Aircraft, using a wall jet to create a lift for flight, with advanced controls of aircraft motion.

Field of invention

This invention pertains to an aircraft that uses a wall jet to create a lift and with advanced controls of aircraft motion.

Background of the invention

For several decades engineers have attempted to design a new kind of aircraft with ability of vertical take-off and landing, that would be safer, faster, and more quiet than helicopters. One of such attempts is so called ,,circular aircraft" designed in 1991 in US Patent No 5 054 713, that uses wall jet (sometimes also called Coand's effect) to create a lift, while changes of aircraft direction of motion are achieved by sudden interruption of wall jet on the respective side of the airplane to which the aircraft should tilt. The disadvantage of this solution of directional control of such aircraft is that it creates strong turbulency and results in flight instability, loss of power and increase of noise.

The mentioned disadvantage prevents further utilizations of aircrafts using a wall jet. Design of an aircraft with advanced controls of motion would also enable wider deployment of this type of aircraft.

Summary of the invention

The above mentioned drawbacks of the prior art are removed with an aircraft according to the present invention that uses wall jet to generate a lift, comprising a rotor located on the

aircraft ¹ S fuselage and fully circumferential or discontinued ring surrounding the rotor, with an outlet gap between the lower surface of the ring and the opposite surface of the fuselage to direct the air pushed to the outlet gap by a rotor, substance of which aircraft consisting in that it comprises control means for gradual change of velocity- difference and air flow rates difference between at least two mutually different places at the outlet gap circumference during the flight of the airfcraft .

According to one of the advantageous embodiments the control means comprises a rotor that is configured so that during the flight of the aircraft the position of a rotor's axis relative to the fuselage can be controllably changed.

According to another advantageous embodiment the control means comprises a ring that is configured so that during the flight of the aircraft the position of at least part of the lower ring surface with respect to the opposite surface can be controllably changed, thus changing also the geometry of the outlet gap. This can be achieved e.g. by using flaps with controllably adjustable position forming at least a part of outer area of the ring. Alternatively, the ring can have in all its positions constant shape and its position is controlled by tilting the ring. Another option is that at least part of the ring is flexible and in changed position the ring is elastically deformed.

According to another advantageous configuration the control means comprises adjustable rotor blades that are configured so that during the flight of an aircraft the relative angle of adjustment with respect to the rotor to which the blades are

attached is controlled. The rotor blades can be configured to enable collective or cyclic adjustment of a blades collection. According to another advantageous configuration the control means comprises adjustable vanes that are configured for controllable change of their angle of adjustment during the flight of an aircraft and are located in the outlet gap. These vanes can be configured to enable collective or cyclic adjustment of a blades collection.

Brief description of the drawings

The invention and its advantageous embodiments will be further described in detail with reference to attached drawings on which the fig. 1 shows the general view of an aicraft according to the present invention, fig. 2a shows a partial schematic cross-section of an aircraft that uses the tilt of the ring to control the motion of an aircraft according to the first example of embodiment , fig. 2b shows a partial schematic cross-section of an aircraft that uses the elastic deformation of the ring to control the motion of an aircraft according to the second example of embodiment , fig. 2c shows a partial schematic cross-section of an aircraft that uses flaps at the end of the ring to control the motion of an aircraft according to the third example of embodiment , Fig. 3 shows a schematic cross-section of the fourth example of embodiment of an aircraft that uses the tilt of the rotor to control the motion of an aircraft, Fig. 4 shows a schematic cross-section of the fifth example of embodiment of an aircraft that uses the collective and cyclic adjustment of rotor blades to control the motion of an aircraft, and Fig. 5 shows a schematic cross- section of the sixth example of embodiment of an aircraft that uses the collective and cyclic

adjustment of vanes in the outlet gap to control the motion of an aircraft .

Description of the preferred embodiments

Fig. 1 shows the general view of the aircraft 1 that uses the wall jet to create a lift for flight (referred hereinafter as „aircraft") .

The aircraft's fuselage 2 has an oval shape similar to an elipsoid. Attached pictures show, for simplification, a spherical shape of the fuselage 2 of the aircraft 1. Above the fuselage 2 an axial type rotor 3 (can be diagonal or radial as well) is located, with diameter smaller than the diameter of the aircraft 1, tightly surrounded by a ring 4. The input to the rotor 3 is from the top, the output from the rotor 3 is onto the upper wall of the fuselage 2 and into a narrow gap 5 which is defined by the lower side of the ring 4 and upper wall of the fuselage 2 of the aircraft 1. The profile of the ring 4 is similar to a wing profile. This profile gives to ring 4 very low air resistance during flight, provides smooth air flow entry into the rotor 3, and also provides fluent air flow output onto the top of fuselage 2 at the same time. The ring 4 of this shape also effectively dampens aerodynamic noise caused by the rotor 3. The landing gear of the aircraft 1 is designed as four swing-out legs 12 which could also be collapsible telescopical legs or similar.

The lift is generated by a flow of air sucked in by the rotor 3, which on the output from rotor 3, due to the effect of the outlet gap 5, creates a thin flow (so-called wall jet) which, with aid of underpressure, is further kept near the wall of the fuselage 2 and continuously flows around the fuselage 2

towards its lower part. Flowing around the fuselage 2, the flow is gradually mixed with external air and this air gets partially assumed by the wall jet. Near the center of lower part of the fuselage 2 the wall jet gradually deviates from the wall and flows in the downward direction into the open air.

The total amount of the lift can be affected by changing the turning speed of the rotor 3, which will change, on all sides of aircraft 1 simultaneously, velocity and flow rate of air sucked by the rotor 3.

The motion control of the aircraft 1 around the vertical axis is provided by large number of adjustable vanes 6 located past the output from the rotor 3, unlike with the mentioned prior art where the aircraft motion control around the vertical axis is provided by combination of large number of fixed vanes and few adjustable vanes, which direct the wall jet to apropriate direction of rotation so the aircraft 1 turns into desired direction.

The flight direction control of the aircraft 1 is provided by leaning the aircraft 1 which is caused by the change of lift forces on various sides of the aircraft 1. Resulting tilting moment will tilt the aircraft 1 and this will create a horizontal component of total lift force which will set the aircraft 1 in motion in given direction.

With aircrafts according to the mentioned prior art, the aircraft's tilt is achieved by sudden interuption of the wall jet with gates, perpendicular flaps or by auxiliary air flow from slots on different sides of the aircraft. As it was previously mentioned, the disadvantage of this type of control

is mostly in the inception of strong turbulency resulting in flight instability, loss of power and increase of noise.

On the other hand, the tilt of the aircraft 1 according to the present invention is controlled by using control means described below, wherein the control of tilting is based on a gradual change of velocity and air wall jet rate on various sides of an aircraft 1.

Additionaly, with use of the control means according to this invention and with simultaneous and identical change of velocity and flow rate of the air wall jet on the opposite or all sides of the aircraft 1, the gradual change of total lift force is achieved, which is faster than with the change of the rotor's 3 turning speed.

Further, examples of embodiments ofthe aircraft according to the invention using various arrangements of the control means, which arrangements can also be combined, are described. In these examples of embodiments the aircraft 1 contains in apropriate places servomotors 11 and levers with regular and ball joints which can be connected to mechanical or electronical flight control units and flight computers. Adjustable vanes 6 for vertical axis flight control of the aircraft are mechanicaly tied (Figures show the use of the connecting ring 7 that is connected to each vane 6) so the servomotor can adjust one adjustable vane 6 and all other vanes are adjusted at the same time (collective flight control of the aircraft 1 around the vertical axis) . The example of embodiment that also uses the adjustable vanes 6 for directional flight control features the connecting ring 7 that is connected to four servomotors 11 and in addition also controls the rotation of vanes 6 in such way that the air wall

jet velocities and flow rate on various sides of the aircraft change (cyclic flight direction control of the aircraft 1) .

As an alternative, each adjustable vane 6 can be connected to standalone servomotor and adjustment of vanes collection 6 can be done electronically.

The following is a description of aircraft embodiment examples according to this invention.

a) Aircraft with flight direction control by gradual change of the outlet gap width on various sides of the aircraft (Fig. 2a, 2b, and 2c) .

By changing the width of the outlet gap 5 the air velocity and wall jet rate will change accordingly on various sides of the aircraft 1. The ring 4 can be rigid so the width of the outlet gap 5 is changed by a tilt and vertical shift of the entire ring 4 - this configuration is shown in Fig. 2a. Fig. 2b shows the ring 4 made of flexible material so the width of the outlet gap 5 is changed by elastic deformation of portion of the ring 4. Another configuration is shown in Fig. 2c where the control means comprises the flaps 9 located at the outer boundary of the ring 4. To change the width of the outlet gap 5 the flaps at the outer boundary of the ring 4 are gradually tilted with respect to the fuselage 2 of the aircraft 1.

The different change of the outlet gap 5 width on various sides of the aircraft 1 will change the wall jet velocity and flow rate accordingly and will create a gradual lift change on these sides of the aircraft 1, which will make it tilt.

By a simultaneous and identical change of the outlet gap 5 width on all (or the opposite) sides of the aircraft 1 the wall jet velocity and flow rate change in this places identically and gradual change of the overall lift will be achieved.

b) Aircraft with flight direction control by tilting the rotor with respect to the aircraft's fuselage (Fig. 3)

This configuration of flight direction control of the aircraft 1 uses a control means shown in Fig. 3. Tilting of the rotor 3 which is mounted through a universal joint 13 will cause gradual decrease in wall jet velocity and flow rate on one side of the aircraft 1 while causing a gradual increase in wall jet velocity and flow rate on the other side of the aircraft 1. This will change the lift forces on respective sides of the aircraft 1 and the aircraft 1 will tilt. The transfer of torque from the motor 10 to rotor 3 is provided by dual universal joint 14.

c) Aircraft with flight direction control by cyclic and collective angle adjustment of the rotor blades (Fig. 4)

Collective change of the blades' 8 angle of the rotor 3 means that all blades 8 will change their angle by the same amount. Cyclic change of the blades' 8 angle of the rotor 3 means that each blade 8 will change its angle by the amount depending on the blade's 8 position with respect to the aircraft 1.

During the cyclic change of the blades' 8 angle (Fig. 4) the wall jet velocity and flow rate will gradually decrease on one side of the aircraft 1 while gradually increase on the other

side of the aircraft 1. This will change the lift forces on respective sides of the aircraft 1 and the aircraft 1 will tilt. During the collective change of the blades' 8 angle the wall jet velocity and flow rate will gradually change on all sides of the aircraft 1. This will also change the total lift force. Cyclic and collective change of the blades' 8 angle can be combined. The blades 8 of the rotor 3 are adjusted by a control rim 15 that rotates along with the rotor 3 and is connected through a sliding connection to a control cylinder 16 which can, if tilted and axially shifted, tilt and axially shift the control rim 15. The control cylinder 16 does not rotate and can be tilted and shifted axially by means of the attached control levers .

d) Aircraft with flight direction control by cyclic and collective angle adjustment of vanes in the outlet gap (Fig. 5)

Connecting ring 7 that controls the cyclic and collective adjustment of vanes 6 is connected to four servomotors 11 and can rotate with respect to the vertical axis (and so controls the collective angle change of the vanes 6) and also can move in horizontal plane (thereby controlling the cyclic angle change of the vanes 6) .

During the cyclic angle change the vanes 6 will change their angle so that the wall jet velocity and flow rate will gradually increase on one side of the aircraft 1 while in a corresponding manner gradually decrease on the other side of the aircraft 1. This will make the lift forces on respective sides of the aircraft 1 change accordingly and the aircraft 1 will tilt.

During the collective angle change the vanes 6 will change their angle by the same amount. This will change the rotation of the wall jet and the aircraft 1 will angle along the vertical axis.

Cyclic and collective change of the vanes 6 angle can be combined .

As it was previously suggested, the use of wall jet for aircrafts with vertical take-off and landing has so far been problematic, mainly because of insufficient means of its flight control and lack of suitable ring shape that provides the air intake into the rotor and outlet of the wall jet from the rotor onto the wall of the fuselage.

With use of the control means of the aircraft according to this invention, which contains a ring of suitable shape, the wall jet is gradually changed on various sides of the aircraft and this control is substantially more effective and accurate than the one used with the prior art aircraft. This invention significantly improves the maneuverability of the aircraft based on the use of wall jet, because there is no turbulence occurrence during the flight direction changes, the control of the amount and distribution of lift forces on the aircrafts boundary surface is very precise and unlike with previous solutions allows to counterbalance any potential nonuniform payload distribution in the aircraft by changing the distribution of the lift force. New shape of the ring also shields and dampens the aerodynamic noise from the rotor.

Newly designed types of landing gear provide very good stability during the take-off and landing and are, if retracted in the fuselage, very space efficient.

Due to new control mechanism the invented aircraft has excellent flight properties and it is easily controlled. The aircraft can, of course, utilize all available modern types of engine, besides common electrical or combustion engines it is very appropriate to use a gas turbine. For aircraft design it is recommended to use light metal alloys and composite materials. For navigation it is very common today to use autopilots and inflight computers that make flight control easier especially on long distance flights, difficult flying conditions and complicated flying maneuvers.

Aircraft with control mechanism according to this invention is very useful as an alternative to helicopters in unmanned- version or crew-version and has a wide potential of use.