New structural G-limit feature

[Bellator]

Hi,

Read about the new structural G-limit feature, or load factor, and immediately got curious as to how you determined the limits for each aircraft?

Also would it be possible with a G-limit pr. aircraft list?

Finally how does it work exactly, does damage occur when exceeding the std. safe load factor or when closing to design maximum?

Thanks.

[AndyJWest]

As far as I'm aware, the only specific details given about this were in the initial TD announcement of the feature:
At present all aircraft in IL2 have a single fixed Structural G limit of +13G. It only really becomes an issue with aircraft with exceptionally light elevators such as the P51. Pull more than +13G and you loose your wings. The real life situation is a little more complicated. Real aircraft are designed with an Ultimate load and In Service design load. Both are for a defined configuration and weight.

The in Service load is the typical G available to the pilot. As long as this the G is not exceeded then no aircraft damage will occur. Exceed the In service G limit then damage of varying degrees may occur .. like bent airframes etc. Exceed the Ultimate load then severe damage will occur typically resulting in structural failure ... like wings coming off etc.Typically a safety factor of 1.5 is used. So an Fighter aeroplane with a design In service G limit of say +8G will have an Ultimate load of +12G. As external stores and or weight is increased above the design weight both G limits reduce accordingly. Reduce weight (by dropping bombs or burning fuel etc) and your G limits increase. Bomber and Transport aircraft have G limits much lower than fighters.
So if you abuse the limits you damage the aircraft. Once damaged then its structural integrity is reduced so the ultimate load reduces as well. In other words keep bending the airframe and you will eventually weaken it to the point that very little extra G is required to induce structural failure. A bent airframe wont perform as well either.

The DT team have now simulated this for the first time in IL2. Each aircraft has been given a unique Structural G profile for Ultimate load, In service limit, and dynamic Weight based limits . In addition this is dynamically modified with its own G induced damage profile. The basic Design Ultimate load configuration and weight has been defined as Default load + 100% Fuel. The actual Ultimate design load has been based on Historical values where they are known and guesstimation where they are not known. In broad brush terms for fighters have an Ultimate design load of +12G with an In service limit of +8G. Lets abbreviate this to 8G/12G

How does this work in game ? You take your stock standard Fighter MK 1 with Default armament +100% Fuel your limits are +8G/+12G. You add 2 x 500lbs bombs. your limits now reduce to 5G/8G. So prior to the target you need to be a little more careful with your aeroplane. Lets say pre target you pull + 6G, you have exceeded the In service limit, you will hear a damage sound cue and suffer a slight aerodynamic penalty. In addition your G limits have now reduced to say 4G/6G. (Bust these again and further aerodynamic penalties and further reductions will apply). You progress to the target and release your bombs. Since the weight is reduced your limits will increase but since you already bent the airframe you wont get back your original limits. You might then get say +6G/+9G. As you can see if you keep abusing the limits you will end with a very weakened airframe.

In the case of heavy bombers G limits will prevent any real aerobatic manoeuvers. You will still be able to evade quite well but you wont be able to BFM with aeroplanes like the A20 anymore. Bombers will be just that: Bombers. G limits will be applicable to AI planes as well and they will fly in a more realistic way too.

Is G displayed? Unless the aircraft in game is equipped with a G meter then no. So you will need to re think how you fly. Random snatches particularly at high speeds are going to hurt .... just as they do in real life. You will need to be aware of Corner speeds because any time you are faster than Corner speed you run the risk of an Over G event. (We are yet to finalise the display side of things)
http://forum.1cpublishing.eu/showthread.php?p=136666&highlight=Structural+profile#post136666

I suspect any further info about this will have to wait until the patch is released - hopefully not too long now.

[Tempest123]

This is probably my favorite feature of 4.10, I think it will change some of the extreme unrealistic maneuvers that occur both online and offline.

[swiss]

bad news for the spit crowd - or say some of them...

[julian265]

bad news for the spit crowd - or say some of them...

I reckon it'll be worse for the P-51/190 crowd myself - high speed manoeuvrability more easily allows excessive G's than the spit's elevator.

[Bellator]

Well if they use the real life limit load factors then it would be pretty bad for Spitfire pilots as the limit load factor for the Spitfire was some 5.33 G's compared to the std. German 8 G's and US 7.33 G's.

But then again, most pilots back then blacked out at around 4 G, so anything above 5 G is gonna entail flying in the blind anyway :P

[ATAG_Dutch]

As far as I'm aware, the only specific details given about this were in the initial TD announcement of the feature:

http://forum.1cpublishing.eu/showthread.php?p=136666&highlight=Structural+profile#post136666

I suspect any further info about this will have to wait until the patch is released - hopefully not too long now.

I wasn't aware of this being a feature until now, I tend to simply wait for patches to arrive.
This is great news though. It's always been a gripe of mine, when He111's and B-17's perform impossible feats of aerobatics.
It might also reduce the prevalence of BandZ-ers online.
BandZ is so boring. Even when I do it myself!:grin:

[Tempest123]

Well if they use the real life limit load factors then it would be pretty bad for Spitfire pilots as the limit load factor for the Spitfire was some 5.33 G's compared to the std. German 8 G's and US 7.33 G's.

But then again, most pilots back then blacked out at around 4 G, so anything above 5 G is gonna entail flying in the blind anyway :P

5.33 g's for a spitfire max g-limit? Where does this information come from? For example the F8F Bearcat was restricted to 7.5 g's after failures of its wingtip ejection system, I highly doubt that a lighter and smaller fighter which saw exponentially more combat than the Bearcat, and with no history of chronic failures would have a limit of 5.33 g's. The g-limit would vary between aircraft, not between countries.

[AndyJWest]

I'd be wary of comparing G-limits between aircraft without being sure that they were actually measured the same way. An operational G limit would presumably be based on the expected failure point, minus a safety factor. But would all safety factors be the same? Unless you know this, you can't make comparisons.

[Bellator]

5.33 g's for a spitfire max g-limit? Where does this information come from? For example the F8F Bearcat was restricted to 7.5 g's after failures of its wingtip ejection system, I highly doubt that a lighter and smaller fighter which saw exponentially more combat than the Bearcat, and with no history of chronic failures would have a limit of 5.33 g's. The g-limit would vary between aircraft, not between countries.

Now according to what I've read British aerospace std. requirement was a limit load factor of 5.33 G for their fighter aircraft, and the Spitfire was designed & built according to this. The German aerospace std. limit load factor was by comparison 8 G's and the US std. was 7.33 G's

The advantage of the lower British std. was the ability to build their aircraft somewhat lighter.

The ultimate design load factor is usually found by multiplying the design limit load factor by 1.5, at which point you arrive at the designs breaking point. So the Spitfire should be able to take 7.99 G's before breaking up, whilst aircraft such as the Bf-109, P-51 & Fw190 could take between 11 to 12 G's before breaking up.

[AndyJWest]

'British aerospace'? Anachronistic to say the least in relation to WW 2 aircraft.

Can you provide references, Bellator? Including the safety factors that otherwise make such figures of little significance. As I've already said, you have to compare like with like.

EDIT
I've found a recent thread on the Ubi forum that refers to this - it appears that British, US, and German standards were different: http://forums.ubi.com/eve/forums/a/tpc/f/23110283/m/8531075258/p/3

[Bellator]

Hi Andy,

Like I said it's only what I've read, but it seems to be true enough.

Kettenhunde at the Ubi forum knows it better than me it seems though:

That margin for damage to the airframe is "1" for US, British, and French aircraft, Bill. In technical terms, that means there is no margin.

That means if it says 6G, then the aircraft will be damaged if you exceed that limit. There is no buffer from the published limits.

The Germans had a 1.35 margin of safety for damage limits. That means there is a buffer from the published limits if you make a comparison to United States, Britain, and French standards. In other words, for the same airframe strength, the Germans will publish lower limits. If the published limits are the same, the German aircraft is stronger.

The United States, Britain, and France had a 1.5 margin of safety limit for airframe failure. The Germans had a 1.8 margin of safety limit for failure.

[Ernst]

I reckon it'll be worse for the P-51/190 crowd myself - high speed manoeuvrability more easily allows excessive G's than the spit's elevator.

Spit elevator is very responsive at high speed, ailerons are not good.

[AndyJWest]

Bellator, I understand what you are saying, but I'd be a bit wary of taking such figures too literally - they seem to imply (a) that there is a fixed ratio between G force necessary to cause airframe damage and that needed to cause failure, and (b) this ratio differed between Allied and Luftwaffe aircraft.

It's worth noting, at least in passing, that there are suggestions in the thread that early Spitfires were designed for 10 G loads, and actual tests on wings exceeded this.

[JtD]

Spitfires failed past 12g's. Tested.
The handbook says 10g starts to be unsafe (Spit II).

Bottom line: 5.33g might have been a minimum requirement for British fighter aircraft of the day, but the Spitfire could take far more. It's pretty much the same a Fw could take.

[Flanker35M]

S!

Really interesting to see how this is implemented. Over-G can cause deformation, buckled aircraft skin, loose rivets etc. For a new airframe it really needs some punishment, an extreme over-G situation to cause critical failure. In IL-2 all planes are new and they do not wear out or get old, every time you press fly getting a fresh plane.

So basically this new feature will just prevent some extreme moves seen now, but not affect the planes themselves that much. After a bit the players have adapted. Looking forward to see how this will work in SoW. Nevertheless, a nice feature even it can not be implemented 100% due IL2 engine limitations.

[Masi67]

Really hope that this will prevent bombers from doing advanced combat manevers :)

[robtek]

Don't let your hope rise too much, if you are flying red :-)
The Ju88, i.e., was structurally so sound that it also was used as fighter!!!
The Ju87 has also high g-limits.
The only handicap is the power/weight ratio and not enough speed.

[Xilon_x]

Structural dammage G-Limits example and famous video.
http://www.youtube.com/watch?v=XRCbkBfdBrQ&feature=related

[Dano]

infamous CGI you mean.

[Flanker35M]

S!

Over-G is a dynamic situation. Have to take in account speed, AoA, plane weight etc. Done a fair share of the checks myself on planes that have gone over the G limit. Really the worst case scenario for over-G is when the plane is full of fuel and has ordnance carried. It requires far less input to get into the serious over-G. I think the over-G will affect most the bombers in IL-2. Soon we will see..

[Tempest123]

Don't let your hope rise too much, if you are flying red :-)
The Ju88, i.e., was structurally so sound that it also was used as fighter!!!
The Ju87 has also high g-limits.
The only handicap is the power/weight ratio and not enough speed.

Don't forget that "red" won the war ;) In all seriousness the Luftwaffe aircraft where excellent but many of the aircraft of this era are going to be similar in structural limits. For example the DH Mosquito was certainly a better fighter than the Ju-88, and probably a better bomber as well.

[Bellator]

Spitfires failed past 12g's. Tested.
The handbook says 10g starts to be unsafe (Spit II).

Bottom line: 5.33g might have been a minimum requirement for British fighter aircraft of the day, but the Spitfire could take far more. It's pretty much the same a Fw could take.


The Spitfire II might be able to take ~12 G's before suffering a catastrophic failure, if those tests are accurate mind you, but damage would occur way before.

Point is though that the Spitfire got a lot heavier through each version, and by the time of the Spitfire Mk.IX you'd have crept up around the 5.4 G load limit area with a 1.5 safety factor for the point of failure. (8 G breaking point)

And by Kettenhunde:

That margin for damage to the airframe is "1" for US, British, and French aircraft, Bill. In technical terms, that means there is no margin.

That means if it says 6G, then the aircraft will be damaged if you exceed that limit. There is no buffer from the published limits.

The Germans had a 1.35 margin of safety for damage limits. That means there is a buffer from the published limits if you make a comparison to United States, Britain, and French standards. In other words, for the same airframe strength, the Germans will publish lower limits. If the published limits are the same, the German aircraft is stronger.

The United States, Britain, and France had a 1.5 margin of safety limit for airframe failure. The Germans had a 1.8 margin of safety limit for failure.

So the Fw190 A8 which has a 6 G load limit factor by German standards has one of 8.1 G by US & UK standards, and a 12 G safety limit for failure.

So it really aint true what you're saying, i.e. that the Spitfire's wings could take as much as the Fw190's, which would also seem abit odd as the Fw190's wings look a lot more robustly constructed.

[WTE_Galway]

The Spitfire II might be able to take ~12 G's before suffering a catastrophic failure, if those tests are accurate mind you, but damage would occur way before.

Point is though that the Spitfire got a lot heavier through each version, and by the time of the Spitfire Mk.IX you'd have crept up around the 5.3 G load limit area with a 1.5 safety factor. (8 G breaking point)

By comparison the Fw190 A-8 had a load limit factor of 6 G at take off weight with a safety factor of 1.8. (10.8 G breaking point)

So it really aint true what you're saying, i.e. that the Spitfire's wings could take as much as the Fw190's, which would also seem abit odd as the Fw190's wings look a lot more robustly constructed.

Among other differences the fw190 undercarriage is outboard and the wheels fold inwards.

[Flanker35M]

S!


Galway, there is much more to it than how your landing gear is attached or how it folds. The inner structure of the wing and how it is attached to the fuselage determines more than just one LDG component.

We get G-limits in IL-2 on planes that are always factory fresh. We do not have to worry about the FI(Fatigue Index) on the airframe, how much the plane has been strained during it's service. Older structure that has been flown hamfisted will loose it's strength thus the risk of damage or even critical failure in a High-G situation. A new plane can take a lot of beating without breaking.

What we get is a simplified feature of something that involves more than just how much G a plane can pull. It will add to the realism without being fully realistic feature. This with a 13 year experience on working with military jets every day.

[AndyJWest]

Bellator, all you've done is repeat your earlier assertions, and add a few more besides. Do you have the slightest grounds for doubting the accuracy of Spitfire structural tests? No, you don't. And do you really think you can determine the strength of a wing by looking at it?

You've still provided no evidence at all to back up your claims. As far as I'm aware, the only source for an alleged 5.33 G limit for Spitfires is an unreferenced Wikipedia article, which is flatly contradicted by the Pilots' Notes.

[JtD]

Bellator, the Fw A-8 figure of 6-8.1-10.8g is valid for a plane weight of 4450 kg.

A Spitfire MkIX, the most common of all Spitfires, weighted 3440kg. This means that, if it had the same structural strength the Fw has, it could take 7.8-10.5-14.0g. The fact that it doesn't, shows that the Fw is stronger.

Still, if you correct the safety factor of the Spit II of "about 10"g to the weight of the Spit IX, you end up with about 8g's - that's pretty much as good as the 8.1g's of the Fw.

So, what might be a bit of a misunderstanding - I'm saying that the Spit can take about as many g's as the Fw. I'm not saying that the wings are structurally as strong.

[Ernst]

Since we have no data i must agree with JtD, the FW wings had to be stronger since it was more heavier but this not imply it can take more g's, period. And we need data for such comparison.

I agree with Flanker too, all aircraft in IL2 are brandly new and can take a lot of punishment. However i guess some aircraft had more quality than others and its structure remains safe for longer time than others. We must remenber the bad conditions of the battlefield. In this case where we do not have new aircraft all time, the aircraft with better structural quality, more resistant to time conditions, continuous operations (umidity, oxidation, continuous stressing etc) and more easy to repair or change damaged parts in the battlefield had the edge, maintaining its performance integrity for longer time. This is the case of FW wich was a very ruged aircraft and can operate in almost all time and in very poor conditions, and such conditions were much more frequently in the eastern front (bad conditions of time, runways in poor conditions etc).

I have no data but i guess FW is a much better overall, all weather conditions and easy to repair fighter than its western rivals. Since IL2 does not simulates this features i think FW has lost one of its most powerfull advantages in RL.

[Friendly_flyer]

the aircraft with better structural quality, more resistant to time conditions, continuous operations (umidity, oxidation, continuous stressing etc) and more easy to repair or change damaged parts in the battlefield had the edge, maintaining its performance integrity for longer time. This is the case of FW wich was a very ruged aircraft and can operate in almost all time and in very poor conditions,

The Hurricane too was known for being able to operate from bad airfields, under adverse conditions, easy to repair (as long as it flew with RAF) and serving for a long time. Do you imply that the Hurricane was a strong plane too?

There's no need to worry about the ruggedness of the FW-190, we won't see it in BoB anyway.

[AndyJWest]

There's no need to worry about the ruggedness of the FW-190, we won't see it in BoB anyway.
The, new G-related effects are part of the upcoming 4.10 patch from TD, Friendly_Flyer. I'm sure there will be lots more discussion (read 'blazing rows' :rolleyes:) when it is released.

[Flanker35M]

S!

The "workaround" will be that most people will be flying with even less fuel = lighter planes. That alone helps to reduce the adverse effects as less weight = higher G can be pulled. Applies to fighters mostly.

Most I am interested in the bombers and how this G thingy affects them. The plane itself can withstand some G(far less than a fighter) but the bomb racks for sure can not withstand forces of high G with payload hung in them. The locks will fail thus causing damage or even explosion inside the plane. With a bomb load the maximum G is much lower, even on modern jets.

[Tempest123]

Yeah, that's def. whats gonna happen, should make for some more realistic dogfights. Does anyone know what kind of structural limitations, or g-limits were found on soviet aircraft such as Yaks and La-s. I know that Yaks are highly maneuverable and I would have thought that could withstand some higher g's?

[Friendly_flyer]

The, new G-related effects are part of the upcoming 4.10 patch from TD, Friendly_Flyer.


Ouch, serves me well for not paying attention.

My point about the Hurri still stands. The arguments about what plane can take the worst beating are downright silly. There are ways to find this out, mainly the known loading strengths of the spars, wing area and plane weight. German safety standards and and rugged planes kind of arguments are silly.

As for the Hurri, I don't expect her to stand extreme G-loads. If anything her saving grace would be them thick wings, stopping her from building up dangerous speeds.

[Flanker35M]

S!

Hurricane's design was rugged and the structure could take some beating without breaking. The wings were thick and this caused that most contemporary fighters could with relative ease just out accelerate it in a dive and gain distance. Finnish tests showed that even the controls were good and quite easily managed, the roll rate was not very good. To this added the guns being out in the wing and the ammo load.

Another thing is the wing. Early Mk.I's had the fabric covered wing and it did not withstand damage very well, a short burst or even only a few bullets could cause the fabric to rip off and that is not a good thing. Finns lost at least 1 Hurricane Mk.I in a dive when the fabric covered wing peeled off thus there were limitations set for speeds used. Also the performance of the fabric winged Hurricane deteriorated much faster than on the metal winged one.

What made the Hurricane most easily shot down plane by Finns was the reason that even being structurally decently strong it caught fire very easily. Pilots were taught to aim in front of the cockpit where an oil and fuel tank were located, result was in most cases a flying torch. Also hits from low 6 were effective as it punctured the cockpit floor, radiator etc.

This just as an example. Structure can be good but other things cause the failure. In this case flammable liquids and the fabric cover of the wing. For the Fw190 a hit in 20mm or 30mm ammo could cause an explosion ripping the wing off, Mustangs were lost due the MLG uplock failing in high speed high G situation, Yaks and La-5's breaking up in dives due wing failure, Bf109G-6 lawn darting due wooden tail disintegrating in a dive..the list goes on. Every plane had it's vices. But in IL-2 we always have fresh planes that are "built to the specs", no sabotage or poor craftmanship etc.

I am waiting for 4.10 a lot :)

[Ernst]

My arguments are in the sense that some aircraft could had its lifetime structure
integrity lasting for much more time in war conditions. I do not known about Hurricanes, but if it is adequated for poor conditions and easy to repair, its structure will last more time inside the specifications of its fabrication. If it had disadvantanges or advantages in its fabrication time then it ll remain in this standarts for longer time.

[Tempest123]

S!

This just as an example. Structure can be good but other things cause the failure. In this case flammable liquids and the fabric cover of the wing. For the Fw190 a hit in 20mm or 30mm ammo could cause an explosion ripping the wing off, Mustangs were lost due the MLG uplock failing in high speed high G situation, Yaks and La-5's breaking up in dives due wing failure, Bf109G-6 lawn darting due wooden tail disintegrating in a dive..the list goes on. Every plane had it's vices. But in IL-2 we always have fresh planes that are "built to the specs", no sabotage or poor craftmanship etc.



+1, too many factors involved. Il2 can only simulate factory fresh aircraft w. no defects.

[jameson]

It would be fairly simple to implement some kind "wear factor" into offline campaigns, I would have thought. The prospect of having survived 15 missions and then have your plane crack up with fatal consequences, would add a bit to IL2, don't you think? And some similar overlay for the AI would be fun.

[Ernst]

It would be fairly simple to implement some kind "wear factor" into offline campaigns, I would have thought. The prospect of having survived 15 missions and then have your plane crack up with fatal consequences, would add a bit to IL2, don't you think? And some similar overlay for the AI would be fun.

Depends on your mechanic :grin: If he is good your aircraft will be ever in good conditions and performance. I am a F-1 fan and think aircraft could be like an F-1 car if you do not adjust it well you can lose the race. :grin:

[Friendly_flyer]

I look forward to this, the whine-fest will be of epic proportions!

[Flanker35M]

S!

There will be whining and complaints for sure, but again people will adjust and fly accordingly. In every single game genre people learn to "game the game" and IL-2 is not an exception.

[Friendly_flyer]

Quite so, and when the whiners have learned to fly with the load limits, they will hail it asone ofthe things that makes IL-2 so great.

[Xilon_x]

to fly with the load limits must also have interfaces to set them.
example:
actualy i chose fuel in il-2 this is option 0%--25%--50%--75%--100% of fuel.
is possible chose fuel precisely from 1to100? 10%12%36% 40%ecc.ec.?
another example the kg of pilots medium pilot is 70kg
and bombs? 1000kg 2000kg ecc.ec.

[Tempest123]

to fly with the load limits must also have interfaces to set them.
example:
actualy i chose fuel in il-2 this is option 0%--25%--50%--75%--100% of fuel.
is possible chose fuel precisely from 1to100? 10%12%36% 40%ecc.ec.?
another example the kg of pilots medium pilot is 70kg
and bombs? 1000kg 2000kg ecc.ec.

This is actually a good point, it would be nice to have the option outside of the FMB to set the fuel from any point between 0 to 100%.