Hello all. Ive recently been refining my spaceplane building and flying (particularly cargo lifters), and come to a question regarding ascent profile.
I normally keep a quite shallow ascent to keep the speed up for the rapiers to keep their 200+ Kn of thrust. When nearing the 10 Km mark, i try to gain as much speed as possible with a shallow climb. Now at what point do you switch the rapiers to close cycle mode? I've found that I can get up to 1520m/s depending on the heat tolerance of the parts used, but the last ~40m/s are gained very slowly. Am I better switching to close cycle at some point before this?
And the main question: when switching to close cycle, do you pitch up, if so, how much? I've found that often I loose a lot of speed in the pitch manouvre, and I feel like I might just keep going straight (actually about 5-10 degrees of positive pitch)- the curvature of Kerbin and the speed you'redoing by now will guarantee you leave the atmosphere soon anyways.