[RESOLVED] Phantom Thrust Issues

[Hallofo]

Hello everyone,

I've been over the forums with the search tool and my Mk.1 eyeball and haven't found a similar issue. Please forgive me if I missed something obvious. I have a few steps I'll be taking once I'm off work, but I wanted to check to see if this was a known issue. Also, this is my first bug report so any feedback on the formatting or presentation of the issue would be greatly appreciated.

The Issue:

I'm getting "phantom" thrust forces, even when all engines are off and RCS is disabled. My speed increases and orbit changes as if I were thrusting, but my fuel load and Delta-V statistics stay the same.

Test cases:

Case 1: (initial discovery): I launched a small "rescue" craft to pick up 2 Kerbals that somehow found themselves in orbit. The first stage burn went well, but I overshot the target apoapsis. I killed the engines with X to coast and circularize/ correct. When I went to the map to time-warp, I got the message "you cannot time warp while the ship is under acceleration". I then exited map view, hit X again and confirmed that I didn't have RCS or SAS enabled. I then disabled the main engine via the right-click menu and went back into the map. Once in the map view, I saw that my orbit had radically changed and was continuing to change as if I was firing the engine. I reverted the flight back to launch.

Case 2: I duplicated the error as described in Case 1 with the same results.

Case 3: I reverted to the VAB and checked my staging, action groups and overall setup - everything looked good. Re-launched and had the same error.

Case 4: I reverted and exited the game. I restarted the game and launched again, same result.

The Environment:

OS: Windows 7 x64, fully updated

KSP: 32-bit 1.0.4

Notes: This problem is new behavior, as I've been able to run the game fine before my last batch of mods.

Ship Setup

A basic ship, to say the least. Everything is stock except the Kerbal Engineer and MJ modules - this thing is meant only to ferry tourists and rescue kerbals. The active engine is a skipper stacked on top of a Rockomax X200-32 tank. The upper stage is a poodle under a X200-8, some RCS packs, PV panels, reaction wheels and assorted lights/ modules.

Mods:

* denotes a mod that's been added since the last successful mission

** Denotes that this has worked in previous installations/ versions of KSP, but is new to this save.

- New-to-this-save Mods -

FAR**

MechJeb* (so sue me, I've launched a few hundred rockets and have gotten bored putting things in LKO)

MK2 Essentials*

MarkIV System 2*

EVA Enhancements*

Docking Port Alignment Indicator**

Vessel Viewer (Complete version)*

Raster Prop Monitor**

Ship Manifest*

Hull Camera VDS**

Asteroid Day*

RCS Build Aid*

Infernal Robotics**

- Mods that were installed and working before the issue -

KAS

KAX

KIS

Stage Recovery

DMagic Orbital Science

Kerbal Alarm Clock

SCANSat

Tweakscale

Toolbar

Firespitter

Chatterer

Kerbal Engineer

Part Wizard

Broken Aerospace flag pack

Performance with these mods is quite acceptable. I'll get some stuttering while launching or when new ships load, but overall it's very playable. Most of what I add is "behind the scenes" to make the game more realistic (FAR), easier to manage (Kerbal Engineer, Alarm Clock, etc) or just more fun (everything else).

My Theory: Since it's the only "new" mod that has an effect on my rescue ship, I think that MechJeb is the cause. However, I'd like to see if it's the mod itself or an interaction with another mod that's causing the problem. I'm well past the "n00b" phase of needing MJ, I just want it to take some of the tedium out of getting ships to orbit or long-range flying for contracts.

Next Steps:

- Load a different ship to see if the behavior persists

- Load a different save, test

- Uninstall MJ, test

- Start the fun game of "take out one new mod, test, take out another mod, test" until the symptoms go away.

Thank you all for your input!

Edited August 24, 2015 by Hallofo
Updating title

[innomin8]

In my experience, this is caused by trim being set on the craft. Disable SAS and see if your craft starts to spin on it's own.

Alt-X should reset your trim and most likely resolve the issue.

[Hallofo]

Issue resolved.

The problem was twofold: FAR was the mod causing the phantom thrust issue. This is exceptionally odd since the issue was noticed in space as well as in atmosphere! The other problem was a massive derp on my part, I was running KSP 1.0.2 with mods made for 1.0.4.... no wonder I had problems! Of the list of mods, FAR was the only one that caused a noticeable problem. However, I had an issue with Raster Prop Monitor as well that I didn't catch: many of the values in the MFDs were "NaN". I had originally attributed this to not having a specific module installed or a missing mod (the "Engine Igniter" mod for instance). After patching to 1.0.4 all the displays worked, I'll also be trying FAR again to make sure it was a version mismatch. Since the cause of the error is known and there is a workaround in place, I'll call this problem "resolved".

Thank you for your input innomin8, I gave trim resetting a try as soon as possible. Even if it wasn't the solution, I appreciate the input.