Well I tried flying the Spitfire and Hurricane so far. I saw a tutorial on how to start the engine and the person clicked on the mixture and slid it up and down easily. But so far all I can do is have it at 0% or 100% mixture which I don't think is meant to be. I managed to take off but the instant I lifted off I knew something was wrong. I had it at 0% mixture and the plane was VERY slow and shaking a little. When I chose the only other option of 100% mixture my plane got very loud and started shaking very violently. If I went up or down past a 45 degree angle my engine would cut out. What I'm trying to ask is if it's normal to not be able to have any mixture level between none(0%) or full(100%) and maybe if there's some other problem causing the shaking.
Here's one of the videos for reference.