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F-5E can pull 13+G?


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On 1/20/2024 at 9:54 AM, zerO_crash said:

Which manual are you refering to? (If you're unsure if it's legal, don't link it here, simply give me the name or version.).

Export version: Page I5, Figure 2. Speed vs max G graph.


Edited by Pavlin_33

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26 minutes ago, Pavlin_33 said:

Export version: Page I5, Figure 2. Speed vs max G graph.

 


Yeah, that is only partial understanding, in Russian Air Forces, it's called "operational overload". Again, refer to my previous comment. The whole chapter has information on intricacies of flight and design. Page 9 of the Su-27SK manual confirmes Su-27SK being 9G capable. The constant 8G is again, due to extending the service life of the airframe as much as possibly doable. My former comment explains this.

 

What ought to be said, is that much depends on weight (mostly due to fuel load). Su-27 has no external tanks, because it's a design that essentially is a jack of all trades. If you go to combat, you practically never carry more than 50% fuel internal, often less. Anything above that, is either a carefully tailored mission with on-station time or long initial/final flight, or ferry. It's not a configuration that stresses performance.

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On 1/29/2024 at 11:22 AM, zerO_crash said:


Yeah, that is only partial understanding, in Russian Air Forces, it's called "operational overload". Again, refer to my previous comment. The whole chapter has information on intricacies of flight and design. Page 9 of the Su-27SK manual confirmes Su-27SK being 9G capable. The constant 8G is again, due to extending the service life of the airframe as much as possibly doable. My former comment explains this.

 

What ought to be said, is that much depends on weight (mostly due to fuel load). Su-27 has no external tanks, because it's a design that essentially is a jack of all trades. If you go to combat, you practically never carry more than 50% fuel internal, often less. Anything above that, is either a carefully tailored mission with on-station time or long initial/final flight, or ferry. It's not a configuration that stresses performance.

Well if the operational limit is 8G (for what ever reason) then it should be the a base reference. I mean, if an air frame can technically sustain certain load, but it's limited, DCS should reflect that. I mean it should not matter what the air frame could pull off theoretically or only one- or sometimes, but rather what corresponds to reality.

Same thing we have with the Hornet, which is supposed to be a 7.3G fighter, but in DCS it's more like the Eagle.

Us pretending that every air frame in DCS is brand new and disposable is not really realistic, in my humble opinion.

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2 hours ago, Pavlin_33 said:

Well if the operational limit is 8G (for what ever reason) then it should be the a base reference. I mean, if an air frame can technically sustain certain load, but it's limited, DCS should reflect that. I mean it should not matter what the air frame could pull off theoretically or only one- or sometimes, but rather what corresponds to reality.

Same thing we have with the Hornet, which is supposed to be a 7.3G fighter, but in DCS it's more like the Eagle.

Us pretending that every air frame in DCS is brand new and disposable is not really realistic, in my humble opinion.


You are not reading thoroughly! The operational limit is 9G, however it's not recommended as a sustained (again, has nothing to do with what the airframe sustains, only a recommendation as to extending airframe service life) G-load. This is further confirmed by the statement in the manual that claims the following;

 

"at V > M0.85, the maximum sustained G-load ("Pu") is 8G, but should not exceed 9G."

 

Everything is correct in DCS, and in accordance with real life operating procedures. What you have to understand, is that G-load is not a static number per se. Depending on the aircraft, aircraft weight, speed, altitude, etc... the conditions will dictate what you can pull in G. The eastern crowd was introduced to this (those that didn't know) much earlier, nowadays however, the western crowd finds out about this dynamic with e.g. F-15E. Yes, if you pull more than 7.5G with a heavy loaded F-15E, you will bend the wings irreversibly. Yes, if you exceed 9G for longer than an instant with the A-A configuration (light), the wings will also start to bend beyond shape and format. Now, you have to finally respect factoes like: speed, altitude, pressure, aircraft weight, and more...

 

As to Hornet, there is a distinction between "soft limit" and "hard limit" of stick travel. I explained this before to you, the F-18 is built as a 9G fighter aircraft (Finland has F-18s that are not carrier-operated - they are rated at 9G max.). However, since the USN F-18 are already operating in a highly unfavourable environment (salt is reducing service life of quipment at accelerated rated), in order to mitigate the issue of shorter airframe life, the operational G-load was reduced to 7.5G (it's not 7.3G as you stated). Now, operational means - everyday use under normal circumstances. If a pilot should end up in an emergency, or actual combat (not training) and need the extra G, he can push the stick past the soft limit (you have to activate a lever on the stick first) and to the hard limit. That will allow to yield more than 7.5G, and potentially 9G or even more, at your own caution. Now, IRL, if you'd done that, the mechanics would know, and you would have to answer why a national asset was stressed beyond the "standard" envelope to the CO/XO. Depending on the explanation, you might have been reprimanded or not.

 

In DCS, this is something that I imagine gets abused online, because people have little dignity in their flying, and take DCS with varying levels of professionalism and investment. DCS as a simulator allows you to train military aviator proficiency, but it also allows to goof around. I am personally an ultra-purist, and e.g. few servers come even close to replicating actual environments. Also, how you fly, is something that you should monitor, not a "bar" or "level" showing use/misuse. You know when you exceed limitations, and when you don't. Even if you join the supposedly "pure simulator" servers, you will see people sometimes flying recklessly and as if respawn is faster to the AO, than flying back and rearming. How many people do you think plan their route properly, do fuel calculation and ordnance planning before taking off? Granted, there is much missing (e.g. the whole intel section of actual planning), but then you have to adapt. Still, people join and take off in less than 10 minutes. Do you really wonder why they get shot down? I won't even mention what I hear and imagine is blue-blue on quake servers...

 

Another example; IRL, a multirole airframe is meant so that multiple services and squadrons, focusing on different missions (CAP, CAS, SEAD, etc...), can use the same aircraft, which is economically lucrative for the whole branch. In DCS, as realistic as it allows you to be, an average server is filled with people outfitting their F-18 with AIM-9X/AMRAAMS, GBU12/39s and AGM-88 at the same time. Essentially flying a AC-130 trying to win the war alone. My point is, let them enjoy theirs, but if you struggle with finding good servers, then either you are not looking well enough, or you might be bound to singleplayer scenarios (there are a few decent servers out there though).

 

Let's stick to topic though.


Edited by zerO_crash

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On 2/1/2024 at 1:06 PM, zerO_crash said:


You are not reading thoroughly! The operational limit is 9G, however it's not recommended as a sustained (again, has nothing to do with what the airframe sustains, only a recommendation as to extending airframe service life) G-load. This is further confirmed by the statement in the manual that claims the following;

 

"at V > M0.85, the maximum sustained G-load ("Pu") is 8G, but should not exceed 9G."

 

Everything is correct in DCS, and in accordance with real life operating procedures. What you have to understand, is that G-load is not a static number per se. Depending on the aircraft, aircraft weight, speed, altitude, etc... the conditions will dictate what you can pull in G. The eastern crowd was introduced to this (those that didn't know) much earlier, nowadays however, the western crowd finds out about this dynamic with e.g. F-15E. Yes, if you pull more than 7.5G with a heavy loaded F-15E, you will bend the wings irreversibly. Yes, if you exceed 9G for longer than an instant with the A-A configuration (light), the wings will also start to bend beyond shape and format. Now, you have to finally respect factoes like: speed, altitude, pressure, aircraft weight, and more...

 

As to Hornet, there is a distinction between "soft limit" and "hard limit" of stick travel. I explained this before to you, the F-18 is built as a 9G fighter aircraft (Finland has F-18s that are not carrier-operated - they are rated at 9G max.). However, since the USN F-18 are already operating in a highly unfavourable environment (salt is reducing service life of quipment at accelerated rated), in order to mitigate the issue of shorter airframe life, the operational G-load was reduced to 7.5G (it's not 7.3G as you stated). Now, operational means - everyday use under normal circumstances. If a pilot should end up in an emergency, or actual combat (not training) and need the extra G, he can push the stick past the soft limit (you have to activate a lever on the stick first) and to the hard limit. That will allow to yield more than 7.5G, and potentially 9G or even more, at your own caution. Now, IRL, if you'd done that, the mechanics would know, and you would have to answer why a national asset was stressed beyond the "standard" envelope to the CO/XO. Depending on the explanation, you might have been reprimanded or not.

 

In DCS, this is something that I imagine gets abused online, because people have little dignity in their flying, and take DCS with varying levels of professionalism and investment. DCS as a simulator allows you to train military aviator proficiency, but it also allows to goof around. I am personally an ultra-purist, and e.g. few servers come even close to replicating actual environments. Also, how you fly, is something that you should monitor, not a "bar" or "level" showing use/misuse. You know when you exceed limitations, and when you don't. Even if you join the supposedly "pure simulator" servers, you will see people sometimes flying recklessly and as if respawn is faster to the AO, than flying back and rearming. How many people do you think plan their route properly, do fuel calculation and ordnance planning before taking off? Granted, there is much missing (e.g. the whole intel section of actual planning), but then you have to adapt. Still, people join and take off in less than 10 minutes. Do you really wonder why they get shot down? I won't even mention what I hear and imagine is blue-blue on quake servers...

 

Another example; IRL, a multirole airframe is meant so that multiple services and squadrons, focusing on different missions (CAP, CAS, SEAD, etc...), can use the same aircraft, which is economically lucrative for the whole branch. In DCS, as realistic as it allows you to be, an average server is filled with people outfitting their F-18 with AIM-9X/AMRAAMS, GBU12/39s and AGM-88 at the same time. Essentially flying a AC-130 trying to win the war alone. My point is, let them enjoy theirs, but if you struggle with finding good servers, then either you are not looking well enough, or you might be bound to singleplayer scenarios (there are a few decent servers out there though).

 

Let's stick to topic though.

 

Well, when you listen to US Navy pilots that flew the Hornets, thay say they were never allowed to go over the limit, in this case the "soft" limit as you have mentioned of 7.5G ( I made a typo in earlier post).

They were not told to go over this limit in a dogfight or in certain situations, they were instead instructed NEVER to go over this limit. If the manual states the same (and the F/A-18 was modeled by it), then this should be the baseline and not some potential limit that is not realistic and/or sustainable. Again what ever the reason in RL might be.

These kind of performance excursions in DCS should be high-risk situations, where you might be ok but most probably won't, and not something where you operate most of the time comfortably.

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4 hours ago, Pavlin_33 said:

Well, when you listen to US Navy pilots that flew the Hornets, thay say they were never allowed to go over the limit, in this case the "soft" limit as you have mentioned of 7.5G ( I made a typo in earlier post).

They were not told to go over this limit in a dogfight or in certain situations, they were instead instructed NEVER to go over this limit. If the manual states the same (and the F/A-18 was modeled by it), then this should be the baseline and not some potential limit that is not realistic and/or sustainable. Again what ever the reason in RL might be.

These kind of performance excursions in DCS should be high-risk situations, where you might be ok but most probably won't, and not something where you operate most of the time comfortably.

The structural testing program for the F-5 expected many excursions above the 7.33 limit and, thus, tested the aircraft to this expectation over several aircraft “lifetimes” (4000 hours)

Here is the graph showing what was expected and tested. 
 

image.png

You can see from the chart approximately 45 9G excursions per 1000 hours were expected with some undefined number of 9+ G excursions to also be expected. 
 

While folks here love to posit that fighter pilots rigorous adhere to prescribed procedures and limitations without deviation, there is much available evidence that isn’t the case nor is it desired. 
 

G limits are for longevity of the airframe. 
 

If you don’t expect to be using the aircraft again, limits do not apply and should be disregarded until such time that one can, once again, expect the aircraft to successfully complete its current sortie and be available for future sorties. 

 

 

 

 

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5 hours ago, Pavlin_33 said:

Well, when you listen to US Navy pilots that flew the Hornets, thay say they were never allowed to go over the limit, in this case the "soft" limit as you have mentioned of 7.5G ( I made a typo in earlier post).

They were not told to go over this limit in a dogfight or in certain situations, they were instead instructed NEVER to go over this limit. If the manual states the same (and the F/A-18 was modeled by it), then this should be the baseline and not some potential limit that is not realistic and/or sustainable. Again what ever the reason in RL might be.

These kind of performance excursions in DCS should be high-risk situations, where you might be ok but most probably won't, and not something where you operate most of the time comfortably.

 

It is as I stated, and NAVY pilots have nothing to fear at 9G in their Hornets. Notice the graph from Dawger above. Again, the reprimand to exceed those limits, would not come from mechanical failiure (given that the airframe is within expected lifetime), rather from the given pilot's CO. Also, as stated earlier by me, in DCS, few respect those limits online. That's why, you have to find the right servers, or fly singleplayer. People abuse not only this, but even G-fatigue of the pilot, pullling moves and twists you would never see in real life. That's the problem on many servers online. Many just want to have "fun" between their job and taking their dog out. Hopefully, with time, the maturity will go up.

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G fatigue of the crew is severely misunderstood by the flight sim community. 
 

In the F-15 community, 9 G breaks are standard practice. 

The C model can sustain 7.5 indefinitely and the pilots can sustain this until the fuel is gone. 

Rapid negative/positive transitions are the only area of pilot physiological weakness I see abused online.  

 

 

 

 

 

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15 minutes ago, =475FG= Dawger said:

G fatigue of the crew is severely misunderstood by the flight sim community. 
 

In the F-15 community, 9 G breaks are standard practice. 

The C model can sustain 7.5 indefinitely and the pilots can sustain this until the fuel is gone. 

Rapid negative/positive transitions are the only area of pilot physiological weakness I see abused online.  

 

Not only the Eagle, but also many others. You can ride 7-8G+ until the juice runs out.

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Having looked at a good couple of centrifuge runs, I would certainly not say that a pilot can do it a lot. 2x 30-second runs typically drain the pilot to a solid exhaustion. Again, with aircraft nowadays, it's the pilot that is the weak link. Then you get to the mood-side of things. A pilot has better and worse days for sustaining G-loads. I guess most military fighter pilots can hold 9Gs for a short time these days, but after 2-3 runs, based on observation, I'd say that they better rotate (change with a less active CAP-flight) for the day. There are of course others who handle even 11Gs (referring to the famous centrifuge run O_o), but that does look pretty rare.

 

I'm mostly talking about, as you mention altering between positive and negative G-loads, pulling funnel while at high-G, etc... There's a lot of poor and unrealistic piloting on quake servers. It's not an environment for someone who wants at least a little realism.

 

I'm not even mentioning turning around and looking behind you, during a dogfight (if that happens). In certain aircraft (e.g. MiG-21Bis), the pilot is strapped to the seat without the ability to move around - zero ability to look past whatever your neck will twist. Consider now someone with TIR moving their head 20-30 degrees at most, to look behind them... yeah. Too bad one cannot restrict users from joining based on TIR/VR. 
 

EDIT: I'll add that as you point you Dawg, dedicated CAP squadrons are selected and trained in G-strain tolerance, no doubt there.


Edited by zerO_crash

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On 2/1/2024 at 1:06 PM, zerO_crash said:


You are not reading thoroughly! The operational limit is 9G, however it's not recommended as a sustained (again, has nothing to do with what the airframe sustains, only a recommendation as to extending airframe service life) G-load...

 

If you look at the G-meters in respective cockpits of Flanker and Fulcrum, the the numbering on them seems to reinforce what the manuals are saying:
29's goes up to 9G, while 27's stops at 8G

27g.png 29g.png

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35 minutes ago, Pavlin_33 said:

If you look at the G-meters in respective cockpits of Flanker and Fulcrum, the the numbering on them seems to reinforce what the manuals are saying:
29's goes up to 9G, while 27's stops at 8G

27g.png 29g.png


I already told you what the manual is stating! On the accelerometer of Su-27, the red mark covers 8G+ - 9G. That is to remind the pilot that effectively, the air force doesn't want him to pull more than 8G for durability reasons. You can also see on the MiG-29 a red line on 7G, which works in pretty much the same way, albeit here, the manual lists no specific limit, other than general 9G sustain. For comparison, on Su-27SK, the air force doesn't want you to pull 9G prolonged, therefore 8G below red line, and 9G within.

 

You seem to have a problem with understanding that, even worse, you attempt to read a technical manual in a language you do not operate with. Don't do that, you will often lose the coherency of syntax - context. 

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2 hours ago, zerO_crash said:


I already told you what the manual is stating! On the accelerometer of Su-27, the red mark covers 8G+ - 9G. That is to remind the pilot that effectively, the air force doesn't want him to pull more than 8G for durability reasons. You can also see on the MiG-29 a red line on 7G, which works in pretty much the same way, albeit here, the manual lists no specific limit, other than general 9G sustain. For comparison, on Su-27SK, the air force doesn't want you to pull 9G prolonged, therefore 8G below red line, and 9G within.

 

You seem to have a problem with understanding that, even worse, you attempt to read a technical manual in a language you do not operate with. Don't do that, you will often lose the coherency of syntax - context. 

Looks like you might be right, on this Ukranian Flanker from 2010 the limit (never exceed) seems to be 9G:

image.png

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It's wrong to read the red bar as "limit never exceed", that is not a term used by the manual, and that, for a very specific reason. Any airframe, depending on the type, will be able to sustain 133% - 150% the limit which is  stated in the flight/operating manual. "Limit never exceed", is something that is typically stated in technical documentation from the manufacturer (as opposed flight/operating manual, which is an air force document). This mainly concerns engineers working on the airframe. The reason is simple; pilots are to adhere to limits sets by the air force, not aircraft designers.

 

Of course I am right, I just explained the distinction made in the Su-27SK flight manual (Rus) as to what the different G-limits are. I am partly from there, thus I speak Russian/cyrillic. People generally don't have any understanding for how documents are made, who is to follow what, and which way documentation goes, especially since there isn't any common standard being followed internationally.

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