If you're wondering why my PV-40 hasn't made any progress, it's impossible to make.
First of all, if you know any aircraft knowledge at all, you have to put the CoM (Center of Mass) upfront of the CoL (Center of Lift). The problem is to make a VToL, you have to make the CoM and CoT (Center of Thrust) at the same place as each other. But, the engines are attached to the wing making it impossible to make it fly well and take-off vertically. So basically, it defies the laws of physics.
I think I can try (But I'm too lazy)
The mass and position of the engines makes all the difference. If you are still having trouble with it, tag me on unlisted. I might be able to help.
Center of lift moves when the aircraft tilts it's wings. By default it will be ahead, but when wings are tilted up it moves behind.