Another thing about TWR

[Spaced Out]

Why is it so advantageous to have a lower TWR?

[shynung]

Because you can build your rockets to have a lower structural mass, since it doesn't have to withstand high G acceleration.

Note that having low TWR isn't without its drawbacks. The rocket would lose a lot of deltaV due to gravity drag - it'd have to spend more fuel keeping itself flying in the early stages of launch compared to a similar rocket that has a high TWR.

[Bill Phil]

Having a low TWR is generally a symptom more so than a cause. It's a symptom of lots of weight with only slightly more thrust. Maximizing vehicle mass for a given thrust isn't a bad idea, and that means you'll have a lower TWR.

[wumpus]

Empty Earth fuel/oxidizer fuel tanks are much lighter than Kerbal ones.  I've heard that their fuel+oxidizer mass/to empty tank mass is higher than that of a coke can (which in turn is an impressive feat of finite analysis.  Coke cans are about 1/3 the weight of  3-4 decades ago).  In a liquid fueled rocket, decreasing TWR from 1.5 to 1.1 implies more than 30% more fuel, which typically offsets the huge gravity losses you will get (well, maybe not.  The Saturn V had a TWR of 1.15, and used unbelievable amounts of fuel just to clear the launch tower.  I'd hate to think of the cost of TWR=1.10).

With solid rockets, things are more limited by aero forces (although shuttle launches were limited to not crushing astronauts with their own weight) and most of this goes out the window.