I agree. Very rarely do pilots actually exceed 9/10 Gs in flight.
J-20 5th Gen Fighter Thread V
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I agree. Very rarely do pilots actually exceed 9/10 Gs in flight.
plawolf
Lieutenant General
G force is determined by momentum acting against the new direction when a plane changes vectors.
The faster the change in vector (turn), the higher the G force, but that is dependant also on the original momentum (airspeed).
The J20 in that video made a very rapid turn, but its airspeed was low, so I doubt the g-force was all that great.
For all the training and equipment, a pilot takes a risk every time he pushes his plane to 9Gs and beyond.
It is very unlikely a J20 test pilot (indeed any pilot) would push his plane that hard, that low over a populated urban area.
If you need to push the bird to the limit, you do that over remote test ranges and at high altitude. So you have plenty of altitude (time) to recover if anything goes wrong, and if the worst happens, you can punch out without having to worry about collateral damage on the ground.
What this video does show is that the J20 has very good low speed handling, and impressive acceleration.
Maybe someone better versed on engines could correct me if wrong, but I think the J20, even with interim AL31s, should be capable of, for the lack of a better term, supercruise-lite.
What I mean by that is, with an airframe designed and optimised to supercruise, once the J20 punched through the sound barrier with afterburners, it might be able to switch back to military power and maintain supersonic flight.
It might not meet the 'textbook' definition of supercruise (which btw, amusingly seems to change based on the performance of other aircraft so it remains just out of reach of all but the raptor, but never mind), but in operational terms, its pretty much the same thing.
The faster the change in vector (turn), the higher the G force, but that is dependant also on the original momentum (airspeed).
The J20 in that video made a very rapid turn, but its airspeed was low, so I doubt the g-force was all that great.
For all the training and equipment, a pilot takes a risk every time he pushes his plane to 9Gs and beyond.
It is very unlikely a J20 test pilot (indeed any pilot) would push his plane that hard, that low over a populated urban area.
If you need to push the bird to the limit, you do that over remote test ranges and at high altitude. So you have plenty of altitude (time) to recover if anything goes wrong, and if the worst happens, you can punch out without having to worry about collateral damage on the ground.
What this video does show is that the J20 has very good low speed handling, and impressive acceleration.
Maybe someone better versed on engines could correct me if wrong, but I think the J20, even with interim AL31s, should be capable of, for the lack of a better term, supercruise-lite.
What I mean by that is, with an airframe designed and optimised to supercruise, once the J20 punched through the sound barrier with afterburners, it might be able to switch back to military power and maintain supersonic flight.
It might not meet the 'textbook' definition of supercruise (which btw, amusingly seems to change based on the performance of other aircraft so it remains just out of reach of all but the raptor, but never mind), but in operational terms, its pretty much the same thing.
No doubt there are very real limits, and that even depends on how a given pilot is feeling that day, the point is that G-suits, the Raptor has not only G Pants, but a G vest????are only part of the equation, structural considerations of the aircraft, powerplant, avionics etc all factor into the equation? and yes no doubt their is ongoing research to push those limits up??
Let me agree with you first of all that the maneuver you observed on the video is no doubt a
"hard pull", my guess being around 6 Gs, having said that, master Wolfie is right, the airspeed is likely around 350 to 400 knots, as he begins the maneuver he likely pushes the levers up into burner and that will indeed add to the Gs as the aircraft would have even greater momentum and want to continue on the initial vector.
You bring in the burner, because the hard pull by itself will "bleed energy" rapidly, the "secret" of the "360 overhead", if you pull hard enough the speed will "go away" allowing you to throw out the gear and flaps and add the necessary drag to make a safe approach and landing. Even in a general aviation aircraft, those steep turns require the addition of power to maintain altitude, and minimize energy bleed.
The argument that G forces are only limited by the "pilot" and that he is somehow the weak link in the chain is specious to say the least. He is NOT the weak link in the chain, and the only reason to desire high maneuverability, is to allow you the "luxury" of the up close personal LOOK at the bad guy, and the ability to intimidate him into withdrawing, while at the same time having the edge in maneuverability and agility, so that if he decides to "engage" you may "out-maneuver" him and get the shot.
Having said all of that, one of the reasons that TVC is no longer considered a necessity, is that fighter dogma is now to avoid the "merge" altogether, and shoot the bad guy BVR??? Not always possible or practical, and often on an intercept, you are just there to say, don't step over this line or I'm gonna shoot ya, maintaining that agility gives you the option of doing whichever is most expedient in the given situation?
Ultra
Junior Member
But didn't F-22's recent woes are related to the human factor - the headlines are saying the human is now the "weak link" as F-22 is so high performance it literally cause problem for the pilots when they do the maneuvers. And this is happening with highly advanced highly specialized anti-G flight suits that F-22 pilots are wearing.
Which begs the question, what kind of flight suits J-20 pilots are wearing?
Which begs the question, what kind of flight suits J-20 pilots are wearing?
Only F-22 pilots wear the "combat edge" upper vest due to the F-22s extreme maneuverability at very high altitudes. The upper pressure garment was not releasing after applying pressure with the high G forces, and that was constricting airflow to the lungs and not allowing pilots to breath properly. Now that that issue is behind us, the Raptor is alone in the extremely high Gs it can sustain at altitude, most other aircraft have a significant degradation of performance at altitude, as General Norton Schwartz reported, "the Raptor can pull 6Gs at 50,000ft, what other aircraft can do that?"
As to the J-20s pressure suit, it is likely very similar to that of J-15 or J-11 pilots???
Guys ... I know the time until the pre-serial appears is very much boring, but right now You are more than right in the middle of a much more aerodynamics- and aerial-combat-related topic than necessary for a J-20-tread !
Thanks,
Deino
Thanks,
Deino
so we must certainly be getting close??? master Deino is getting "edgy"??? or maybe school is almost out??? HEH! HEH! I am very surprised we have never seen a "two ship" of this bird??? Do we have any pictures of this aircraft in formation with another J-20 or even the "chase aircraft"?
It would not surprise me to see 3 to 4 new birds hit the flight line in fairly rapid succession, owing to "batch production"??? it will be interesting to see if there are any further changes to the pre-production standard configuration?
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