Plane vtol, problem with of motors

Hello I am new is the world of airplanes VTOL and I would ask if they can help me, I’m doing a pruyecto with the Nimbus 1800 as a project in my university, I wanted to ask for help, my problem is:
Already make all the settings and I make the transitions from VTOL to plane but the engines only rotate in plane mode and when switching to VTOL mode stop spinning, you know if I have to change any parameters?

Can you post your .param file? Perhaps just a setting or two needs to be changed.