Actuators
- The actuator consists of the control surfaces and associated servomechanisms, and is used to change the missile attitude and trajectory or flight path.
- Most actuators for missile applications can be of the hydraulic, pneumatic, electro-mechanical or piezoelectric type, depending on the maximum hinge moment of the control surface.
- The selection and design requirements for actuators usually depend on the following:
- The bare airframe - space requirements
- Flight conditions - forces and torques
- Guidance system - bandwidth and delays
- Noise feeding into other sub-systems - EMC
- For example, for a missile of limited flight duration, a hydraulic system has very attractive performance, weight and volume, as shown from experience with the Sparrow and Hawk missiles.
- However, it can suffer from problems after long storage i.e. from dirt, deterioration of seals etc.