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[RESOLVED] AV8B goes supersonic after dropping 10 GBU-38's


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Loadout:

TPOD

10 GBU-38's (2 pair on inner pylons, 3 pair on middle pylons)

 

Load up the plane with 10 GBU-38's.  TPOD may or may not be necessary.

Climb above 12,000 feet.  Drop all 10 GBU-38's.  

 

The plane will slowly start to accelerate beyond Mach 1.0 in straight and level flight (or even in a slight climb!).  It's as if the plane became magically lighter than it's normal empty weight.  You'll be able to hear the sonic boom and everything.  Eventually the plane will accelerate past Mach 1.06 and the wings will fail shortly thereafter.

 

I have recorded a YouTube video showing this and will upload here when it is ready.  The problem does not happen if you takeoff with nothing loaded.  I haven't tried any other ordinance, so it might only be a problem with the GBU-38's.

 

 

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  • Xpendable changed the title to AV8B goes supersonic after dropping 10 GBU-38's

So on the attempts you showed there, I did not see you indicate what % your throttle was at, only on the unarmed take off. I dont use full throttle unless im maneuvering or taking off. Attempting this with 80% to 90% throttle I was unable to exceed M0.97 and even there I received severe buffeting Regardless. The Harrier is not meant to go supersonic. It is capable of going supersonic and definitely can go there with the trust it has. HOWEVER, there are many many MANY indicators and guides to tell you you should not attempt it, and if you are going that fast you should be reducing your speed immediately. Just because you can. Does not mean you should. 

Know and use all the capabilities in your airplane. If you don't, sooner or later, some guy who does use them all will kick your ass.

 

— Dave 'Preacher' Pace, USN.

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The throttle does not have to be at 100%.  But you DO have to start with a bunch of bombs (like GBU-38's) and then drop them.  Trust me, this is a BUG.  Straight and level flight after dropping a bunch of GBU-38's with less than full throttle and the plane WILL go supersonic and will continue accelerating until the wings rip off.  It does NOT do that if you start with an empty plane.  You cannot recreate it unless you start with GBU-38's (I suggest 10) and then drop them.  That's the bug.  Watch the full video and you'll see it.

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On 12/12/2020 at 7:08 AM, Xpendable said:

The throttle does not have to be at 100%.  But you DO have to start with a bunch of bombs (like GBU-38's) and then drop them.  Trust me, this is a BUG.  Straight and level flight after dropping a bunch of GBU-38's with less than full throttle and the plane WILL go supersonic and will continue accelerating until the wings rip off.  It does NOT do that if you start with an empty plane.  You cannot recreate it unless you start with GBU-38's (I suggest 10) and then drop them.  That's the bug.  Watch the full video and you'll see it.

Trust me, I watched the video, i attempted the same parameters you did. Our FM dev looked into all of the parameters and the SME even had a go but no adjustments to the FM would correct the behaviour. So as I mentioned before, while you Can go supersonic, theres quite a few warning signs that should prevent you front continuing past M1.0, in any mission I dont even let the jet get up past .95.

Know and use all the capabilities in your airplane. If you don't, sooner or later, some guy who does use them all will kick your ass.

 

— Dave 'Preacher' Pace, USN.

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As a fix short term could not be found, and due to it being an odd bug that happens under very certain circumstances its being put on the back burner. Logically you would not be hauling 10 GBUs into combat, even on a MP server it hampers you more than is effective.

Know and use all the capabilities in your airplane. If you don't, sooner or later, some guy who does use them all will kick your ass.

 

— Dave 'Preacher' Pace, USN.

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Did you fly the plane long enough for it to accelerate past Mach 1.0 and all the way to Mach 1.6?  It doesn't happen in seconds, it takes a bit of time to reach that speed.  But it will happen, 100% of the time as shown in the video.  I've had 2 other people independently verify this both online and offline and recreated the exact same thing using my instructions on the very first try.  It's disappointing that you can't recreate it, because everybody else who tries seems to be able to.  Should we have other people record videos to prove it to you?

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On 11/29/2020 at 5:46 AM, Xpendable said:

Loadout:

TPOD

10 GBU-38's (2 pair on inner pylons, 3 pair on middle pylons)

 

Load up the plane with 10 GBU-38's.  TPOD may or may not be necessary.

Climb above 12,000 feet.  Drop all 10 GBU-38's.  

 

The plane will slowly start to accelerate beyond Mach 1.0 in straight and level flight (or even in a slight climb!).  It's as if the plane became magically lighter than it's normal empty weight.  You'll be able to hear the sonic boom and everything.  Eventually the plane will accelerate past Mach 1.06 and the wings will fail shortly thereafter.

 

I have recorded a YouTube video showing this and will upload here when it is ready.  The problem does not happen if you takeoff with nothing loaded.  I haven't tried any other ordinance, so it might only be a problem with the GBU-38's.

 

 

 

Had the same issue last night. Was able to slow down before any damage though. I was not at full throttle. Exactly the same load out.

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I am able to re-create this bug, was able to get to Mach 1.11, level flight, autopilot, once the weapons had been jettisoned. This only happens when weapons are jettisoned which indicates a bug - if it wasn't a bug and if the harrier was somehow capable of hitting M1.1 in level flight, then it would also happen without weapons. 

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15 hours ago, Xpendable said:

Did you fly the plane long enough for it to accelerate past Mach 1.0 and all the way to Mach 1.6?  It doesn't happen in seconds, it takes a bit of time to reach that speed.  But it will happen, 100% of the time as shown in the video.  I've had 2 other people independently verify this both online and offline and recreated the exact same thing using my instructions on the very first try.  It's disappointing that you can't recreate it, because everybody else who tries seems to be able to.  Should we have other people record videos to prove it to you?

I'll have to have the FM Dev take a deeper dive but that wont happen until mid January. In all honesty, why would you willingly continue to accelerate beyond m.95? Like if you keep accelerating and know that you're going to rip the wings......why continue? Just cut the throttle and turn outbound. Im confused.

Know and use all the capabilities in your airplane. If you don't, sooner or later, some guy who does use them all will kick your ass.

 

— Dave 'Preacher' Pace, USN.

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  • RAZBAM_ELMO changed the title to [INVESTIGATING] AV8B goes supersonic after dropping 10 GBU-38's

I just had another person recreate the same issue using my instructions, and they confirmed the bug as well.  I was just about to do a livestream on Twitch to show other Harrier pilots the bug. 

 

In regards to "...if you keep accelerating and know that you're going to rip the wings.....why continue? Just cut the throttle and turn outbound. Im confused."  Just trying to report a bug that Razbam was obviously unaware of. That's it. Fix it or don't fix it.  I don't care. 


Edited by Xpendable
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  • 4 weeks later...

FM Dev is currently reviewing and investigating the issue.

Know and use all the capabilities in your airplane. If you don't, sooner or later, some guy who does use them all will kick your ass.

 

— Dave 'Preacher' Pace, USN.

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On 12/18/2020 at 5:04 PM, RAZBAM_ELMO said:

In all honesty, why would you willingly continue to accelerate beyond m.95? Like if you keep accelerating and know that you're going to rip the wings......why continue? Just cut the throttle and turn outbound. Im confused.

Why would a Harrier accelerate to mach 1.6? I'm also confused. 

A clean F-18 in full afterburner takes several minutes to reach mach 1.6, at high altitude, not at 12k feet! And yet you seem to think it's normal that a Harrier gets to mach 1.6 at full throttle, and somehow this is user / pilot error. 

 

The massively draggy air intakes of the Harrier won't make it past mach 1 because they have no way to slow down the incoming air. The engine would seize. 

Good that you passed it to the devs, 'cause it's definitely a bug

Windows 10 - Intel i7 7700K 4.2 Ghz (no OC) - Asus Strix GTX 1080 8Gb - 16GB DDR4 (3000 MHz) - SSD 500GB + WD Black FZEX 1TB 6Gb/s

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7 hours ago, bkthunder said:

Why would a Harrier accelerate to mach 1.6? I'm also confused. 

A clean F-18 in full afterburner takes several minutes to reach mach 1.6, at high altitude, not at 12k feet! And yet you seem to think it's normal that a Harrier gets to mach 1.6 at full throttle, and somehow this is user / pilot error. 

 

The massively draggy air intakes of the Harrier won't make it past mach 1 because they have no way to slow down the incoming air. The engine would seize. 

Good that you passed it to the devs, 'cause it's definitely a bug

Well besides the snarkyness there bucko, I dont think that a Harrier should reach M1.6, my question was why would you. Thats all I was asking. How was someone think gosh this is really fast for a Harrier....and then keep going lol. Its a very odd instance because in its normal flight parameters, our SME and the pilots in their squadron who have flown our Harrier say that its better than the sims they have.

Know and use all the capabilities in your airplane. If you don't, sooner or later, some guy who does use them all will kick your ass.

 

— Dave 'Preacher' Pace, USN.

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2 hours ago, RAZBAM_ELMO said:

Well besides the snarkyness there bucko, I dont think that a Harrier should reach M1.6, my question was why would you. Thats all I was asking. How was someone think gosh this is really fast for a Harrier....and then keep going lol. Its a very odd instance because in its normal flight parameters, our SME and the pilots in their squadron who have flown our Harrier say that its better than the sims they have.

I think, you mixed up who posted what? At least I can not see any snarkyness in bkthunder's posting ...

And as to why let the aircraft acellerate beyond it's envelope: to demonstrate this bug. It's like "Gosh, this is really fast for a Harrier. Should this even be physically possible? Let's see where we end up with!"

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On 1/15/2021 at 4:14 AM, RAZBAM_ELMO said:

Well besides the snarkyness there bucko, I dont think that a Harrier should reach M1.6, my question was why would you. 

No snarkyness intended.

I'm just very puzzled by how you look at the problem. "Why should you"? Well, for instance because you're coming off the target and you have a bandit on your ass, full throttle and, oh look, M 1.6! 

It doesn't take some "special skills" or a crazy maneuver to do this. 

But the real question you should be asking is, why does the FM allow you to reach M 1.6? 

And besides, apart from this specific bomb-drop related bug, the FM regularly allows you to reach M 1.06 in level flight, which is also unrealistic as far as the available references suggest.

 

By your logic, the FM could let us reach Mach 5, or you could load 300 bombs on the pylons, 'cause "why should you"? 

 

I totally understand the issue: the Harrier has a very high T/W ratio and beats an F-15 in the initial climb, under certain conditions. However it is also very draggy and not supersonic AT ALL. 

Making the FM is probably a balance between giving it enough thrust and enough drag kicking in at the right speed, and that balance is a bit off. Totally understandable, but it should be fixed and not met with a "why should you". That's all I was saying.

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Its getting fixed, I'm just stating that im curious anyone ever pushed the jet that far out of its envelope to find it, nowhere did I say that its not a bug and ignoring it.. FM dev seems to have rooted out what is causing it but might be a bigger can of works than we thought. Weird drag numbers going on between a TER rack and a single bomb.


Edited by RAZBAM_ELMO

Know and use all the capabilities in your airplane. If you don't, sooner or later, some guy who does use them all will kick your ass.

 

— Dave 'Preacher' Pace, USN.

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if your curious, i was on the F10 map yesterday and when i got back to cockpit view i found myself (forgot to turn AFC on) going down from 35k feet alt in a 45° angle uncontrolled spin at MACH 1.25 with one wing tip missing 😂

after that even if i got to MACH 1.2 it didnt break the other wing though 🙈

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  • 2 weeks later...

Marking as RESOLVED and moving to RESOLVED

 

Know and use all the capabilities in your airplane. If you don't, sooner or later, some guy who does use them all will kick your ass.

 

— Dave 'Preacher' Pace, USN.

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  • RAZBAM_ELMO changed the title to [RESOLVED] AV8B goes supersonic after dropping 10 GBU-38's
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