Over-G Damage

[hawker111]

Hello to all,

What aircraft have the most realistic over-G damage modelling? If you could recommend a few to download I would appreciate it.

Thanks,

Hawker111

 

[Caesar]

Specific system damage, a-la DCS or other more in-depth simulators isn't modeled in SF2.  Rather, each main component of the aircraft (wings, stabs, fuselage, etc) is taken into account and if you exceed the g-limit times the structural factor, have a chance of breaking.  Normally what happens is the wings get ripped off.  Sometimes the aircraft starts smoking, and if you have the debug on, you can see if the aircraft is considered "destroyed" even though you're still flying it.  It's been a while since I've broken an aircraft, but I know I ripped the wings off a B-2 during SAM defense about a year ago, so it still happens at the current patch level.  Way back (nearly 10 years ago) I recall ripping both wings and a stab off of an F/A-18 in a 24g pull up just to see what would happen.

[Spinners]

Yes, the F/A-18 immediately springs to mind. 

[+baffmeister]

It's not that easy to break some airplanes, a lot depends on how much "available G" they have. ThirdWires F-16 is the only one I've broken recently, just for fun. At low level the available G is huge in the transonic zone so becomes breakable if you just yank back on the stick at high speed. Someone will correct me but I think, in general, the break point is about twice the rated G so a plane rated at 7G's might not actually break up until about 14G. Some structural damage/deformation might happen prior to the break point, and it could be enough to write off the airplane. I remember reading somewhere about a Mirage F-1 accidentally pulling something like 15-17G's and still landing safely, although the airframe was a write off. Also, I think some of the ThirdWire FM's, and my own, for that matter, are unbreakable because the available G is less than the actual plane may be capable of.  That's to try and keep the pitch response from getting too sensitive at high speeds in my case, and maybe for TW FM's as well. I usually target  a maximum of about 12 G's, which still gives the player the option of a "Hail Mary" high G turn.

[Caesar]

1 hour ago, baffmeister said:

It's not that easy to break some airplanes, a lot depends on how much "available G" they have. ThirdWires F-16 is the only one I've broken recently, just for fun. At low level the available G is huge in the transonic zone so becomes breakable if you just yank back on the stick at high speed. Someone will correct me but I think, in general, the break point is about twice the rated G so a plane rated at 7G's might not actually break up until about 14G. Some structural damage/deformation might happen prior to the break point, and it could be enough to write off the airplane. I remember reading somewhere about a Mirage F-1 accidentally pulling something like 15-17G's and still landing safely, although the airframe was a write off. Also, I think some of the ThirdWire FM's, and my own, for that matter, are unbreakable because the available G is less than the actual plane may be capable of.  That's to try and keep the pitch response from getting too sensitive at high speeds in my case, and maybe for TW FM's as well. I usually target  a maximum of about 12 G's, which still gives the player the option of a "Hail Mary" high G turn.

In the data.ini, the max g is multiplied by the structural factor, so it's usually 1.2-1.5x the maximum g.  I can't remember the default value, 1.2 seems to stick in my head, but you can modify each component's "StructuralFactor=" line to suit what you want.  Still, the aircraft doesn't immediately break when you overshoot this, it just has a higher chance.  Normally, it takes a massive overstress to outright break components off the airplane, but the more small excursions above max g*SF, the more likely something will come off.  It all changes based on patch levels; I remember one of the 2012 patches was a lot more sensitive and the aircraft would break more quickly from overshooting.  Currently, it seems like it happens much more rarely.

[MigBuster]

5 hours ago, baffmeister said:

It's not that easy to break some airplanes, a lot depends on how much "available G" they have. ThirdWires F-16 is the only one I've broken recently, just for fun. At low level the available G is huge in the transonic zone so becomes breakable if you just yank back on the stick at high speed. Someone will correct me but I think, in general, the break point is about twice the rated G so a plane rated at 7G's might not actually break up until about 14G. 

Apparently the ultimate load limit was 150% universally of the max G for the specific configuration and flight conditions (4 Gen anyway). That is what they are tested to so the break point is unknown unless someone goes through it outside of testing and breaks something.

  

[hawker111]

If the engine mounts broke on a fighter because it pulled a high G for too long, what would happen? How could this be modelled in the sim?

 

[Caesar]

1 hour ago, hawker111 said:

If the engine mounts broke on a fighter because it pulled a high G for too long, what would happen? How could this be modelled in the sim?

 

I don't think you can model something that specific.  If memory serves, you can damage or set your engines on fire if the fuselage section is considered "damaged" or "destroyed" by the overstress, but that's about as far as it goes.

[MigBuster]

Depends.

Extent of damage to engine mounts?, one engine mount damaged or more?, what else is keeping the engine in place?  etc etc etc etc

Only example I know of the F-4 flew back to base and landed.

Another case might be different.

Who would know? Only someone who either has years dealing with multiple cases of Over G damage or can access records on over G damage in an airforce.

Any point sticking in a computer game? None whatsoever the amount of work required considering 99.9% of the player base can't have any idea of the reality or ever care means a pointless endeavour. 

Realistic damage modelling to a practical level is all you could ever expect.....for anything else join an Airforce. 

 

 

 

 

[hawker111]

2 hours ago, Caesar said:

I don't think you can model something that specific.  If memory serves, you can damage or set your engines on fire if the fuselage section is considered "damaged" or "destroyed" by the overstress, but that's about as far as it goes.

Thanks for the reply Caesar.

So in your opinion, having the engines damaged or having them go on fire would be a good way to model engine mount failure due to over-G?
 

[Caesar]

That's hard to say.  As MB said, damaged engine mounts can mean any number of things, from no noticeable performance degradation to the engine catching fire.  If you really want your aircraft to start breaking and rip off wings or damage engines, you can set the StructuralFactor= values to 1.0 and start overshooting regularly to see what happens.  As to how accurate SF2 simulates the breakage, the answer is "not very".

[+baffmeister]

To further complicate matters, most of the older flight manuals mention the hazards of "rolling G",  which can substantially reduce the safety factor when pulling high G's, I assume due to additional wing stress from torsional forces.  I doubt the game takes that into account.

After mentioning the wing breakage on the TW F-16 I was wondering, with all the computers on board, does the F-16 have an automatic G limiting system? If so it might be possible to model that but would require lot's of trial and error adjusting the max control speeds and mach tables for the H-stabs.

[hawker111]

10 minutes ago, baffmeister said:

"To further complicate matters, most of the older flight manuals mention the hazards of 'rolling G',  which can substantially reduce the safety factor when pulling high G's, . . ."

Excellent point Baffmeister. I have also heard that this is true. But you don't think this is modelled in SF?
 

Edited February 22, 2019 by hawker111

[+baffmeister]

1 minute ago, hawker111 said:

But you don't think this is modelled in SF?

I would be surprised, but could probably be tested. [I'm too busy]

[Caesar]

55 minutes ago, baffmeister said:

To further complicate matters, most of the older flight manuals mention the hazards of "rolling G",  which can substantially reduce the safety factor when pulling high G's, I assume due to additional wing stress from torsional forces.  I doubt the game takes that into account.

After mentioning the wing breakage on the TW F-16 I was wondering, with all the computers on board, does the F-16 have an automatic G limiting system? If so it might be possible to model that but would require lot's of trial and error adjusting the max control speeds and mach tables for the H-stabs.

This is spot-on.  Rolling limits are lower than symmetrical due to torsion.  It is not modeled in SF2 to my knowledge, or at the bear minimum, it won't cause early breakage if you're within the aircraft's max g * structural factor - I don't know if the airplane breaks faster if you're doing something like a 10g snap roll or whatever.  As to the hard limiter on the F-16 (which the aircraft does have in reality), I know the third party F-16s and F/A-18s utilize the CAT1 G Limiter developed by one of the folks here at CA (can't remember specifically who; Fubar maybe?).  We used it for our AI F-14s in the Super Pack to stop them from doing a one-and-done max G pull at the start of combat to make them slightly more survivable, but you can put it into whatever aircraft you want.

[CAT1_G_Limiter]
SystemType=HIGHLIFT_DEVICE
DeploymentMethod=AUTOMATIC_G_loading
CLiftdc=-2.7500
CDdc=0.0
Cmdc=-0.350
AreaRatio=2.000
SmoothDeployment=TRUE
Setting[1].Angle=45.0
Setting[1].DeployValue=7.33
Setting[1].RetractValue=7.25
MaxDeflection=20.0
MinDeflection=0.0
ControlRate=5.0
ModelNodeName=Internal

It allows you to pull up to, but not beyond the deploy value.  I don't think the TW F-16 uses such a limiter, and hence why it can overshoot 9G.