why is my planes tail pulling up? and why can it only hop?

[sussy imposter gaming]

so i

tried building a HE 162 and i had a small problem with the col arrow, it is pointing slightly backwards, making my tail want to pull up and making it imposssible to fly the airplane., does anyone know why the arrow is pointing this way? or how to fix this problem? (hopefully without altering the desing too much. heres a demonstation video :

 

Edited May 21, 2023 by sussy imposter gaming
Small grammar corection and Addition of tags

[sussy imposter gaming]

Sorry for very bad grammar 

Edited May 21, 2023 by sussy imposter gaming
Autocorrect srewed me xd

[Streetwind]

Right... so, there are two things going on here.

One, your center of lift is too far behind the center of mass. You want to have them roughly on top of each other, just a little bit behind. If it's too far behind, all the lift goes towards lifting your tail only, while nothing carries the nose. This makes the front of the plane flop forwards/downwards.

Additionally, you have a single engine mounted on top, not in line with the center of mass. This means the engine thrusts past the CoM, thereby inducing torque that tries to turn the entire plane around the CoM like a jet-powered spinning top. In your case, that torque goes into the same direction as the plane's natural inclination of flopping nose down due to the misaligned CoL, so both effects add to each other and ensure you cannot ever pull your nose up.

Take a look at this guide. It's for KSP1, so disregard any comments about the aero/physics model, but the basic design principles still hold true in KSP2.