LV-909 Maximum Thrust on Launch Pad = 15.1 kN with TL set at 100% WTH?

[Foxster]

Depends on the payload mass of course but yes. My stock satellite launcher for anything in the Kerbin system is still a BACC first stage and a Terrier second stage. Likewise, most if not all of my crewed ships based on 1.25m parts, use Terriers as their orbital insertion stage (which is usually the second stage). Get them high enough and they work just fine in atmosphere.

Fair enough. For anything that small almost anything will work though.

[Laie]

Works bigger as well. Yesterday I spent some time optimizing a promising design in the hopes that it could top out the payload fraction challenge: starts with one KR2L and two LFBs; by the time the LFBs run out, the KR2L can continue on it's own.

With a Poodle for the final ~800m/s, that rocket had ~70t payload for a 25% payload fraction. Not exactly small, and quite respectable performance (if I had made a submission, it would rank #2 among the rockets).

[Xannari Ferrows]

Each engine [except AirBreathing] has a fixed fuel consumption rate. Because of this, engines with a lower atmospheric Specific Impulse have less thrust in order to keep with the rate of consumption.