correct as-is Concerns about G-Onset and Damage to wings

[Tiger-II]

There is no fuel in the wings, so it's a question of what stores you have loaded at the time.

Rolling g limits are a thing, and it appears they've either added it or tightened it up. If you roll sufficiently aggressively you can pull the stores off (I have done this in the A-10 and the F-5 intentionally).

If you're fast, pulling g to the pitch limit, and then rolling as well, you can very easily overload the wing (and in fact it is a prohibited maneuver in pretty much any aircraft I can think of).

If you want to be safe, don't pull more than about +4 g if you want to roll as well. If you're flying ACM then you probably won't be pulling much over this anyway otherwise you'll be bleeding speed the entire time (undesirable in itself).

If you have stores, then +2.5 g is a reasonably safe limit to roll. The g load at the stores can be +2 or +3 g higher than what you're experiencing in the cockpit at the roll centerline. If you make an abrupt roll maneuver on top of all of this (instantaneous load), an overload condition is very likely.

Let's say you're pulling +5 g with wing stores and then roll - the wing can be experiencing +8 g or more, which has exceeded the g limit, and will either cause damage, pull the stores off, or worse.

Try and make it habit to unload before rolling aggressively if you're pulling at the g limit. You certainly can't put in full roll input above +1 g unless you want to break something.

This isn't to say you can't roll and pull g. You can. It's a question of "how much". If you don't pull pitch to the g limit and then roll, you can do more than you think.

A clean aircraft can pull +7 g safely, but with wing stores is limited to +5 g or so, so your margin is much lower with anything hanging off a pylon. It also assumes coordinated flight. Rolling can induce an increasing yaw rate, and often sustained roll rates are also prohibited due to this (side loads can exceed pylon limits).

I appreciate there is a lot to consider, but to keep it simple: if you want to pull g and maneuver aggressively, you can only do so with a clean jet.

Edited March 21, 2022 by Tiger-II

[SparrowLT]

I have had several times the wings break off just flying past a bandit in close merges .. like if the wake of the other jet would be what breaks them

[Bucic]

Does tacview record flight control position? This way we could ivestigate properly, case by case. There are some documents mentioning structure stregth considerations but I feel we have "a DCS thing" at hand.

[Bucic]

BTW, have you guys noticed that commercial sticks have the pitch neutral point in the center of the movement range? So DCS maps that to the in-sim controls, basically increasing the rates by ~100% for pitch up. And it does the opposite for pitch down. The ratio is ~3/8 in real F-5E and the ratio in commercial joysticks is 1/1.

[Raisuli]

On 2/23/2023 at 2:04 AM, SparrowLT said:

I have had several times the wings break off just flying past a bandit in close merges .. like if the wake of the other jet would be what breaks them

I landed a hop last night with the max G needle pegged at 10 and no detectable ill-effects to anything.  Come to think of it the other G-needle was pegged at -4.  Guess I should be gentler with the stick, but I was out practicing to miss with bombs and not kill QM-21 drones.

<edit>

Ok, I confess, if I want to reduce weight the wings are the first thing to jettison.  The aircraft flies remarkably well without wings, though.  I was able to flame my way back to the airfield and eject right over the O-club.  The aircraft just kept going, and going, and maybe flew better without me as the pilot than it did with me.  Tried to hop in another aircraft to shoot it down, but it despawned.  Pity. 

</edit>

Edited April 27, 2023 by Raisuli

[crazyave]

On 2/23/2023 at 1:04 AM, SparrowLT said:

I have had several times the wings break off just flying past a bandit in close merges .. like if the wake of the other jet would be what breaks them

I get this too.  If I fly behind a TU-22 and he makes any kind of quick turn or movement my wings go bye-bye.  Even with hands off the stick.  Is that realistic?

Edited April 28, 2023 by crazyave

[=475FG= Dawger]

On 4/28/2023 at 2:04 PM, crazyave said:

I get this too.  If I fly behind a TU-22 and he makes any kind of quick turn or movement my wings go bye-bye.  Even with hands off the stick.  Is that realistic?

 

No, its actually really silly. 

[Bucic]

On 4/28/2023 at 9:04 PM, crazyave said:

I get this too.  If I fly behind a TU-22 and he makes any kind of quick turn or movement my wings go bye-bye.  Even with hands off the stick.  Is that realistic?

 

Could you re-create the scenario and post a track?

[crazyave]

I went back to all the track files for a mission that produces the issue and tried to play them back but they just end after 10 seconds, whereas the missions are about 1.5hrs.  I'd either have to live stream it or literally put a gopro looking at my monitor due to the playback bug which doesn't allow playback, LOL.  They are 52MB each, what a waste of disk space.

 

The conditions in my mission are having an F-5 with full fuel, or close to it, two sidewinders on the wingtips.  Chase down a fully loaded TU-22 and shoot it with guns, as he maneuvers or turns sharply, if you're in the wake turbulence the wings will rip off.

Edited April 30, 2023 by crazyave

[Sarge55]

Setup a mission, air start behind the Tu-22, get him to maneuver, snap the wings then quit the mission.

Should be a much smaller track file and “probably” play back ok. 

[BIGNEWY]

if you can reproduce with a short track please PM me with it, I am happy to take a look. 

Just keep in mind your aircraft weight and how many G's you are pulling. 

thanks

[Braunn]

You dont need the wings anyway. Just use rudder for roll.
 

 

[Cab]

On 5/9/2023 at 10:20 AM, BIGNEWY said:

if you can reproduce with a short track please PM me with it, I am happy to take a look. 

Just keep in mind your aircraft weight and how many G's you are pulling. 

thanks

Here you go.

 

F-5 wing demo.trk

[Cab]

Back on May 25 I posted a track showing the wings breaking here:

But since it wasn't in the Bugs section and there have been no additional comments there, I am reposting it here to make sure it is seen and reviewed. People can judge for themselves if this can be attributed to normal behavior.

With the proven popularity of the F-5 in the Enigma Cold War server, this problem has only become more critical.

 

 

F-5 wing demo.trk

[BIGNEWY]

posts merged and moved

in the track you are 100% fuel for a weight of around 15891lbs 

in a dive at around 500kts you pull to 9g 

we would need to take a look at the data but it is putting a lot of strain on the airframe. 

thank you

[Noctrach]

48 minutes ago, BIGNEWY said:

posts merged and moved

in the track you are 100% fuel for a weight of around 15891lbs 

in a dive at around 500kts you pull to 9g 

we would need to take a look at the data but it is putting a lot of strain on the airframe. 

thank you

This would imply less than 23% safety margin between the rated 7.33G and actual airframe destruction for a clean configuration. This would also mean an F-5 with just a centreline 5xMk-82 ripple rack should start suffering catastrophic wing failure at less than 7.5G.

To me this seems rather unlikely for any airframe, let alone one that has such a reputation of mechanical reliability while being used in an aggressor role.

(That said I don't think I've ever seen the wings break off my F-5 in hundreds of DCS hours, so I think something else is going on)

Edited June 21, 2023 by Noctrach

[Cab]

38 minutes ago, BIGNEWY said:

posts merged and moved

in the track you are 100% fuel for a weight of around 15891lbs 

in a dive at around 500kts you pull to 9g 

we would need to take a look at the data but it is putting a lot of strain on the airframe. 

thank you

Fair enough. I doubt any fighter that broke under those conditions would be accepted, but that's a subjective opinion and checking the numbers is prudent.

I would offer that even if the numbers supported the likelihood of a break, then the problem may be getting to that point with very little effort on the part of the player. In other words, I had very little stick movement, so maybe that is what needs to be adjusted.

Edited June 21, 2023 by Cab

[ricktoberfest]

Maybe ED should look at a different way to punish over G rather than breaking the wings off. Break the missiles, or pylons, or spring a fuel leak- something that makes more sense than the all or nothing wing break. I’ve given up on the F5 since the wing break mechanic was instituted. Just makes no sense given the lack of feedback leading up to the event. 

[=475FG= Dawger]

Putting aside the rather obvious fact that the F-5 would not have survived 5 decades in service if this modeling was anything resembling reality, other aircraft are not modeled in the same fashion.
 

Another module with nearly identical limitations verbiage does not suffer from catastrophic wing failures. 
 

The issue with the F-5 is a combination of several factors. The limitations have been very poorly interpreted. An example is the limitations stating that FULL aileron deflection is prohibited under condition X yet minor aileron deflection will crack the wings off.

The idea that catastrophic failure of the major structural component of a BRAND NEW tactical aircraft would occur precisely 1.5 times the limit the very first time said limit is reached without failure of weaker structures first is ludicrous. No one would fly the aircraft much less take it into a dogfight.

There is some very suspect modeling. The aircraft will show high “G” before the nose moves. This is backwards from the physics. The indication of acceleration must occur before the instrument measuring said acceleration can display it.

We are two years into this debacle with zero chance of its reversal. The egos involved prevent any honest evaluation with the potential for admission of error.

The poor DCS F-5 struggles on with its glass wing, sawed off shotgun weapon dispersion, suspect flight control modeling and strange RWR implementation, fighting third party produced modules whose wings don’t break, guns shoot straight as lasers, and fire radar missiles fully capable of “look down, shoot down” years before their existence in reality.

Personally, I will not buy anything but a third party module now. They are a labor of love and aren’t going to be subjected to a sudden update that makes the wings fall off. No third party developer could take the hit to his heart or wallet.

 

[Raisuli]

43 minutes ago, =475FG= Dawger said:

The poor DCS F-5 struggles on with its glass wing, sawed off shotgun weapon dispersion, suspect flight control modeling and strange RWR implementation, fighting third party produced modules whose wings don’t break, guns shoot straight as lasers, and fire radar missiles fully capable of “look down, shoot down” years before their existence in reality.

Personally, I will not buy anything but a third party module now. They are a labor of love and aren’t going to be subjected to a sudden update that makes the wings fall off. No third party developer could take the hit to his heart or wallet.

 

The graphics are bad, the front office needs redecorated, the wings fall off, the guns can't hit much, the radar can't see a flat metal plate the size of a barn door 100 meters away, the RWR is twitchy...honestly, there's nothing there not to like.

She still one of my favorites, warts and all.

In theory ED is giving her some attention, which will be nice if it happens in my lifetime, and if not, no worries.  Also got the F-14 and the F-4 coming up for cold war, but the F-5 has her place.

[Art-J]

I don't think it's primarily a problem of "egos involved", but rather of all ex-Belsimtek devs working directly for ED now, which, as predicted years ago when merge was done, caused all Belsimtek modules to fall near the bottom of priority list of  fixes and support. 

Imrovements coming were hinted in January and Huey guys got their partial revision of FM at last (which, judging from the relevant posts seems to have caused new accuracy issues next to fixing the old ones) but it only shows it's going to take few next years until major overhaul of F-86, MiG-15 and F-5 happens.

[Bucic]

13 hours ago, =475FG= Dawger said:

An example is the limitations stating that FULL aileron deflection is prohibited under condition X yet minor aileron deflection will crack the wings off.

Which "FULL" lateral deflection value are you referring to? Up to (6.4") or past the spring limiter to the absolute max (8.0")? Your source?
 

[=475FG= Dawger]

8 hours ago, Bucic said:

Which "FULL" lateral deflection value are you referring to? Up to (6.4") or past the spring limiter to the absolute max (8.0")? Your source?
 

 

[Bucic]

18 hours ago, =475FG= Dawger said:

 

Thanks! Plenty of reading for later, including a full downloadable document.

 

[Flappie]

I did a few instantaneous G load tests with a filled internal tank and an empty payload :

• F-5 : wings snap when G > 10.2 (seems correct)
• MiG-15bis : wings are OK at 10.3G (I couldn't reach higher Gs) (seems too much)
• F-86 : wings are OK at 13G (I couldn't reach higher Gs) (seems too much)
• F-15C : wings snap when G > 12 (seems correct)
• L-39C : wings snap when G > 14 (seems too much)
• MiG-29 : wings snap when G > 15 (seems too much)

Do we have some official documentation claiming the F-5E could withstand more than 10G, especially as an instanenous load ?  (manuals often only mention sutstained Gs)

Aside from the wings being ripped off at 10G, I'm puzzled by the pilot not getting gLOC while I pull to 10G. Maybe the real problem is here? How could we know we're pulling 10G when the pilot doesn't seem to be under heavy G?