O.Thetford, P.Gray German Aircraft of the First World War (Putnam)

Rumpler 4A 15
   This first Rumpler Grossflugzeuge appeared in March 1915 and became the prototype for the later G I. The machine made a test climb, carrying ten personnel, to an altitude of 3,200 m. on 15th March 1915, and later the same day attained a height of 1,800 m. while carrying sixteen personnel. On 17th April 1915 this prototype was destroyed. Engines, two 150 h.p. Benz Bz III. Span, 18.75 m. (61 ft. 6 1/4 in.). Length, 11.8 m. (38 ft. 8 5/8 in.).


Rumpler G I (5A 15)
   The Rumpler G I went into small-scale production in 1915 after the tail surfaces had been revised. It was of conventional wood and fabric construction, and a crew of three was carried. The twin engines, which drove pusher airscrews, were neatly encased with fairings extending right down to the lower wing. Car-type radiators were mounted on the forward end of the engine nacelles. Engines, two 160 h.p. Mercedes or 150 h.p. Benz. Span, 19.28 m. (63 ft. 3 1/8 in.). Length, 11.8 m. (38 ft. 8 5/8 in.). Height, 4.0 m. (13 ft. 1 1/2 in.). Area, 78.68 sq.m. (850 sq.ft.). Weights: Empty, 1,998 kg. (4,396 lb.). Loaded, 2,938 kg. (6,574 lb.). Speed, 145 km.hr. (90.625 m.p.h.). Climb, 800 m. (2,624 ft.) in 7 min., 4,000 m. (13,120 ft.) in 2 hr. Duration, ca. 4 hr. Armament, one Parabellum machine-gun in nose cockpit.


Rumpler G II (5A 16)
   This machine differed little from the G I and, as far as can be ascertained, was virtually the same aircraft fitted with more powerful 220 h.p. Benz Bz IV engines. Armament, one Parabellum machine-gun in nose cockpit and one aft of wings.


Rumpler G III (6G 2)
   Final development of the Rumpler twin-engined bombers, the G III followed the previous trend, but now had the engine nacelles considerably cleaned up and mounted well clear of the lower wing. Lateral control was improved by the introduction of horn-balanced ailerons. Engines, two 260 h.p. Mercedes D IVa. Span, 19.30 m. (63 ft. 3 7/8 in.). Length, 1200 m. (39 ft. 4 1/2 in.). Height, 4.50 m. (14 ft. 9 1/4 in.). Weights: Empty, 2,295 kg. (5,049 lb.). Loaded, 3,620 kg. (7,964 lb.).

А.Александров, Г.Петров Крылатые пленники России

Серийных двухмоторных бомбардировщиков в России тоже не существовало, тогда как германские аппараты класса Г в нашем небе летали. В ноябре 1916 г. над Браиловым (Румыния) опытный летчик георгиевский кавалер сотник Ф. Г. Зверев, возглавлявший 4-й авиационный отряд истребителей, сумел сбить большой двухдвигательный "Румплер". Всего лишь одна пуля попала в его правый мотор и разворотила картер, решив дело: аэроплан с номером 7 на фюзеляже (83, а и б) спустился в 15 км от города и попал в плен. "Ньюпор" Зверева пострадал больше, получив 37 пробоин, включая дыру в маслобаке, потеряв винт... Даже шлем летчика был пробит, да и не мудрено: подступиться к вооруженному 2 подвижными пулеметами "Парабеллум" бомбардировщику оказалось нелегко. Один стрелок находился в носу, а другой - в кабине, за коробкой крыльев, откуда мог вести огонь даже вниз, через специальную открывавшуюся амбразуру. Судя по этому описанию, жертвой Зверева стал "Румплер Г. II" - аппарат с двумя 220-сильными толкающими "Бенцами" в двух гондолах, размещенных в бипланной коробке крыльев. Модель создавалась в 1916 г. как развитие предыдущей, выпускавшейся в 1915 г. и несшей "Мерседесы" 160 л. с. или "Бенцы" 150 л. с. Пятьдесят восемь "Г-первых" были на фронте с середины 1915 по август 1916 гг.; 10 "Г-вторых" находились в боевых частях к октябрю 1916 г. (всего построено 72 аппарата). В 1917 г. на смену этим моделям пришла третья, с двумя "Мерседесами" в 260 "лошадей" каждый, и в общей сложности карьера данной конструкции длилась до августа 1918 г. Бомбовозы "Румплер" оказались вполне удачными машинами, хотя им не удалось испытать славы их "собратьев" от компаний "Гота" и "Фридрихсхафен".

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

Rumpler Bombers

   Rumpler produced a comparatively small number of bomber designs that saw modest production in keeping with their performance. In addition to at least three prototypes, 58 Rumpler production bombers of all types were built as detailed in the adjacent table.
   With limited engineering resources, Rumpler eventually abandoned bomber design in favor of more critical fighters and reconnaissance airplanes.

Rumpler Bomber Production
Type Quantity Serials
G.I 4 15-18/15
G.II 24 106-117/15 &. 119-130/15
G.III 30 300-329/16. See Note.
Note: Idflieg ordered 50 Rumpler G.III bombers but only 30 were built.


Rumpler 4A15

   In July 1914 Rumpler was among several manufacturers asked to develop a Kampfflugzeuge, a battleplane or aerial cruiser. The aircraft was to have a crew of two or three with a flexible gun for the observer/gunner mounted in the front cockpit, and was to have at least 200 hp.
   Rumpler's response was the 4A15, a twin-engine biplane of conventional wood, wire, and fabric construction powered by 150 hp Benz Bz.III engines mounted in pusher configuration. Each engine was mounted on the lower wing and enclosed in a nacelle housing a frontal Windhoff radiator and a 310 liter fuel tank. A gravity tank was installed above each engine. The 4A15 had a span of 18.75 m and a length of 11.8 m. The simple landing gear included a pair of wheels under each engine and another pair under the nose to prevent nose-overs on landing.
   The 4A15 first flew in March 1915 and achieved a maximum speed of 135 km/h at sea level. During informal flight demonstrations the aircraft carried ten people to 3,200 m on March 15th and then carried 16 people to 1,800 m. On 22 March the aircraft reached 2,300 m in 55 minutes while carrying 12 people. However, while flying to Munich on April 10 the 4A15 was forced to make an emergency landing and was damaged. On April 17, 1915 it was destroyed following a carburetor fire. However, during its brief life the 4A15 set the basic configuration for all Rumpler bombers that followed.


Rumpler G.I
  
   Rumpler continued bomber development with the 5A15. Based on the 4A15, the 5A15 used the same basic structure and engines but had a number of refinements. The wing span was increased slightly, the shape of the vertical tail surfaces was revised, and a single gravity tank under the top wing replaced the two separate gravity tanks over the engines. The gunner in the front cockpit was given a windshield and the rear crew member now had a flexible gun.
   The 5A15 first flew on September 4, 1915 and demonstrated acceptable performance, although flight testing revealed a number of improvements were needed. The test pilot, probably Friedrich Budig, then chief test pilot at Rumpler, complained that the fuel system was too complicated and the gravity tank was the sole feed to the carburetors, creating a single point of failure. The aircraft was also too tail heavy and the pusher propellers were subject to damage from debris thrown up by the landing gear. Inadequate clearance (4 cm) between the fuselage and the propeller arc sometimes caused the propellers to hit the screen protecting the rear gunner from the propeller arc.
   The 5A15 passed its acceptance flight on September 16, 1915, and Idflieg ordered it into limited production as the Rumpler G.I, only four aircraft being built. Photographs show the production aircraft had an enlarged rudder for better directional control after an engine failure. The very small number ordered indicates that the aircraft were primarily intended for operational evaluation. One aircraft, G.16/15, was delivered to Kampgeschwader der Obersten Heeresleitung 1 (Kagohl 1) for operational evaluation, where it was flown for a time by Leutnant Ray, while two others, G.17/15 and G.18/15, served briefly that year with Brieftauben Abteilung Metz, or BAM.

Rumpler G.l Specifications
Engines: 2 x 150 hp Benz Bz.III
Wing: Span 19.3 m
Area 78.68 m
General: Length 11.8 m
Height 4.0 m
Empty Weight 1,998 kg
Loaded Weight 2,938 kg
Maximum Speed: 145 kmh
Climb: 800m 7 min
2000m 21 min
4000m 120 min
Service Ceiling: 4000 m
Range: 600 km
Armament: 1 flexible MG & 150-200 kg of bombs


Rumpler G.II

   In November 1915 Idflieg ordered 24 improved aircraft as the Rumpler G.II. The most important change was the use of more powerful, 220 hp Benz Bz.IV engines for improved speed, climb, and ceiling. The G.I airframe was used with minor modifications, but flight testing soon revealed the need for additional modifications for improved flying qualities. The prototype G.II, Rumpler internal designation 5A16, was tail heavy and insufficiently stable. Testing revealed the need for larger propellers to efficiently absorb the greater engine power, so propellers of 3.1 m diameter were fitted and the fuselage was narrowed slightly to provide sufficient clearance.
   Rumpler chief test pilot Friedrich Budig determined that modifications to the lower wing near the propellers were needed, and on May 27, 1916 large cut-outs were made in the lower wing in front of the propellers on the second production aircraft. This modification greatly reduced tail heaviness as determined by Budig during a successful test flight on May 30.
   Rumpler G.II 117/15, the last aircraft of the first production series, was fitted with more powerful 260 hp Mercedes D.IVa engines and larger propellers of 3.17 m diameter. Idflieg accepted this modified aircraft and it went on to serve with Kagohl 2 on the Eastern Front in the summer of 1916. No other G.II aircraft used this engine, but it was a harbinger of things to come in the Rumpler G.III.
   The Rumpler G.II saw much of its service with Kagohl 2. Originally formed from the Brieftauben Abteilung Metz, or BAM, in December 1915, Kagohl 2 had six Kampfstaffeln, Kastas 7-12. Five of these had single-engine C-type aircraft, but one was equipped with the Rumpler G.II and AEG G.III. Kagohl 2 was transferred to the Eastern Front in July 1916 and was eventually stationed at Lasnaja aerodrome. Kagohl 1, originally formed from the Brieftaubenabteilung Ostend, or BAO,was also transferred to the Eastern Front in June 1916, and had some Rumpler G.II aircraft along with other G-types. In September 1916 Kagohl 1 was transferred to northern Bulgaria where it flew a number of bombing missions against Romanian troops. Kagohl 2 was transferred back to the Western Front in October 1916, followed by Kagohl 1 in May 1917.
   The Rumpler G.II bombers were better armed than the C-types and on the Eastern Front were used as long-range reconnaissance aircraft and as escorts for the smaller C-types on bombing raids.

Rumpler G.II Specifications
Engines: 2 x 220 hp Benz Bz.IV
Wing: Span 19.3 m
General: Length 11.8 m
Height 4.0 m
Empty Weight 1,990 kg
Loaded Weight 2,990 kg
Maximum Speed: 164 kmh
Armament: 2 flexible MGs & bombs

  
Rumpler G.III

   The Rumpler G.II had proven itself moderately successful and Idflieg placed an order for the proposed Rumpler G.III in September 1916. Retaining the basic size and configuration of the earlier G.II, the G.III was a new design. Although wingspan was the same as the earlier types, wing area was reduced by a smaller lower wing. The engine nacelles were more streamlined and more powerful 260 hp Mercedes D.IVa engines were fitted in place of the 220 hp Benz engines of the G.II. To reduce the danger of fire the fuel tanks were now mounted in the fuselage instead of in the nacelles. Unfortunately, the weight of the new aircraft increased substantially due to increases in the empty weight and also the designed payload.
   Flight testing of the new prototype, factory designation 6G2, began in December 1916 and quickly revealed unsafe flying qualities. Like the earlier designs, the G.III prototype was tail heavy in flight. To solve this problem the horizontal stabilizer was raised and the fuselage near the plane of the propellers was modified to improve airflow, and these changes greatly alleviated the tail-heaviness. Test pilot Friedrich Budig stated the revised G.III was more stable and had better flying qualities than the G.II. However, adding the rear gunner's gun and ammunition again caused tail-heaviness, and the upper wings had to be moved rearward to restore pitch stability and trim.
   The G.III that arrived at the front in December 1916 was the aircraft assigned to Kagohl 2, which had used the earlier G.II. Some G.III bombers served into at least March 1918 with Kampfstaffel 9 of Kagohl 2.
   The final Rumpler bomber prototype, factory designation 6G4, had increased wing span and tractor-mounted 4-bladed propellers. The first test flight on 18 February 1918 indicated marginal flight characteristics when the aircraft swung to the right on takeoff and the pilot, Budig, was barely able to correct it. With extensive modifications necessary to improve its poor flying qualities and higher priority programs underway, further bomber development was abandoned.

Rumpler G.III Specifications
Engines: 2 x 260 hp Mercedes D.IVa
Wing: Span 19.3 m
Area 78.68 m2
General: Length 12.0 m
Height 4.5 m
Empty Weight 2,365 kg
Loaded Weight 3,620 kg
Maximum Speed: 150 kmh
Climb: 3000m 22 min
Service Ceiling: 5000 m
Range: 660 km
Armament: 2 flexible MGs St 225 kg of bombs