The VFW VAK 191B was an experimental German
vertical take-off and landing
A vertical take-off and landing (VTOL) aircraft is one that can take off and land vertically without relying on a runway. This classification can include a variety of types of aircraft including helicopters as well as thrust-vectoring fixed-win ...
(VTOL)
strike fighter
In current military parlance, a strike fighter is a multirole combat aircraft designed to operate both as an attack aircraft and as an air superiority fighter. As a category, it is distinct from fighter-bombers. It is closely related to the c ...
of the early 1970s. VAK was the abbreviation for ''Vertikalstartendes Aufklärungs- und Kampfflugzeug'' (Vertical Take-off Reconnaissance and Strike Aircraft). Designed and built by the
Vereinigte Flugtechnische Werke
Vereinigte Flugtechnische Werke (VFW) was a West German aerospace manufacturer.
The company was formed by the 1964 merger of two German aerospace firms, Focke-Wulf and Weser Flugzeugbau GmbH (Weserflug). The formation of VFW was a natural outco ...
(VFW), it was developed with the purpose of eventually serving as a replacement for the Italian
Fiat G.91
The Fiat G.91 is an Italian jet fighter aircraft designed and built by Fiat Aviazione, which later merged into Aeritalia. The G.91 has its origins in the NATO-organised NBMR-1 competition in 1953, which sought a light fighter-bomber (offici ...
then in service with the
German Air Force
The German Air Force (german: Luftwaffe, lit=air weapon or air arm, ) is the aerial warfare branch of the , the armed forces of Germany. The German Air Force (as part of the ''Bundeswehr'') was founded in 1956 during the era of the Cold War a ...
. Operationally, it was intended to have been armed with
nuclear weapons
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions (thermonuclear bomb), producing a nuclear explosion. Both bomb ...
as a
deterrent against aggression from the
Soviet Union
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...
and, in the event of a major war breaking out, to survive the first wave of attacks by deploying to dispersed locations, rather than conventional airfields, and to retaliate against targets behind enemy lines.
The VAK 191B suffered from a protracted development cycle, spanning ten years between inception and flight, in part due to changing requirements, changing partnerships and the difficulties inherent in the development of VTOL-capable aircraft. Ultimately, during the late 1960s, VFW took the decision to demote the development programme from targeting the type's production and instead only to test-fly a limited number of prototypes, using the VAK 191B effectively as a technology demonstrator and experimental aircraft to support the company's other activities and future programmes. On 10 September 1971, the first prototype conducted the type's
maiden flight
The maiden flight, also known as first flight, of an aircraft is the first occasion on which it leaves the ground under its own power. The same term is also used for the first launch of rockets.
The maiden flight of a new aircraft type is alwa ...
. A total of 91 flights were performed prior to the retirement of all three prototypes in 1975. These aircraft have been preserved and two are now on public display in museums.
Design and development
Background
During the 1950s, rapid advances in the field of
jet propulsion
Jet propulsion is the propulsion of an object in one direction, produced by ejecting a jet of fluid in the opposite direction. By Newton's third law, the moving body is propelled in the opposite direction to the jet. Reaction engines operating o ...
, particularly in terms of increased thrust and compact engine units, had contributed to an increased belief in the technical viability of vertical takeoff/landing (
VTOL
A vertical take-off and landing (VTOL) aircraft is one that can take off and land vertically without relying on a runway. This classification can include a variety of types of aircraft including helicopters as well as thrust-vectoring fixed-win ...
) aircraft, particularly within
Western Europe
Western Europe is the western region of Europe. The region's countries and territories vary depending on context.
The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the ancient Mediterranean ...
and the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
.
[Hirschel, Prem and Madelung 2012, p. 451.] During 1950s and 1960s, multiple programmes in Britain, France, and the United States were initiated; likewise, aviation companies inside
West Germany
West Germany is the colloquial term used to indicate the Federal Republic of Germany (FRG; german: Bundesrepublik Deutschland , BRD) between its formation on 23 May 1949 and the German reunification through the accession of East Germany on 3 O ...
were keen not to be left out of this emerging technology. Shortly after 1957, the year in which the post-
Second World War
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
ban upon West Germany operating and developing combat aircraft was lifted, German aviation firms
Dornier Flugzeugwerke
Dornier Flugzeugwerke was a German aircraft manufacturer founded in Friedrichshafen in 1914 by Claude Dornier. Over the course of its long lifespan, the company produced many designs for both the civil and military markets.
History
Originally ...
,
Heinkel
Heinkel Flugzeugwerke () was a German aircraft manufacturing company founded by and named after Ernst Heinkel. It is noted for producing bomber aircraft for the Luftwaffe in World War II and for important contributions to high-speed flight, with ...
, and
Messerschmitt
Messerschmitt AG () was a German share-ownership limited, aircraft manufacturing corporation named after its chief designer Willy Messerschmitt from mid-July 1938 onwards, and known primarily for its World War II fighter aircraft, in partic ...
, having also been allowed to resume their own activities that same year, received an official request from the
German Federal Government
The Federal Cabinet or Federal Government (german: link=no, Bundeskabinett or ') is the chief executive body of the Federal Republic of Germany. It consists of the Federal Chancellor and cabinet ministers. The fundamentals of the cabinet's or ...
that urged them to perform investigative work on the topic of VTOL aircraft and to produce concept designs.
[Hirschel, Prem and Madelung 2012, pp. 451–452.]
As such, multiple companies commenced work on their own conceptual designs for VTOL-capable
interceptor aircraft
An interceptor aircraft, or simply interceptor, is a type of fighter aircraft designed specifically for the defensive interception role against an attacking enemy aircraft, particularly bombers and reconnaissance aircraft. Aircraft that are cap ...
; in order for these designs to be operationally relevant and viable, it was recognised that it would be necessary for the flight performance to equal that of conventional interceptors of the era, such as the contemporary
Lockheed F-104G Starfighter
The Lockheed F-104 Starfighter is an American single-engine, supersonic air superiority fighter which was extensively deployed as a fighter-bomber during the Cold War. Created as a day fighter by Lockheed as one of the "Century Series" of ...
.
[Hirschel, Prem and Madelung 2012, p. 452.] Over time, two separate and distinct requirements emerged, one calling for a VTOL-capable successor to the F-104G interceptor while the other sought a VTOL successor to the Italian
Fiat G.91
The Fiat G.91 is an Italian jet fighter aircraft designed and built by Fiat Aviazione, which later merged into Aeritalia. The G.91 has its origins in the NATO-organised NBMR-1 competition in 1953, which sought a light fighter-bomber (offici ...
ground-attack fighter. According to aerospace publication
Flight International
''Flight International'' is a monthly magazine focused on aerospace. Published in the United Kingdom and founded in 1909 as "A Journal devoted to the Interests, Practice, and Progress of Aerial Locomotion and Transport", it is the world's oldes ...
, this call for a Fiat G.91 replacement, which came under a
NATO
The North Atlantic Treaty Organization (NATO, ; french: Organisation du traité de l'Atlantique nord, ), also called the North Atlantic Alliance, is an intergovernmental military alliance between 30 member states – 28 European and two No ...
requirement, known as
NBMR-3
NBMR-3 or NATO Basic Military Requirement 3 was a document produced by a North Atlantic Treaty Organisation (NATO) committee in the early 1960s detailing the specification of future combat aircraft designs. The requirement was for aircraft in two ...
, was a crucial trigger and greatly influenced the development programme that would lead to the VAK 191B.
[Flight International 1972, p. 502.]
In conjunction with these requirements being on offer, Germany's
Federal Ministry of Defence
The Federal Ministry of Defence (german: Bundesministerium der Verteidigung, ), abbreviated BMVg, is a top-level federal agency, headed by the Federal Minister of Defence as a member of the Cabinet of Germany. The ministry is headquartered at ...
(BMVg) championed for the merger of the competing companies; it deliberately withheld the issuing of a development contract in order to incentivise companies to undertake such activities.
[Hirschel, Prem and Madelung 2012, pp. 583–584.]
As such, during September 1961, a new German aircraft company, known as
Vereinigte Flugtechnische Werke
Vereinigte Flugtechnische Werke (VFW) was a West German aerospace manufacturer.
The company was formed by the 1964 merger of two German aerospace firms, Focke-Wulf and Weser Flugzeugbau GmbH (Weserflug). The formation of VFW was a natural outco ...
(VFW), was formed as
joint venture
A joint venture (JV) is a business entity created by two or more parties, generally characterized by shared ownership, shared returns and risks, and shared governance. Companies typically pursue joint ventures for one of four reasons: to acces ...
between
Focke-Wulf
Focke-Wulf Flugzeugbau AG () was a German manufacturer of civil and military aircraft before and during World War II. Many of the company's successful fighter aircraft designs were slight modifications of the Focke-Wulf Fw 190. It is one of the ...
and
Weser Flugzeugbau
Weser Flugzeugbau GmbH, known as Weserflug, was an aircraft manufacturing company in Germany.
History
The company was founded in 1934 as a subsidiary of the ship and machine company Deutsche Schiff- und Maschinenbau AG (DESCHIMAG). It began prod ...
, to develop its own VTOL strike aircraft.
[Flight International 1972, pp. 502, 504.] Initially,
Italian
Italian(s) may refer to:
* Anything of, from, or related to the people of Italy over the centuries
** Italians, an ethnic group or simply a citizen of the Italian Republic or Italian Kingdom
** Italian language, a Romance language
*** Regional Ita ...
aircraft manufacturer
Fiat
Fiat Automobiles S.p.A. (, , ; originally FIAT, it, Fabbrica Italiana Automobili di Torino, lit=Italian Automobiles Factory of Turin) is an Italian automobile manufacturer, formerly part of Fiat Chrysler Automobiles, and since 2021 a subsidiary ...
was also a participating company in VFW, however, Italy later chose to withdraw from the joint development agreement with Germany during 1967. Despite this decision, Fiat remained as a major sub-contractor for the venture, being responsible for the production of various structural elements such as wings, tailplanes and some of the fuselage.
Concept and definition
![Aircraft engine VAK191B hover swing nozzles LH 2](https://upload.wikimedia.org/wikipedia/commons/8/8f/Aircraft_engine_VAK191B_hover_swing_nozzles_LH_2.jpg)
The VAK 191B was similar in concept to the British
Harrier jump jet
The Harrier, informally referred to as the Harrier jump jet, is a family of jet-powered attack aircraft capable of vertical/short takeoff and landing operations (V/STOL). Named after a bird of prey, it was originally developed by British ma ...
, but was designed for a supersonic dash capability (
Mach number
Mach number (M or Ma) (; ) is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a boundary to the local speed of sound.
It is named after the Moravian physicist and philosopher Ernst Mach.
: \mathrm = \frac ...
1.2–1.4) at medium to high altitudes.
It was judged that having a single engine would create too much drag, but the two lift engines were dead weight in cruise, and the small cruise engine gave a poor thrust to weight ratio. The VAK 191B had been provided with relatively small and highly loaded wings. By contrast, the Harrier possessed a significantly higher
thrust-to-weight ratio
Thrust-to-weight ratio is a dimensionless ratio of thrust to weight of a rocket, jet engine, propeller engine, or a vehicle propelled by such an engine that is an indicator of the performance of the engine or vehicle.
The instantaneous thrust-to-w ...
, it was effective as a
dogfight
A dogfight, or dog fight, is an aerial battle between fighter aircraft conducted at close range. Dogfighting first occurred in Mexico in 1913, shortly after the invention of the airplane. Until at least 1992, it was a component in every majo ...
er, and had larger wings which were put to good use when performing rolling short takeoffs.
The choice of lift/propulsion system was an obvious critical element of the aircraft's design.
According to Flight International, there were several options available in the field of
vectored thrust
Thrust vectoring, also known as thrust vector control (TVC), is the ability of an aircraft, rocket, or other vehicle to manipulate the direction of the thrust from its engine(s) or motor(s) to control the attitude or angular velocity of the ve ...
propulsion during its development, these being the twin-nozzle
Rolls-Royce/MAN Turbo RB153
The Rolls-Royce/MAN Turbo RB.153 was a high-performance dry thrust turbofan engine developed jointly by Rolls-Royce Limited and MAN Turbo. Developed for the German EWR VJ 101D interceptor with a German-developed thrust-deflector system. The ...
and the four-nozzle
Bristol Siddeley BS.94 engines.
[Flight International 1972, pp. 502–503.] Ultimately, VFW's design team decided to adopt the
Rolls-Royce/MAN Turbo RB.193-12 engine to provide both
lift
Lift or LIFT may refer to:
Physical devices
* Elevator, or lift, a device used for raising and lowering people or goods
** Paternoster lift, a type of lift using a continuous chain of cars which do not stop
** Patient lift, or Hoyer lift, mobile ...
and
cruise, which was augmented by a pair of Rolls-Royce vertical lift engines. In practice, this arrangement meant during vertical hover, all of the lifting thrust could either be generated by the propulsion engine, or entirely produced by the two lift engines, or some combination thereof; analysis determined that the optimum thrust-generation configuration would be a 50–50 split between both engine types.
[Flight International 1972, p. 503.]
During mid-1963, the in-development aircraft received its design designation of ''VAK 191B''. Reportedly, the initials in this designation stood for ''Vertikalstartendes Aufklärungs-und Kampfflugzeug'' (in English: vertical take-off reconnaissance and fighter aircraft), the numbers were to indicate its role as a successor to the Fiat G.91, while the ''B'' suffix was to show that the aircraft was the second of the four designs to be studied for this purpose.
The rate of progress on the programme was noticeably slow; ten years passed between its inception and the first prototype performing its
maiden flight
The maiden flight, also known as first flight, of an aircraft is the first occasion on which it leaves the ground under its own power. The same term is also used for the first launch of rockets.
The maiden flight of a new aircraft type is alwa ...
on 10 September 1971.
The slow progression can be viewed as a natural result of specification changes, such as a revised operational requirement that called for the aircraft to possess greater manoeuvrability issued during 1965.
Scaling-back and termination
Even prior to the first flight of the type, the programme had been heavily affected by political changes. Amongst these were the effective irrelevance of the original NBMR-3 requirement and the decreasing importance of the strike mission as a result of a German government decision to abandon the nuclear role, a divergence of opinion between partner countries, the withdrawal of the Italian government from participation during August 1967, and a growing awareness of the programme's escalating costs.
At one stage, the Italian government had agreed to take on 40 per cent of the programme's development costs, thus their departure meant that a substantial amount of funding was lost for the venture.
The emergence of a new German/American "Advanced Vertical Strike" (AVS) programme also played a role in diminishing the type's perceived value; the prospective aircraft which was on offer from the Americans via a cooperative venture with Germany had somewhat eclipsed the VAK 191B in the eyes of the German Air Force and served to effectively undermine support for the programme. Finally, during 1968, officials at VFW decided that the VAK 191B should be reclassified as an experimental programme, and that the resultant aircraft should principally function only as
technology demonstrator
A technology demonstration (or tech demo), also known as demonstrator model, is a prototype, rough example or an otherwise incomplete version of a conceivable product or future system, put together as proof of concept with the primary purpose of ...
s instead.
The initial programme had called for the construction of three single-seater and three two-seater aircraft; however, amid escalating costs, this intended test batch was first converted to become six single-seat aircraft, and was later on cut down to only involve three single-seat aircraft following Italy's withdrawal.
[Flight International 1972, p. 504.]
During April 1969, the first prototype was rolled out at VFW's facility in
Bremen
Bremen (Low German also: ''Breem'' or ''Bräm''), officially the City Municipality of Bremen (german: Stadtgemeinde Bremen, ), is the capital of the German state Free Hanseatic City of Bremen (''Freie Hansestadt Bremen''), a two-city-state consis ...
, and was later displayed at that year's
Hannover Air Show.
Over the course of the following 17 months, it went through a flight-qualification programme, during which some issues were discovered, most of these associated with the
hydraulic system
Hydraulics (from Greek language, Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is th ...
. During February 1971, trials commenced using the cruise engine for the first time.
The first hovering flight performed by the VAK 191B was conducted at Bremen on 20 September 1971.
A total of three VAK 191B aircraft were flown in the flight test program, which was conducted between 1970 and 1975, during which a total of 91 flights were performed. The first transition from vertical flight to horizontal and vice versa was achieved on 26 October 1972 in
Munich
Munich ( ; german: München ; bar, Minga ) is the capital and most populous city of the States of Germany, German state of Bavaria. With a population of 1,558,395 inhabitants as of 31 July 2020, it is the List of cities in Germany by popu ...
. At one stage, the prototypes were used for testing some of the concepts that were then being considered for the European MRCA programme (which led to the
Panavia Tornado
The Panavia Tornado is a family of twin-engine, variable-sweep wing multirole combat aircraft, jointly developed and manufactured by Italy, the United Kingdom and West Germany. There are three primary Tornado variants: the Tornado IDS (inter ...
strike fighter), including the use of
fly-by-wire
Fly-by-wire (FBW) is a system that replaces the conventional manual flight controls of an aircraft with an electronic interface. The movements of flight controls are converted to electronic signals transmitted by wires, and flight control co ...
technology. According to Flight International, the VAK 191B was well-suited to this purpose due to its modern flight-control system and its general characteristics.
[Flight International 1972, p. 505.]
Surviving aircraft
* An example of the VAK 191B can be seen at the
Deutsches Museum Flugwerft Schleissheim
Flugwerft Schleissheim is an aviation museum located in the German town of Oberschleißheim near Munich, it forms part of the Deutsches Museum collection and complements the aviation exhibits on display at the main site. The museum was opened on ...
at
Oberschleißheim
Oberschleißheim () is a Municipalities of Germany, municipality in the Munich (district), district of Munich, in Bavaria, Germany. It is located 13 km north of Munich (centre). As of 2005 it had a population of 11,467.
Oberschleißheim is ...
near Munich.
* The second remaining VAK 191B is part of the
Wehrtechnische Studiensammlung
The Bundeswehr Museum of German Defense Technology also known as ''Wehrtechnisches Museum Koblenz'' and ''Wehrtechnische Studiensammlung Koblenz'' (WTS-Koblenz) is the official Bundeswehr's Defense Technology Study Collection in Koblenz. It is o ...
(''Military technical collection'') at
Koblenz
Koblenz (; Moselle Franconian language, Moselle Franconian: ''Kowelenz''), spelled Coblenz before 1926, is a German city on the banks of the Rhine and the Moselle, a multi-nation tributary.
Koblenz was established as a Roman Empire, Roman mili ...
,
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
.
* The third VAK 191B was reported as being put into storage in 1976.
[Jackson,1976. p.144.] Its current location is at Airbus in Bremen.
Operators
;
*
German Air Force
The German Air Force (german: Luftwaffe, lit=air weapon or air arm, ) is the aerial warfare branch of the , the armed forces of Germany. The German Air Force (as part of the ''Bundeswehr'') was founded in 1956 during the era of the Cold War a ...
(''Luftwaffe'')
Specifications (VAK 191B)
See also
References
Citations
Bibliography
*Buttler, Tony and Jean-Louis Delezenne. ''X-Planes of Europe: Secret Research Aircraft from the Golden Age 1946-1974''. Manchester, UK: Hikoki Publications, 2012.
* Hirschel, Ernst Heinrich., Horst Prem and Gero Madelung. ''Aeronautical Research in Germany: From Lilienthal until Today.'' Springer Science & Business Media, 2012. .
* Jackson, Paul A. ''German Military Aviation 1956–1976''. Hinckley, Leicestershire, UK: Midland Counties Publications, 1976. .
*
External links
Paul Nann, Photo of VAK191BV/STOL Fighter Programs in Germany: 1956–1975
{{DEFAULTSORT:Vfw Vak 191b
Abandoned military aircraft projects of Germany
1970s German attack aircraft
1970s German experimental aircraft
VAK 191
V/STOL aircraft by thrust vectoring
Single-engined jet aircraft
Aircraft with auxiliary jet engines
High-wing aircraft
Aircraft first flown in 1971