Backup ADI wandering.

[G.J.S]

Only noticed this on last couple flights, first with Hornet - unable to resolve - the backup ADI would slowly tip over to starboard after around 30 minutes flying time, as if you were flying a 10 - 20 degree left bank, yet the aircraft, and HUD, were straight and level.

Same for F-16, under similar circumstances, ie after about 30 minutes.

F-14 has the same, haven’t gone through other modules I own, but suspect they will be afflicted too.

 

Could this be something with the host sim? It has not been noticed before by myself, so it is recent.

Can’t remember which module it was, but tried switching the backup ADI feed from norm, to INS, but that didn’t clear it.

 

To reiterate, this - when it happens - ONLY affects the backup, HUD is not affected.

 

Anybody else noticed the same?

 

*Edit, I’m latest beta, forgot to state.

Edited August 11, 2020 by garyscott

[FoxTwo]

Yeah I've noticed the same thing.

[G.J.S]

Okay, I’ve checked the other modules I own, and the issue DOES afflict them all.

The timings before it manifests itself varies - can be about 10 minutes - but generally more than that.

Heavy manoeuvres, just following a course, doesn’t matter, the backup WILL tip.

HUD’s (in a/c that have them) remain unaffected and true.

 

Simulated equipment failures turned off. Still happens.

[Gierasimov]

I noticed that in Black Shark 2 as well.

[Nealius]

Not only the SAI in a few modules, but the main ADIs in all the warbirds is absolute trash. They will decalibrate within 5 minutes of recaging.

[G.J.S]

Seems like might need a sh*t-thunder type workaround, where the viewpoint is external and behind the aircraft . . . Because that would be more reliable than using the backup instrumentation INSIDE the aircraft.

And I know that even backups have a failure rate, but from experience I can say not anywhere near as quick as is shown now in DCS.

[FoxTwo]

This is after a 90 minute mission in the gulf where I just orbited a tanker for about 20 minutes, I don't think I pulled more than 6g the entire mission. I can't imagine this is even remotely normal behavior otherwise why even have the damn thing in the cockpit?

 

[Lanzfeld113]

I do know one thing for sure though if you were in a continuous bank for 20 minutes then the SAI would most definitely think of THAT bank as level. It’s a Gyro and it drifts like any other gyro. It uses gravity to tell itself which way is down. So if you were in a bank and Pulling lights G for 20 minutes it would re-define gravity. Does that make sense? It’s the same thing with a gyrocompass how you have to reset it every 10 or 15 minutes because it drifts. You don’t have to do that with a standby attitude indicator because it uses gravity for that function. This only happens with standby systems as the INS has something to prevent this.

[G.J.S]

I do know one thing for sure though if you were in a continuous bank for 20 minutes then the SAI would most definitely think of THAT bank as level.

 

Only if you held the bank WITHOUT pulling, like a 'not-quite knife edge', say like the angle displayed in FoxTwo's screenshot, and held that for a silly amount of time, then you MAY be able to tumble the backup ADI sufficiently due to "settling".

 

"MAY" being the operative word.

 

That being the case then you would ground the jet for work, as the backups are supposed to be your last ditch, reliable, get you home equipment.

In my former career i have had one instance where had to use backups, due to the ring laser gyro going t*ts during a low level which also took out the GPWS (a no-go as the GPWS relies on the gyro to know where "up" is, so if you went too close to the ground in a bank it could give false advisories, like "roll left!" to go level, when you already ARE level).

[Machalot]

I have noticed the same thing in the Viper.