Here is an image https://steamcommunity.com/sharedfiles/filedetails/?id=3789188263

Did you calculate it for atmosphere or vaccum?
Did you calculate it for the correct planet?
Are your stages correct and throttle properly up?

The last one might seem like I am looking down on you but you would be surprised how often I mess up staging during conception and have to adjust it while flying even after hundreds of hours in this game.
Similarly, the throttle can be important when you switch from solid boosters (always full thrust until they run out) to normal engines that respect your current throttle.


Those are pretty important questions because in low altitude on a planet with atmosphere, a lot of engines are quite a bit weaker.
If you are using Kerbal Engineer Redux (highly recommended if you are not), it has buttons to show you the stats in atmosphere and even a slider for various altitudes in it.
It can also show you the stats for various planets and moons.

A terrier engine for example could have 3.5 TWR in vaccum and 0.8 at sea level on Kerbin due to having less than 1/4th of the thrust in kerbin's atmosphere at that altitude.
Of course, those vaccum-specific engines are always the worst in atmosphere (on top of having fairly low thrust even in vaccum but higher efficiency) but all engines have this to some extent.

Originally posted by J hill:

Here is an image https://steamcommunity.com/sharedfiles/filedetails/?id=3789188263

i think your rocket has bigger problems than not going up

Originally posted by Bubertoo:

Originally posted by J hill:

Here is an image https://steamcommunity.com/sharedfiles/filedetails/?id=3789188263

i think your rocket has bigger problems than not going up

This is true, space planes mounted like that are also near impossible to fly

Also when you said you “calculated” the TWR did you look at the in game tool for it or did you attempt to manually do it on paper

Did you drain the fuel tanks in the VAB to check the empty center of gravity and center of thrust and forget to refill them before going to the launch pad?

Note that with a centre of lift that high that even if you did make it off the pad, you would find your rocket quickly deciding it wants to kiss the ground.

those fins are way to high, it looks like you have a mid stage with its own engines, they have as much thrust as your lifter stage. and arn't being used.

i can't tell what kind of side boosters you have there because the engine looks clipped into the fuel tank. be aware if a engine is clipped to far into something it will produce 0 thrust and instead heat your ship up.

between possibly broken boosters, using only half your available lift, lifting way more engines then are needed, and the fin issue you will have if you got moving over 80m/s your probably gona need a rework.

The Only Stage Has 400 mps and is the top

I calculated for earth which has 0.01 m/s less than kerbin and got nearly 8
the fins are to prevent the craft from cartwheeling i dont have rcs i am still like 40 short
checked all the stages are firing corectly they are

here is the stats of the rocket https://steamcommunity.com/profiles/76561199379878366/screenshot/%p1%/
And the fins wont fit anywhere else and if i scale them down the craft wont stay upright

The fuel tanks are full and the twr is 7.8 it waighs like 38 and the first stage preduces 240kn

i have reworked the craft like 5 times this ones upper stage can get to orbit if inf fuel is enabled everything else ether corkscrews or cant even get off the launchpad

Thanks for the feedback everyone. Swapped the engines and it now gets of the pad and still has only a 3rd of what i need for orbit and also
Uh what is even going on here https://steamcommunity.com/sharedfiles/filedetails/?id=3789762845

Originally posted by J hill:

Thanks for the feedback everyone. Swapped the engines and it now gets of the pad and still has only a 3rd of what i need for orbit and also
Uh what is even going on here https://steamcommunity.com/sharedfiles/filedetails/?id=3789762845

This has happened to me too once, the craft file is haunted and you probably can’t fix it. I certainly couldn’t.