correct basic principle, improvements were needed in many areas. As a result, various "Tauben" were built, powered by 50-70 and 100 hp Gnome, 70, 100 and 120 hp Argus, 70 and 120 hp Austro-Daimler, 70 and 100 hp Daimler-Mercedes, 80 hp Hiero (Werner and Pfleiderer), 70 hp Dixi (Fahrzeugwerk Eisenach), 50 hp Antoinette, 95 hp NAG as well as 70 hp Daimler with hanging cylinders and 50 hp V8 Rumpler-Aeolus engine.
  Although the company began building seaplanes in 1911, it was not until 1913 that it built the seaplane station at Muggelsee in Berlin-Kopenick.
  The outstanding personality from an aviation point of view in the 2nd decade of the 20th century was Rumpler's chief pilot Hellmuth Hirth.
  With Hirth at the top, Rumplers flight school progressed and became one of the most successful institutions in flight training. Hirth achieved lasting fame by flying from Munich to Berlin in June 1911 on a Rumpler-Taube. In 1912, Hirth was the star of almost every large flight competition and with that became the most successful and renowned aviator from Johannisthal. He changed employers in early 1913 and then became the chief technology officer of the Albatros-Works, also at Johannisthal.
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Jane's All The World Aircraft 1913

RUMPLER. E. Rumpler, Luftfahrzeugbau G.m.b.H., Siegfriedstrasse 202, Berlin-Lichtenberg, also Johannisthal b. Berlin. Established 1909 by E. Rumpler and R. Haessner for the construction in Germany of Etrich (see Austria) Monoplanes. These now vary considerably from the original Etrich. Capacity at present about 200 to 300 machines a year. Standard models are as follows:--

   1912. 1912. 1913.
   Monoplane. "Taube." Hydro.

Length......feet(m.) 29? (9.50) 34 (10.30) 33 (10)
Span........feet(m.) 41? (12.65) 46 (14) 49? (15)
Area...sq. feet(m?.) 247 (23) 336 (32) 387 (36)
Weight,
   total...lbs.(kgs.) 1398 (630) 1190 (540) 1328 (600)
   useful..lbs.(kgs.) 771 (350) 551 (230) 485 (220)
Motor...........h.p. 95 Mercedes 100 Argus 100 Argus
Speed,
   max...m.p.h.(km.) 81 (130) 59 (95) 56 (90)
   min...m.p.h.(km.) ... ... ...
Endurance.......hrs. 6-7 4-6 ...
Number built
   during 1912, 1 60 3

R.Mikesh, A.Shorzoe Japanese Aircraft, 1910-1941 (Putnam)

Isobe Rumpler Taube Aeroplane

   After resigning from the Navy, Onokichi Isobe was one of the principals in the establishment of the lmperial Flying Association formed on 23 April, 1913. The Association sponsored his travel to Germany to receive flying instruction, and to buy two Rumpler Taubes through Mitsui & Co.
   When Japan became involved in the First World War, the Army purchased these two aeroplanes from the Association in October 1914 and sent them with an Army contingent to the Tsingtao campaign and Isobe was engaged by the Army to accompany the two aeroplanes and serve as an instructor. One Taube was damaged when flown by 2-Lt Jiro Takeda while still in Japan during flying training, and the other, to be flown by Isobe, arrived at Tsingtao too late to
participate in the battle.
   Now that the Association was without its aeroplanes, it purchased a 90hp Austro Daimler six-cylinder inline water-cooled engine from Britain for use in a japanese-version of the Rumpler Taube they built in the Imperial Flying Association's hangar at Tokorozawa. Taking charge of design, Isobe made modifications to modernize the structure to some degree. Instead of having the flexible dove-like wings with negative incidence at the wingtips for control, Isobe incorporated hinged-ailerons. The empennage had hinged flying control surfaces instead of the larger flexible bamboo structure of the original Taube. The forward half of the two-seat fuselage structure was made of welded-steel tubing, the rear section having a wooden framework. The sides of the cockpit and part of the wing root where the pilot's position was located were covered with celluloid sheeting to provide a downward view.
   This aeroplane, completed on 5 April, 1915, was commonly called the Kaizo (meaning modified) Rumpler Taube, and used mostly by Isobe and Toriumi in their engineering work with the Association. Later it was used as a trainer by students Yukiteru Ozaki and Takeji Senno. (see Ozaki Aeroplane) On 30 May, 1915, while Isobe was flying solo at Tokorozawa, a gust of wind caused the port wing of the Taube to strike the ground, causing heavy damage to the aircraft. Only the front part of the fuselage and its engine could be salvaged. The parts were stored for a while and later used in the Ozaki Soga-go Aeroplane. Following the loss of its aeroplanes the Imperial Flying Association was soon re-equipped with Type Mo 1913 and Type Mo-4 aircraft through the assistance of the Army.
   One month after his accident with the Kaizo Rumpler Taube, Onokichi Isobe resigned from the Imperial Flying Association and joined the French Army. He entered the Premier Regiment Etranger before being assigned as a pilot with SPA 57. Flying Nieuport 11 Bebes with this unit, (Flight) Lieutenant Isobe was severely wounded on 6 March, 1917, while on patrol. For his service, he was awarded the Legion d'Honneur and Croix de Guerre with citations that described him in part as being ' ... as a foreigner fighting for the cause of France, he showed exemplary military qualities in the Squadron by demonstrating his aggressiveness in combat.' He resigned from the French Army in December 1917 and withdrew from aviation, but became involved again in Japan by establishing the Nippon Glider Club (later Nippon Glider Association) in April 1929 as an active promoter of sailplane activities. He died on 14 February, 1957, at the age of 80.

Журнал Flight

Flight, June 5, 1914.

THE PRINCE HENRY CIRCUIT, 1914.

MACHINES IN PRINCE HENRY CIRCUIT.

The Rumpler Taube is a very compact business-looking machine. The upper wing bracing, it will be seen, is now effected by cables running to a pyramidal pylon of steel tubes, and the Zanonia form of wing has been retained. Instead of the usual flexing wing tips, ailerons are fitted. These, it should be noted, are hinged along an axis forming an angle with the transverse axis of the main planes.


Flight, September 18, 1914.

AIRCRAFT "MADE IN GERMANY"
WHICH MAY BE EMPLOYED AGAINST THE ALLIES.

29. The Rumpler Taube
   differs from other monoplanes of the Taube type only in the shape of its fuselage and in the type of chassis fitted. The fuselage is very deep and narrow, and is fitted with the usual turtle-back, which is, however, considerably higher than is usually found. The chassis consists of two telescopic tubes fitted with coil springs and anchored to the upper longerons of the fuselage. At their lower extremities these telescopic tubes carry the wheel axle, and each of them is kept in place by two steel tubes running forward and backward to the lower longerons of the fuselage. The radiators are mounted on each side of the fuselage below the leading edge of the wings. Openings have been cut out in the inner front portion of the main planes, and through these the passenger obtains a view of the ground below. Wings as well as tail planes are of the usual Taube type. With a 100 h.p. Mercedes engine the speed of this machine is 62 miles per hour.


Flight, October 16, 1914.

AIRCRAFT "MADE IN GERMANY"
WHICH MAY BE EMPLOYED AGAINST THE ALLIES.

16. The Rumpler Taube
   is exactly similar to the Rumpler Taube land machines, with the exception of the chassis. The floats are plain, non-stepped, and placed comparatively close together. They are built up of two layers of mahogany over a framework of ash, and are supported from the fuselage by stout streamline struts.