Unstable rocket

[Has4312]

Having problems manouvering in space, especially executing manucer nodes.

How do i make rockets that manover well preferably without adding WEIGHTMine currently have no reaction wheels and all parts are mirrired radially (sometimes double & tripple ect on same rocket).

 

On the staging indicator (bottom left). There are the normal orange arrows and the pink ones that are off center.

 

thanks

Edited February 23, 2018 by Has4312

[monstah]

Moving thread to the Gamplay Help sub-forum, since it's about flying in the game rather than real-life science and spaceflight.

First, if you have no reaction wheels, then you need RCS. Otherwise, the only source of control in your ship will be gimbaled engines (if you have those), and they only work during powered flight. Notice that pods and some probe cores have integrated reaction wheels, so you don't need extra parts if you're using one of those (only the Probe Sphere has no reaction wheel, I think? Maybe the thinner ones, too).

Second, if you have pink markers off center, that means you are applying trim to the ship: press alt+x to remove it. Trim is like a constant nudge in one direction, like an off-center control. It helps flying airplanes, since you usually have to keep the nose a little up.

Third, welcome to the forum, @Has4312!

[Gargamel]

Imagine building a car, then not adding a steering wheel.   Then complaining it doesn't maneuver well. 

If you don't have reaction wheels, how do you expect it to maneuver?   I like to add on at least one wheel to most of my craft to help get it to turn. 

Welcome!

[Has4312]

Thanks for your replies

i could understand reasons behind it being slow to manuver. However if balcanced i wouldnt see why it would veer off to one side. Seen somewhere that reaction wheels placed off the COM can induce rotation but even with the wheels turned off (reaction wheels on the capsual) the craft still veers off to one side.

 

it pitches more to one side when built symetrically id have thought engine gimballing would work

Edited February 23, 2018 by Has4312

[DeadMG]

There's a bug in the game which can cause rockets to veer even when built symmetrically- I've had a few craft suffer from this. Recommend rebuilding the craft from scratch- this usually alleviates the problem.

[Aegolius13]

4 hours ago, Has4312 said:

i could understand reasons behind it being slow to manuver. However if balcanced i wouldnt see why it would veer off to one side. Seen somewhere that reaction wheels placed off the COM can induce rotation but even with the wheels turned off (reaction wheels on the capsual) the craft still veers off to one side.

Can you elaborate a bit on what's going on?  I gather this is all happening in space (altitude greater than 70,000 meters), which means that there are no aerodynamic forces going on.  

Does this veering thing happen when you fire your engines?  Or is this a thing where, if you're drifting, the craft starts rotating in an unexpected direction?

If it only happens when engines are running, it might involve off-center thrust.  If your ship is completely symmetrical (and fuel is draining evenly), you should not see this, but there are a lot of little ways symmetry can potentially be broken, by small build issues or potentially by bugs.  

If it's happening when you're drifting in space, well, that's fairly confusing.  If you've turned all your reaction wheels off (including the built-in ones in command pods and probe cores), and are not using RCS thrusters, your ship should not be undergoing any rotation.  Does this happen when you have SAS on, off, or both?  ("T" key toggles).  You can sometimes get unwanted rotation if you accidentally have SAS on and set to hold in a particular direction.

In any event, a screenshot would probably help diagnose the issue.

 

[Starman4308]

4 hours ago, Has4312 said:

Thanks for your replies

i could understand reasons behind it being slow to manuver. However if balcanced i wouldnt see why it would veer off to one side. Seen somewhere that reaction wheels placed off the COM can induce rotation but even with the wheels turned off (reaction wheels on the capsual) the craft still veers off to one side.

 

it pitches more to one side when built symetrically id have thought engine gimballing would work

Again, screenshots would be very helpful.

Also, engine gimbaling in KSP is fairly weak; most engines gimbal less than 5 degrees. If the thrust vector is heavily offset from center-of-mass, you're not going to be able to gimbal enough to compensate for that.

[Has4312]

Happens with every combination of RCS and SAS however

46 minutes ago, Aegolius13 said:

Can you elaborate a bit on what's going on?  I gather this is all happening in space (altitude greater than 70,000 meters), which means that there are no aerodynamic forces going on.  

Does this veering thing happen when you fire your engines?  Or is this a thing where, if you're drifting, the craft starts rotating in an unexpected direction?

If it only happens when engines are running, it might involve off-center thrust.  If your ship is completely symmetrical (and fuel is draining evenly), you should not see this, but there are a lot of little ways symmetry can potentially be broken, by small build issues or potentially by bugs.  

If it's happening when you're drifting in space, well, that's fairly confusing.  If you've turned all your reaction wheels off (including the built-in ones in command pods and probe cores), and are not using RCS thrusters, your ship should not be undergoing any rotation.  Does this happen when you have SAS on, off, or both?  ("T" key toggles).  You can sometimes get unwanted rotation if you accidentally have SAS on and set to hold in a particular direction.

In any event, a screenshot would probably help diagnose the issue.

 

Hapens with every combination of RCS and SAS 

using SAS usually helps stabalise all the crafts, but if the "imbalance" is big enough it i will only be able to manover one way in a certain axis

e.g roll and pitch may be centered but i may only be able to pitch down. As a result i or the SAS have to compensate for this.

to my knowlege in the bottom left

where the roll, yaw and pitch instriments are the pink arrows represent the natural path of the craft if left unpiloted. The orange ones represent the input of the pilot plus the pink arrow (natural path)

Assuming i want to stay in one orientation

if the pink arrow is all the way at one end (pitch up) and the i go to correct it by pitching down the net effect is zero.however this means i can only pitch up

ACTUALLY monstah told me that pink arrows were the trim. I keep resseting it by pressing L1 amd x at the same time 

please correct any of this information 

thanks for the support

Edited February 23, 2018 by Has4312

[Spricigo]

Yes, it's trim. Unfortunately control sheet I found is not clear about trim:

 

[GrouchyDevotee]

16 hours ago, Has4312 said:

On the staging indicator (bottom left). There are the normal orange arrows and the pink ones that are off center.

You might have the trim set.

 

[Has4312]

Found this

second to last heading 

trim is mentioned.  This should fix it. . Great advice thanks