The German VFW SG 1262 ''Schwebegestell'' (hover rig) was designed and built in 1965 by

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) as an

experimental aircraft An experimental aircraft is an aircraft intended for testing new aerospace technologies and design concepts. The term ''research aircraft'' or ''testbed aircraft'', by contrast, generally denotes aircraft modified to perform scientific studies, ...

to assist with the development of several

vertical takeoff 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) military aircraft types that included the

VFW VAK 191B The VFW VAK 191B was an experimental German vertical take-off and landing (VTOL) strike fighter of the early 1970s. VAK was the abbreviation for ''Vertikalstartendes Aufklärungs- und Kampfflugzeug'' (Vertical Take-off Reconnaissance and Strike ...

, the

EWR VJ 101 The EWR VJ 101 was an experimental German jet fighter vertical takeoff/landing (VTOL) tiltjet aircraft. VJ stood for ''Versuchsjäger'', (German for "Experimental Fighter"). The VJ 101 was one of the first V/STOL designs to have the potential for ...

and the

Dornier Do 31 The Dornier Do 31 is an experimental vertical take-off and landing (VTOL) jet-propelled transport designed and produced by West German aircraft manufacturer Dornier. The development of the Do 31 was motivated principally by heavy interest expre ...

transport. The 1262 designation relates to the initial numbering of the VAK 191B project by

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 ...

. Tethered test flights were followed in August 1966 by free flights that included an appearance at a

Hanover Hanover (; german: Hannover ; nds, Hannober) is the capital and largest city of the German state of Lower Saxony. Its 535,932 (2021) inhabitants make it the 13th-largest city in Germany as well as the fourth-largest city in Northern Germany ...

air show. Although the German VTOL programme did not proceed test results were used during development of 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 ...

. The SG 1262 is displayed at the

Bundeswehr Museum of German Defense Technology 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 on ...

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 ...

Background

As part of the development of the VFW-Fokker VAK 191B vertical take-off aircraft, it was necessary to configure and test the monitoring of its

flight control A conventional fixed-wing aircraft flight control system consists of flight control surfaces, the respective cockpit controls, connecting linkages, and the necessary operating mechanisms to control an aircraft's direction in flight. Aircraft e ...

system. In order to minimise costs and risks during the development of the 191B the SG 1262 rig was designed and built in 1966 to simulate essential functions. Of high importance was the necessity to test the

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 ...

flight control system, a redundant flight controller and a self-diagnosis system. A total of approximately 650 hours of simulation time, 2,000 hours of test runs on system test benches and 6,900 hours of

wind tunnel Wind tunnels are large tubes with air blowing through them which are used to replicate the interaction between air and an object flying through the air or moving along the ground. Researchers use wind tunnels to learn more about how an aircraft ...

tests were documented during the design phase of the project.
Flugrevue-Der deutsche Harrier
' www.flugrevue.de (German language) Retrieved:6 June 2022

Technical description

The aircraft was based on a

trapezoid A quadrilateral with at least one pair of parallel sides is called a trapezoid () in American and Canadian English. In British and other forms of English, it is called a trapezium (). A trapezoid is necessarily a Convex polygon, convex quadri ...

al frame without any skin panels. Deviating from the

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 ...

engine concept of the VAK 191B, five

Rolls-Royce RB.108 The Rolls-Royce RB.108 was a British jet engine designed in the mid-1950s by Rolls-Royce specifically for use as a VTOL lift engine. It was also used to provide horizontal thrust in the Short SC.1. Design and development The RB.108 was the f ...

turbojet The turbojet is an airbreathing jet engine which is typically used in aircraft. It consists of a gas turbine with a propelling nozzle. The gas turbine has an air inlet which includes inlet guide vanes, a compressor, a combustion chamber, and ...

lift engines with thrust each were mounted vertically. In addition to extensive sensor equipment, the rig used an auxiliary gas turbine for autonomous electrical power supply supply, it was also fitted with a

Martin-Baker Martin-Baker Aircraft Company Limited is a British manufacturer of ejection seats and safety-related equipment for aviation. The company's origins were originally as an aircraft manufacturer before becoming a pioneer in the field of ejection s ...

ejection seat In aircraft, an ejection seat or ejector seat is a system designed to rescue the aircraft pilot, pilot or other aircrew, crew of an aircraft (usually military) in an emergency. In most designs, the seat is propelled out of the aircraft by an ex ...

. The control commands were transmitted via an electrical control (

) system with mechanical feedback. The flight control system had triple redundancy and double electro-hydraulic servo units with integrated self-monitoring. The control commands for the three axes were accomplished with compressed air nozzles that were actuated by a high-pressure

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 ...

, movement of the main engines for control purposes was deliberately omitted. A direct mechanical back up of the compressed air control system was provided for emergencies.

Operational history

40 tethered flights were initially carried out using a fixed telescopic apparatus before the aircraft flew in free flight for the first time on 5 August 1966. 150 free flights were made during the 18-month test program, including a demonstration flight at the 1968 Hanover Air Show at Hanover-Langenhagen. Despite the discontinuation of all German vertical take-off programs the findings from experiments with the SG 1262 and experience gained from the VAK 191B project were used by German engineers during the development of the Multi Role Combat Aircraft (MRCA) project which became the

Aircraft on display

The SG 1262 is preserved and on display at the

.Bundeswehr WTS collection
www.bundeswehr.de Retrieved: 6 June 2022

Specifications

References

Notes

Bibliography

* Taylor, John W.R. ''Jane's Pocket Book of Research and Experimental Aircraft'', London, Macdonald and Jane's Publishers Ltd, 1976. . * Kuckuk, Pophanken and Schalipp. ''Ein Jahrhundert Luft- und Raumfahrt in Bremen'', Edition Falkenberg, 2016 (German language).

External links

V/STOL Fighter Programs in Germany: 1956-1975 PDF, in flight image of SG 1262, p. 39
{{VFW-Fokker aircraft SG 1262 1960s German experimental aircraft VTOL aircraft Aircraft first flown in 1966