Roughly calculate additional deltaV for gravity loss / drag in VAB

[Gordon Dry]

So, assume I need 7,700 m/s for earth orbit and the rule of thumb tells me "add 1,500 m/s" but for large and huge rockets this is not enough, it can be 2,000 m/s on top or more...

Is there anything I could read out of FAR / KER values and calculate with it to have a value to add?

Edited May 29, 2016 by Gordon Dry

[Boris-Barboris]

no

[mk1980]

i don't play RSS, but if the gravity turn works similar to a kerbin ascent, "add 1500 m/s" won't work. kerbin has ~2300 m/s orbital velocity and you usually need something like 3400+- m/s to orbit, so a simple rule of thumb would be more like "+50%" 

[Streetwind]

As a rough rule of the thumb, for an ascent to LEO: 70% of dV goes to orbital velocity, 24% goes to gravity, 6% goes to aerodynamics.

Again, this is a ballpark figure. Exact numbers will vary from rocket to rocket, and even for the same rocket depending on how you fly it.

[Nich]

Gravity losses will very closely correspond with TWR.