Thrust vs Mass

[KC5SDY]

How would I calculate how much thrust I would need for a given mass?

I have a lander that I am modifying for Kethane mining but the original engines on it are no longer strong enough to get the lander off the ground. How can I calculate how much thrust I would need in order to get it off the ground?

I would appreciate it if the insults can be kept to yourself, please. I asked a question before on another topic and was insulted because I did not already find the answer previously. I would appreciate it if you can answer my question, then please do. If you are going to insult me, I ask that you do not respond at all.

Thanks

[Genius Evil]

I would recommend using Kerbal Engineer Redux. It calculates your thrust/weight ratio in the VAB and in flight, along with some other useful information.

Edited August 26, 2013 by Genius Evil
Typo.

[KC5SDY]

Thanks. That just may be what I am looking for.

[Megapead]

I would recommend looking at this page on the wiki. This page gives you the equations for thrust to weight ratios in KSP.

Where:

F_T is the thrust of the engines

m the total mass of the craft

g the local gravitational acceleration (usually surface gravity)

As seen from the wikipage. However, if you don't like to calculating it yourself use Kerbal Engineer Redux as suggest by Genius Evil

[KC5SDY]

I have to say, I am constantly amazed at all the add-ons that are available. If you can think of it, there is an add-on for it. I bet there is an add-on that allows Jeb to moon everyone.

[Respawn]

So when I'm not using the engineer mod. (does not happen.)

however its easy math.

rough estimate.

Weight (t) * local g * 10 = (gives you in kN what power you would need to have 1 TWR)

so anything more than that would get your craft to lift of, anything less than that will not.

on kerbin at sea level (asl) the local g is 1,

on the mun it's 0.166 g

on minmus it's 0.05 g

on eve its 1.7 g

on gilly its 0.005 g ..and so on.. (its listed in the info thingy in map view)

[KC5SDY]

So when I'm not using the engineer mod. (does not happen.)

however its easy math.

rough estimate.

Weight (t) * local g * 10 = (gives you in kN what power you would need to have 1 TWR)

so anything more than that would get your craft to lift of, anything less than that will not.

on kerbin at sea level (asl) the local g is 1,

on the mun it's 0.166 g

on minmus it's 0.05 g

on eve its 1.7 g

on gilly its 0.005 g ..and so on.. (its listed in the info thingy in map view)

Other than the mod that was suggested, this is exactly what I was looking for. Thank you, thank you, thank you!

[blizzy78]

You might also want to check out my online engine layout calculator (see signature.) It allows you to enter payload mass (among other things), and it will tell you how to configure central stack and booster stacks for an asparagus-style staging, with the exact sum of thrust you need.