Aircraft on vertical takeoff and landing

A aircraft on vertical takeoff and landing (of which the Acronyme is v.t.o.l ) is a Aéronef with aerofoil fixes conceived to free itself from the tracks which is normally necessary for him for the Décollage and the Atterrissage. This type of plane is sometimes called hybrid or convertible , especially in the case of plane with tilting engines of type Tiltrotor. This category recovers neither the balloons and Dirigeable S, nor the Hélicoptère S. corresponding anglophone designation is VTOL ( Vertical Takeoff and Landing aircraft ).

Introduction

The v.t.o.l were initially developed by the soldiers, who feared that their planes are not nailed on the ground after a bombardment of the track. This type of plane can indeed be used with an infrastructure reduced on the ground, just like a Hélicoptère. Within the naval framework, it is possible to build Navire S of carrying which will not need a track of Appontage as long as on a traditional Porte-avions (case of the Porte-aéronefs). In the civil field, the interest is especially to combine the advantages of a helicopter with those of a plane, thus allowing takeoff from a reduced platform and the hovering with a higher cruising speed and a payload.

A major defect of the v.t.o.l is to have a fuel consumption very high in the phases of takeoff and landing, from where an autonomy and a payload limited, which makes them nonviable like civil aircraft and limit their interest like military aircraft. These defects were partially solved with the concept of STOVL ( Short Take Off Vertical Landing ), where vertical takeoff is replaced by a takeoff runs.

If the v.t.o.l were very with the mode in the years 1960 with many projects being studied, only two of them succeeded, during the XXème century, with an effective startup:

More recently appeared:

  • the military transport aircraft Boeing V-22 Osprey (brought into service in 2005)

And two projects must lead by 2010:

  • the American fighter Lockheed F-35B
  • the civil transport aircraft Beautiful/Agusta BA609 which carried out its first presentation in flight with the public at the time of the Paris airshow 2007.

Techniques used

Several ways were explored to make it possible to shorten, to even remove the distance covered horizontally.

  • the aircraft takes off with the vertical like a rocket, rocks with horizontal for the normal flight, then rebascule with the vertical for the landing (system indicated tail-sitter , examples: Snecma C450 Coléoptère, Convair XFY-1 Pongo)

  • the aircraft remains with horizontal during all the phases of flight, these are only the engines which rock of the vertical for takeoff/landing with horizontal for the normal flight (system indicated Tilt-rotor in the case a propeller engine and tilt-jet with a reaction engine or tilt-wing if it is the whole wing which rocks, examples: Boeing V-22 Osprey, EWR VJ 101)
  • the aircraft uses the combination of rotors for lift and propellers for the translation, the engines involving one or the other thanks to a system of progressive first shaft, example: Kamov Ka-22 .
  • the aircraft uses two word groups different following the phase from flight: engines known as of lift placed vertically for takeoff and the landing, and of the traditional engines of propulsion placed horizontally for the normal flight (system indicated flat-riser , example: Dassault Mirage IIIV)
  • the aircraft remains with horizontal, it has only one engine fixes with which one is satisfied to vary the orientation of flow (system of deflection of the push, example: Hawker Siddeley Harrier)
  • a combination of the two last solutions, with before and engine lift jets of propulsion with deflection of pushed with the back (examples: Yakovlev Yak-38 To forge, Lockheed F-35 Lightning II)

One calls transition the moment during which the v.t.o.l passes from the vertical flight to the level flight at the conclusion of takeoff, or of the level flight to the vertical flight before the landing. The first transition is very delicate because the Portance must be transferred from the engines with the wings, but the wings play their part only provided that the horizontal speed of the plane is sufficient. The swing is thus made in a progressive way.

History

If a certain number of engineers proposed as of the end of the 19th century of the machines heavier than the air able to take off and land vertically, few of these projects can be regarded as true v.t.o.l and none exceeded the stage of the prototype. In fact, the first real research in this field was initiated by German during the Second world war, because the need then appeared to have fighters able to do without landing strips vulnerable to the bombardments.

Among the German projects, one can quote Focke-Achgelis F 269 (embarked hunter with tilting rotor which did not exceed the training course of the wind tunnel tests), the Focke-Wulf Triebflügel, and a study of an engineer of the company Heinkel which proposed five similar apparatuses and described for the first all the phases of the flight (including the two transitions vertical/horizontal then horizontal/vertical). Again however, none of these projects reached the stage of the prototype.

It was necessary to await the beginning of the year 1950 to see the first experimental tests of v.t.o.l to the the United States, with the Convair XFY-1 Pongo and the Lockheed XFV-1 Salmon . These projects were launched in 1951 at the request of the US Navy: they were planes of the type tail-sitter equipped with a Turbopropulseur Allison XT-40. The XFY-1 Pongo made its first flight on August 1st, 1954, only in flight vertical, and successful its first transition towards the level flight on November 2nd, 1954. The XFV-1 Salmon made its first official flight on June 16th, 1954, without however being able to take off vertically because of the insufficient power of the engine compared to the weight of the cell. Finally, in front of the difficulties of piloting of these planes and their lack of performances vis-a-vis the jets which started to appear, the US Navy gave up these projects in 1956.

In 1947, the US Navy had signed a contract with Ryan Aeronautical Company for an experimentation of v.t.o.l with reaction: the X-13 Vertijet. Flying testing grounds were tested as from October 1950. In 1953, for budgetary reasons, the program was dealt with by the US Air Force which ordered two prototypes. Equipped with a provisional three-wheeled train allowing a traditional takeoff, X-13 made its inaugural flight on December 10th, 1955. In mode v.t.o.l, X-13 was deprived of traditional landing gear and was put at the vertical by raising the platform on which it was installed. First vertical flight take place on May 28th, 1956 and the first transition horizontal/vertical on November 28th, 1956. Lastly, the first complete cycle with vertical takeoff, level flight and vertical landing was carried out on April 11th, 1957. The trial flights proceeded until the end of the year 1957.

In France, the company SNECMA launched in 1952 the project of the C-450 Coléoptère while being pressed on the engines Atar which it had developed. After some flying testing grounds intended to validate the operation of the engine placed at the vertical, a prototype was built and accomplished its first vertical flight on April 17th, 1959. This prototype was however destroyed on July 25th, 1959, at the time of one of the first attempts at transition towards the level flight, which caused the complete stop of the program.

With the beginning of the year 1960, research was directed towards planes of the " type; flat-riser" (one will quote for example the Dassault Mirage IIIV or the Dornier Do 31) but it is the idea to use the same engine with directional conduits which made it possible to produce the first really operational v.t.o.l: the Hawker Siddeley Harrier. The demonstrator Harrier P.1127 began his in-flight tests in 1960, first Harrier of series flew in 1966 and the plane was brought into service as from 1969. Their sides, Soviet developed the Yakovlev Yak 38 equipped with 2 engines of lift at before and of an engine of propulsion to directional conduits with the back: the first complete cycle of the demonstrator took place in 1963 and the series production started in 1975.

More recent, the Lockheed F-35B is intended to replace the Harriers as from the years 2010. The formula retained for this plane is however closer to that of Yak 38 than of that of Harrier, since it is equipped with a Soufflante of lift with before and of an engine of propulsion to directional conduit with the back. Prototype X-35B carried out its first vertical landing on June 23rd, 2001.

Another technology was explored for the v.t.o.l with the tilt-rotor (driving with propellers) and tilt-jet (reaction engine), to see tilt-wing if the wing swivels at the same time as the engine, which rest on the same principle: engines which can be directed either vertically for takeoff or the landing, or horizontally for the normal flight. One will quote the projects Vought XC-142 (transport aircraft whose wing was directional quasi-verticalement, first flight on September 29th, 1964) and Canadair CL-84 Dynavert (first flight in May 1965) both tested by the American army, but also the German projects of EWR VJ 101 (first flight in April 1963) and of VAK 191B (first flight on September 10th, 1971), both with reaction.

There still, few projects however really succeeded. Afterwards many difficulties and 20 years of work, the first specimens of series of the Boeing V-22 Osprey (military transport aircraft, first flight on March 19th, 1989) were delivered at the end of 2005. A similar project of civil transport aircraft is the Bell/Agusta BA609, which made its first flight on March 6th, 2003 and must enter in service about 2010.

Prototypes

At the end of the years 1990, the European Union financed some studies on the v.t.o.l Eurofar with tilting rotors (see)

Anecdotes

The albums of Buck Danny S.O.S flying saucers and a prototype disappeared put in scene a prototype of apparatus at takeoff and vertical landing which resembles the Snecma C450 Coléoptère.

One also finds the prototype French of the Balzac V in an adventure of Jacques Renne published by the editions Miklo (Héritage collection). The drawing and the scenario were carried out by Francis Bergèse, draftsman and current scenario writer of the adventures of Buck Danny.

See too

External bonds

  • planes v.t.o.l on Prototypes.com

  • planes v.t.o.l on Aerostories
  • the drone Eagle Eye de Bell Textron
  • the European project ''' EUROFAR '''

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