Hi! I'm a new user who came from simpleplanes, i have a question.

(btw im talking serious here but i talk like a memer on discord eksdee)

For changing engine power, for rocket engines download Overload, click on "edit xml" on the part parameters, then on the upper section of the newly appeared tab, click on the left arrow and then modify the "nozzleThroatSize".

If you need more help, make sure to check SRC, here

@QarabinaKa Ah, i see. Thank you for your help.

@AzureCorp
In that case, if, once again, you are on PC, you can use the overload mod to edit some XML. As for using external programs to edit the XML files, I can't tell you, as I haven't delved much in XML.

@QarabinaKa Thank you! But what i meant by changing engine power percentage, i meant by XML. But anyways, thank you for responding, i appreciate it!

I am assuming you're on PC. Left Shift throttles up and Left Ctrl throttles down, Z is full throttle immediately and X kills throttle. And yes, there is a simplerockets discord server, the SRC. Welcome to the site, and have fun.