I just can't figure out why this happens

[Eli Phillips]

https://drive.google.com/file/d/1xirhAwjtLnSxauVgpPPgfebeAxlgfYPl/view?usp=sharing

Ok so when I fly this craft it starts to spin at a certain altitude and I have checked I have 1.4 TWR and the center of mass is where the thrusters are and I need some help here is the image

[securityinstruts]

This is just a guess but I'm betting that the flipping out of control is actually about speed.
If so, just lower your thrust and maintain your speed under 1 mach until you are ~15km up and remember not to pitch too much out of your prograde marker unless you know your craft can handle it.
You could also manage your speed by terminal velocity; here's a link that managed to find easily
https://coeleveld.com/kerbal-space-program-how-to-get-into-orbit-and-back/

You could also do well by adding fins/control surfaces to your 3rd stage

[The Aziz]

52 minutes ago, securityinstruts said:

This is just a guess but I'm betting that the flipping out of control is actually about speed.
If so, just lower your thrust and maintain your speed under 1 mach until you are ~15km up and remember not to pitch too much out of your prograde marker unless you know your craft can handle it.
You could also manage your speed by terminal velocity; here's a link that managed to find easily
https://coeleveld.com/kerbal-space-program-how-to-get-into-orbit-and-back/

You could also do well by adding fins/control surfaces to your 3rd stage

How old this tutorial is? Straight up and quick turn to 45⁰ at 10km stopped being correct 8 years ago.

[securityinstruts]

I do not regard the age of that tutorial to be of issue when discussing terminal velocity and you might have skimmed over this part;
1000m – 10.000m  Terminal Velocity & Initiate Gravity Turn
Pitch 10 degrees from vertical towards the east

I think we might find common ground if I were to say that every craft has its own optimal launch trajectory and the only heading one should burn during ascend is towards prograde marker... Well, until the craft is out of the thick part of the atmo, then one can pitch towards horizon and continue burn until AP is looking good.

BTW; Do you have better guess as to why OP has this problem repeatedly at certain altitude and what do you think of the speeds indicated in the link?

[The Aziz]

19 minutes ago, securityinstruts said:

you might have skimmed over this part;
1000m – 10.000m  Terminal Velocity & Initiate Gravity Turn
Pitch 10 degrees from vertical towards the east

I didn't, I know that gradual change in pitch until we're at 45⁰/10k and then more gradual until horizontal at roughly 40km is how it should work. Not some 10⁰ until 10k, rapid 45⁰ until 18k and horizontal  from there. Yes, sometimes the launch vehicle can't make it just right, but the general idea is to make slight corrections. Any craft with TWR around 1.4 should be able to do that. Speed didn't matter much. Unless of course one went with TWR>2, then the aero losses started to matter (too much drag, harder to steer). But keeping it slow meant only losing fuel - gravity losses. The trick was to find the balance between the two.

But that was KSP1. Aero overlay showed the drag arrow and I knew not to make it poke too much to the side, but keep it pointing down from the engine. Throttle down a bit when it appeared too long (Kerbal version of maxQ, this time maxDrag). Easy to fly anything.

KSP2 on the other hand right now has wonky, unpredictable aerodynamics. Nothing should flip when going straight up if the craft is perfectly symmetrical. The same way nothing should flip if it follows the prograde marker, right? And yet it happens. I see some antennas and solar panels sticking out, for what I know they could be super draggy all of a sudden - for no reason other than the aero system is buggy. I could try recreate the craft there to see what's what later, but my two guesses are: sticking out parts causing drag, and wonky aerodynamics.