the blue, red and green fuselage can be deleted
but the red fuselage is connected to the front(spinning part of red rotator)
and green fuselage to green rotator

but the green rotator back connected to red fuselage

you can delete the fuselages, and straight to connect green rotator back part to front red rotator part.
and connect your HUD to the front of green rotator part

make sure to set the disableaircraftcollision to true
and check the camera output variables, look pitch is for Y / Pitch / vertical movement, look yaw is for X / yaw / horizontal movement

red rotator just

lookX/180 , inversed, or not check accordingly
set the rotator limit to 180° (idk if necessary)

green rotator

lookY/90 , inversed if needed
set the limit to 90°

blue fuselage is just the anchor because sometimes the camera offset itself? need to be confirmed

the seat was pulled backward