plawolf
Lieutenant General
Does anyone know how to slow those gifs down a bit? It would be interesting to observe how the control surfaces operate to create the various maneuvers displayed, but it's not very easy when the frames are moving so fast.
I am also not 100% on the canards angling down when the J20 pitches up. In that picture paintgun posted, the leading edge flaps are also pitch down, indicating that the J20 is indeed diving.
I do not know much about aerodynamics, so I could be talking completely nonsense here, and if so, please correct me, but from my limited understanding, the only reason I can see for the canards to be angling in the opposite direction as the plane is pitching (so this could be the plane pitching up, or banking) is if it was an artificial limited written into the FBW software to stop the plane from pitching too hard and diverting from controlled flight and/or pulling too many Gs as to incapacitate/kill the pilot.
We have all heard how planes have different instantaneous and sustained turn rates, it could be that when we see the J20 banking with the canards angled in the opposite direction as that the plane is turning, that is just the plane's FBW keeping it limited to the safe maximum sustained turn rate. Whereas if the canards were moving in the save direction as the angle of banking, we would be in the instantaneous part of the flight envelope.
Also bare in mind that we are still very early days in the flight test programme, so only a fraction of the plane's flight envelope has been explored so far, thus, this opposite positioning could just be an example of the deliberate limiting of the turn rate at present, which will be relaxed as they get more test data, so in the final production version, all the control surfaces may well be all moving in the same direction when the plane pitches to produce a far better turn rate.
I am also not 100% on the canards angling down when the J20 pitches up. In that picture paintgun posted, the leading edge flaps are also pitch down, indicating that the J20 is indeed diving.
I do not know much about aerodynamics, so I could be talking completely nonsense here, and if so, please correct me, but from my limited understanding, the only reason I can see for the canards to be angling in the opposite direction as the plane is pitching (so this could be the plane pitching up, or banking) is if it was an artificial limited written into the FBW software to stop the plane from pitching too hard and diverting from controlled flight and/or pulling too many Gs as to incapacitate/kill the pilot.
We have all heard how planes have different instantaneous and sustained turn rates, it could be that when we see the J20 banking with the canards angled in the opposite direction as that the plane is turning, that is just the plane's FBW keeping it limited to the safe maximum sustained turn rate. Whereas if the canards were moving in the save direction as the angle of banking, we would be in the instantaneous part of the flight envelope.
Also bare in mind that we are still very early days in the flight test programme, so only a fraction of the plane's flight envelope has been explored so far, thus, this opposite positioning could just be an example of the deliberate limiting of the turn rate at present, which will be relaxed as they get more test data, so in the final production version, all the control surfaces may well be all moving in the same direction when the plane pitches to produce a far better turn rate.
This is a fantastic question guys that someone who is aerodynamicaly savvy should tackle, Scratch you might see if Jeff could jump in as he is a "real engineer". Scratch this is why I was wondering out loud about the planform of the sino jet as the Mig 1.42/1.44 are so configured, but the Russians seem to have abandoned this approach and gone with the F22sky? Any way the all flying stabilator on a conventional main wing forward package is actually quite straightforward, throw a canard on the front and I get a "little confused". They haven't changed the laws of aerodynamics, but they have learned to "cheate a little bit" in a good way.
