Terminal velocity

[GreyscaleSibyl]

I've seen the term thrown around here a couple times, can someone explain to me what it means exactly, and how it affects my rockets?

[Cranium]

Terminal Velocity is simply the speed at which the force of the drag caused by wind resistance equals the amount of gravitational force being applied on any object.

Basically, it is the fastest speed an unassisted object will fall.

http://en.wikipedia.org/wiki/Terminal_velocity

[SuperFastJellyfish]

To put what Cranium said in terms of KSP, going faster or slower than terminal velocity while in an atmosphere will increase either drag losses or gravity losses, respectively. Thus, decreasing fuel efficiency. Telemetry mods like Kerbal Engineer Redux or Mechjeb(although I've never used mechjeb) will tell you your real time atmospheric efficiency and having one or the other is a game changer with the info either one provides.

Here is terminal velocity of Kerbin as it changes with altitude:

Altitude (m) Velocity (m/s)

0 97.3

1000 110

3000 130

5000 160

8000 215

10000 260

15000 425

32000 2250

Stay as close to those speeds as possible at the designated altitude and you will have a pretty efficient ascent profile.

Edited June 5, 2013 by SuperFastJellyfish