For starter, there is no such thing as 'good' or 'poor'. Only comparators such as 'better' or 'poorer' or 'lesser'. To say 'good' or 'poor' implies absolutes which is not true. Am not being pedantic, just accurate when it comes to technical issues.
Now, what are 'flight controls laws'? It has nothing to do with managing airlines and airliners in the sky.
Description Modern large commercial transport aircraft designs rely on sophisticated flight computers to aid and protect the aircraft in flight. These are governed by computational laws which assign flight control modes during flight. Aircraft with fly-by-wire flight controls require computer...
www.skybrary.aero
Am going to simplify this as much as possible.
This is a 'push-pull' rod.
A push-pull rod is a mechanical linkage from the cockpit to the flight controls surfaces, with pneudraulics in-between for heavier aircrafts.
If a push-pull rod have length of 100 cm, for example. That 100 cm is a law. If that push-pull rod have a load rating, that rating is a law. If that push-pull rod have a travel distance, that distance is a law. Because the push-pull rod is a mechanical device, all those
laws are non-negotiable.
When the F-16 came on the scene, flight controls laws became much more flexible due to its fly-by-wire FLCS. The limiters are the actual flight controls surfaces themselves and the hydraulics system. The early F-16 flight controls laws writers were electronics engineers because the A/B models were analog computers. The digital FLCS have more software based flight controls laws. Essentially, %99 of the flight controls system's mechanical components became virtual. First, they became capacitors, resistors, and transistors. Then with digital technology, the mechanical components became 1s and 0s.
Most flight controls components became virtual and their virtual characteristics are negotiable.
How does this affects flight axes controls? For this, we go to the F-18SH example.
F/A-18F Super Hornet, pilot report
www.ausairpower.net
2.2 The Virtual Speedbrake
The next handling demonstration involved involved the speedbrake and some high alpha low speed handling, an area in which many fighters experience problems in maintaining direction and avoiding a departure into uncontrolled flight.
The first demonstration involved the virtual speedbrake effectiveness and handling in this configuration. The F/A-18A-D, like the F-15 series, employs an upper fuselage hydraulically deployed speedbrake. The Super Hornet has no such device, yet achieves the same effect through what can only be described as digital magic. The speedbrake function is produced by a balanced deployment of opposing flight control surfaces, generating drag without loss of flight control authority or change in aircraft pitch attitude.
Dave demonstrated the speedbrake function, and I was asked to observe over the shoulder and in the mirrors the raised ailerons, lowered trailing flaps, raised spoilers and splayed out rudders. Deceleration is smooth and there is no observable pitch change.
At Mach 0.63 Dave invited me to fly another 360 aileron roll, to observe that the aircraft retains considerable control authority despite the fact that the rudders are splayed out, and the ailerons, spoilers and flaps are generating balanced opposing pitching moments. I applied roughly 1/2 stick input and the aircraft very cleanly rolled through 360 degrees at about 90 degrees/sec roll rate. I commented on the lower roll rate and Dave observed that we were significantly slower, he then proceeded to demonstrate the roll again with a full stick input, producing around 180 degrees/sec with a slight overshoot on recovery. The aircraft feels very stable throughout the manoeuvre and there is no observable change in control forces or control input response by the FCS.
To create a
VIRTUAL speedbrake, the SH's flight controls laws were written to deploy all flight controls surfaces in precise rate of movement, degrees of movements, and final positions to slow down the jet and still enable the pilot to maneuver the jet. The absence of a real mechanical speedbrake equals to the absence of several hundred kilos of physical weight, and yet, the
FUNCTION of the speedbrake still exists via a combination of displacements by the entire FLCS. The SH's flight controls laws were even written to allow full stick input even when all flight controls surfaces were in virtual speekbrake mode.
Is it possible to remove the yaw axis stabilator and have the other FLCS components works in its place? Not only is it possible but
ALREADY DONE: The B-2.
The reason the B-2 is less maneuverable than the F-22 is because of its flying wing design, not because of the absence of the vertical stab.
This is the first in a series of articles that will take a historical look back to the early days of aviation and traces the birth of John Northrop’s dreams for an all-wing design for aircraft.
www.afmc.af.mil
Northrop found the Model 1 to have remarkable maneuverability and performance with speeds 25% greater than contemporary designs of similar power and capacity.
When there is the vertical stab, aerodynamics forces acts upon both sides of that structure, keeping physical pressure on that structure and eventually keeping the aircraft stable in the yaw axis. The rudder is a component of the vertical stab on the trailing edge of the stab. The rudder deflects, aerodynamics pressure changes which changes physical pressure which changes the direction of the aircraft.
There is some serious technology and ingenuity involved in making a 172-foot-wide, bomb-carrying aircraft "disappear." Find out how the B-2 bomber deals with enemy radar.
science.howstuffworks.com
In the above image, the outer ailerons are splitted to create a virtual yaw axis stab, and the inner surfaces functions as normal pitch/roll axis controls.
For the F-22 with thrust vector controls, the TVC are flight controls laws components.
The initial control law version did not have active thrust vectoring.
Many enhanced capabilities were added to the YF-22 control laws as the prototype program matured and flight test approached. The use of thrust vectoring nozzles to augment the aerodynamic pitch control power of the aircraft was incorporated into the control laws and the high angle of attack control laws were also added to the basic structure.
For the J-20 with the canards, the canards are flight controls laws components. If the J-20 will be equipped with TVC, the TVC can be written as flight controls laws components or leave as manual options for the pilot like how the Russians done it the Su series.
The advantage for the having the TVC as flight controls laws is that it is less flying burden for the pilot. The
POTENTIAL disadvantage is that the laws
COULD BE less flexible than what the pilot need, especially in BFM. Personally, I prefer the auto version.
The evolution of the next generation of combat fighters to have no yaw axis structure is inevitable and it is speculated that the US '6th gen' fighter is such. Since low radar observability requires twin canted vertical stabs, the removal of these two major physical structures would add to that 'stealthy' capability, like how the B-2 have it, plus, reduction in weight.
Is it possible for the existing F-22 and J-20 to remove their twin canted vertical stabs and have new flight controls laws to replace the twin canted vertical stabs? Yes, but why? The development time would require both platforms to nearly start from their beginnings because you now have to put both platforms back into wind tunnel testings, modify a few existing jets, test flights, data analyses, and so on. Might as well start anew.
… in several of your lasts post you rem,ember others to prove what they say and always refer to me, but you yourself ignore this, refuse to answer and explain. Not only I but several too are still waiting for an explanation and source, why the J-15T should be of an aerodynamic revised shape / form and should have different approach speeds, Still all of your wrong claims - numbers of aircraft built, J-15s for Shandong - are uncommitted!
