Taxiing on Gravel

[Piet Barber]

I often find the DG-IV and DG-XR1 jump around a lot while taxiing; this only happens when I have a date further in the future.

I taxi around and the G-meter is jumping all over the place, like I'm rolling over the bumpiest tarmac in the world. In fact, the further into the future I go, the worse the bumpiness. If I go far enough into the future with the same scenario, the jumpiness is so awful that the DGIV's gear will collapse.

I have also witnessed this with the UMMU astronaut walking around; either on Earth or on the Moon.

Does anybody have any idea what this is?

 

[Urwumpe]

Only numerical errors in the measurements of G by the MFDs or flight instruments. The Gs are practically always the same inside orbiters engine, but the calculations make them vary a bit.

 

[Andy44]

Well, it does seem that in real life the upkeep of roadways seems to become shoddier with time...

 

[pattersoncr]

I've seen that happen too. The solution is to open the scenario editor, select your craft, click "Location" then "Apply"

For some reason, the craft's state gets set to something other than "Landed". That's what causes the bounciness.

 

[Andy44]

I sometimes notice a similar effect after landing when the acceleration doesn't settle on zero even after you cut all the engines.

 

[Scarecrow]

I sometimes notice a similar effect after landing when the acceleration doesn't settle on zero even after you cut all the engines.

What usually causes that is that I have something like the level horizon autopilot left on.

 

[Andy44]

What usually causes that is that I have something like the level horizon autopilot left on.

Yes, but even when all that is turned off it still happens. It's a bug of some sort.

 

[Piet Barber]

PattersonCR -- correct -- that is what i had to do to get it to stop.

The thing to remember is that you have to do it while in cockpit view mode; if you're in external view mode it doesn't work. I suspect it is some sort of bug. I see that it doesn't seem to matter whether or not it is in the future or not; i have a scenario here that is 2001 and it's shaking all around.

I suspect that this is a but with Orbiter itsself, and not the add-ons?

 

[dbeachy1]

I suspect that this is a but with Orbiter itsself, and not the add-ons?

You are correct, this behavior is inherent to the Orbiter core (i.e., it is not a bug in the XR fleet). I suspect it has to do with how Orbiter computes the value for VESSEL.GetForceVector as the ship rolls down the runway, which may be related to how the core computes whether the ship is in contact with the ground or not. If VESSEL.GroundContact() constantly changes state and therefore the Orbiter core "bounces" the vessel based on touchdown velocity, that would cause the G meters to "bounce around" as we are seeing.

BTW, rolling down the runway should never collapse your XR gear because the ship knows it hasn't taken off yet and the gear touchdown/collapse/crash logic takes that into account. If your XR gear collapses while rolling down the runway, let me know because that would be a bug.

 

[MattNW]

It's left over from several Orbiter versions back. Orbiter old timers called it the, "Bounce Bug". It's exactly as dbeachy1 describes, part of the Orbiter core and it is much much better now than it was especially on Earth. No Scenario Editor back then so you had to close Orbiter down and restart it from, "Current State" to stop the bouncing. It was negligible on Earth but the less gravity the worse it was.

 

[Piet Barber]

BTW, rolling down the runway should never collapse your XR gear because the ship knows it hasn't taken off yet and the gear touchdown/collapse

You are right, It has never happened with XR, but it defintely has happened with the DGIV (or was it the DGIII)? I once was just taxxing around and WHOOMP, no gear. Lots of pieces, lots of wreck rolling away.