Rocket Not Flying.

[Zucal]

This rocket's been consistently leaning to one side then flipping before it even reaches 5k meters. Steering it doesn't work past the first 1k. Can anybody tell me whether it's because I have SAS on, or the rocket's too tall, etc?

Thanks in advance!

Edited April 29, 2015 by Zucal

[Anquietas314]

Mostly your rocket looks okay, but you should probably add some winglets (replica or not). They'll hopefully keep it flying straight

[Xannari Ferrows]

Everything is symmetrical? ...Okay, great. Are you clipping any parts? It looks like such down at your engines. That can result in some phantom forces.

Are you sure that's not the issue? ...Really? Well, I'll take your word for it.

I'd blame on the aerodynamics, but somehow I don't think that's the problem... At least, if you're not trying any gravity turns.

It's hard to tell just from a picture.

Upon launch, look at your torque displays. See them with, and without SAS on. If you see them off center, hit Alt+X to reset them.

I'd go back to the phantom forces idea if that doesn't work. Perhaps it is somewhere.

[stibbons]

A TWR of 1.6 seems high. I wouldn't even launch at full throttle, and without easing back it will almost certainly become unstable.

[WOODY01]

I am guessing the engines for the first stage thrust is not symetical and a little off.

Also try turning very slightly a couple of seconds off the pad to get your momentume going towards a gravity turn. I know you say you have no control but you should have enough that early for a slight turn of say 3-5 degrees. I have launched similar rockets, without clipping the motors, with no control surfaces, no gimballed engine and only SAS for guidance. Really need to watch your speed, try turning early but not too much, then just let it go and handle itself until it clears the lower atmosphere. Took me rather a few tries to get it right.

[micr0wave]

That payload looks like there are 4 winglets on it clipped in, i think they create some drag and drag on the top isn't too good to have.

[Claw]

That payload looks like there are 4 winglets on it clipped in, i think they create some drag and drag on the top isn't too good to have.

This is almost certainly the first problem. Those fins create not only drag, but destabilizing lift forces. You need to either put them in a fairing or add fins to the bottom of the rocket. I would recommend at least as many fins on bottom as you have on top, and probably a few extra to be safe. Since you are using fins, you can also turn on the CoM and CoL indicators to help you out.

Cheers,

-Claw

[Zucal]

It seems the winglet was the problem, thank you! Duly replaced with the white small hardpoint.