The F-16 flight control system used an automatic variable wing camber to maximize the L/D ratio at all regimes of flight. Due to the relaxed stability requirements the flight control system was absolutely critical to the operation of the aircraft. It had 2 flaperons, 2 all-moving horizontal tails, and 1 rudder. It used integrated servo actuators with 4 independent electrical branches. It was decided to use only FBW because the aircraft wouldn’t be able to be controlled without it. The Relaxed-static stability meant that the aircraft would not be controllable without the electronic flight control system therefore, there was no need for a mechanical backup. The flaperons were fail-operative/fail-safe and the rudder was fail-operative/fail-operative. This was accomplished by comparing the servo position with the expected model and if there is an error of more than 20% of a stroke the servo was centered. The aircraft was aerodynamically safe with a rudder or a single flaperon centered. It used a Quad channel active selection algorithm. Each independent signal source originates as 4 channels, each of which are processed individually.[^7] Early engineering simulations examined the use of a MACH controller from 1993-1996. The F-16 uses an AOA-based feedback augmentation system.[^3] The -A variant used a quad-redundant analog system with no backup.[^5] The gains are scheduled using air data.[^7] The flight control systems provides dynamic stability augmentation.[^7] it also provides interconnects between the rudder and aileron.[^7] The FCS stabilizes the relaxed-stability of the aircraft.[^7] It also includes AOA and normal acceleration limiting.[^7] The F-16 sidestick uses quadrex force sensors in each axis.[^7] It is identical to the stick sensing unit deployed on the A-7.[^7] The sensing element is adapted from the F-111 grip.[^7] The F-16 also used roll-rate, G-limiting, yaw-rate limiting, and AOA limiting.[^8] The rudder control comes from a minimum-displacement rudder bar.[^8] The pitch integrators tend to drive to hardover because they don’t have interloop feedbacks.[^8] Therefore each branch integrator output must be maintained close to the branch output.[^8] In case of a failure this prevents large surface commands.[^8] Production aircraft use weight-on-wheel 4-pole limit switches.[^8]
[[F-16 Leading Edge Flap]]
[[F-16 Trailing Edge Flaperons]]
[[F-16 Aerodynamics]]
[[F-16 Speed Brakes]]
[[F-16 FCS Actuator]]
[[F-16 Control System Block Diagram]]
[[YF-16 Control System Block Diagram]]
[[Servoactuator Redundancy]]
[[F-16 Stabilators]]
[[F-16 Active Selection Algorithm]]
[[F-16 Air Data Selection]]
[[F-16 High AOA Enhancement Features]]
[[F-16 Roll Coordination]]
[[F-16 Roll-Rate Limiter]]
[[F-16 Rudder Fadeout]]
[[F-22 Flight Control System]] – had a basic command architecture similar to the F-16
[[F-117 Flight Control System]] – used a modified F-16 system
[[Lear Astronics]] – produced many F-16 system components[^4]
[[Force Command Architecture]] – used on early F-16A
[[Application of Multivariable Control Theory to Aircraft Control Laws]] – developed dynamic inversion control laws for the F-16
F-22 Flight Control System – initial control system was similar to the F-16
[[F-16 Control Surfaces]]
[[F-16 Auto-GCAS]] – added to analog computers of the pre-Block 40 aircraft
[[F-16 Analog FCC]]
[[F-16 Sidestick]]
[[F-16 Rudder Bar]]
[[F-16 Rate Gyro]]
Sources
- [1] The General Dynamics Case Study on the F-16 Fly-By-Wire Flight Control System.
- [2] 20100033140
- [3] T. T. IVlyers, D. E. Johnston, and D. T. McRuer, “Space Shuttle Flying Qualities and :Flight ~Control System Assessment Stu«:ly — Phase II”.
- [4] R. Loschke, “Development of the F-117 Flight Control System,” in AIAA Guidance, Navigation, and Control Conference and Exhibit, Austin, Texas: American Institute of Aeronautics and Astronautics, Aug. 2003. doi: 10.2514/6.2003-5762.
- [5] K. T. Knoll, “Risk Management in Fly-By-Wire Systems.” Accessed: Jul. 05, 2024. [Online]. Available: https://ntrs.nasa.gov/api/citations/19930013514/downloads/19930013514.pdf
- [6] “Control Power Criteria for Statically Unstable Aircraft.”.
- [7] C. A. Anderson, “DEVELOPMENT OF AN ACTIVE FLY-BY-WIRE FLIGHT CONTROL SYSTEM”.
- [8] “F-16 flight control system redundancy concepts.” Accessed: Sep. 09, 2024. [Online]. Available: https://arc.aiaa.org/doi/epdf/10.2514/6.1979-1771
Backlinks
[[A-7 Flight Control System]]
[[F-16]]
F-22 Flight Control System
[[F-111 Flight Control System]]
[[Fail-Operative Systems]]
[[Honeywell Multi-Application Control (MACH)]]
[[Superaugmented Aircraft]]
[[YF-16