Explodes at start of taxi

[Gianky]

It looks like someone edited out of this thread some posts (IIRC).

Anyway, @Hiob said that it could have something to do with instantaneous huge increase of Gs on the structures and it could be so: this is a picture I took after a "bump" on Anapa taxiway, where the pilot blacked out; I'm guessing since I was light (only fuel onboard) and taxying slowly I didn't explode. As you can see, the Gmeter max and min hands are at the above +12 and -6; I always reset it during startup, so those values were recorded during the "bumping".

Same thing later, during a lesser "bumping", Gmeter reads about +4 and -1,5.

EDIT: Btw, as I wrote earlier, I only exploded when online, but it's true that I never played offline on Anapa, so it could just be that some airport in Caucasus are safe, others are not. Offline, I used Batumi, Kutaisi and Senaki without problem, online I tried Anapa, and always had troubles during taxy, and Senaki, where everything went fine (on two different servers, though).

Edited December 7, 2022 by Gianky

[Hiob]

15 hours ago, Gianky said:

It looks like someone edited out of this thread some posts (IIRC).

Anyway, @Hiob said that it could have something to do with instantaneous huge increase of Gs on the structures and it could be so: this is a picture I took after a "bump" on Anapa taxiway, where the pilot blacked out; I'm guessing since I was light (only fuel onboard) and taxying slowly I didn't explode. As you can see, the Gmeter max and min hands are at the above +12 and -6; I always reset it during startup, so those values were recorded during the "bumping".

Same thing later, during a lesser "bumping", Gmeter reads about +4 and -1,5.

EDIT: Btw, as I wrote earlier, I only exploded when online, but it's true that I never played offline on Anapa, so it could just be that some airport in Caucasus are safe, others are not. Offline, I used Batumi, Kutaisi and Senaki without problem, online I tried Anapa, and always had troubles during taxy, and Senaki, where everything went fine (on two different servers, though).

 

That was in a different thread:

 

[Gianky]

Aaaah, I thought it was this one! Really I'm getting old!

 

[gulredrel]

Some tracks I posted this morning but these were lost during the forum downtime and backup.

Kobuleti cold ramp start, first solo, no wind, than with backseater, more fuel and weapons, wind...

Always wiggled the stick before disengaging the control lock. In the past I thought this could be a problem. Don't know, as it was no problem in the first tries.

Interesting one is this:

MB-339_20221208_04_massive_bump_max_weight_wind_two_seat.trk

I was taxiing the same way and suddenly massive bump, g-meter maxed out at +9 / -5, nose wheel broke, nose wheel gear door came down. I guess if I were faster, I would blackout and maybe explode, cause the g-stress would be higher?

 

The same setup, but this time no problem.MB-339_20221208_05_no_bump_max_weight_taxi_TO_bomb_lan_taxi.trk So this is all really weird.

Jens

MB-339_20221208_05_no_bump_max_weight_taxi_TO_bomb_lan_taxi.trk MB-339_20221208_04_massive_bump_max_weight_wind_two_seat.trk MB-339_20221208_03_no_bump_wind_two_seat.trk MB-339_20221208_02_no_bump_two_seat.trk MB-339_20221208_01_no_bump_no_wind_one_pilot.trk

[granspeed]

Same issue persist after the DCS 2.8.1.34437 Open Beta update.  Resulted in broken front gear at 7-9 Knots on taxi way

SA_MB339_Invisible_Taxi_BumpsPostUpdate.trk

Edited December 17, 2022 by granspeed

[Bigskill]

2 hours ago, granspeed said:

Same issue persist after the DCS 2.8.1.34437 Open Beta update.  Resulted in broken front gear at 7-9 Knots on taxi way

SA_MB339_Invisible_Taxi_BumpsPostUpdate.trk 797.92 kB · 0 downloads

 

Mmmmm weird I flown on siria for 2 hours last night taxing and testing out brakes and 0 issue or explosions. Try to do the same but without rearming and refueling until the last last moment.

[gulredrel]

Single player here in Caucasus. Plane didn't explode but I had g-spikes shortly after I started taxiing, +9/-5 this didn't resulted in any damage:

I did my flight and after landing taxied back to parking, during the turn at low speed to the parking spot, next g-spike +12 / -4.5 including pilot short blackout:

Damage to the batteries and hydraulic system:

   

 

Please find trackfile attached.

Thanks

edit: Added second track. Same mission, same taxi route. This time no g-spikes.

@6S.Duke and @BIGNEWY Really weird, I've no further idea how to constantly reproduce this issue. Do you have any hints how we could recreate and help the devs?

MB-339_20221218_bump_taxi_TO_Matra_land_taxi_bump_damage.trk

MB-339_20221218_no_bump_taxi_TO_Matra_land_taxi.trk

Edited December 18, 2022 by gulredrel
added second track

[6S.Duke]

Thanks for reporting.
Back again to work to solve the issue.
We are sorry for this but we are facing a really randomic and unknown issue.
Please share your mission and how you reporduce the problem. Thanks

Inviato dal mio ASUS_I005D utilizzando Tapatalk

[gulredrel]

2 hours ago, 6S.Duke said:

Please share your mission and how you reporduce the problem. Thanks

That's exactly the problem. It's the same mission. One time the problem occured, the second time there was no problem. Couldn't find a way to reproduce it permanently. The mission attached was used for the tracks above.

I always start at ramp position 19(?, see mission for details). Startup, taxi to RW 07. In the first track above, I got the g-spike short after I started taxiing being on the main taxiway. No problems on the rest of the taxiway. After landing on RW 07 I taxied back to the same ramp position via the way behind the ground equipment. Turning to the parking spot, as can be seen in the screenshot above, I experienced the massive g-spike and damage to the aircraft.

On the second attempt. nothing happened, using the identical taxi path.

 

MB-339_Kobuleti_target_practice.miz

[Bigskill]

This is really weird, flown for at least 3 hours, on PG and Siria and had 0 problem, landed and rearmed multiple time, but on MP server, Greyflag. 

[gulredrel]

Hello again,

today, 3 attempts, same mission. On all three attempts I encountered the g-spikes while taxiing in the first part of the taxiway but at different places.

Tracks 01 without blacking out, track 02 with shortly blacking out.

In track 03 the blackout lasted very long and I switched to external view. The front of the aircraft was jittering up and down like crazy as well as the AoA value below -100 and well above +100.

I noticed the massive AoA values in the status bar. Just an assumption. Could the problem be related to wind conditions, especially wind from the rear that in some circumstances this has a weird effect on taxi behavior?! Wind related front gear movements where a problem in F1 early beta too, I believe.

In yesterday's damage screenshot, the AoA value is even higher.

Thanks

Jens

MB-339_20221219_03_g_spike_taxi.trk MB-339_20221219_02_g_spike_taxi.trk MB-339_20221219_01_g_spike_taxi.trk

Edited December 20, 2022 by gulredrel

[gulredrel]

On 12/18/2022 at 11:14 PM, Bigskill said:

This is really weird, flown for at least 3 hours, on PG and Siria and had 0 problem, landed and rearmed multiple time, but on MP server, Greyflag. 

I have flown several sorties today, same mission as above, but with zero winds. There was no problem.

@Bigskill Do you know, what the wind conditions where during your MP flights?

[Bigskill]

On 12/21/2022 at 2:26 PM, gulredrel said:

I have flown several sorties today, same mission as above, but with zero winds. There was no problem.

@Bigskill Do you know, what the wind conditions where during your MP flights?

Well the server is alwasys changing weather condition, I flown also under heavy tunderstorm but , that day i believe was something like 14 kts but I dont recall the direction.....

 

[gulredrel]

Just a heads up from my side.

I've taxied and flown from different airfields. Always zero wind at ground level and did not had the behavior described above. 

Syria map Ramat David, with the elevation changes while crossing the runways and taxiway intersections. Wujah al Hajar with the sloped runway. Pinarbasi, Kings Field and Akrotiri on Cyprus. Kobuleti in Caucasus.

Would like to check some crosswind flights but currently I'm afraid of encountering the g-spikes on the ground again.  

[Hiob]

Here is another short track (fast forward the cold start).

It didn't explode, but made a huge jump as if hitting a speed bump.

TaxiIssues3.trk

[TK-421]

Any updates to this? I just exploded while taxing at King Hussein Air College on Enigmas cold war server. 

Exactly the same issue, few bumps at first caused the pilot to black out, and then it exploded. 

This should be added to the known issues list for the MB-339 

[Hiob]

6 hours ago, TK-421 said:

Any updates to this? I just exploded while taxing at King Hussein Air College on Enigmas cold war server. 

Exactly the same issue, few bumps at first caused the pilot to black out, and then it exploded. 

This should be added to the known issues list for the MB-339 

@6S.Duke has been very quiet here for a few weeks now - perhaps he's on holidays. I hope he is fine and we will hear of him soon.

[crcr7]

+1 Still exploding often when taxiing, single player, SA map.  Did not test other maps recently.

We are all very patient but it is very annoying.

[Jel]

Wow and i thought "wtf?" just now until i read this thread. Happens every now and then (Sochi Airfield) and is probably one of the most annoying things a bug can do to you

Any updates on the progress ?

[6S.Duke]

Wow and i thought "wtf?" just now until i read this thread. Happens every now and then (Sochi Airfield) and is probably one of the most annoying things a bug can do to you
Any updates on the progress ?

Unfortunately I am not able to reproduce it.
We will investigate again the issue. Sorry for the inconvenience

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[Jel]

Seems to be like a small bump on the taxiway produces immense ammount of "G-Force" on the frame. Today i taxied down Alpha at Incirlik, close to the runway threshold i stopped and just as i was about to continue taxi, the pilot suddenly blacked out - like i was pulling 10-12g.

Let us know if you need anything to help you reproducing this issue. 

 

Edited February 8, 2023 by Jel

[6S.Duke]

Thanks guys, send me your new tracks via private message on discord.
Tracks made with previous DCS versions are often broken

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[gulredrel]

4 hours ago, 6S.Duke said:

Thanks guys, send me your new tracks via private message on discord.
Tracks made with previous DCS versions are often broken

New tracks in discord PM and also attached here. Still happening in 2.8.2.

My workaround is zero winds, of course, this only works on own SP missions not MP when weather is forced to some other than zero winds at groundlevel.

20230208_02_MB339_multiple_g-spikes_blackouts_while_taxiing_and_damage.trk 20230208_MB339_multiple_g-spikes_blackouts_while_taxiing.trk

[Otto pallen]

Even with the new OB we still explode while taxiing, sob

[Jel]

Seriously ?