investigating G overload damage limit decreases with the increase of speed

[LowRider88]

33 minutes ago, GGTharos said:

There is a very good number of 10g+ over-g's in fighters, a few with 12g - none of this is anecdotes, it's part of the USAFs g-tolerance research..   No, you probably couldn't do more than 10 in an F-5, that is pretty much close to or at the ultimate structural limits.  I don't know why you say that 10g kills pilots; it doesn't.  It's more dangerous than 9g from the GLOC perspective, but it's not some sort of instadeath.

The rules get broken and few die.  Not 'some die' and 'some live' as if it was some sort of unknowable number, most of the time things are ok (not necessarily fine) but breaking rules will end in punishment depending on circumstances.

 

Your last sentence sounds as subjective as mine.  If you don't know the number, how do quantity some vs few?

 

Where are your sources for 12 G USAF?

This is what I found, simple search only, below.

25 to over 40 Gs.  But this is gradual acceleration in a rocket sled, and not in a fighter plane.

Forces were front to back rather than top to bottom, like the centrifuge. 10 Gs front to back do different damages and have different effects to the body than top to bottom.

In the fighter plane the acceleration of G is more than a gradual increase in the rocket sled.

If it is not instadeath, g loc at 10 Gs could lead to death if the plane continues in the same maneuver that induced the g loc.  If you can't recover you'll either crash or die from the g loc.  You certainly can't shake off the g lock with a pinkie.  10 G s certainly does not allow a pilot to continue a 10 G scissor fight.

 

Whatever the case, if I am wrong about dying at 10 G (whether instantly or due to g loc), you also agree the F-5 can't handle over 10Gs, which is the main point of this thread.

The problem here is we have more realistic wing damage for overstress now, but people break them off with their pinkies because they don't use force feedback and don't get the resistance to tell them not to do that.  That and they fly with afterburner all the time, and try to dogfight while transonic.

 

[GGTharos]

7 hours ago, LowRider88 said:

Where are your sources for 12 G USAF?

Actual F-15C incidents in combat and training, and the USAF's G-LOC research.  Not going to search it again, it's old and tired.

 

7 hours ago, LowRider88 said:

In the fighter plane the acceleration of G is more than a gradual increase in the rocket sled.

If it is not instadeath, g loc at 10 Gs could lead to death if the plane continues in the same maneuver that induced the g loc.

Yes, none of this is relevant.  Could/would etc.  Does it?  The answer is in some cases yes, in many cases no.  A 10g pull will be transient, no one's really going to hold 10g in a turn.

7 hours ago, LowRider88 said:

Whatever the case, if I am wrong about dying at 10 G (whether instantly or due to g loc), you also agree the F-5 can't handle over 10Gs, which is the main point of this thread.

I agree, but this is why we should stick to discussing the fuselage.  There are fairly hard engineering limits.  10 or 11g doesn't matter, pilots don't need to pull this much and typically would simply not do so.  This is less the case with 4th gens but basically the g incidents increase to higher g as the 'gen' goes up, up to a limit.   The 12g excursions for example, one was in an engagement and very transient, the other lasted a few seconds (pilot was trying to save his life coming out of a dive) and that aircraft never flew again.  It landed but couldn't be maintained.

Edited December 19, 2021 by GGTharos

[LowRider88]

36 minutes ago, GGTharos said:

Yes, none of this is relevant.  Could/would etc.  Does it?  The answer is in some cases yes, in many cases no.  A 10g pull will be transient, no one's really going to hold 10g in a turn.

This is just another subjective comment.  If it does in some cases, then yes, it is still relevant to consider the way in which the G was induced.

But don't worry, I am also getting bored of challenging your corrections, especially if you don't cite the sources.

I brought up 10 Gs as possibly killing people as a question initially, which no one answered until now.

The whole point of asking that is to confirm whether someone can dogfight and do a scissors fight at 10Gs, which still seems highly unlikely if that level of G is transient, or can't be maintained.

Yes, I agree, focus on the fuselage.  And the wings.

 

If this were my bug report, I would consider this the bug:

- The plane should not be stable or flyable/controllable when the wings rip off.  It should act the same way it does when it gets shot down and tumble.

- There should be a DCS setting to switch between using force feedback and not using.  When not using, the controls should not be as responsive, even if we push hard on our controls, so help simulate the difficulty in pulling that many Gs.  No inadvertent pinky movements.

- If it really is possible to invoke those forces at max g in the real F-5 with a pinky, then there is no bug.  People should fight around corner speeds.

- Read somewhere here that the accumulated damage may be from the multiplayer spawning, that should be investigated, as many of us don't see this in single player.

- Read also G limit may be different at different speeds.

[GGTharos]

6 minutes ago, LowRider88 said:

The whole point of asking that is to confirm whether someone can dogfight and do a scissors fight at 10Gs, which still seems highly unlikely if that level of G is transient, or can't be maintained.

Scissors are done at low speed typically, it's not a high-g maneuver.   Even it started that way, it wouldn't last long - you win the scissors by getting slower than the other guy.

6 minutes ago, LowRider88 said:

If this were my bug report, I would consider this the bug:

- The plane should not be stable or flyable/controllable when the wings rip off.  It should act the same way it does when it gets shot down and tumble.

Most likely but not necessarily.  I think for the F-5 unless you lose both wings at the same time it would be unstable obviously, if you lose both wings maybe you could fly it - it could even be stable-ish but forget about anything but gentle maneuvering.   In other words, a sitting duck.  But at the same time I suspect losing both wings would drain hydraulics so it's moot point anyway.

6 minutes ago, LowRider88 said:

- There should be a DCS setting to switch between using force feedback and not using.  When not using, the controls should not be as responsive, even if we push hard on our controls, so help simulate the difficulty in pulling that many Gs.  No inadvertent pinky movements.

I don't think that's a good solution.  Because IRL these controls are assisted and pushing them hard isn't that difficult.   It would also be perceived as some sort of input lag.   No need to save people from themselves.

6 minutes ago, LowRider88 said:

- If it really is possible to invoke those forces at max g in the real F-5 with a pinky, then there is no bug.  People should fight around corner speeds.

You fight the speeds you end up fighting at, be it 120kts, Mach 2 or whatever's in-between.   I don't know what this pinky movement is about - it may be that the flight control system in the F-5 isn't set up quite right and that would be a bug.   But without seeing what was done and what happened, can't really say anything.

6 minutes ago, LowRider88 said:

- Read somewhere here that the accumulated damage may be from the multiplayer spawning, that should be investigated, as many of us don't see this in single player.

- Read also G limit may be different at different speeds.

The last is correct, transonic speeds require gentler handling overall.  Depending on what data you can find, you'll find most aircraft are rated at 'less g' in that zone.

[LowRider88]

2 hours ago, GGTharos said:

Scissors are done at low speed typically, it's not a high-g maneuver.   Even it started that way, it wouldn't last long - you win the scissors by getting slower than the other guy.

Most likely but not necessarily.  I think for the F-5 unless you lose both wings at the same time it would be unstable obviously, if you lose both wings maybe you could fly it - it could even be stable-ish but forget about anything but gentle maneuvering.   In other words, a sitting duck.  But at the same time I suspect losing both wings would drain hydraulics so it's moot point anyway.

I don't think that's a good solution.  Because IRL these controls are assisted and pushing them hard isn't that difficult.   It would also be perceived as some sort of input lag.   No need to save people from themselves.

You fight the speeds you end up fighting at, be it 120kts, Mach 2 or whatever's in-between.   I don't know what this pinky movement is about - it may be that the flight control system in the F-5 isn't set up quite right and that would be a bug.   But without seeing what was done and what happened, can't really say anything.

The last is correct, transonic speeds require gentler handling overall.  Depending on what data you can find, you'll find most aircraft are rated at 'less g' in that zone.

Yep, know that about scissor already.  That is why I questioned how some want to do them at transonic speeds.

 

If both wings are off as shown in some of the screenshots here, they are gone near the root of the wing tip.  How do you fly that with no ailerons and flaps or wing area?  If the wings break asymmetrically, with the control surfaces missing it most likely will tumble.  At any rate if it was transonic at break time, regardless of asymmetric breaking, it will still tumble with no wings.

 

No one fights at Mach 2.  You engage at Mach 2 then slow down and actually fight.

IRL controls are assisted?  So there is no feedback whatsoever?  I find that hard to believe.

Someone here said their gaming setup had issues while they were in afterburner and adjusted it, taking their attention off the action, noticed some slipping and then use daily their pinky to readjust the flight path but this caused the wing to rip off.

You think in real life a fighter pilot can do that at speed and at G, with no feedback?

 

Edited December 19, 2021 by LowRider88

[GGTharos]

32 minutes ago, LowRider88 said:

If both wings are off as shown in some of the screenshots here, they are gone near the root of the wing tip.  How do you fly that with no ailerons and flaps or wing area?  If the wings break asymmetrically, with the control surfaces missing it most likely will tumble.  At any rate if it was transonic at break time, regardless of asymmetric breaking, it will still tumble with no wings.

The aircraft body provides lift and so do the horizontal stabilizers - they also provide control and some stability.

32 minutes ago, LowRider88 said:

IRL controls are assisted?  So there is no feedback whatsoever?  I find that hard to believe.

There is some form of artificial feedback in most cases.  With a sidestick like the F-16, probably none at all.

32 minutes ago, LowRider88 said:

Someone here said their gaming setup had issues while they were in afterburner and adjusted it, taking their attention off the action, noticed some slipping and then use daily their pinky to readjust the flight path but this caused the wing to rip off.

They were also tabbing in and out of the game which can have its own strange consequences.

32 minutes ago, LowRider88 said:

You think in real life a fighter pilot can do that at speed and at G, with no feedback?

Do what, alt-tab out of their plane?  The whole 'pinky' thing is meaningless from all perspectives without a track.

[LowRider88]

8 hours ago, GGTharos said:

The aircraft body provides lift and so do the horizontal stabilizers - they also provide control and some stability.

There is some form of artificial feedback in most cases.  With a sidestick like the F-16, probably none at all.

They were also tabbing in and out of the game which can have its own strange consequences.

Do what, alt-tab out of their plane?  The whole 'pinky' thing is meaningless from all perspectives without a track.

Yes, for F-5 with lifting body style fuselage, there is some lift.  But that is more to decrease drag during high AoA, and not enough to maintain flight.  If the wings broke off before take off, would it take off?  Even if the plane reached transonic speed on the ground?  I doubt that.  So it would most likely fall out of the sky and tumble with no wings.  Seems common sense to me.  Especially when you add any moments resulting from the wings snapping off.

 

Sure, but we are talking about the F-5, not the F-16.  The hydraulics are a boost assist, so feedback from greater forces should be felt by the pilot.

 

Agreed.  Or there were none, and the plane just slipped on its own while increasing to speed, and coupled with that, nothing to prevent the player from exerting major Roll forces with their pinky with no feedback.

Another possibly that was raised was that this could also be only a multiplier phenomenon.

 

I agree.

[GGTharos]

59 minutes ago, LowRider88 said:

Yes, for F-5 with lifting body style fuselage, there is some lift.  But that is more to decrease drag during high AoA, and not enough to maintain flight.

You just have to go fast enough.   Consider missiles which don't have lifting bodies at all.

59 minutes ago, LowRider88 said:

If the wings broke off before take off, would it take off?  Even if the plane reached transonic speed on the ground?  I doubt that.  So it would most likely fall out of the sky and tumble with no wings.  Seems common sense to me.  Especially when you add any moments resulting from the wings snapping off.

No I don't think you're right, nor is it common sense - the body probably provides between 1/4 and 1/3 of the lift, which is significant.  The lifting force increases very quickly with speed.   I'm not going to say anything about takeoff or landing, just that it could theoretically remain in flight but this would be a 'get to a place where you can do a controlled ejection' deal.  You couldn't fight with it.   And again, that's assuming that the hydraulics didn't drain and you still can control the remaining surfaces.

59 minutes ago, LowRider88 said:

Sure, but we are talking about the F-5, not the F-16.  The hydraulics are a boost assist, so feedback from greater forces should be felt by the pilot.

Depends.  The F-15C has no feedback at all from the control surfaces, it's completely artificial and it's all hydro-mechanical, no FBW.  I don't recall how the F-5 is set up, but, either way, you're not going to struggle for g IMHO.

59 minutes ago, LowRider88 said:

Agreed.  Or there were none, and the plane just slipped on its own while increasing to speed, and coupled with that, nothing to prevent the player from exerting major Roll forces with their pinky with no feedback.

Another possibly that was raised was that this could also be only a multiplier phenomenon.

I agree.

Thanks for the discussion

Edited December 19, 2021 by GGTharos

[LowRider88]

4 hours ago, GGTharos said:

You just have to go fast enough.   Consider missiles which don't have lifting bodies at all.

No I don't think you're right, nor is it common sense - the body probably provides between 1/4 and 1/3 of the lift, which is significant.  The lifting force increases very quickly with speed.   I'm not going to say anything about takeoff or landing, just that it could theoretically remain in flight but this would be a 'get to a place where you can do a controlled ejection' deal.  You couldn't fight with it.   And again, that's assuming that the hydraulics didn't drain and you still can control the remaining surfaces.

Depends.  The F-15C has no feedback at all from the control surfaces, it's completely artificial and it's all hydro-mechanical, no FBW.  I don't recall how the F-5 is set up, but, either way, you're not going to struggle for g IMHO.

Thanks for the discussion

 

Possibly, but missiles still fall to earth.  They are also not asymmetric resulting from catastrophic structural failure, and still have their control surfaces.

 

Well it certainly would not be what this is:

I don't see a pilot surviving from a plane whose wings tore off from excessive speed and Gs.

The act of inducing such a violent force on to the plane as to break the wings off would be very unlikely to be soft enough to let it continue to cruise in its original course.  Sorry that seems too arcade-like to me.

 

Then that's the question.  Does the F-5 have power steering where the controls are light to the touch at all speed and load factors, or was it designed to give the pilot a heads up to when they may potentially destroy the plane.  Seems like a design failure of engineers did not build any feedback at all as a precaution.

 

Likewise