Manual brake override

1. A manual brake override system, comprising:

a gear system;

an electric motor in operative communication with the input of the gear system;

a holding brake in operative communication with the input of the gear system, configured to prevent movement within the gear system when engaged; and

a manual handwind in operative communication with the input of the gear system;

wherein the manual handwind and holding brake are configured such that the input of the gear system can be driven, with the manual handwind, whilst the holding brake is engaged.

2. The manual brake override system of claim 1 , wherein

the gear system, electric motor, holding brake and manual handwind form part of an actuator.

3. The manual brake override system of claim 2 , wherein the actuator is a rotary actuator.

4. The manual brake override system of claim 1 , wherein the gear system is a multi-stage gearbox.

5. The manual brake override system of claim 1 , wherein the electric motor and the holding brake are connected in series along an axle.

6. The manual brake override system of claim 1 , wherein the holding brake is configured such that it is engaged when depowered.

7. The manual brake override system of claim 1 , wherein the holding brake is configured to provide a braking torque τ brake ; and

wherein the manual handwind is configured such that it can impart a torque, τ handwind which is greater than τ brake , in response to a manually applied torque τ manual applied through the manual drive handwind.

8. An aircraft, comprising:

the manual brake override system of claim 1 .

9. The aircraft of claim 8 , wherein the gear system, electric motor, holding brake and manual handwind form part of a rotary actuator that is used to fold a wing of the aircraft.

10. The manual brake override system of claim 1 , wherein the holding brake is configured such that it is engaged when depowered.

11. A manual brake override system, comprising:

a gear system;

an electric motor in operative communication with the input of the gear system;

a holding brake in operative communication with the input of the gear system, configured to prevent movement within the gear system when engaged; and

a manual handwind in operative communication with the input of the gear system;

wherein the manual handwind and holding brake are configured such that the input of the gear system can be driven, with the manual handwind, whilst the holding brake is engaged;

wherein the holding brake is configured to provide a braking torque τ brake ; and

wherein the manual handwind is configured such that it can impart a torque, which is greater than, in response to a manually applied torque applied through the manual drive handwind;

wherein the ratio of the manually applied torque τ manual and the imparted torque by the handwind τ handwind is greater than 5:1.

12. An aircraft, comprising:

the manual brake override system of claim 8 .

13. The aircraft of claim 12 , wherein the gear system, electric motor, holding brake and manual handwind form part of a rotary actuator that is used to fold a wing of the aircraft.

14. The manual brake override system of claim 8 , wherein

the gear system, electric motor, holding brake and manual handwind form part of an actuator.

15. The manual brake override system of claim 8 , wherein the gear system is a multi-stage gearbox.

16. The manual brake override system of claim 8 , wherein the electric motor and the holding brake are connected in series along an axle.

17. A method comprising:

providing a gear system;

providing an electric motor in operative communication with the input of the gear system;

providing a holding brake in operative communication with the input of the gear system, configured to prevent movement within the gear system when engaged;

providing a manual handwind in operative communication with the input of the gear system; and

manually driving the input of the gear system whilst the holding brake is engaged.

18. The method of claim 17 , wherein the gear system, electric motor, holding brake and manual handwind form part of an actuator.

19. The method of claim 18 , wherein said actuator is a rotary actuator.

20. The method of claim 17 , wherein method is used manually fold a wing of an aircraft.