Category and engine go to abrester34 and the weightless 26gal small fuel tank (the small speck in the center) is somebody's (idk who, just not mine). Anyway, the trick here is to get to about 84%-100% as quickly as possible at start in only two locations: Ice Base Assault and Bandit Airport. You can do Water Takeoff, but you only get about 300k mph, wheras in bandit or ice hase, you get about 1,000,000+ if you do it right (you can tell if you did it right if the sky starts to look a little weird, and by that I mean a circle-ish pattern starts to form at about 600k ft). Anyway, this Yeet Xpress is capable of extremely high altitudes. I got it to go above 5 million feet, and in fact, it went as high as 15 million feet high before it started falling. The way you can see the circle pattern is by looking up. If you are going to copy the engine, credit abrester34 for it.