GB2432348A

GB2432348A - Helicopter emergency control device

Info

Publication number: GB2432348A
Application number: GB0523389A
Authority: GB
Inventors: Peter Gregory Lloyd
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-11-16
Filing date: 2005-11-16
Publication date: 2007-05-23
Anticipated expiration: 2025-11-16
Also published as: GB2432348B; GB0523389D0

Abstract

A device for allowing control of a helicopter in the event of a tail rotor failure, the device comprising a thrust generator 7 and a thrust vector unit 8 mounted to the tail of the helicopter, the thrust vector unit 8 being controllable to direct the thrust from the rocket motor 7 so as to control the helicopter. The thrust generator 7 is preferably a solid rocket motor, but could alternatively be a liquid rocket, a hybrid rocket, a turbojet engine or an electric fan. The device may comprise an ignition device which may be operated, automatically or manually by a pilot, in the event of a tail rotor failure. The device may further comprise a control device linked to the thrust vector unit 8, the control device being operable rotate the thrust vector unit 8 and provide control of helicopter tail. The control device may further be an integral part of a set of rudder pedals.

Description

1 2432348 Emergency Device

1. Background.

The problem addressed by this invention is one experienced by operators of helicopters that incorporate a tail rotor or tail mounted thrust device such as a fan.

Many helicopter crashes occur when the tail rotors or fans fail or are damaged by external objects striking them. When a helicopter loses the thrust from its tail rotor or fan the main body or fuselage of the helicopter will begin to rotate about the axis of the main rotor due to the natural tendency of the fuselage to spin in that direction because of basic mechanical reaction summarised by Newton's third law, namely For every action there is an equal and opposite reaction'. The helicopter will begin to spin faster unless some force is applied to the tail or other fuselage component. When such uncontrolled spins occur following a failure of the tail rotor or fan the helicopter usually becomes uncontrollable and the pilot disoriented, the result usually being a crash when the helicopter reaches the ground or other object in its path.

2. The basic concept of the invention.

The basic concept of the invention is to provide an auxiliary thrust mechanism that may be brought into action by the pilot or by an automatic on-board system that will allow the controlled flight to be maintained even after the loss of thrust from the tail rotor or fan for enough time under most circumstances for the pilot to bring the helicopter in to a safe landing. The preferred method of this invention is to use a solid rocket motor and a thrust vectoring device that the pilot may control the thrust to counter the spinning tendency and guide the helicopter safely for a certain time.

3. The Invention Described.

Figure 1 shows the situation for a helicopter with a tail rotor under normal circumstances. The helicopter fuselage, containing all the normal functioning internal parts such as engines, gear box, main rotor head, tail rotor drive take off and drive shaft together with fuel tanks, pilot controls and accommodation for the occupants of the helicopter is represented by 1 in the figure 1. The main rotor blades are represented by 2 and their direction of rotation in the case shown by the arrow 3. The reaction of the helicopter to the forces of the spinning main rotor blades is for the fuselage I to rotate in the direction shown by the arrow 4. The tail rotor 5 when spinning under normal circumstances produces a flow of air in the direction shown by arrow 6. This mass of air produces a reaction on the tail that counters the tendency of the helicopter fuselage to spin in direction of arrow 3.

When the tail rotor is not functioning correctly it is the lack of the air flow shown by arrow 6 that results in the emergency situation and creates the conditions where a crash is likely.

Figure 2 show the main components of the invention A solid rocket motor 7 and thrust vector control unit 8 with axe! 9 are aligned such that the rocket exhaust 10 may be deflected to the side as shown. This rocket exhaust is used as the auxiliary means of countering the tendency of the helicopter to spin about the axis of the main rotor.

In figure 3 the thrust vector control unit has been rotated about the axel 9 so that now the rocket exhaust is to the other side. Such control of the thrust vector is desirable so that the pilot may rotate the helicopter in either direction prior to landing in order to ) 3 allow any landing gear or skids that the helicopter is equipped with to be aligned with the direction of travel over the ground. This latter point being very great important since if the helicopter touches the ground with a horizontal motion present, which is very likely under the circumstances of the emergency, any sideways motion relative to the landing gear will possibly cause the helicopter to role over and therefore be damaged.

The rotation of the thrust vector unit in accordance with the pilots wishes can be accomplished in a variety of ways, such as the axe! 9 being mechanically attached to the control mechanism used to control the thrust developed by the tail rotor under normal circumstances. The pilot applies pressure to the "rudder" peddles in the cockpit with his feet under normal circumstances and cables or rods are used to transmit this rotational motion to the tail section where it is used to change the pitch of the tail rotors and thus change the thrust generated by the tail, this in turn cause the tail of the helicopter to rotate in the direction desired by the pilot. In the emergency situation for which this invention is intended to be brought into use the cables and or rods used to change the pitch of the tall rotors could also be used to rotate the thrust vector unit 8 by being attached to the axel 9 via a horizontal lever, with the lever and the axel forming a T' shape and the cables being attached to the ends of the lever.

Alternatively, the thrust vector axel 9 and lever may be moved by an entirely independent actuator which is powered by electrical current, pneumatic or hydraulic sources. The pilot in these later cases would have to operate a separate control within the cockpit which may or may not be activated via the rudder peddles. If not via the rudder peddles the alternate power sources for controlling the rotation of the thrust vector unit would require a control knob or switch to allow pilot control of the rocket thrust direction.

Also required, but not shown in the diagrams, would be an igniter to activate the rocket 7. This could take the form of a hot wire that melts when current is passed through it, an exploding bridge wire detonator or a spark generator, or other standard methods of setting off pyrotechnics devices remotely. The activation switch for the igniter would be placed within easy reach of the pilot.

Alternate forms of thrust generators could be liquid fuelled rockets, hybrid rockets that use solid fuel elements and gaseous or liquid oxidisers, a turbojet engine or an electrically driven fan. The preferred method of this invention is the solid fuel rocket with oxidiser chemicals integral to the solid fuel as this is simplest and lightest configuration.

Figure 4 shows the invention attached to the tail of a helicopter and the rocket having been activated. The deflected rocket exhaust 10 is shown countering the tendency of the helicopter to spin without the functioning of its tail rotor 5.

Claims

Claims 1. A device incorporating a solid rocket motor and thrust vector

unit that allows the thrust to be directed in the direction of the angled faces of the thrust vector control unit and mounted on the tail of a helicopter such that the thrust may be used as an alternative to the thrust provided by the tail rotor of the helicopter.

2. A remote igniter switch or control device within easy reach of the pilot of the helicopter such that the pilot may activate the rocket as in 1 in the event that the tail rotor becomes inoperative or ineffective.

3. A thrust vector unit control input device within easy reach of the pilot or fitted as an integral part of the normal tail rotor control device or "Rudder Peddles" such that the pilots desire for changing the direction of motion or rotation of the tail of the helicopter may cause the rotation of the thrust vector unit about its directional axis and thus cause the rocket exhaust to be directed so as to force the helicopter tail to move as desired by the pilot as in 1 after 2 has been used.

4. An alternative to tail rotor thrust for a helicopter as in 1 that may be brought into action by an automatic system that may be fitted on the helicopter and may also be automatically controlled without pilot intervention.