FR2655612A1 - COMBINED HELICOPTERS. - Google Patents

Abstract

A lift rotor (13,14) providing most of the lift for vertical takeoff / landing, hovering and low speed flight of a combined helicopter (10) is driven, via a reducer (18), by a gas turbine engine (16) having a variable section final exhaust nozzle (33). The motor also provides the driving power for a blower (21) generating air flow within a tail boom (12). The air is exhausted through slots (23) in the tail boom to control the flow of air expelled by the rotor over the beam, which generates a lateral force opposing the effect of the torque of the rotor. Air is also exhausted through outlets (24,25) to produce lateral yaw control forces. In high-speed flight, most of the lift is provided by a fixed wing (15). The nozzle is adjusted so that almost all of the engine's power is used for propulsion and the rotor and blower are unloaded. In high speed flight, yaw control is performed by an aileron (27) and a rudder (28) mounted on the tail boom. This maximizes the use of engine power for propulsion, and the tail boom drag is lower, resulting in higher forward speeds.

Description

The present invention relates to combined helicopters. Basically, a

  combined helicopter can be defi-

  nor as a helicopter with means to generate

  to provide lift and / or propulsion, in addition to

lift rotor.

  A particular combined helicopter is a helicopter in which, in horizontal flight, some lift component is produced by a fixed wing and at least one propellant component is produced

  by means other than the lift rotor.

  In the operation of such a helicopter

  combined, the lift rotor is used to

  generate forces for the modes of vertical takeoff / landing and hovering and it is gradually discharged when the horizontal speed is established and the lift component

  produced by the wing increases Since the rotor of sus-

  temptation is discharged and propelling forces are produced by other means, a combined helicopter may reach higher horizontal speeds than a conventional helicopter but, depending on a number of factors, this may be

  at the expense of yield and one can meet various in-

  suitable For example, if the lift rotor

  is driven by a motor via a re-

  conductor, there is always a need for anti-torque means to counter the effect of the torque of the lift rotor in the modes of vertical takeoff / landing, hovering and low speed, and certain means allowing the control of yaw movements If a standard tail rotor is used for these functions, this results in drawbacks in that, in horizontal flight, the tail rotor absorbs power which could otherwise be used for propulsion and it generates

  also drag loads.

  A combined helicopter has been proposed (see for example GB-A-1 032 771) in which propelling forces

  sion are produced by a propeller placed in a con-

  duit and mounted at the end of a tail beam

  tending towards the rear Vertical flaps or gou-

  varnishes mounted on the outlet side of the duct deflect the propelling air for controlling yaw movements and, if necessary, for producing a force

  lateral opposing the effect of the torque of the rotor

  temptation Although a propeller is a relatively

  effective in producing a propellant thrust, it does not

  stops a drive shaft extending along the entire length of the tail beam and places a weight in a place where it is very detrimental to a favorable position

of the center of gravity.

  In order to obtain horizontal flight speeds greater than the maximum horizontal speed of certain current conventional helicopters, for example greater than 370 km / h (200 knots), the propeller of such a combined helicopter must be capable of absorb power

  maximum available from the motor when the support rotor

  tation is unloaded To meet this condition, the size of the propeller and its associated duct must be very large and the drive shaft must be very

  heavy, which aggravates the aforementioned weight problem.

  It is known, in conventional helicopters, to regulate the air circulation on a tail boom surface by blowing air from the tail beam

  so as to generate a lateral force whose ampli-

  study and direction are appropriate to oppose

  the effect of the torque of the lift rotor Two

  sitives of this type are described in GB-A-959 075 and

  GB-A-2,012,223 GB-A-959,075 further describes a provision

  fin of rudder and rudder producing forces

  lateral for yaw control during horizontal flight

  zontal Since these are descriptions of helicopters

  conventional propulsion forces for horizon flight-

  tal come entirely from the lift rotor.

  Other descriptions of helicopters include

  as a motor driven blower to provide air flow inward and backward along a tail boom structure, air being released to the atmosphere at the rear end of the beam for torque reaction and propulsion functions, are given in US-A-2,486,272, US-A-3,807,662 and

US-A-3,957,226.

  The rear end of the tail boom of the helicopter described in USA-3 807 662 has a configuration aft of the boat and it has articulated fins to control the direction of the air leaving the tail beam The air is introduced inside the tail boom by a blower

  with axial flow and variable pitch, and the fins can

  can be adjusted so that air is expelled laterally

  so as to generate lateral thrusts

  to oppose the effect of the torque of the lift rotor

  tion and for controlling yaw movements, or they can be adjusted so that the air is

  expelled backwards to generate a propelled thrust

  sive This document also describes the use of

  tion of slots, in the tail boom, through the-

  which air is blown to control the circulation

  tion of air around the tail boom in order to obtain

  an additional lateral force to oppose the ef-

  however, the lift rotor torque

  most efficient use of supply air to generate

  drive propulsive forces in flight at higher speeds

  res is not obtained with the device described in this document, since air is used to generate

  lateral yaw control forces in horizontal flight

  zontal, which reduces the propulsion component and creates an additional drag This drag results from a variation of momentum of the deflected blown air, in the direction of flight This effect is sharper

  when air is released to the perpendicular atmosphere-

  to the flight direction to make a change

  fast steering in high speed horizontal flight.

  In the device of US-A-3,957,226, a he-

  the halter having two small wings is equipped with three nozzles at the rear end of a tail beam structure Each nozzle includes a butterfly valve to control the rejection to the atmosphere of the air introduced inside the beam tail by a variable pitch blower A first of the nozzles, mounted on a

  side of the tail boom, emits air to-

  generate a lateral thrust which opposes the effect of the torque of the lift rotor and, by adjusting its butterfly valve, this thrust can be varied to control yaw movements during the flight

  stationary or at low speed A second of the

  yères, mounted on the opposite side of the tail boom, is

  used in combination with the first nozzle for ef-

  perform yaw control only during auto

  rotation The third nozzle is placed in the end

  removed from the tail boom so that it faces backwards and is used to discharge air to

  the atmosphere in order to generate a thrust for the pro-

  impulsion in high speed flight This arrangement of the nozzles does not make the best use of the blown air, in hover and at low speed, since an air flow of greater energy than is necessary in other solutions must be supplied to the first nozzle

  in order to generate the lateral force necessary to oppose

  apply to the torque of the lift rotor.

  This requirement for higher energy air alone can-

  be satisfied by an increase in mas-

  sic at the same ejection speed, which requires a larger diameter blower, or by a larger

  ejection speed at the same mass flow rate These two solutions

  tions require greater power from the blow-

  flowing and, furthermore, a large blower is difficult

  to install and causes weight disadvantages.

  GB-A-2 130 984 describes a combined helicopter comprising a variable cycle gas turbine engine which has an outlet nozzle of variable section, the engine driving a lift rotor by means of a reducer The power transmitted by the motor shaft to the rotor can be reduced in horizontal flight to discharge the rotor and thus reduce the components of

  lift and propulsion generated by the rotor.

  The variable section nozzle is adjusted to produce a

  propellant thrust compensating for the reduction in the composition

  propulsive force generated by the rotor Ce do-

  cument does not describe the use of means opposing the effect of the torque of the lift rotor, or of means

  for producing lateral forces to control the

this.

  An object of the present invention is to improve

  improve the operating performance of a combined helicopter. Another object of the present invention is to provide a combined helicopter in which the lateral forces for opposing the effect of the torque of the main rotor and for yaw control are produced by

  means other than a conventional tail rotor, and

  these propulsion for horizontal high-speed flight

  tesse are produced by means other than a propeller driven, so that the weight and drag of a

  tail beam structure forming part of the heli-

  combined copters are minimized and that substantially all

  te engine power is available for propulsion

  sion in horizontal or forward flight at high speed. In its broadest aspect, the present invention provides a combined helicopter comprising a fuselage structure including a beam structure

  tail extending backwards, a set of ro-

  lift tor to generate a major part of lift in vertical takeoff / landing, hover and low speed flight, a fixed wing to generate a major part of lift during forward flight at high speed, motor means coupled by reduction means to drive the lift rotor assembly,

  means of final exhaust nozzles with variable section

  ble connected to said motor means to generate

  propulsion forces in forward flight at high speed

  se, means of producing an air flow inside

  laughing and backward along said tail beam structure, means for discharging said air to the atmosphere from said tail beam structure to generate appropriate lateral forces which oppose the effect of the torque of the lift rotor on said fuselage structure and which allow the control of yaw movements at least during takeoff / vertical landing, hovering and

  low speed flight, and aileron and governor means

  vernail mounted on said tail boom structure to generate yaw control forces during the

forward flight at high speed.

  The means of rejection of air to the atmosphere so

  to generate lateral forces to oppose the ef-

  torque of the lift rotor and for the com-

  lace yarn can be combined and can include

  dre one or more slots extending longitudinally in a tail beam extending rearward, through which air is blown to control the circulation of the air driven down by the lift rotor on the tail beam, so that appropriate lateral forces acting on the tail beam

tail are spawned.

  In such a combined arrangement, means

  are provided to control the rejection of air to the atmos-

  sphere so that the lateral force can be varied so as to generate an imbalance with the torque

  of the lift rotor, for controlling the movements

lace yarn.

  As a variant, the means for rejection at the

  air mosphere from the tail boom may include slots that extend over at least a portion of the length of the tail boom and through

  which air is blown to control the circulation

  lation of the air expelled downwards by the suspension rotor

  temptation on the tail boom, so that a lateral force of appropriate size and direction to counter the effect of the torque of the lift rotor

  is generated, said air rejection means to the atmosphere-

  sphere further comprising air outlet openings

  fitted with pivoting closing fins placed on each

  that side of the tail boom, so that air can be selectively released to the atmosphere so as to

  generate lateral forces for the control of the

lace clothing.

  The means of producing an air flow to

  the inside of the tail beam structure can

  wind comprise a blower driven by transmission means connected to the motor and the reduction gear, or

  indeed a blower driven by an auxiliary motor.

  The blower can be an axial blower

  comprising variable pitch vanes.

  The drive means may comprise at least one gas turbine engine having a final exhaust nozzle of variable section which is part of the engine or

  well, alternatively, the final exhaust nozzle dry-

  variable tion can be part of another device

  connected to or cooperating with the motor.

  The motor or each motor may be a variable cycle motor and means may be provided for adjusting the power on the motor shaft supplied for

  drive the lift rotor so that the power

  power supplied to the lift rotor is substantially

  reduced as forward speed increases.

  A special variable cycle gas turbine engine suitable for use in a helicopter

  handset according to the present invention comprises a com-

  low pressure presser, main gas generator

  which drives the compressor, a power turbine in-

  dragged by the outlet of the main gas generator and coupled so as to drive a power output shaft, and a final exhaust nozzle of variable section downstream of the power turbine, the nozzle receiving the exhaust from the turbine of power and

  being maneuverable so as to modify the power ab-

  absorbed by the power turbine and to be modified simul-

  temporarily the propulsive thrust produced by the nozzle.

  In another aspect, the invention provides

  a combined helicopter comprising a fuselage structure

  The beam which has a tail beam structure extends

  tending towards the rear, a rotor device for

  temptation which has a plurality of rotor blades

  to generate a major part of the lift

  gluing / vertical landing, hovering and

  in flight at low speed, a fixed wing extending laterally

  on each side of the fuselage to generate a

  part of the departure during the forward flight

  at high speed, means' gas turbine engines ac-

  coupled via reduction means for driving the lift rotor device, final exhaust nozzle means with variable section which cooperate with said motor means to generate propulsive forces for forward flight at large

  speed and so you can adjust the power

  this provided for driving said lift rotor device, means for generating an air flow

  inward and backward along said structure

  tail beam structure, means provided on said tail beam structure for discharging said air to the atmosphere so as to control the circulation of air

  driven down by the main rotor on an over-

  outer face of said tail beam structure in order to produce on said tail beam structure a lateral force whose size and direction are

  suitable to counter the effect of the torque of the ro-

  lift tor on said fuselage structure when said lift rotor is driven to

  generate most of the lift,

  these air outlet comprising pivoting closing means for selectively rejecting said atmosphere to the atmosphere

  air coming from said main tail beam structure

  so as to generate lateral forces for yaw control when said lift rotor is driven

  to provide most of the lift, and mo-

  yen with aileron and rudder mounted on said structure

  tail beam structure, said rudder means being maneuverable so as to generate yaw control forces during forward flight at

  high speed when said fixed wing provides the ma-

part of the lift.

  A combined helicopter according to the present invention may include an on-board computer which can receive signals from sensors which detect engine and flight operating parameters, as well as command requests made by the crew, and provide signals optimization

of the vehicle.

  The invention will now be described in detail, by way of example only and with reference to the accompanying drawings in which: Figure 1 is a schematic side view

  of a combined helicopter conforming to an embodiment

  sation of the invention; and Figure 2 is a section along the line

I-I in Figure 1.

  We first refer to Figure 1 A heli-

  combined beetle 10 includes a fuselage structure 11 having a tail boom structure 12 extending towards

  rear A lift rotor device 13 comprising

  carrying a plurality of rotor blades 14 is placed above the fuselage 11, and a fixed wing 15 extends laterally on each side of the fuselage 11 Means

  gas turbine engines include one or more mo-

  gas turbine torches 16 mounted on the fuselage 11 and

  coupled to drive the suspension rotor device

  temptation 13 through an output tree

  motor 17, a reducer 18 and a drive shaft

  main rotor 19 Each motor 16 is also coupled, via the reduction gear 18 and a fan drive shaft 20, to drive a fan 21 which is suitably mounted in the tail beam structure 12 Blower air inlet openings (not shown in Figure 1) are provided in the structure on each side

  of the combined helicopter, and they are located towards the a-

  it is in relation to the blower 21 A duct 22 is

  provided in the tail beam 12 to guide the intro air

  blown by the blower 21 along the tail boom.

  Means for discharging air into the atmosphere to control the circulation of air on the tail beam include, in this embodiment, longitudinal slots 23 provided in a lateral surface of the tail beam 12 near its upper part and

  of its lower part Although, in this mode of rea-

  reading, each slot 23 is of continuous length, the means of rejection to the atmosphere can be constituted by a plurality of aligned slots Valves (not shown) are provided to communicate the

  slots 23 with the conduit 22 so that one can com-

  order the rejection of air from the blower through the slots 23 In operation, when the

  lift rotor is driven to create a sus-

  temptation, an air flow is directed downwards by the rotor on each outer lateral surface of the tail beam By air rejection through the slots, down, the speed of the air flow down on this side of the tail beam is increased and a lower pressure is obtained than the pressure prevailing on the opposite side of the tail beam This generates a

  net lateral force on the tail boom, the large

  deur and the direction of this force being suitable to oppose the tendency to the rotation of the fuselage in reaction to the torque of the lift rotor If the lift rotor device 13 rotates anticlockwise in order to above,

  then the fuselage tends to rotate clockwise

  those of a watch and the slots 23 are placed on the side

  starboard side of the tail boom so that the force la-

  resulting teral on the tail beam is directed from

port to starboard.

  Takeoff / vertical landing, in flight

  stationary and in low speed flight, lateral forces

  for yaw control around the equilibrium point

  free between the torque of the lift rotor and the lateral force of reaction on the tail boom are generated by rejection of air to the atmosphere through air outlet openings 24 provided on each side of the tail beam near from the end 26 remote from the blower 21, the orifices 24 being able to be closed

  by pivoting fins 25 (see Figure 2).

  A tail fin device 27 comprising a rudder 28 is provided at the free end 26 of

  the tail boom 12, the rudder 28 being operated

  real to control a yaw movement during the

  horizontal or forward flight at high speed.

  In this embodiment, each engine 16 includes a variable cycle gas turbine engine

  comprising a low pressure compressor 30, a general

  central gas generator 31 which drives the low pressure compressor 30, a power turbine 32 which is driven by the exhaust of the gas generator, and a

  variable section final exhaust nozzle 33 Tur-

  power bine 32 is coupled to the drive shaft

ment 17.

  During the operation of the helicopter com-

  twin 10, for takeoff, landing, flight modes

  stationary and low speed flight, each engine travels

  is worth at or near its maximum power, the

  variable section yere 33 being in its dry position

  maximum power The high power of the motor shaft is brought to the gearbox by the drive shaft 17 and is used to drive the lift rotor device 13, the collective pitch of the rotor blades 14 being adjusted to generate the appropriate lift forces At the same time, a cyclic pitch can be applied to the rotor blades in order to generate forces

  side and / or front-rear for equilibrium functions

  release and operation The power is also transmitted by the reduction gear and the drive shaft 20 to the blower 21 which is preferably of the axial type and with variable pitch blades The blower sucks in air

  through the blower air inlets (not shown

  tees) and it represses this has under a stronger pres-

* sion along the conduit 22 from where it is rejected at atmos-

  sphere through the slots 23, down on the over-

  outer side face of the tail boom so

  increase the speed of the air circulating on this

  face and thus generate a net lateral force on the tail boom, the size and direction of this force being suitable to oppose the reaction of the fuselage to the torque of the lift rotor To help

  the directional control opens the pi- fins

  voting 25 on either side of the tail boom

  in order to release air from the ori into the atmosphere

  associated air outlet 24 as necessary to generate a lateral force causing movement of

fuselage lace.

  A combined helicopter in accordance with the present invention eliminates the need for a conventional tail rotor, by blowing air onto the tail boom in order to

  to take advantage of the energy available in the flow of-

  ascent of the lift rotor to obtain a force

  lateral opposing the torque of the lift rotor.

  This gives the possibility of generating the forces required

  its anti-torque lift rotor while

  thinking less energy than in the case where the lateral force

  required rale is obtained by expelling air through

an ejection nozzle.

  Horizontal flight is started by application

  cyclically forward to the rotor blades

  as the forward speed increases and the wings 15

  generate an increasing lift, we decrease progress-

  the collective pitch, which unloads the rotor and has the consequence of reducing the need for adjusting the circulation on the tail boom to produce a lateral force opposing the effect of the torque of the lift rotor At the same time, we set the cyclic step

  to maintain a substantially horizontal rotor disc.

  Forward speed is established by reducing the

  section of the final exhaust nozzle 33, for

  to drive an increasing propulsive thrust by the exhaust nozzle

  When the forward speed is established, the air flow speed over the tail fin 27 increases, so that lateral forces for yaw control can be obtained by maneuvering.

  of the rudder 28 The lift rotor being

  loaded, it is not necessary to compensate the torque of the lift rotor and, since the rudder is available for yaw control, the blower 21 can be stopped, which leaves a driving power

  additional available for propulsion.

  Since a combined helicopter complying with the

  present invention does not include a propeller

  air flow mounted at the end of the tail boom to generate propulsive forces in horizontal flight

  at high speed, as has been proposed in other

  very combined helicopter configurations, avoiding the need for a drive shaft extending along the tail boom, which saves weight and helps keep the center of gravity in line with the center

of lift.

  An additional advantage is that drag loads, produced by the release of air to the atmosphere from the air outlet ports for yaw control, do not occur in high-speed horizontal flight from a combined helicopter according to the present invention. Another advantage of a combined helicopter according to the present invention is that it can maintain a substantially horizontal attitude in flight towards the

  before and during acceleration / deceleration.

  It is understood that modifications of detail can be made in the shape and construction of the device according to the invention, without going beyond the ambit

of it.

Claims (8)

  1. Combined helicopter (10) comprising a   fuselage structure (11) including a power structure   tail tail (12) which extends rearward, a lift rotor device (13) for generating   most of the liftoff / take-off   vertical sage, hover and low speed flight, a fixed wing (15) to generate a major part of the lift during forward flight at high speed, motor means (16) connected by means of reduction (18) for driving the lift rotor device, characterized in that it comprises   means of final exhaust nozzles with cross section   riable (33) connected to said motor means for generating   to propel forces for forward flight at high speed, means (21) for producing an air flow inside and towards the rear along said tail beam structure, means (23, 24) rejection to the atmosphere of said air coming from said structure of   tail beam to generate lateral forces ap-   properties opposing the effect of the torque of the rotor   temptation on said fuselage structure and allowing the   control yaw movements at least during the   sticking / vertical landing, hovering and low speed flying, and fin and rudder means (27,28) mounted on said tail boom structure to generate yaw control forces   during forward flight at high speed.   2. Combined helicopter according to the claim   tion 1, characterized in that the means for discharging air from said tail beam structure (12) to the atmosphere comprise slots (23) which extend   over at least part of the length of said structure   ture of tail boom and through which said air is blown to control the circulation of the air driven downwards by the lift rotor on the   tail beam structure so that a lateral force   a size and direction appropriate to oppose the effect of the torque of the lift rotor is generated, said means for discharging air into the atmosphere further comprising air outlet orifices (24) , provided with pivoting closing fins (25), located on each side of said tail beam structure so that said air can be selectively rejected   to the atmosphere so as to generate lateral forces   blocks for controlling yaw movements.   3 Combined helicopter according to the claim   cation 1 or 2, further characterized in that the means for producing an air flow within said tail beam structure includes a blower   (21) driven by transmission means (20) ac-   coupled to said motor means (16) and reduction means (18).   4. Combined helicopter as claimed   cation 3, further characterized in that said blowing   te is an axial blower with variable pitch blades.   5. Combined helicopter according to any one   that of the preceding claims, further characterized   in that the drive means comprise at least one   gas turbine engine (16) having a variable section final exhaust nozzle (33) constituting a part of the engine.   6. Combined helicopter according to the claim   tion 5, further characterized in that the or each mo-   tor (16) is a variable cycle engine and means   are provided to adjust the power supplied on the   bre of the motor for driving said device   lift rotor, so that the power   denies said lift rotor device is sensitive to   considerably reduced when the speed of said helicopter combined forward increases.   7. Combined helicopter according to the claim   tion 6, further characterized in that the or each mo-   variable cycle tor (16) comprises a low pressure compressor (30), a central gas generator (31) for driving the compressor, a power turbine   (32) driven by the exhaust of the central gas generator   tral and coupled so as to drive a output shaft   power tie (17), said variable section final exhaust nozzle (33) being connected so as to receive the exhaust from the power turbine and   being manoeuvrable to vary the power absorbed   opened by the power turbine and vary simultaneously   particularly the propulsive thrust generated by the nozzle.   8. Combined helicopter (10) comprising a   fuselage structure (11) including a power structure   tail tail (12) which extends rearward, a provision   lift rotor sitive (13) including a plurali-   rotor blades (14) to generate a major part   tie of lift in vertical takeoff / landing, volstationary and low speed flight, a fixed wing (15) extending laterally on each side of said fuselage structure to generate a major part   lift during forward flight at high speed   size, gas turbine engine means (16) coupled   plés by means of reduction means (18) for   drive the lift rotor device, character-   terized in that it includes exhaust nozzle means   final variable section (33) which cooperate with   said motor means for generating propelling forces   sives for forward flight at high speed and   so that the motive power provided for the drive   ment of said lift rotor device can be adjusted; means (21) for producing an air flow inside and towards the rear along said tail beam structure; means (23) provided on said tail beam structure for rejecting   said air to the atmosphere in order to control the circulation   tion of the air expelled downwards by the support rotor   tation on an external surface of said tail beam structure so as to generate on said tail beam structure a lateral force whose size and direction are suitable for canceling the effect of the torque of the lift rotor on said   fuselage structure when said lift rotor   tion is trained so as to generate the major par-   tie lift; air outlet ports (24)   provided with pivoting closure means (25) for rejection   selectively tering said air from said tail beam structure to the atmosphere in order to generate lateral forces for yaw control when said lift rotor is driven so as to provide   most of the lift; and means of   shore and rudder (27,28) mounted on said struc-   beam structure, said rudder means (28) being manoeuvrable to generate control forces of   yaw during high-speed forward flight when   that said fixed wing provides most of the tance.