Delta V

[Hank82]

I have seen the Delta V map and I am a little confused on how to actually use it to get two different celestial bodies. Is there a way to tell what the total delta V of my rocket is before a launch it off into space and lose a bunch of Kerbals?

[Vanamonde]

Add up the numbers on the path between where you are and where you want to be. If your ship has more, you can make it. 

[RoninFrog]

There are blue numbers in the staging menu with the amount of delta-V for each stage.

Edited April 23, 2020 by RoninFrog

[Superfluous J]

1 hour ago, RoninFrog said:

There are blue numbers in the staging menu with the amount of delta-V for each stage.

Just make sure you click the dV button on the bottom of the screen and switch to "Vacuum" or you'll have inaccurate estimates.

Regarding the map, just add the numbers as you go, but note that sometimes those numbers need to be all done in one burn even though they're different arrows. For example, to get to Duna you need ~3400 to get to orbit, that's essentially one burn, or at least one logical group of stages of your rocket. Then you need 950+130 to get to Duna. That's not a 950 burn and a 130 burn, it's actually a 1080 burn that is all done in Low Kerbin Orbit and ends up with a near- or even actual-encounter with Duna. It takes timing and planning.

If you want to do it the "easy" way you actually need a lot more dV, about 800m/s more. You burn that 950 to escape Kerbin's SOI, and then while orbiting the Sun you plot a maneuver to get to Duna, just like you'd plot one to get to Mun from Kerbin orbit only on a much larger time frame.

But the dV map doesn't tell you that kind of burn because it's inefficient.

[HansonKerman]

On 4/22/2020 at 11:56 PM, Superfluous J said:

do it the "easy" way

me. I never learned transfer windows, so I did that. It did take a lot moar dV, but it got things done. It does end up that you need nuke engines, and a 2.5m first stage just in case.

dV is precious without transfer windows. I will never learn them without KAC

[Dirkidirk]

use this for transfers: https://alexmoon.github.io/ksp/ I guess.

It's more useful IMO then a delta-V map.

Edited April 24, 2020 by Dirkidirk

[ExtremeSquared]

There are efficient transfers that don't require the use of transfer windows. Honestly, the two-burn transfer is the only way to do Moho and the best way to transfer back from outer planets. Hohmann transfers are just an option.

[magnemoe]

59 minutes ago, Dirkidirk said:

use this for transfers: https://alexmoon.github.io/ksp/ I guess.

It's more useful IMO then a delta-V map.

Mechjeb has this included. But don't use mechjeb as an crutch, use it as an tool to be more efficient once you know how to fly. 
Granted some of my larger stuff are so laggy its hard to dock manual.
However real rockets upper stage tend to kind of walk into orbit, this can be done in KSP too. Especially useful if you launch massive interplanetary ships or bases, don't burn prograde until you pass Ap while in the atmosphere, tilt a bit up and move Ap in front of you. 
 

[HansonKerman]

On 4/24/2020 at 11:03 AM, Dirkidirk said:

use this for transfers: https://alexmoon.github.io/ksp/ I guess.

It's more useful IMO then a delta-V map.

oh cool thank youuuu

[OhioBob]

On 4/24/2020 at 11:03 AM, Dirkidirk said:

use this for transfers: https://alexmoon.github.io/ksp/ I guess.

It's more useful IMO then a delta-V map.

There's also a mod version of it...

 

[Klapaucius]

On 4/23/2020 at 2:10 PM, Hank82 said:

Is there a way to tell what the total delta V of my rocket is before a launch it off into space and lose a bunch of Kerbals?

If you don't mind mods, Kerbal Engineer is wonderful for this.  It is very clear, and it allows you to easily design for each stage.  It also gives you really useful thrust-to-weight ration information, so you don't waste resources overpowering (or underpowering) your rockets. I'm just finally learning how to do this properly myself, and KE is just fantastic.