Flipping Ship

[JTeam1]

I am having trouble when I try and launch my rockets.  I get through my boosters and then after I get rid of them my  main part keeps on flipping when I try and start turning for an orbit.  Is there too much weight at the top of the rocket?

[tater]

26 minutes ago, JTeam1 said:

I am having trouble when I try and launch my rockets.  I get through my boosters and then after I get rid of them my  main part keeps on flipping when I try and start turning for an orbit.  Is there too much weight at the top of the rocket?

There is not enough mass at the top of the rocket.

It's like a dart, it needs to have the center of mass forward.

[Palaceviking]

Or drag, have you got fins near the bottom?, also how fast are you going at what altitude when this happens? 

And screenshots always get more/better responses here btw.

[JTeam1]

The mass was middle of the rocket but I did not have fins.  It would flip around 8k.  Tried fins, that seems to have fixed the problem.

[ForScience6686]

Another trick with the new fuel setup is to set the tank priorities so they drain from the bottom up in a stack of multiple tanks.   this helps move the com  forward.   By doing this I find I don't need fins anymore on rockets.

[DD_bwest]

i second what forscience says,  its under advanced tweakables if you dont have it on.  one of the best additions theyve added

[cephalo]

19 hours ago, ForScience6686 said:

Another trick with the new fuel setup is to set the tank priorities so they drain from the bottom up in a stack of multiple tanks.   this helps move the com  forward.   By doing this I find I don't need fins anymore on rockets.

Unless you have a draggy payload, such as a big fat fairing. Then you might need to counter it with fins.

[WanderingKid]

On ‎11‎/‎13‎/‎2016 at 8:18 AM, JTeam1 said:

I am having trouble when I try and launch my rockets.  I get through my boosters and then after I get rid of them my  main part keeps on flipping when I try and start turning for an orbit.  Is there too much weight at the top of the rocket?

There's a few possible concerns here.

First, are you trying to 'newb turn' by basically going straight up for a while then hanging a 45 degree angle?  If so, that doesn't work in the new aero model and we can go over that.  You typically need to start that turn even while the SRBs are running though.

Next is a pic of your ship would help, but you mentioned fins fixing the problem.  That usually means you've got more drag (not just weight) on top than on bottom and you're coming off prograde.  The higher the difference in drags, the more likely even being slightly off prograde is going to flip you over the faster you go.  After a point you just can't fix it.  Fins (in particular control surface ones) give you additional control on the rocket's positioning as well as equalizing the drag values.  Adjusting weight locations can help to counterbalance this via fulcrum points.

[ForScience6686]

On 11/14/2016 at 7:37 AM, cephalo said:

Unless you have a draggy payload, such as a big fat fairing. Then you might need to counter it with fins.

Understandable,  but proper engineering requires no fins.  I just sent my entire minmus  base on rockets with no fins.   this included: drill rig,  fuel stores,  habitat module and power module with sky crane.  

So it can be done.   The point is to keep the mass forward.   The rocket essentially becomes a Fox tail (does anyone remember these toys)  and it cannot fly in reverse.

Edited November 16, 2016 by ForScience6686