g-override switch?!

can anyone please explain the functionality of the g-override switch in the hornet?

i've already searched the internet to get some more information, but couldn't find very much about it.

what does it do exactly?

does it allow to exceed the standard g-limit to "unlimited Gs" or does it set the g-limit in the hornets flight computer to a higher g-level i.e. from 7.5G to 9G?

i've also heard that us F-18s do have different (lower) g-limits than the hornets operated by european countries.

what does it mean?

is it programmend differently in the flight computer system or do the european hornet-pilots always have their g-override switches set to on/override?

From the actual manual. Emphasis is mine.

11.1.7 G−Limiter. The g−limiter function in the FCS limits commanded load factor under most

flight conditions to the symmetric load limit (NzREF) based on gross weight below 44,000 pounds gross

weight (maximum NzREF limit of 7.5 g). Above 44,000 pounds, NzREF is held constant at 5.5 g. The

negative load factor limit command is fixed at negative 3 g’s for all gross weights. At weights greater

than 32,357 pounds the g−limiter does not provide adequate negative g protection and aircraft

overstress is possible.

During rolling maneuvers, the g−limiter reduces commanded load factor up to 80% NzREF. The

additional reduction begins with 0.75 inch lateral stick up to 80% at full lateral stick input of 3 inches.

Very abrupt stick commands can exceed the capabilities of the system and result in an overstress. The

g−limiter can be disengaged during emergency situations by pressing the paddle switch to allow 33%

more load factor capability, but overstress is much more likely in this condition. During decelerations

through transonic flight conditions (0.88M - 1.04M) NzREF is decremented to account for dynamic

pitch−up transients. This FCS function, called the G−bucket, automatically unloads the aircraft to

prevent exceeding the design load limit.

I have not heard that about European hornets... But could that be true due to their lower weight because of lack of certain USN specific equipment/avionics?

I have not heard that about European hornets... But could that be true due to their lower weight because of lack of certain USN specific equipment/avionics?

They ought to come pretty similarly loaded in what comes to avionics and stuff: where something that would be Navy specific for instance is left out, something local or civilian equivalent is put in, and they have their own share of extras (such as identification light that is missing from the Navy ones). To my eye, the current European (Finnish/Swiss) standard appears to be newer than the specific model simulated in DCS; for instance, at least some of the UFCs have been replaced with E/F-style touch screens. Anyways, what comes to W&B, I'd expect there to be only minute differences, perhaps among the most significant ones being such as Finns using M61A2 cannon instead of A1, affecting more the balance.

G-limiter function is the same, I understand.

7.5 Gs plus 33% = 9.975 Gs

is this correct?

G-limiter function is the same, I understand.

I would think so. Weight limitations will be with respect to gross weight. If the euro hornets have a lower basic weight this won't make any difference with respect to available G.

7.5 Gs plus 33% = 9.975 Gs

 

is this correct?

Yes.

I would think so. Weight limitations will be with respect to gross weight. If the euro hornets have a lower basic weight this won't make any difference with respect to available G.

While not directly related to the g-limiter override, but to the Euro Hornets anecdotally, there was some minor hubbub here on the European side of the pond (Finland) that was noted in the local public press as well, when the fatigue life of the center "barrel" structure (the center fuselage portion to which the wings attach) turned out to be less than expected. I've not gone any deep into it, but mainly from what I've read about it, the level of cracking found during major mid-life inspections was more than was expected, and necessitated some specific repairs and reinforcements at least in some air frames.

Reportedly, the issue was analyzed and reasoned together with the manufacturer so that basically the flight hour accumulation (by which the inspections were mainly scheduled) did not match the expected stress accumulation. Around here, the training areas where the air combat maneuvering and all takes place are almost immediately next to the air force bases. Supposedly, the disproportionately low hours of positioning, simple transit flying, in comparison to the maneuvering flight, skewed the aging of the air frame some.

I don't know if Swiss guys had any similar experience.

Reportedly, the issue was analyzed and reasoned together with the manufacturer so that basically the flight hour accumulation (by which the inspections were mainly scheduled) did not match the expected stress accumulation. Around here, the training areas where the air combat maneuvering and all takes place are almost immediately next to the air force bases. Supposedly, the disproportionately low hours of positioning, simple transit flying, in comparison to the maneuvering flight, skewed the aging of the air frame some.

 

I don't know if Swiss guys had any similar experience.

Wow that makes a lot of sense! I think I recall that this issue has come up with other types of air frames in European service. European airspace is definitely a lot more confined than across the pond haha

the Exported Hornets that have the solid wings have a Higher G-Limit.

the Exported Hornets that have the solid wings have a Higher G-Limit.

That's interesting, where are those used? I didn't know such existed.

the Exported Hornets that have the solid wings have a Higher G-Limit.

You mean a version that does not have wing-fold?

Anyway that version remains the G-Override, no?

You mean a version that does not have wing-fold?

Yea, I wonder that too, never heard of such version (not at all saying that there couldn't be one somewhere). For a fact, at least Finnish and Swiss C/D-models retain their wing fold function and it is used for a good benefit.

One nice touch in Hornet, in comparison to many other fighters of the era, is its dynamically computed G-limit, depending on the computed actual gross weight. This provides some protection against structural overstress

G-Limit isnt Static,

7.5 G is the Design Limit as well as for Pilot Safety,

The Exported Hornets that use different materials and Wing Construction do have a Design Limit of 9G instead of 7.5.

However, FCS will impose a limit based on aircraft take off weight, stores loaded and other factors.

G-Limit isnt Static,

 

7.5 G is the Design Limit as well as for Pilot Safety,

 

The Exported Hornets that use different materials and Wing Construction do have a Design Limit of 9G instead of 7.5.

 

However, FCS will impose a limit based on aircraft take off weight, stores loaded and other factors.

Okay, that's interesting. I didn't know there were different designs of the wing (even if g-limit can of course be configured). Any idea what export batches are affected by this mod, and what are the differences to the USN?

 

However, FCS will impose a limit based on aircraft take off weight, stores loaded and other factors.

Then, if there is a fault related to that system, caution G LIM 7.5 appears

and we will know that something is not right.

what a wonderful systems this plane offers to us :thumbup:

Then, if there is a fault related to that system, caution G LIM 7.5 appears

and we will know that something is not right.

what a wonderful systems this plane offers to us :thumbup:

6.5G here ;)

That I believe is the regular, dynamically computed g limit as per weight.

That I believe is the regular, dynamically computed g limit as per weight.

It is !

Okay, that's interesting. I didn't know there were different designs of the wing (even if g-limit can of course be configured). Any idea what export batches are affected by this mod, and what are the differences to the USN?

Swiss Hornets were partly built in Switzerland (two of 34 were delivered directly)

They all have titanium reinforced wings and structure

Unfortunately I can't give you a source for this, I've been searching it for quite a while now :cry:

There was an article about the stress tests they conducted during a mayor overhaul, to see if the components perform as expected

EDIT: not what I meant but as I see some stuff for all the Hornets are made in Switzerland: aileron-trailing-edge-flaps-shrouds

Swiss Hornets were partly built in Switzerland (two of 34 were delivered directly)

They all have titanium reinforced wings and structure

Unfortunately I can't give you a source for this, I've been searching it for quite a while now :cry:

There was an article about the stress tests they conducted during a mayor overhaul, to see if the components perform as expected

Thanks, interesting!

Finnish Hornets were assembled locally as well, aside the first few two seaters. I don't know whether they differ in any significant structural details from the Navy ones, albeit they do have several differences from the baseline (such as afterburner flame holder inspired by Saab Gripen, as the GE original did show some cracking and pieces shedding issues), originally a local data link system, since replaced by Link 16, metric stand by instruments, and so on).

As I've read the public articles available, the wings weren't the issue noted in the major mid-life inspections around here, but the central fuselage structure was. Some reinforcement was reportedly incorporated at that stage at least.

Is overstress going to be modeled after repeated use of the g-override (paddle switch)?

Swiss Hornets were partly built in Switzerland (two of 34 were delivered directly)

They all have titanium reinforced wings and structure

Unfortunately I can't give you a source for this, I've been searching it for quite a while now :cry:

There was an article about the stress tests they conducted during a mayor overhaul, to see if the components perform as expected

 

EDIT: not what I meant but as I see some stuff for all the Hornets are made in Switzerland: aileron-trailing-edge-flaps-shrouds

yeah, the swiss hornets can freely go to 9G to to there different wing structure. There is a cool youtube video out there about the Swiss hornets and they talk about this.

Is overstress going to be modeled after repeated use of the g-override (paddle switch)?

What would you expect to happen? It seems to me (and I admit I could be wrong) that the limit is primarily there to extend the life of the airframe over a period of decades rather than preventing you snapping wings off.

What would you expect to happen? It seems to me (and I admit I could be wrong) that the limit is primarily there to extend the life of the airframe over a period of decades rather than preventing you snapping wings off.

I'm pretty sure the aircraft is going to require some trimming after bending a wing. It's not going to fly straight or the same after that.

So yes, overstressing the aircraft could result in some very interesting behaviours. I expect this to be quite difficult to model, ripping off the wing being the most simple one to model.

Wings are designed to flex though.