Patent Description:
The present invention relates, moreover, to a method for assisting the performance of a manoeuvre for the aforesaid aircraft capable of hovering or a flight simulation system of such an aircraft.

Helicopters comprise, in a known way, an engine system, a main rotor driven by the engine system, having a plurality of blades, and adapted to provide the lift necessary to sustain the helicopter itself and the thrust necessary for the directional control of the helicopter itself.

The tilt-rotor aircrafts comprise, as known:.

The tilt-rotor aircraft can be switched between:.

In the airplane configuration, the rotors behave as the traditional propellers of an airplane and generate the required thrust required to sustain the airplane itself. In such a configuration, the lift required to sustain the airplane is provided by the fixed wing.

In the helicopter configuration, the rotors provide both the lift required to sustain it and the thrust required to the manoeuvrability of the tilt-rotor aircraft along the aforesaid first and second axis.

Helicopters and tilt-rotor aircrafts arranged in the helicopter configuration have a characteristic velocity not to be exceeded during the flight, known as Velocity to never exceed, hereinafter referred to as the velocity VNE.

This velocity VNE is characteristic of each helicopter/tilt-rotor aircraft and is determined either from aerodynamic limits such as the stall of the receding blade and the need to avoid a transonic flow on the advancing blade, or from structural limits, such as the need not to generate excessive loads on the shaft and hub of the main rotor.

The velocity VNE is determined through design evaluation and flight experiments, and depends on numerous parameters characteristic of the flight conditions and the aircraft itself. The most relevant parameters are air temperature, altitude and weight.

In other words, the velocity VNE defines a limit to the flight envelope of the aircraft, i.e. to the value of maximum velocity at which the aircraft can operate at respective altitudes.

Aircrafts capable of hovering of known type comprise an instrument which provides the pilot with an indication of this velocity VNE, as the flight conditions of the aircraft vary.

In commonly used solutions, the velocity VNE that is indicated to the pilot is based only on the air temperature and the actual altitude of the aircraft and on the maximum weight of the aircraft at take-off.

Since a lower actual weight of the aircraft corresponds to a higher velocity VNE, the commonly used solutions result in a default estimate of the velocity VNE and a consequent reduction in the available flight envelope of the aircraft.

There is a perceived need in the industry to provide a more accurate indication of the velocity VNE to the pilot, in order to increase the flight envelope in terms of velocity and reduce the workload on the pilot.

<CIT> describes a method for generating an alarm in case the hovering aircraft exceeds the velocity VNE, which is also evaluated based on the weight of the aircraft.

<CIT> describes a method for calculating the velocity VNE based also on the actual weight of the aircraft.

<CIT> discloses a control unit for control unit for an aircraft capable of hovering according to the preamble of claim <NUM> and a method for assisting the performance of a manoeuvre by means of an aircraft configured to be able to hover according to the preamble of claim <NUM>.

<CIT> discloses an instrument with a computation and display unit which determines the actual and maximum permissible flight speeds depending on measurement data, and compares them with each other. A double-pointer instrument is used to display both analogue values simultaneously. It contains a comparator which instigates a visual and/or audible warning signal when the maximum permissible flight speed is exceeded. In this way, the instruments prevents maximum permissible flight speed from being exceeded without being noticed and hence reduces risk of flight critical situations developing.

Document <CIT> according to its abstract discloses a speedometer for measuring excess speed of a helicopter having a signal processing unit to calculate excess prohibition speed of the helicopter based on signal and data from sensors.

The aim of the present invention is to realize a control unit for an aircraft capable of hovering or for a flight simulation system of said aircraft, which meets the need specified above in a simple and economical way.

According to the invention, this aim is achieved by a control unit for an aircraft capable of hovering or for a flight simulation system of such an aircraft as claimed in Claim <NUM>.

The present invention also relates to a method for assisting the performance of a manoeuvre by means of an aircraft configured to be able to hover, or for a flight simulation system of such an aircraft as claimed in Claim <NUM>.

An embodiment is described below for a better understanding of the present invention, provided by way of non-limiting example with reference to the accompanying drawings, wherein:.

With reference to the <FIG>, an aircraft is shown which is capable of hovering, that is flying at constant height and at zero velocity.

The aircraft is, in the case shown, a helicopter referred to herein below under reference number <NUM>.

Alternatively, the aircraft could be a tilt-rotor aircraft or a drone/UAV.

With reference to <FIG> denotes in particular a helicopter essentially comprising:.

In greater detail, the fuselage <NUM> comprises a pair of lateral sides 5a, 5b defining respective hatches 6a, 6b for accessing the fuselage <NUM>.

The fuselage <NUM> further comprises a nose <NUM> and a tail <NUM>.

It is possible to identify a longitudinal axis X of the helicopter <NUM> directed from the nose <NUM> to the tail <NUM> and a transverse axis Y of the helicopter <NUM>. The axis Y is orthogonal to the axis X and arranged horizontally when the helicopter <NUM> is on the ground or in a normal flight configuration.

It is also possible to identify an axis Z orthogonal to the axes X, Y and arranged vertically, when the helicopter <NUM> is on the ground or in a normal flight configuration.

The helicopter <NUM> further comprises a plurality of devices <NUM> selectively operable in respective operating configurations.

Non-limiting examples of such devices <NUM> are:.

The helicopter <NUM> further comprises, in certain embodiments, a plurality of optional kits <NUM> (only schematically indicated in <FIG>), which may be selectively installed and/or selectively operable in respective operating configurations.

Non-limiting examples of such kits <NUM> are:.

The velocity VNE is determined by numerous parameters, such as, for example, the need to avoid the stall of the receding blades <NUM> of the rotor <NUM>, to avoid the establishment of a transonic flow at the advancing blades <NUM> of the rotor <NUM> or the need not to exceed a determined level of loads on the rotor <NUM> itself.

The helicopter <NUM> is moreover characterized by a value of maximum forward velocity, hereinafter referred to as the velocity Vmax.

The velocity Vmax corresponds to the minimum value of the maximum velocities permitted to the helicopter <NUM>, when one or more of the devices <NUM> and/or kits <NUM> is installed and actuated or arranged in the relative operating configuration.

In other words, the actuation in the operating configuration of one or more devices <NUM>, the installation of one or more kits <NUM> and/or the actuation in the operating configuration of one or more kits <NUM> themselves impose a reduction of the maximum velocity of the helicopter <NUM> from the velocity VNE to the velocity Vmax, in the cases in which the velocity Vne is greater than the velocity Vmax.

For example, the use of the load device <NUM> requires a reduction of the maximum operating velocity of the helicopter <NUM> from the velocity VNE to the velocity Vmax.

In the embodiment shown, the propulsion system <NUM> comprises at least one pair of turbines <NUM>.

The propulsion system <NUM> further comprises a control unit <NUM> programmed to control the turbines <NUM>.

The control unit <NUM> is programmed to provide, as output:.

Alternatively, the propulsion system <NUM> comprises a single turbine <NUM>.

In such a case, the control unit <NUM> is programmed to provide, as output:.

The helicopter <NUM> further comprises (<FIG>):.

The interface <NUM> is electrically interfaced with the control unit <NUM>.

The interface <NUM> is configured to allow the crew to enter a plurality of data associated with an actual weight GW of the helicopter <NUM>.

In the case shown, the interface <NUM> comprises a display, for example of the touch-screen type. Alternatively, the interface <NUM> could comprise a multifunction control and display unit known as MDCU or any panel that allows the crew to enter data and/or information.

The control unit <NUM> is electrically interfaced with the interface <NUM>, the display system <NUM>, the devices <NUM>/kits <NUM> and the fuel management system <NUM>.

The display system <NUM> is electrically connected with the control unit <NUM>, the sensors <NUM> and the control unit <NUM>.

The control unit <NUM> is also programmed to receive in input the information entered by the crew in the interface <NUM>.

The display system <NUM> comprises, in turn, a plurality of display devices <NUM> preferably arranged in the cockpit <NUM>.

The display device <NUM> is programmed to receive in input:.

The helicopter <NUM> also comprises a processing system <NUM> programmed to evaluate the value of the velocity VNE.

It is important to underline that the processing system <NUM> is distributed between the interface <NUM>, the control unit <NUM> and the display system <NUM>, i.e. it comprises a plurality of stages arranged within the interface <NUM>, the control unit <NUM> and the display system <NUM>, as will become clear from the remainder of the present description.

Advantageously, the processing system <NUM> is programmed to process:.

Preferably, the processing system <NUM> is programmed to:.

Each table T1, T2,. Ti of the same set S1, S2,. Sj associated to a predetermined interval I1, <NUM>,. , Ij also corresponds to a respective AEI, OEI, Power off condition of the propulsion system <NUM>.

In other words, the number of tables T1, T2,. Tn is equal to n= ixj where j is the number of intervals <NUM>, I2,. Ij and i is the number of AEI, OEI, Power off conditions.

In more detail, the processing system <NUM> comprises:.

In more detail, the storage stage <NUM> is programmed to:.

With particular reference to <FIG>, the values of velocity Vne of the velocity profile High_VNE are greater than those of the velocity profile Medium_VNE.

The velocity values of velocity Medium_VNE are greater than those of the velocity profile Low_VNE.

The values of the actual weight GW in the interval <NUM> are greater than the values of the actual weight GW in the interval <NUM>. The values of the actual weight GW in the interval <NUM> are greater than in the interval <NUM>.

The processing stage <NUM> is programmed to use the velocity profile Low_VNE associated to the interval <NUM> with maximum values of the actual weight GW as the default velocity profile.

Preferably, the interval I1 comprises values of the actual weight that are lower than GW1, the interval <NUM> comprises values of the actual weight ranging between GW1 and GW2, and the interval <NUM> comprises values of the actual weight that are greater than GW2.

Even more preferably, the interval I1 comprises values of the actual weight that are lower than GW1-ΔGW1, the interval <NUM> comprises values of the actual weight ranging between GW1-ΔGW1 and GW2-ΔGW2, the interval <NUM> comprises values greater than GW2-ΔGW2, wherein ΔGW1, ΔGW2 are configurable values to take into account any uncertainties on the quantity of fuel present in the tank <NUM>.

Even more preferably, the processing stage <NUM> is programmed to process the velocity profile High_VNE, Medium_VNE, Low_VNE after the actual weight GW is maintained in the relative interval I1, <NUM>,. , Ij for a predetermined selectively settable time interval PT, to take into account the contribution of manoeuvres at a high angle of inclination of the helicopter <NUM> with respect to the horizon.

In particular, the values PT, ΔGW1, ΔGW2 can be set within the processing stage <NUM>.

The processing stage <NUM> is programmed to receive from the system <NUM> the value of the quantity of fuel in the tank <NUM> and to calculate the actual weight GW also based on this quantity.

More precisely, the processing stage <NUM> is programmed to calculate the actual weight GW based on the data entered by the crew in the interface <NUM> and based on the quantity of fuel present in the tank <NUM>.

The processing stage <NUM> is, moreover, programmed to acquire from the interface <NUM> a confirmation signal CONFIRM STATUS that enables the calculation of the velocity VNE based on the actual weight GW.

This signal CONFIRM STATUS can assume either a TRUE or FALSE value, depending on whether velocity VNE processing based on the actual weight GW is enabled or disabled, respectively.

In particular, the processing stage <NUM> is programmed to transmit to the display device <NUM>:.

The processing stage <NUM> is, moreover, programmed to transmit the default profile Low_VNE to the display device <NUM>, in the case in which the sensor <NUM> detects that the helicopter <NUM> is on the ground.

In other words, the processing stage <NUM> performs a reset cycle, when the sensor <NUM> detects that the helicopter <NUM> is on ground.

The processing stage <NUM> is also programmed to transmit to the interface <NUM>: the total weight of the fuel present in the tank <NUM>, the actual weight GW and the processed profile High_VNE, Medium_VNE, Low_VNE.

In the case shown, the velocity profiles High_VNE, Medium_VNE, Low_VNE, the intervals <NUM>, <NUM>,. Ij and the sets S1, S2,. Si are three in number.

Consequently, the tables T1, T2,. , Tn are nine in number.

The processing system <NUM> is, moreover, programmed to evaluate the value of the velocity Vmax.

In greater detail, the storage stage <NUM> has, in its memory, a file <NUM> wherein the installed kits <NUM> and the relative operating configurations and the operating configurations of the devices <NUM> are indicated.

The processing stage <NUM> is programmed to acquire from the interface <NUM>:.

This signal VMAX DISABLE STATUS can assume TRUE or FALSE value in the case of disabling or enabling the calculation of the velocity Vmax, respectively.

The processing stage <NUM> is programmed to calculate, as value of velocity Vmax, the minimum value between the values of the velocity Vmax that are associated to the respective devices <NUM>/kits <NUM> installed on the helicopter <NUM> and to the relative operating conditions.

Preferably, the processing stage <NUM> is programmed to process as velocity Vmax the smaller between the aforesaid minimum value and the velocity Vmaxcustom.

The control unit <NUM> is also programmed to:.

The storage stage <NUM> comprises a further table TX within which a plurality of values of the velocity Vmax associated with respective devices <NUM>/kits <NUM> installed on the helicopter <NUM> and relative conditions indicated in the file <NUM> are stored.

The processing stage <NUM> is also programmed to transmit the value of velocity Vmax to the display device <NUM> either in the case in which the signal CONFIRM STATUS assumes TRUE value or in the case in which it assumes FALSE value.

The processing stage <NUM> is, moreover, programmed to interrupt the calculation of the velocity Vmax in the case in which the signal VMAX DISABLE STATUS assumes TRUE value.

The processing system <NUM> is programmed to display on an indicator <NUM> of the display device <NUM>:.

The processing system <NUM> comprises, moreover, a generator <NUM> programmed to generate inside the cockpit <NUM>:.

The display device <NUM> acquires from the control unit <NUM> :.

The display device <NUM> of the display system <NUM> is programmed, in the case in which a signal VMAX DISABLE STATUS assumes TRUE value, to:.

The display device <NUM> of the display system <NUM> is programmed, in case the signal VMAX DISABLE STATUS assumes FALSE value, to:.

In the case in which the display system <NUM> does not receive or has lost the velocity profile High_VNE, Medium_VNE, Low_VNE processed by the processing stage <NUM> or in the case in which it receives an invalid velocity profile High_VNE, Medium_VNE, Low_VNE, a first malfunction condition is generated.

In this first malfunction condition, the storage stage <NUM> is programmed to:.

In this first malfunction condition, the display device <NUM> of the display system <NUM> is configured to display the value of velocity VNE and the message "Default VNE - invalid data".

In the case in which the storage stage <NUM> does not receive or has lost the value of velocity Vmax or in the case in which it receives an invalid value of velocity Vmax, a second malfunction condition is generated.

Upon the occurrence of this second malfunction condition, the display device <NUM> of the display system <NUM> is programmed to:.

The display system <NUM> acquires from the sensors <NUM> the actual value of velocity of the helicopter IAS and is programmed to transmit this value to the generator <NUM> in the case in which the actual velocity signal IAS exceeds the signals of velocity VNE or Vmax.

In the case shown, the processing stage <NUM> is carried by the control unit <NUM>.

The storage stage <NUM> is carried by the display device <NUM>.

The generator <NUM> is arranged inside the control unit <NUM>.

The display device <NUM> comprises an indicator <NUM> known as the Attitude and Direction Indicator "ADI".

The indicator <NUM> integrates the functions of attitude indicator or "artificial horizon", and of "Flight Director" i.e. it provides a representation of the optimal flight trajectory in order to maintain a desired flight path.

In greater detail, the indicator <NUM> comprises (<FIG>):.

The position of the indication <NUM> on the scales <NUM> and <NUM> is representative of the respective roll and pitch angles of the helicopter <NUM>.

The indications <NUM> and <NUM> are shown on the graduated scale <NUM> at the respective notches <NUM> corresponding to the velocity VNE and to the velocity Vmax, respectively.

Preferably, the indications <NUM>, <NUM> are formed by respective labels "VNE Threshold" and "Vmax threshold".

With reference to <FIG>, the interface <NUM> allows the crew to enter the data necessary to calculate the actual weight GW and to calculate the velocity Vmax.

In more detail, the interface <NUM> comprises:.

The area <NUM> in turn comprises (<FIG>):.

The fields <NUM> allow the entry of data relative to the basic operating weight of the helicopter <NUM>, the position of the base centre of gravity of the helicopter <NUM>, the weight of the crew, the weight of the equipment of the cockpit <NUM>, the weight of the devices <NUM>/kits <NUM> installed on the helicopter <NUM> and the weight of the baggage.

The fields <NUM> display the total weight of the fuel detected by the system <NUM>, the actual weight GW of the helicopter <NUM>, the position of the centre of gravity of the helicopter <NUM> and the velocity profile High_VNE, Medium_VNE, Low_VNE processed by the processing stage <NUM>.

The field <NUM> allows the activation/deactivation of the signal CONFIRM STATUS.

In the case shown, the fields <NUM>, <NUM>, <NUM> are conformed like rectangles and are arranged according to a plurality of horizontal lines superimposed on each other.

The area <NUM> comprises (<FIG>), in turn:.

The field <NUM> allows activating/deactivating the signal VMAX DISABLE.

The field <NUM> allows activating/deactivating the installation of respective devices <NUM>/kits <NUM>.

In the case shown, the fields <NUM>, <NUM>, 93a, 93b are conformed like rectangles and are arranged according to a plurality of horizontal lines superimposed on each other.

The operation of the helicopter <NUM> is described starting from an ignition condition. In this condition, the confirmation signal CONFIRM STATUS assumes FALSE value and the processing stage <NUM> of the processing system <NUM> selects the default velocity profile VNE_Low Profile.

The storage stage <NUM> acquires the AEO, OEI, Power off condition indicated by the system <NUM> and selects the corresponding table T1,. Ti from the set S1, S2,. Sj associated with the default velocity profile Vne_Low Profile.

The velocity VNE displayed in the indication <NUM> varies during operation of the helicopter <NUM>, depending on the signals ALT, OAT detected by the sensors <NUM> and based on the signals AEO, OEI, Power off when the propulsion system <NUM> comprises at least two turbines <NUM> or on the signals AEO, Power off when the propulsion system <NUM> comprises only one turbine <NUM>.

The display device <NUM> displays the velocity VNE on the indication <NUM>.

Either in the case in which the helicopter <NUM> is on the ground or in the case in which the helicopter <NUM> is flying, the processing step <NUM> of the processing system <NUM> continues to select the default velocity profile VNE_Low Profile until the crew activates the confirmation signal CONFIRM STATUS via the field <NUM> of the interface <NUM>.

After activation, the signal CONFIRM STATUS assumes TRUE value.

In the case in which it is desired to initialise the calculation of the velocity VNE based on the actual weight GW, the crew enters the data relative to the base operating weight BOW of the helicopter, the weights of the crew, the weights of the equipment installed in the cockpit, the weight of the baggage and the weight of the devices <NUM>/kits <NUM> in the fields <NUM> of the area <NUM>.

The processing stage <NUM> calculates the value of the actual weight GW based on the aforesaid data, and the velocity profile High_VNE, Medium_VNE, Low_VNE associated with this actual weight GW.

More specifically, the processing stage <NUM> updates the velocity profile High_VNE, Medium_VNE, Low_VNE, based on the respective interval I1, <NUM>,. , Ij associated with the actual weight GW.

The storage stage <NUM> associates a set S1, S2,. Sj of tables T1, T2,. , Ti to the updated velocity profile High_VNE, Medium_VNE, Low_VNE.

The storage stage <NUM> selects one of the tables T1, T2,. , Ti of the set S1, S2. Sn selected, based on the actual AEO, OEI, Power off condition detected by the control unit <NUM>, and processes the value of velocity VNE from the table T1, T2,. , Ti selected and based on the values of altitude ALT and outside temperature OAT detected by the sensors <NUM>.

The processing stage <NUM> moreover processes the value of velocity Vmax associated with the devices <NUM>/kits <NUM> installed on the helicopter <NUM> based on the data contained in the file <NUM> and on what the crew has entered in the interface <NUM>.

In particular, the processing stage <NUM> calculates as the value of velocity Vmax the minimum value between the values of the velocity Vmax associated to the respective devices <NUM>/kits <NUM> installed on the helicopter <NUM> and to their relative operating conditions.

Preferably, the processing stage <NUM> is programmed to calculate as velocity Vmax the smaller between the aforesaid minimum value and the velocity Vmaxcustom.

The interface <NUM> displays in the field <NUM> of the area <NUM> the actual weight GW of the helicopter <NUM> and the velocity profile High_VNE, Medium_VNE, Low_VNE processed by the processing stage <NUM>.

The processing stage <NUM> enables the field <NUM> of the area <NUM>.

The crew confirms via the field <NUM> the data entered via the fields <NUM> of the area <NUM>.

The display device <NUM> displays the values of velocity VNE, Vmax respectively on the indications <NUM>, <NUM> of the indicator <NUM>.

During the mission and as a result of weight changes of the helicopter <NUM>, the processing stage <NUM> continuously updates the value of the actual weight GW and the corresponding velocity profile High_VNE, Medium_VNE, Low_VNE.

The storage stage <NUM> continuously updates the set S1, S2,. Sj of tables T1, T2,. Ti associated with the updated velocity profile High_VNE, Medium_VNE, Low_VNE.

The storage stage <NUM> continuously updates the table T1, T2,. Tn selected from the updated velocity profile High_VNE, Medium_VNE, Low_VNE, based on the actual AEO, OEI, Power off condition detected by the control unit <NUM>.

The storage stage <NUM>, moreover, continuously updates the velocity VNE selected from the table T1, T2,. Tn selected, based on the values of altitude ALT and outside temperature OAT detected by the sensors <NUM>.

When the sensor <NUM> detects that the helicopter <NUM> is on ground, the processing stage <NUM> transmits the default profile Low_VNE to the display device <NUM>, thus performing the reset cycle.

Otherwise, in case the crew does not confirm via the field <NUM> the data entered via the fields <NUM> of the area <NUM>, the signal CONFIRM STATUS continues to assume FALSE value.

The crew can enable the display of the velocity Vmax via the field 93b of the area <NUM> of the interface <NUM> and activate/deactivate the installation of the devices <NUM>/kits <NUM> via the field <NUM> of the area <NUM> of the interface <NUM>.

Finally, the crew can enter a value Vmax custom via the field 93a of the area <NUM> of the interface <NUM>.

The processing system <NUM> acquires the data entered in the fields <NUM>, 93a, 93b and evaluates the velocity Vmax based on the file <NUM> stored in the storage stage <NUM> and on the table Tx stored in the storage stage <NUM>.

The processing system <NUM> displays, on the indication <NUM> of the indicator <NUM>, this value of velocity Vmax or the value Vmax custom if set and lower than the processed velocity Vmax.

In case the VMAX DISABLE button is pressed in the field <NUM> of the area <NUM> of the interface <NUM>, the processing system <NUM> interrupts the processing of the velocity Vmax.

The generator <NUM> generates inside the cockpit <NUM>:.

In particular, these predetermined rates could in turn be functions of the respective velocities VNE and Vmax.

With reference to <FIG>, <NUM>' denotes a training system for a crew adapted to simulate the aerodynamic behaviour of a helicopter <NUM>'.

The system <NUM>' essentially comprises:.

The system <NUM>' comprises, moreover, a processing system <NUM>' entirely similar to the processing system <NUM>. In particular, the processing system <NUM>' comprises storage stages <NUM>', <NUM>' entirely similar to the storage stages <NUM>, <NUM> and a processing stage <NUM>' entirely similar to the processing stage <NUM>, and a control unit <NUM>' entirely similar to the control unit <NUM>.

The processing system <NUM>' is similar to the system <NUM> and will be described below only insofar as it differs from the latter; equal or equivalent parts of the systems <NUM>, <NUM>' will be marked, where possible, by the same reference numbers.

In greater detail, the processing system <NUM>' differs from the processing system <NUM> in that it processes a simulated velocity to never exceed VNE' , based on a signal GW' associated with the simulated weight of the helicopter <NUM> and on signals ALT', OAT' associated with simulated values OAT', ALT' of outside temperature and altitude.

The processing system <NUM>' moreover differs from the processing system <NUM> in that it processes a simulated value of the quantity of fuel still available, based on the data entered on the interface <NUM>' and on the commands applied to the control devices <NUM>'.

Similarly, the processing system <NUM>' differs from the processing system <NUM> in that it processes a value of simulated velocity Vmax' of the helicopter <NUM>, based on a simulation of the installation of the devices <NUM>/kits <NUM> and on the relative simulated operating conditions.

More particularly, the simulation devices <NUM>' comprise:.

In particular, the simulated graphical representation is obtained either as a simulation of the pilot's field of view or as a series of simulated flight indications provided to respective flight instruments displayed in the graphical interface <NUM>'.

In particular, the graphical interface <NUM>' comprises an interface <NUM>' and a display system <NUM>' only schematically shown in <FIG>.

The interface <NUM>' and display system <NUM>' are similar to the interface <NUM> and to the display system <NUM>, respectively and will be described below only in so far as they differ from the latter; equal or equivalent parts of the interfaces <NUM>, <NUM>' and of the display systems <NUM>, <NUM>' will be marked, where possible, by the same reference numbers.

In particular, the interface <NUM>' differs from the interface <NUM> in that it allows the crew to enter information and/or data simulated that are associated with the simulated weight GW' of the helicopter <NUM>' and with the simulated operation of the helicopter <NUM>' itself.

The display system <NUM>' differs from the display system <NUM> in that it displays information and simulated flight parameters of the helicopter <NUM> on a display device <NUM>' of the interface <NUM>.

In particular, the display system <NUM>' differs from the display system <NUM> in that it displays the simulated VNE' and simulated Vmax' velocity value.

The processing unit <NUM>' comprises a storage stage <NUM>' wherein significant data of the rotors <NUM>, <NUM> and of the helicopter <NUM> are stored.

The processing unit <NUM>' is, moreover, programmed to generate simulated signals ALT', OAT', IAS', AEO', OEI', Power off', based on the commands applied by the pilot to the control devices <NUM>'.

In use, the trainee pilot performs simulated flight manoeuvres by imparting simulated commands via the control devices <NUM>'. These simulated commands simulate certain flight conditions, e.g. of the thrust values of the rotor <NUM>, and of the flight manoeuvres, for example a low-altitude flight or hovering manoeuvre.

The processing unit <NUM>' generates simulated signals ALT', OAT', IAS', AEO', OEI' and Power off' based on the simulated commands applied by the pilot to the control devices <NUM>'.

The operation of the processing system <NUM>', the interface <NUM>', and the display system <NUM>' is similar to the operation of the processing system <NUM>, the interface <NUM>, and the display system <NUM>, respectively, and is described only as it differs from it.

In particular, the operation of the processing system <NUM>' differs from that of the processing system <NUM> in that:.

The operation of the interface <NUM>' differs from the interface <NUM> in that it allows the crew to enter information and/or data simulated that are associated with the simulated weight GW' of the helicopter <NUM>' and with the simulated operation of the helicopter <NUM>' itself.

The display system <NUM>' differs from that of the display system <NUM> in that it displays information and simulated flight parameters of the helicopter <NUM> on a display device <NUM>' of the interface <NUM>'.

In particular, the display device <NUM>' displays respectively the simulated VNE' and simulated Vmax' velocity value on the indications <NUM>', <NUM>' of the indicator <NUM>' (not visible in <FIG>).

From an examination of the features of the control unit <NUM>, <NUM>'and the method for assisting the performance of a manoeuvre according to the present invention, the advantages it allows to be obtained are evident.

In particular, the processing stage <NUM>, <NUM>' is programmed to process the velocity VNE, VNE' based on the table T1, T2,. Tn associated to the actual weight GW, GW' and to the signals ALT, OAT; ALT', OAT'.

In this way, it is possible to increase the actual or simulated flight envelope of the helicopter <NUM>, <NUM>' in terms of velocity VNE, VNE' and reduce the workload on the pilot.

The tables T1, T2,. Tn are associated to respective velocity profiles High_VNE, Medium_VNE, Low_VNE. In particular, the velocity profiles High_VNE, Medium_VNE, Low_VNE associate respective said interval I1, <NUM>,. ij of the actual weight GW, GW' to their respective constant and different values of velocity VNE, VNE'.

The use of velocity profiles High_VNE, Medium_VNE, Low_VNE with constant values of velocity to never exceed associated with respective intervals <NUM>, <NUM>,. , Ij of actual or simulated weight GW, GW' allows on the one hand to improve the accuracy of processing of the velocity to never exceed without excessive increase, on the other hand, of the computational time. Consequently, the actual or simulated velocity VNE, VNE' can be displayed in real time on the indicator <NUM>, <NUM>'.

The indication <NUM>, <NUM>' provides the crew with the value of the actual or simulated velocity VNE, VNE' on the indicator <NUM>, <NUM>' "ADI" and at the indication <NUM> relative to the actual or simulated forward velocity IAS, IAS' of the helicopter <NUM>, <NUM>'. Thanks to this, the indicator <NUM>, <NUM>' makes the value of the actual or simulated velocity VNE, VNE' visible to the crew in an easily visible area of the cockpit <NUM> and to which the crew continually pays attention during the actual or simulated flight manoeuvres of the helicopter <NUM>, <NUM>'.

The acoustic signal provided by the generator <NUM> gives the crew a clear acoustic indication that the actual or simulated velocity IAS, IAS' is approaching the velocity VNE, VNE'. This acoustic indication is useful if the crew is in an emergency manoeuvring condition in which the crew is unable to constantly maintain the attention on the indicator <NUM>, <NUM>'.

The indication <NUM>, <NUM>' and/or the acoustic signal generated by the generator <NUM> can be selectively deactivated, allowing different actual or simulated configuration modes of the helicopter <NUM>, <NUM>' according to respective actual or simulated operating scenarios.

Finally, the simulation system <NUM>' provides the crew with a simulated evaluation of the velocity VNE', allowing a simulation of the conditions that the crew will actually encounter on the helicopter <NUM>'.

Finally, it is clear that modifications and variations can be made to the control unit <NUM>, <NUM>' and the method for assisting the performance of an actual or simulated manoeuvre for the helicopter <NUM> described above without thereby departing from the scope of the appended claims.

In particular, the aircraft <NUM> could be unmanned or could be a drone.

In such a case, the indicator <NUM> would be arranged on a remote interface controlled by a user on the ground.

The tables T1, T2,. , Tn could be stored within a storage stage arranged in the control unit <NUM>.

The file <NUM> could be stored in the display system <NUM>, <NUM>' instead of in the control unit <NUM>, <NUM>'.

The tables T1, T2,. , Tn could be associated with their respective intervals I1, <NUM>,. , Ij within the display system <NUM>, <NUM>' instead of the control unit <NUM>, <NUM>'.

The actual weight GW, GW' could be processed within the display system <NUM>, <NUM>' instead of the control unit <NUM>.

Claim 1:
Control unit (<NUM>, <NUM>') for an aircraft (<NUM>, <NUM>') capable of hovering or for a flight simulation system of said aircraft (<NUM>, <NUM>'), said control unit (<NUM>, <NUM>') being programmed to receive at input at least a first signal associated with real or simulated flight parameters (ALT, OAT; ALT', OAT') of said aircraft (<NUM>, <NUM>') and provide at output a second signal (VNE, VNE') associated with a forward velocity to never exceed of said aircraft (<NUM>, <NUM>');
said control unit (<NUM>, <NUM>') being programmed to:
- process a third signal (GW, GW') associated with an actual or simulated weight of said aircraft (<NUM>, <NUM>');
characterized in that said control unit (<NUM>, <NUM>') is programmed to:
- associate plurality of tables (T1, T2, .. , Tn) to respective intervals (<NUM>, <NUM>, .. Ij) of values of said third signal (GW, GW'); each said table (T1, T2, .. , Tn) associating a plurality of values of said second signal (VNE, VNE') with a respective said first signal (ALT, OAT; ALT', OAT'; AEO, OEI, Power off; AEO', OEI', Power off');
- process said second signal (VNE, VNE'), based on said table (T1, T2, .. , Tn) associated with the relative interval (T1, T2, .. Ij) of said third signal (GW, GW') and the respective first signals (ALT, OAT; ALT', OAT');
- receive at input a fourth signal (AEO, OEI, Power off; AEO', OEI', Power off') associated with at least one further actual or simulated flight parameter of said aircraft (<NUM>, <NUM>');
- store a plurality of profiles of velocity to never exceed (High_VNE, Medium_VNE, Low_VNE) associated with respective said intervals (<NUM>, <NUM>, .., Ij) of said effective weights (GW, GW');
- associate each said velocity profile (High_VNE, Medium_VNE, Low_VNE) with a respective set (S1, S2, .. Sj) of said tables (T1, T2, .. Tn); each said table (T1, T2, .. Tn) of a said set (S1, S2, .., Sj) being associated with a respective value of said fourth signal (AEO, OEI, Power off; AEO', OEI', Power off');
- select within said set (S1, S2, .. Sj) of said tables (T1, T2, .. Tn) the table associated with the respective said fourth signal (AEO, OEI, Power off; AEO', OEI', Power off'); and
- using said selected table (T1, T2, .. Tn) to evaluate the value of said second signal (VNE, VNE').