The 'fly-by-wire' flight control system continues to confuse people. But it is understandable...
When the F-16 was under design, the philosophy was to create an exceptionally maneuverable fighter, one that would stress the human pilot more than the aircraft itself could be designed. When we finally admitted that the best the human pilot could withstand is 9g, that became the benchmark for maneuverability. The F-16 was designed with certain g-limit but it was based on the human limit. If General Dynamics wanted to, they could have designed the F-16 to withstand 20g, but what would be the point in that when the human pilot can handle only 9g ? So they designed the F-16 to be 10-ish g-limited. I was on the F-16 for five yrs. I know what 9g felt like on my body and to my vision.
Anyway...How to make such a maneuverable fighter ?
Traditional aircraft designs have always been about stability. The problem is that the higher the airspeed, the greater that stability to the point where the aircraft could not maneuver at all. It may sound somewhat odd but a certain degree of instability is needed to make maneuvers possible. What GD did was designed the F-16 to be unstable, not 'stable with some degrees of instability'. Do not confuse aerodynamics with stability. They are two separate things. Related -- but distinct. It soon became clear that the more unstable the design, the less the human pilot will be able to keep the aircraft under control.
Now there are three distinct items...
- Aerodynamics
- Stability
- Controllability
Item one -- easily done.
Items two and three -- serious problems.
General Dynamics resorted to using computers to replace the flight control system from cockpit to hydraulic actuators. Basically, there are only three truly mechanical components in the FLCS: stick, rudder, hydraulic actuators Everything in between are electrical wires. Some people might nitpick and consider the gyros and accelerometers as also mechanical components but that would be missing the larger point.
The system is a closed loop. At a high level explanation, when the pilot initiate a command thru the stick, the computer respond by moving the hydraulic actuator, which changes the aircraft's attitude such as pitch up/down or wings roll left/right. As the aicraft changes its attitude, the gyros and accelerometers senses the changes and feed that back to the computer, who then compares the result against the pilot's command. The entire loop works fast enough that stability and controllability are achieved and maintained throughout the maneuver, whether it is pitch up/down or wings roll left/right.
So to answer your question: There is no such thing as limited or full FBW FLCS.
What I explained above is either you have a FBW in an FLCS axis or a traditional mechanical FLCS in that axis.
I maybe wrong, but I think you misunderstood the design philosophy of the JF-17. The JF-17 was designed to have pitch instability but roll and yaw are primarily stable, so the pitch axis have FBW-FLCS but roll and yaw are traditional mechanical FLCS. Some people called this as 'limited' but it is incorrect. Does this mean the JF-17 design philosophy is the same as the F-16 ? No. The F-16 have all three axes as unstable.
Some people might say that if an aircraft have FBW-FLCS, that mean the design is unstable. That is incorrect. Airbus and Boeing moved to full FBW-FLCS in all three axes in their highly stable airliners. Weight is a penalty in flight. Airbus and Boeing literally saved thousands of kilos in weight by using FBW-FLCS. The FBW-FLCS actually made maneuvers even more stable and controlled in these large body aircrafts. Take-offs and landings in high and/or cross wind situations are safer because the computers can respond faster to attitude changes, large and small, created by the wind.
Hope that helped.
You did a very good job of explaining
Avionics has nothing to do with digital FBW. Are you sure we are in the same note? Hello?
