Single Burn to Orbit?

[Apexazimuth]

I was curious about this before I became an ROholic (Realism Overhaul).  Now it's clear as day.  Kerbin is ridiculously tiny, with a disproportionately voluminous atmosphere.  There really isn't any point to a gravity turn for launching to orbit from kerbin. It's most efficient to get out of the atmosphere quickly, gaining a bit of horizontal velocity on the way, then do a short burn to circularize.

On earth, that horizontal burn takes MUCH longer, and the rocket will fall back to the Earth unless the upper stage is ridiculously powerful (thrust wise), or if the first/second stages take care of most of the horizontal velocity on the way up, which is what real rockets do.

My whole concept of "throttling" was squished once I started playing with RO to see how real rockets work.  MOST rocket engines aren't throttle-able, even new ones.  The RS-25 (Space Shuttle Main Engine) is often quoted because it is seen as a "common" engine, since it's on the space shuttle, but there's nothing common about the RS-25 at all.  It's extremely high tech, extremely expensive, and extremely complicated.  Not at all a model example of a typical rocket engine.

Reducing G-load and dynamic pressure on a rocket without throttling requires simply starting off with a bunch of engines and shutting them off as the acceleration increases, balancing load across the whole flight.  The Saturn V actually shut off some of it's powerful engines in mid flight to do just this.  Booster rockets that are separated mid-flight serve this purpose as well.

[RainDreamer]

Another thing is that the burns are not done manually. So they can manage burns with much more precision than doing it manually like in KSP, allowing them to do it much easier.