GB2460246A - A helicopter emergency power system - Google Patents

A helicopter emergency power system Download PDF

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Publication number
GB2460246A
GB2460246A GB0809197A GB0809197A GB2460246A GB 2460246 A GB2460246 A GB 2460246A GB 0809197 A GB0809197 A GB 0809197A GB 0809197 A GB0809197 A GB 0809197A GB 2460246 A GB2460246 A GB 2460246A
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GB
United Kingdom
Prior art keywords
propellant
power unit
helicopter
rotor
auxiliary power
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Granted
Application number
GB0809197A
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GB2460246B (en
GB0809197D0 (en
Inventor
Matthew P Wood
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Individual
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Individual
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Priority to GB0809197.7A priority Critical patent/GB2460246B/en
Publication of GB0809197D0 publication Critical patent/GB0809197D0/en
Publication of GB2460246A publication Critical patent/GB2460246A/en
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Publication of GB2460246B publication Critical patent/GB2460246B/en
Expired - Fee Related legal-status Critical Current
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C27/00—Rotorcraft; Rotors peculiar thereto
    • B64C27/04—Helicopters
    • B64C27/12—Rotor drives
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C27/00—Rotorcraft; Rotors peculiar thereto
    • B64C27/006—Safety devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C27/00—Rotorcraft; Rotors peculiar thereto
    • B64C27/04—Helicopters
    • B64C27/12—Rotor drives
    • B64C27/16—Drive of rotors by means, e.g. propellers, mounted on rotor blades
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENTS OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D41/00—Power installations for auxiliary purposes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
    • F02C3/00—Gas-turbine plants characterised by the use of combustion products as the working fluid
    • F02C3/20—Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products
    • F02C3/26—Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products the fuel or oxidant being solid or pulverulent, e.g. in slurry or suspension
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
    • F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
    • F02C7/32—Arrangement, mounting, or driving, of auxiliaries
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
    • F02C9/00—Controlling gas-turbine plants; Controlling fuel supply in air- breathing jet-propulsion plants
    • F02C9/26—Control of fuel supply
    • F02C9/46—Emergency fuel control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2270/00—Control
    • F05D2270/01—Purpose of the control system
    • F05D2270/09—Purpose of the control system to cope with emergencies
    • F05D2270/093—Purpose of the control system to cope with emergencies of one engine in a multi-engine system
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00—Aeronautics or air transport
    • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Abstract

A helicopter 1 comprises a main power unit 2 operative to drive a rotor 4, and emergency power system / auxiliary power unit 3 operable to temporarily drive the rotor. Preferably the emergency power unit comprises a turbine 10 which is drivable by a propellant (in chamber 9). The propellant may be a solid explosive (eg. cordite) or a liquid propellant, possibly a monopropellant comprising hydrogen peroxide. A firing device 8 may be used to detonate the propellant, or a catalyst may initiate decomposition to initiate the gas generation. The rate of flow of the propellant into a reaction chamber may be controlled by a throttle. During an emergency when power to the rotorcraft fails, the emergency drive will kick in to drive the driveshaft of the main rotor to enable a safe landing. The emergency / auxiliary power unit may be initiated by control unit 7 either manually 12 or from sensor 11 signals.

Description

Helicopter with auxiliary power unit The present invention relates to a helicopter with an auxiliary power unit.
A helicopter relies on a powered main rotor to provide lift during flight and so is vulnerable to any shortage of power supplied to the main rotor.
If a helicopter suffers power failure to its main rotor or rotors, for example due to engine failure or a transmission failure, then the main rotor will only rotate under its own rotational inertia, with this rotation opposed by drag forces experienced by the rotor, resulting in a decay of the rotation. If the rotor of the helicopter is operating at a high pitch setting then the rotational velocity of the rotor will decay rapidly if a pilot fails to immediately lower the collective.
In the unpowered condition, the rotor will be unable to produce enough lift to support the weight of the helicopter, resulting in downwards acceleration of the helicopter.
Since the tail rotor is generally coupled to the main rotor, loss of power to the main rotor results in a loss of tail rotor thrust and a resultant loss of directional (yaw) control.
In limited circumstances it is possible for a helicopter experiencing such power failure to land safely by using an aerodynamic phenomenon known as autorotation whereby, as the helicopter descends, the resultant flow past the main rotor causes rotation of the rotor which results in a generation of lift that acts to slow the descent of the helicopter.
However, at present, if the power failure occurs below a certain height above groundlsea level andlor below a certain rotor rotational velocity then the helicopter will crash into the sealland before the velocity of air passing through the main rotor, as the helicopter accelerates downwards, is sufficient to rotate the main rotor fast enough to produce enough lift for a safe landing.
An important feature of safe helicopter flight is maintaining the rotational velocity of the main rotor above a certain minimum value. If the rotational velocity of the main rotor falls below this value then this can lead to an unrecoverable stall of the rotor blades and a resultant crash.
A further problem with current helicopters is that their operational envelope is limited.
For example, there is a maximum "ceiling" altitude at which helicopters can fly.
Above this altitude, the density of the air is too low to enable the rotor of the helicopter to produce adequate lift. In addition, some takeoff! landing sites may be at too a high an altitude andlor ambient air temperate for a helicopter to be able to generate enough useful power for take off/landings.
It is the object of embodiments of the present invention to overcome, or at least reduce, the problems discussed above.
According to the invention there is provided a helicopter comprising a main power unit operative to drive a rotor and an auxiliary power unit operable to temporarily drive the rotor.
The main power unit is typically an internal combustion engine, such as a piston engine or a gas turbine engine.
Preferably the auxiliary power unit has a lower mass than the main power unit.
Preferably the auxiliary power unit has a higher specific power output than the main power unit.
The auxiliary power unit preferably comprises a turbine which is drivable by a propellant. In this case, the auxiliary power unit preferably further comprises a propellant.
The propellant may be of any form. The propellant may be a light weight solid explosive, for example one of the family of materials known as cordite. Preferably the propellant has a mass in the range 100 grams to 600 grams. Even more preferably the propellant has a mass in the range 200 grams to 400 grams.
VThere the propellant is a solid, the auxiliary power unit preferably further comprises a chamber and a firing device. The propellant may be provided in the chamber and the firing device may be suitable for initiating an explosion or combustion of the propellant in the chamber. The firing device may be manually operable. In this way, a pilot of the aircraft may activate the firing device to initiate combustion or explosion of the propellant.
The chamber preferably comprises an outlet which is connected to an inlet of the turbine such that the turbine is drivable by a product of combustion or explosion of the propellant.
Generally, once combustion or explosion of the propellant is initiated, the combustion or explosion continues until all of the propellant has been used up. Therefore, the solid propellant may typically only be suitable for a one off use.
Where the propellant is solid, the auxiliary power unit preferably has a specific power output in the range 100 to 300 horse power per kilogram. More preferably the auxiliary power unit has a specific power output of 200 horse power per kilogram.
Alternatively, the propellant may be a liquid. In this case the propellant is preferably a monopropellant and even more preferably comprises hydrogen peroxide. Where the propellant is a liquid, the auxiliary power unit preferably further comprises a storage means, which houses the propellant and is connected at an outlet to a reaction chamber. In this case, the auxiliary power unit may further comprise a gas tank connected at an outlet to the storage means. A pressurised gas may be provided in the gas tank.
Where the propellant is a liquid, the auxiliary power unit preferably has a specific power output in the range 500 to 1500 horse power per kg.
The device may be arranged to pass the pressurised gas from the gas tank to the storage means. This acts to increase the pressure of the propellant relative to the pressure at an outlet of the storage means. The gas is preferably an inert gas, for
example Nitrogen.
Preferably an adjustable valve is provided at the output of the storage means. The valve may be a needle valve. Since the pressurised propellant is at a higher pressure than the air at the outlet of the storage means, the propellant will flow out of the storage means through the outlet and into the reaction chamber when the valve is in an open position. When the valve is in a closed position, the valve will act to stop or prevent the flow of the propellant out of the storage means through the outlet and into the reaction chamber.
Preferably the auxiliary power unit further comprises a catalyst housed within the reaction chamber such that, when the propellant passes into the chamber, the propellant is contacted with the catalyst causing decomposition of the propellant. The catalyst may comprise silver, platinum or any suitable material. The reaction chamber preferably comprises an outlet which is connected to an inlet of the turbine such that the turbine is drivable by a product of the decomposition of the propellant.
The adjustable valve provided at the output of the storage means may be manually operable, for example by a throttle provided in the cockpit of the helicopter. In this way the rate of flow of propellant into the combustion chamber is controllable via the throttle. This enables manual activation and control of power output from the unit to the rotor and enables the auxiliary power unit to be used more than once, depending on the amount of propellant in the storage chamber, since the thermal decomposition may be stopped and started. Once the propellant in the storage chamber has run out, the storage chamber may be re-filled with additional propellant, allowing the auxiliary power unit to become operational again.
The turbine may be drivably connected, directly or indirectly, to an engine, an ancillary gearbox, a main rotor gearbox andlor a rotor shaft of the helicopter.
The turbine is preferably mechanically coupled to the rotor. This mechanical coupling is preferably a transmission since the rotational velocity of the turbine will generally be much greater than the desired rotational velocity of the rotor.
Depending on the propellant used, the auxiliary power unit is preferably arranged such that exhaust from the turbine is fed into the main power unit of the helicopter.
This can act to increase the power output from the main power unit. For example, where the propellant is hydrogen peroxide, the products of its combustion are high temperature steam and gaseous oxygen. The oxygen contained in the exhaust acts to increase power output from the main power unit and the steam contained in the exhaust has a cooling effect on the main power unit.
In the event of failure of power supplied to the rotor, as described above, the auxiliary power unit may supply power to the rotor. This facilitates autorotation at a rotational velocity that is sufficient to produce enough lift for the helicopter to land safely.
Similarly, in the event of a loss of lift produced by the rotor, for example due to blade stall as described above, the auxiliary power unit may supply power to the rotor in order to facilitate recovery from the condition.
In addition, the auxiliary power unit may be used to increase the power produced by the rotor to a level required for certain manoeuvres/coflditiofls, for example to restore sea level power output for takeoff and landings when operating at high altitude or in high temperatures or to permit an emergency take off or landing above normal maximum operating weights.
Preferably the auxiliary power unit further comprises a control unit arranged to cause the auxiliary power unit to automatically drive the helicopter rotor in the event of an emergency condition andlor in the event of other predetermined conditions.
Preferably the control unit is arranged to cause the auxiliary power unit to drive a helicopter rotor when the rotational velocity of the rotor falls below a predetermined value. The control unit may, alternatively or additionally, be arranged to cause the auxiliary power unit to drive a helicopter rotor when one or more of the following conditions exist: a failure of power supplied to the rotor; a loss of lift produced by the rotor, for example due to stall of some or all of the rotor blades; where additional power is required to perform a certain manoeuvre, as previously described, or certain input commands are applied to the flight controls of the helicopter which may lead to any of these conditions.
The control unit may be adapted for connection, directly or indirectly, to one or more sensors of the helicopter. Examples of such sensors are for detecting the rotational velocity of the rotor of the helicopter, the altitude of the helicopter or the angle of attack of the rotor blades. The control unit may be adapted to process a signal or signals generated by the one or more sensors and to initiate andlor control power output from the auxiliary power unit to the rotor of the helicopter based on this signal or these signals. Preferably the control unit is adapted to cause the auxiliary power unit to drive the rotor when the signal or signals from the one or more sensors indicate that one or more of the abovementioned conditions exist.
Where the propellant is a solid, the control unit may be arranged to activate the firing means when the signal or signals from the one or more sensors indicate that one or more of the abovementiOfled conditions exist.
Alternatively, where the propellant is a liquid, the control unit may be arranged to control the adjustable value provided at the output of the storage means when the signal or signals from the one or more sensors indicate that one or more of the abovementioned conditions exist.
Many rotary wing aircraft have a governor system, comprising sensors and a control system linked to an engine of the aircraft and pilot operative controls, which either controls the rotational velocity of the engine or the rotational velocity of a rotor of the aircraft based on input commands of a pilot. For example, where a helicopter has an engine governor, the collective is manually controlled with the throttle being automatically controlled (although capable of being manually overridden) by the governor system in order to maintain engine rotational velocity.
Where the rotor of the helicopter is controlled by a governor system, the control unit may alternatively or additionally be connected to the governor system such that the control unit may control the adjustable valve in dependence on a signal generated by the governor system.
Alternatively, or additionally, where the helicopter comprises a warning device for sensing low rotor rotational velocity, the control unit may be adapted to cause the auxiliary power unit to drive the rotor based on a signal produced by the warning device.
The invention will now be described further by way of example only and with reference to the accompanying drawings in which: Figure i shows a schematic view of a helicopter being a first embodiment of the invention; Figure 2 shows a cross sectional view of an auxiliary power unit of the first embodiment of the invention; Figure 3 shows a schematic view of a helicopter being a second embodiment of the invention; Figure 4 a schematic view of an auxiliary power unit of the second embodiment of the invention, and Figure 5 shows an enlarged schematic view of a reaction chamber of the auxiliary power unit of the second embodiment of the invention.
With reference to figure 1, a helicopter I comprises a main power unit 2, an auxiliary power unit 3, a rotor 4 and a transmissiOn 5. The main power unit 2 and auxiliary power unit 3 are drivably connected to a drive shaft 6 of the rotor 4 via the transmisSion 5.
The auxiliary power unit 3 comprises a control unit 7, a firing device 8, a chamber 9 and a turbine 10.
The control unit 7 is connected to altitude, airspeed, attitude, rotor rotational velocity, engine rotational velocity and input control command sensors 11 of the helicopter 1.
With reference to figure 2, the control unit 7 is connected to the firing device 8, which is provided at one end of the chamber 9.
The chamber 9 is connected at an outlet to an inlet 13 of the turbine 10. An explosive cordite charge is housed within the chamber 9.
The turbine 10 has a number of radially extending blades 15 (shown as a disc) each connected at one end to a turbine shaft 16. The turbine shaft 16 is mechanically coupled to the drive shaft 6 of the rotor 4 via the transmissiOn 5.
The control unit 7 has two selectable settings, automatic and manual. These settings are manually selectable via a switch (not shown), provided in the cockpit of the helicopter 1, connected to the control unit 7.
The control unit 7 receives signals from the altitude, airspeed, attitude, rotor rotational velocity, engine rotational velocity and input control command sensors 11. In the automatic setting, the control unit 7 automatically activates the flring device 8 when these signals show one or more of the following conditions: the rotational velocity of the rotor 4 faIls below a predetermined value; a failure of power supplied to the rotor 4; a loss of lift produced by the rotor 4, for example due to stall of some or all of the rotor blades; where additional power is required to perform a certain manoeuvre, or certain input commands are applied to the flight controls of the helicopter 1 which may lead to any of these conditions.
The control unit 7 is also connected to a manual trigger 12, provided in the cockpit of the helicopter 1. In the manual setting, activation of the manual trigger 12 sends a signal from the trigger 12 to the control unit 7. The control unit 7 then actuates the firing device 8.
In both the manual and automatic settings, the actuation of the firing device 8 initiates an explosion of the cordite charge. This explosion forces gas at high temperature and velocity through the outlet of the chamber 9 and into contact with the turbine blades 15. The high velocity gas impinges on the turbine blades 15, which causes the gas to change direction. The resulting impulse on the turbine blades 15 rotates the turbine shaft 16 at a high rotational velocity.
The rotation of the turbine shaft 16 is transferred to the rotor 4 of the helicopter 1 through the transmission 5 which drives the rotor 4 at a lower rotational velocity than that of the turbine shaft 16.
With reference to figures 3 and 4, in a second embodiment of the invention, a helicopter 17 comprises a main power unit 18, an auxiliary power unit 19, a rotor 20 and a transmission 21. The main power unit 18 and auxiliary power unit 19 are drivably connected to a drive shaft 22 of the rotor 20 via the transmissiOn 21.
The auxiliary power unit 19 comprises a control unit 23, a gas tank 24, a storage chamber 25, a reaction chamber 26, and a turbine 27.
The gas tank 24 houses pressurised nitrogen gas and is connected at an outlet to the storage chamber 25. Between the gas tank 24 and the storage chamber 25, there is provided a gas regulator 30, which controls the rate of flow of the nitrogen gas out of the gas tank 24 into the storage chamber 25, and a non-return valve 31 which only allows flow of the nitrogen gas in a direction towards the storage chamber 25.
The storage chamber 25 houses liquid hydrogen peroxide. The pressurised nitrogen gas in the gas tank 24 passes into the storage chamber 25 and acts to increase the pressure of the hydrogen peroxide.
The storage chamber 25 is connected via an outlet to the reaction chamber 26 and an adjustable valve 32 is provided between the storage chamber 25 and the reaction chamber 26. Since the pressurised hydrogen peroxide is at a higher pressure than the air at the outlet of the storage chamber 25, the hydrogen peroxide will flow out of the storage chamber 25 through the outlet and into the reaction chamber 26 when the adjustable valve 32 is in an open position. When the valve 32 is in a closed position, the valve 32 will act to stop or prevent the flow of the hydrogen peroxide out of the storage chamber 25 through the outlet and into the reaction chamber 26. The valve 32 may occupy a number of positions in between a fully open and closed position. In this way, the position of the valve 32 controls the rate of flow of the hydrogen peroxide into the reaction chamber 26.
The propellants described above provide high levels of energy/power for low weight and bulk. In addition, they are simple to use, can generate power in fractions of a second and can be stored for long periods of time without maintenance.
The control unit 23 has two selectable settings, automatic and manual. These settings are manually selectable via a switch (not shown), provided in the cockpit of the helicopter 17, connected to the control unit 23.
The control unit 23 receives signals from the altitude, airspeed, attitude, rotor rotational velocity, engine rotational velocity and input control command sensors 28.
In the automatic setting, when the signals from the sensors 28 show one or more of the following conditions: the rotational velocity of the rotor 20 falls below a predetermined value; a failure of power supplied to the rotor 20; a loss of lift produced by the rotor 20, for example due to stall of some or all of the rotor blades; where additional power is required to perform a certain manoeuvre, or certain input commands are applied to the flight controls of the helicopter 17 which may lead to any of these conditions, the control unit 23 controls the position of the adjustable valve 32 in dependence on these signals.
The control unit 23 is also connected to a manual throttle 29, provided in the cockpit of the helicopter 17. In the manual setting, the control unit 23 controls the position of the adjustable valve 32 depending on a selected position of the throttle 29.
With reference to figure 5, the reaction chamber 26 houses a catalytic bed comprising a vapouriser catalyst bed 33 and a high temperature catalyst bed 34. When the valve 32 is in an open condition, the hydrogen peroxide flows out of the storage chamber 25 and enters the reaction chamber 26 through an inlet 35 and passes through a spray nozzle 36. The spray nozzle 36 disperses the hydrogen peroxide over the catalytic bed.
As the hydrogen peroxide contacts the catalytic bed it undergoes exothermic decomposition to form high temperature steam and oxygen. The flow of the steam is accelerated as it passes through a convergentdivergeflt nozzle 37 and out of the reaction chamber 26.
An outlet of the reaction chamber 26 is connected to an inlet of the turbine 27. The high velocity steam flows exits the reaction chamber 26 and enters the turbine 27. The turbine 27 has a number of radially extending blades each connected at one end to a turbine shaft. The flow of steam impinges on the turbine blades, which causes the velocity of the steam to change direction. The resulting impulse on the turbine blades rotates the turbine shaft at a high rotational velocity.
The turbine shaft is mechanically coupled to the drive shaft 22 of the rotor 20 through the transmission 21. The rotation of the turbine shaft is transferred to the rotor 20 of the helicopter 17 through the transmission 21 which drives the rotor 20 at a lower rotational velocity than that of the turbine shaft 22.
It can therefore be seen that, in the event of failure of power supplied to the rotor, the embodiments of the auxiliary power unit described above may supply power to the rotor. This supply of power may be manual or automatic and facilitates autorotation at a rotational velocity that is sufficient to produce enough lift for the helicopter to land safely.
Similarly, in the event of a loss of lift produced by the rotor, for example due to blade stall as described above, the embodiments of the auxiliary power unit described above may manually or automatically supply power to the rotor in order to facilitate recovery from the condition.
In addition, the embodiments of the auxiliary power unit described above may manually or automatically increase the power produced by the rotor to a level required for certain manoeuvres/conditionS, for example to restore sea level power output for takeoff and landings when operating at high altitude or in high temperatures or to permit an emergency take off or landing above normal maximum operating weights.
The embodiments of the auxiliary power unit described above have a high specific power output and therefore may be used on a helicopter without adding significantly to the weight of a helicopter.
It is to be understood that the invention is not intended to be restricted to the details of the above embodiments.

Claims (23)

  1. CLAIMS1. A helicopter comprising a main power unit operative to drive a rotor and an auxiliary power unit operable to temporarily drive the rotor.
  2. 2. A helicopter according to claim 1 wherein the auxiliary power unit has a higher specific power output than the main power unit.
  3. 3. A helicopter according to either of claims 1 or 2 wherein the auxiliary power unit comprises a turbine which is mechanically coupled to the rotor and is drivable by a propellant.
  4. 4. A helicopter according to claim 3 wherein the auxiliary power unit is arranged such that exhaust from the turbine is fed into the main power unit of the helicopter to increase the power output from the main power unit.
  5. 5. A helicopter according to either of claims 3 or 4 wherein the auxiliary power unit comprises a propellant.
  6. 6. A helicopter according to any of claims 3 to 5 wherein the propellant is a light weight solid explosive.
  7. 7. A helicopter according to claim 6 wherein the auxiliary power unit has a specific power output in the range 100 to 300 horse power per kilogram. * 18
  8. 8. A helicopter according to either of claims 6 or 7 when dependent on claim 5 wherein the auxiliary power unit further comprises a chamber and a firing device, the propellant is provided in the chamber and the firing device is suitable for initiating an explosion or combustion of the propellant in the chamber.
  9. 9. A helicopter according to claim 8 wherein the firing device is manually operable.
  10. 10. A helicopter according to any of claims 3 to 5 wherein the propellant is a liquid.
  11. 11. A helicopter according to claim 10 wherein the propellant is a monopropellant.
  12. 12. A helicopter according to either of claims 10 or 11 wherein the propellant comprises hydrogen peroxide.
  13. 13. A helicopter according to any of claims 10 to 12 wherein the auxiliary power unit has a specific power output in the range 500 to 1500 horse power per kg.
  14. 14. A helicopter according to any of claims 10 to 13 when dependent on claim 5 wherein the auxiliary power unit further comprises a storage means, which houses the propellant and is connected at an outlet to a reaction chamber.
  15. 15. A helicopter according to claim 14 wherein the auxiliary power unit further comprises a gas tank connected to the storage means so as to increase the pressure of the propellant.
  16. 16. A helicopter according to either of claims 14 or 15 wherein a catalyst is housed within the reaction chamber such that, when the propellant passes into the chamber, the propellant is contacted with the catalyst causing decomposition of the propellant.
  17. 17. A helicopter according to any of claims 14 to 16 wherein the reaction chamber comprises an outlet which is connected to an inlet of the turbine such that the turbine is drivable by a product of decomposition of the propellant.
  18. 18. A helicopter according to any of claims 14 to 17 wherein the rate of flow of propellant into the reaction chamber is controllable via a throttle.
  19. 19. A helicopter according to any preceding claim wherein the auxiliary power unit further comprises a control unit arranged to cause the auxiliary power unit to automatically drive the helicopter rotor in the event of an emergency condition andlor in the event of other predetermined conditions.
  20. 20. A helicopter according to claim 19 wherein the control unit is adapted to process a signal or signals generated by one or more sensors of the helicopter and to initiate andlor control power output from the auxiliary power unit to the rotor of the helicopter based on this signal or these signals.
  21. 21. A helicopter according to either of claims 19 or 20 wherein the control unit is connected to a governor system of the helicopter such that the control unit may control the rate of flow of propellant into the combustion chamber in dependence on a signal generated by the governor system.
  22. 22. A helicopter according to any of claims 19 to 21 wherein the control unit is adapted to cause the auxiliary power unit to drive the rotor based on a signal produced by a warning device for sensing low rotor rotational velocity.
  23. 23. A helicopter substantially as described herein with reference to either figures 1 and 2 or 3 to 5 of the accompanying drawings.
GB0809197.7A 2008-05-21 2008-05-21 Helicopter with auxiliary power unit for emergency rotor power Expired - Fee Related GB2460246B (en)

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GB0809197.7A GB2460246B (en) 2008-05-21 2008-05-21 Helicopter with auxiliary power unit for emergency rotor power

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GB0809197.7A GB2460246B (en) 2008-05-21 2008-05-21 Helicopter with auxiliary power unit for emergency rotor power

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GB0809197D0 GB0809197D0 (en) 2008-06-25
GB2460246A true GB2460246A (en) 2009-11-25
GB2460246B GB2460246B (en) 2012-09-19

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2967133A1 (en) * 2010-11-04 2012-05-11 Turbomeca METHOD OF OPTIMIZING THE SPECIFIC CONSUMPTION OF A BIMOTING HELICOPTER AND BIMOTING ARCHITECTURE WITH A CONTROL SYSTEM FOR ITS IMPLEMENTATION
WO2014009620A1 (en) * 2012-06-15 2014-01-16 Turbomeca Method and architecture for the optimized transfer of power between an auxiliary power motor and the main engines of a helicopter
CN104487345A (en) * 2012-06-29 2015-04-01 涡轮梅坎公司 Method and configuration for an auxiliary power engine to deliver propulsive and/or non-propulsive energy in a helicopter architecture
FR3019588A1 (en) * 2014-04-08 2015-10-09 Snecma DEVICE FOR ASSISTING A SOLID PROPERGOL PROPULSIVE SYSTEM OF A MONOMOTING HELICOPTER, MONOMOTOR HELICOPTER COMPRISING SUCH DEVICE AND CORRESPONDING METHOD
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EP3362357A4 (en) * 2015-10-13 2019-06-12 Newrocket Ltd. Thrusting rockets for enhancing emergency autorotation
RU2722524C1 (en) * 2019-10-14 2020-06-01 Михаил Сергеевич Беллавин Helicopter
US11512645B2 (en) * 2020-03-06 2022-11-29 Goodrich Corporation Solid-propellant gas generator assemblies and methods

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WO2012059671A3 (en) * 2010-11-04 2012-07-19 Turbomeca Method of optimizing the specific fuel consumption of a twin engine helicopter and twin engine architecture with control system for implementing it
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US10059460B2 (en) 2012-06-15 2018-08-28 Safran Helicopter Engines Method and architecture for the optimized transfer of power between an auxiliary power motor and the main engines of a helicopter
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CN106536350A (en) * 2014-04-08 2017-03-22 赛峰飞机发动机公司 Device for assisting a solid propellant propulsion system of a single-engine helicopter, single-engine helicopter comprising such a device
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KR102258405B1 (en) 2014-04-08 2021-05-31 사프란 에어크래프트 엔진 Device for assisting a solid propellant propulsion system of a single-engine helicopter, single-engine helicopter comprising such a device
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US11512645B2 (en) * 2020-03-06 2022-11-29 Goodrich Corporation Solid-propellant gas generator assemblies and methods

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