I have been doing a lot of work recently on a VTOL Bi-copter configuration using X-plane 11 and SITL however there are some serious limitations in X-plane that limit the ability to manipulate the two thrust-vectoring propellers independently of each other. While I can get it to hover half-reasonably, it is playing some havoc with my attempts to tune the transition. Because of this I am considering jumping ship to RF8
With X-plane I have set each of the control surfaces to respond as though controlled by individual servo channels from APM/SITL using individual dataref packets. This abandons the basic pitch-roll-yaw-throttle output from SITL to X-plane and simulates it directly as I hope it to be configured in the real-life airframe. It works very well - the above-mentioned limitations notwithstanding.
Is it possible for RF8 to be configured similarly? i.e. each SITL servo output can drive an arbitrary control surface/function on an RF8 model?
Would love to know prior to spunking USD99 for the software only to find out a different hand is tied behind my back.
How did you get on with RF Andrew? I have also taken the plunge.
I enjoy using RF to burn holes in the sky, Gary, but I’ve not managed to master building the models. I’ve also reworked how I build my X-plane models that now allow me to replicate all the functionality I need for my eVTOL stuff (yeah!) so I’m a happy bunny, so to speak! 
That is exactly where I find myself, did you find tuning RF standard models silly simple compared to X-Plane?
TBH Gary, I haven’t even got as far as SITL with RF and the standard models. I spend my mental energy hacking the Ardupilot codebase in unprofessional ways now, rather than climbing another learning curve that is RF, despite having spunked real and not insignificant moolah on it.
Ah, I’m about to head down the modelling world as I have something in mind.I thought I would try tuning one of the standard models, the Stick as I have owned one and it really just worked,no hardships this has not been my experience of X-Plane models. I suspect I am going to be hitting my head against the wall re modelling this weekend! I wanted to bring something to life from CAD to Creation with simulation on the way.
Good luck, Gary! Let us know how you get on!