Adding a spring to the control stick has the effect of either increasing or decreasing the speed stability of an aircraft. Springs don’t affect the forces during maneuvering flight as the spring force is constant no matter what the load factor is. Dampers can help to improve stick centering. Artificial feel systems may cause a PIO as the increased damping may cause the system roots to go unstable at lower gains. A pilot model must be included with the artificial feel systems.
[[Bobweight]] – increases the natural frequency of the artificial feel system
Dynamic Pressure Feedback – acts as a mechanical gain scheduler
[[F-4C Stick Feel System]]
[[F-8 DFBW Flight Control System]] – added a viscous damper to the stick
[[F-18 Longitudinal Auto Flap Up]] – stick force feel system is provided by pitch rate feedback
[[Pitch Rate Tracking Control]] – by scheduling using dynamic pressure, the pitch-rate feedback system provides good stick force cues
Sources
- Air Force Test Pilot School Edwards Afb Ca, “Volume II. Flying Qualities Phase. Chapter 14: Flight Control Systems.:,” Defense Technical Information Center, Fort Belvoir, VA, Dec. 1988. doi: 10.21236/ADA319984.
Backlinks
[[Aircraft Trim]]
[[Hess Structural Pilot Model]]
[[Load Factor]]
Pilot-Induced Oscillations
[[Pilot-Vehicle Model]]
[[Single-Axis Satellite Dynamics]]
Speed Stability
[[Spring Constant]]