Mechjeb wont work

[Audax]

Hi everyone.

So i installed this mod, it adds the new stuff etc etc.

I followed some tutorials for the ascent autopilot.

I set this:

90 hdg

auto throttle ON

turn start altitude: 10 km

turn end altitude: 70 km

final flight path angle: 0

turn shape: 42%

the i engage the autopilot and and i start the engines. After few seconds the roket flips and crashes.

is not a rocket problem, i used that rocket a lot of times without mechjeb without problems.

Can anyone please help me?

thanks ^^

[swiftgates24]

Your most likely using an old version of MechJeb, or the rocket can't be flown by MechJeb, which happens sometimes.

[DerekL1963]

Hard to diagnose the problem without knowing you MechJeb version and a picture or a .craft file of the rocket in question.

[That guy who builds stuff]

what does your nav ball look like?

[Audax]

http://forum.kerbalspaceprogram.com/showthread.php/12384-PLUGIN-PART-0-19-Anatid-Robotics-MuMech-MechJeb-Autopilot-v2-0-7

this version

[Shuttle]

Make sure MechJeb is installed vertically - I guess That guy who builds stuff wants to say the same thing I installed MechJeb horizontally one time - and it made the rocket fly like the crashed Proton - after I installed Mechjeb vertically the problem disappeared.

[That guy who builds stuff]

That's what I'm thinking, mechjeb will fly assuming whatever you're controlling from is facing away from the direction of thrust. So if your control part is backwards it will try to spin the ship around to face the right way. It seems that mechjeb is the default control part when it's installed so switching to the control module or probe body would fix it.

As always it's hard to diagnose without a picture

[John FX]

I have the same issue. MJ is vertical, my craft flies well and is balanced. If I use `T` then it flies straight very well. If I use mechjeb it flies straight for a while (unlike if MJ is not placed right) then tips to around 45 degrees relative to vertical and then rotates around the vertical axis (planet vertical, not rocket vertical) until it crashes. Sometimes it is as though MJ decides to just stop controlling the craft. Sometimes this does not happen. It seems as though something gets `set` after a few launches and will only reset after a reboot. Just reloading the program does not change things back it seems. This fix does not work all the time.

Javascript is disabled. View full album

Previous versions of MJ have launched this craft without problem and I can continue to do so manually also. It is as though MJ loses the method of controlling the craft. Both launches had MJ autopilot on, only difference was ASAS/SAS. For me also this may be a RemoteTech issue so I will investigate further. First I will copy my game folder, uninstall RT and then try to launch this craft again. EDIT: Removing RT had no effect, it is not an issue of RT denying control to MJ Edited September 2, 2013 by John FX

[BostLabs]

John, I've had this happen. Somewhere you have a connection that is breaking under the stress. When that happens, even though your ship looks like it is in 1 piece, MJ cannot control the ship because the connection between it and the rest of the ship is broken. Could be a battery, a decoupler or something else that is getting crushed during liftoff. The F3 key can help you determine what is breaking.

[DerekL1963]

John, I've had this happen. Somewhere you have a connection that is breaking under the stress. When that happens, even though your ship looks like it is in 1 piece, MJ cannot control the ship because the connection between it and the rest of the ship is broken. Could be a battery, a decoupler or something else that is getting crushed during liftoff. The F3 key can help you determine what is breaking.

Looking at his vehicle, the other thing that might be happening is that he simply doesn't have enough control authority (gimbaling engines, RCS, fins) to keep the vehicle stable. (You can see this by looking at the command needles - Mechjeb *is* trying to stabilize the craft.) That the second ring of solids is very close to the CG probably isn't helping things either.

Long skinny boosters are hard to control, triply so with a long heavy payload on their nose.

[Virtualgenius]

Use the latest Sarbian release of Mechjeb http://forum.kerbalspaceprogram.com/showthread.php/47317-MechJeb-2-Patch-test-bed-release-%28August-31-Ter%29 its got lots of bug fixes in it

[Apollo13]

I was having lots of trouble with tall rockets. I asked for assistance and one of the suggestions provided a good solution. I now use Reaction Wheels on the stages. I no longer depend on the lone SAS/RW in the command module. In order to fly correctly, you may have to toggle the RW to do some maneuvers.