Semi-rigid airship
Encyclopedia
Airship
An airship or dirigible is a type of aerostat or "lighter-than-air aircraft" that can be steered and propelled through the air using rudders and propellers or other thrust mechanisms...
s with a partial framework. These often consist of a rigid, or occasionally, flexible, keel frame along the long axis under the aerodynamic hull envelope. The partial framework can also be located inside the hull. Semi-rigids were built in quantity from the late 19th century but since the 1930s they fell out of favour until the development of the Zeppelin NT
Zeppelin NT
The Zeppelin NT is a class of airships being manufactured since the 1990s by the German company Zeppelin Luftschifftechnik GmbH in Friedrichshafen. The initial model is the NT07...
Principle
More or less integrally attached to the hull are the gondola, engines and sometimes the empennageEmpennage
The empennage , also known as the tail or tail assembly, of most aircraft gives stability to the aircraft, in a similar way to the feathers on an arrow...
(tail). The framework has the task of distributing the suspension loads of these attachments and the lifting gas
Lifting gas
Because of the Archimedes' principle, a lifting gas is required for aerostats to create buoyancy. Its density is lower than that of air . Only certain lighter than air gases are suitable as lifting gases.- Hot Air :...
loads evenly throughout the whole hull's surface and may also partially relieve stresses on the hull during manoeuvres. In early airships which relied on nets, fabric bands, or complicated systems of rope rigging to unite the lifting envelope with the other parts of the ship, semi-rigid construction was able to achieve improvements in weight, aerodynamic, and structural performance. The boundary between semi-rigid and non-rigid airship
Non-rigid airship
A blimp, or non-rigid airship, is a floating airship without an internal supporting framework or keel. A non-rigid airship differs from a semi-rigid airship and a rigid airship in that it does not have any rigid structure, neither a complete framework nor a partial keel, to help the airbag...
s is vague. Especially with small types, it is unclear whether the structure is merely an extended gondola or a proper structural keel.
As in non-rigid airships, the hull's aerodynamic shape is maintained by an overpressure of the gas inside and light framework at the nose and tail. Changes in volume of the lifting gas is balanced using ballonet
Ballonet
A Ballonet is a air-filled flexible container that is located inside the envelope of a non-rigid or semi-rigid airship. Such an airship can have one or more ballonets, commonly one fore and one aft...
s (air filled bags). Ballonets also may serve to provide pitch control
Flight dynamics
Flight dynamics is the science of air vehicle orientation and control in three dimensions. The three critical flight dynamics parameters are the angles of rotation in three dimensions about the vehicle's center of mass, known as pitch, roll and yaw .Aerospace engineers develop control systems for...
. For small types the lifting gas is sometimes held in the hull itself, while larger types tend to use separate gas cells which mitigates the consequences of a single gas cell failure and helps reduce the amount of overpressure needed.
History
In the first decade of the twentieth century, semi-rigid airships were considered more suitable for military use because, unlike rigid airshipRigid airship
A rigid airship is a type of airship in which the envelope retained its shape by the use of an internal structural framework rather than by being forced into shape by the pressure of the lifting gas within the envelope as used in blimps and semi-rigid airships.Rigid airships were produced and...
s, they could be deflated, stored and transported by land or by sea. Non-rigid airships had a limited lifting capacity due to the strength limitations of the envelope and rigging materials then in use.
An early successful example is the Groß-Basenach
Groß-Basenach
Gross-Basenach or Groß-Basenach is the designation for a series of five so-called M-class German military semi-rigid airships constructed by the well-known balloonist Nikolaus Basenach and Major Hans Georg Friedrich Groß of the Royal Prussian Airship Battalion Nr 2 between 1907 and 1914.They...
design made by Major Hans Groß
Hans Georg Friedrich Groß
Hans Georg Friedrich Groß, , was a German balloonist and airship constructor.- Balloons :In the 1890s the Verein zur Förderung der Luftschifffahrt conducted scientific balloon ascents to study the upper atmosphere on the initiative of Richard Assmann...
from the Luftschiffer-Bataillon Nr. 1 in Berlin, the experimental first ship flying in 1907. It had a rigid keel under the envelope. Four more military airships of this design were built, and often rebuilt, designated M I to M IV, up to 1914.
The most advanced construction of semi-rigid airships between the two World Wars took place in Italy. There, the state-factory Stabilimento di Costruzioni Aeronautiche (SCA) constructed several. Umberto Nobile
Umberto Nobile
Umberto Nobile was an Italian aeronautical engineer and Arctic explorer. Nobile was a developer and promoter of semi-rigid airships during the Golden Age of Aviation between the two World Wars...
, later General and director, was its most well-known member, and he designed and flew several semi-rigid airships, including the Norge
Norge (airship)
The Norge was a semi-rigid Italian-built airship that carried out what many consider the first verified overflight of the North Pole on May 12, 1926. It was also the first aircraft to fly over the polar ice cap between Europe and America...
and Italia
Airship Italia
Airship Italia was a semi-rigid airship used by Italian engineer Umberto Nobile in his second series of flights around the North Pole.-Design and specifications:...
, for his overflights of the North Pole
North Pole
The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is, subject to the caveats explained below, defined as the point in the northern hemisphere where the Earth's axis of rotation meets its surface...
, and the W6 OSOAVIAKhIM, for the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
's airship program
Russian airships
This article outlines some of the rigid and semi-rigid airships used in or built in Russia and the Soviet Union.In 1812, desiring to attack Napolean's army during the French invasion of Russia, Alexander I commissioned the German engineer Leppig to build a large fish-shaped airship propelled by...
.
List of other semi-rigid airships
Pre-War and WWI- "Bartolomeu de GusmãoBartolomeu de GusmãoBartolomeu Lourenço de Gusmão , was a priest and naturalist born in the then Portuguese colony of Brazil, noted for his early work on lighter-than-air airship design....
" from Augusto Severo de Albuquerque Maranhão in Brazil in 1894, destroyed in March 1894 by a gust of wind - "Pax" from Augusto Severo de Albuquerque Maranhão in France in 1902, caught fire at its first ascent, killing the pilot
- Le Jaune - Built by Lebaudy FrèresLebaudy FrèresLebaudy Frères was a French sugar producer based in Moisson, France. In addition to sugar, they also made a series of semi-rigid airships in the early years of the twentieth century, some of which saw service with several European armies.-Operation:...
in France, first flight: 1902-11-13. Lebaudy built many other semi-rigid airships, among them the PatrieLebaudy PatrieThe Lebaudy Patrie was a semi-rigid airship built for the French army in Moisson, France, by sugar manufacturers Lebaudy Frères. Designed by Henri Julliot, the company's chief engineer, the Patrie was completed in November 1906 and handed over to the military the following month, thus becoming the...
and the RépubliqueLebaudy RépubliqueThe Lebaudy République was a semi-rigid airship built for the French army in Moisson, France, by sugar manufacturers Lebaudy Frères. She was a sister ship of the Patrie, the main differences between the two being in the dimensions of the gasbag and the ballonet...
.
- ForlaniniEnrico ForlaniniEnrico Forlanini was an Italian engineer, inventor and aeronautical pioneer, well known for his works on helicopters, aircraft, hydrofoils and dirigibles. He was born in Milan...
F.1 Leonardo da Vinci, Italy, 3265 m³, 40 PS, first ascent: 1909; 1910-02-01 damaged beyond repair - The Groß-BasenachGroß-BasenachGross-Basenach or Groß-Basenach is the designation for a series of five so-called M-class German military semi-rigid airships constructed by the well-known balloonist Nikolaus Basenach and Major Hans Georg Friedrich Groß of the Royal Prussian Airship Battalion Nr 2 between 1907 and 1914.They...
-type airship (5 built for the Prussian army) - The Luftschiff von Veeh, (also Veeh 1 or Stahlluftschiff) built by Albert Paul Veeh from Apolda in Düsseldorf in the 1910s
- Siemens-Schuckert I (1911)
- M.1, Italian, first flight 1912, 83 metre long, 17 metre diameter, 2x 250 PS Fiat SA.76-4 engines each with one airscrew, payload: 3800 kg, first with the Army then the Navy, 164 flights, decommissioned 1924
- M.2, Città di Ferrara, Italian, first flight 1913, hull identical to the M.1, 83 metre long, 17 metre diameter, 4×125 PS driving two airscrews, payload 3000 kg, speed: 85 km/h, a Navy airship, stationed in JesiJesithumb|250px|Teatro Pergolesi.Iesi is a town and comune of the province of Ancona in the Marche, Italy.It is an important industrial and artistic center in the floodplain on the left bank of the Esino river before its mouth on the Adriatic Sea.-History:Iesi was one of the last towns of the Umbri...
, on 1915-06-08 shot down by an Austrian flying boat - Forlanini F.2 Città di Milano, Italy, 11,500 m³, 2×85 PS, first flight: 1913-04-09, destroyed 1914-04-09 at ComoComoComo is a city and comune in Lombardy, Italy.It is the administrative capital of the Province of Como....
- SR.1 (M-class) built by Italy for England 1918, 12,500 m³, 83 m long, 17 m Diameter, 9 man crew, internal keel of triangular steel components
1920's and 1930s
- Among the Parseval airships designed by August von ParsevalAugust von ParsevalAugust von Parseval was a German airship designer.As a boy, Von Parseval attended the Royal Bavarian Pagenkorps in Munich from 1873 to 1878, where he took the Fähnrichexamen . He then joined the Royal Bavarian 3rd Infantry Regiment Prinz Carl von Bayern...
in the 1900s-1930s:- PL 26 and PL 27
- Parseval-Naatz designs
- Zodiac V10 was built 1930 for the French Navy
- O-1 (airship)O-1 (airship)The SCDA O-1 was an Italian semi-rigid airship, the only true semi-rigid airship to serve with the United States Navy.-Operational service:...
built by SCDA, Italy, and the only true semi-rigid airship to serve with United States NavyUnited States NavyThe United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
. - RS-1 was the only semi-rigid American military airship (used by the United States ArmyUnited States ArmyThe United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...
) built in the USA. Manufacturer: Goodyear, maiden flight: 1926. - Raab-Katzenstein 27 - maiden flight: 1929-05-04
Nobile's company designed or built the following airships:
- T 34 RomaRoma (airship)- References :NotesBibliography* Tampa Times, February 22, 1922. Page 1.* New York Times, February 22, 1922. Page 1....
, 33,810 m³, sold to the US, successfully crossed Atlantic and later destroyed after collison with high tension wires - N 1 NorgeNorge (airship)The Norge was a semi-rigid Italian-built airship that carried out what many consider the first verified overflight of the North Pole on May 12, 1926. It was also the first aircraft to fly over the polar ice cap between Europe and America...
, 19,000 m³, reached the North Pole in 1926 - N 2 a 7000 m³-airship built in hangars at Augusta, Sicily
- N 3 Sold to Japan as naval Airship No. 6, first flight on 1927-04-06. It was lost in 1927 after encountering a typhoon in the Pacific.
- N 4 ItaliaAirship ItaliaAirship Italia was a semi-rigid airship used by Italian engineer Umberto Nobile in his second series of flights around the North Pole.-Design and specifications:...
Flew to Svarlbard for Arctic expedition 1928, crashed after third polar flight on return from North Pole - N 5 was a project for a 55,000 cubic metre keel airship, many times interrupted, eventually abandoned 1928
- Nobile-designed airships of the Russian airship program, such as the Soviet SSSR-V6 OSOAVIAKhIM (1934–1938)
Current developments
the only flying manned semi-rigid airship is the Zeppelin NTZeppelin NT
The Zeppelin NT is a class of airships being manufactured since the 1990s by the German company Zeppelin Luftschifftechnik GmbH in Friedrichshafen. The initial model is the NT07...
. It comprises a single gas cell kept at a slight over-pressure, ballonets to maintain constant volume, and a triangular keel structure internal to the cell.
CL160 "Cargolifter" was an unrealised design of the now liquidated German Cargolifter AG (1996–2003). Cargolifter Joey was a small semi-rigid experimental airship produced to test the design