Ship tilts immediately after launch

[pillook]

Screenshots at: https://drive.google.com/folderview?id=0BxMn8--P71I-fk9CbExnMjRZa2JLQXlPQjNyT0M3cXZUbTRWOXVGNFVoUzhFcENlcXlaVUU&usp=sharing

For some reason, the images were not showing

I'm completely new to ksp and I recently downloaded the demo version. I'm playing in sandbox mode and I've made the following rocket:

[screenshot 31]

This is my launch procedure: press t to turn on SAS, press space.

After about one second of doing nothing, the rocket tilts a few degrees.

[screenshot 32]

After about six seconds, the rocket seems to tilt way more, probably because gravity is pulling more on one part more than another. It's like an unintentional gravity turn.

[screenshot 33]

I tried again without the stability enhancers and got this (basically the same thing, different direction):

[screenshot 34]

[screenshot 35]

Every time I relaunch it seems to tilt randomly in a different direction. I've gotten the rocket into orbit a few times, but only when I'm lucky enough to have the rocket tilt roughly east in the beginning. Is it because the rocket simply has too much mass to be stable?

Craft file: https://drive.google.com/file/d/0BxMn8--P71I-Q3RIME9nc0VEU2s/edit?pli=1

Edited June 16, 2015 by pillook

[Cairol]

Activate the "Center of mass" indicator and the "Center of lift" indicator in the rocket lab. (buttons at the lower left panel)

The yellow ball is your center of mass. The blue one is the center of lift.

In your design, both are at the same spot, which means, your rocket is unstable.

A good rocket has a center of mass (CoM) higher than the center of lift (CoL). The farther away the yellow ball is from the blue one,

the more stable your rocket will be and more unlikely to tilt. (lawn dart principle)

CAUTION: The upper 4 boosters will heat up the lower ones, destroying them in the process.

Make sure your rockets exhaust is not blocked by anything.

If you remove those upper 4 boosters and shift the lower ones slightly higher and place a single booster at the central core at the bottom,

it will lift off and should bring you almost to orbit.

Unstable:

(The stability enhancers should not intesect with your rocket in your final design. It's wrong on my quick and dirty fix on the picture.)

Much more stable: (could actually still be better)

Also: If you install "Kerbal Engineer Redux" you can check if your rocket has the ability to lift off and how far it will bring you.

Edited June 16, 2015 by Cairol

[Empiro]

I can't see any of your pictures, but the general advice is to put fins at the bottom of your rocket to help stabilize things. Also, make sure that you're using symmetry.

[pillook]

The problem is, the rocket activates in two stages, (sorry, for some reason the images weren't working before) so the center of lift is actually quite far from the center of mass. Your suggestion, Cairol, works, but it is just short of enough fuel to get into orbit (at least for me). I got the apoapis above 70km but I could only get the periapis to 30km.

[Empiro]

It looks like you're pretty early in the career mode, which is indeed fairly challenging to get into orbit. The issue here is that those SRBs don't have thrust vectoring, and your winglets don't have control surfaces. The net result is that you have very little control over the direction of travel.

My suggestion is to use more liquid fuel and not so much in the way of SRBs. The Swivel engine is a good engine to use in the early game, and combined with a pair of the SRBs, can give you good control and TWR.