WEll the thing you will need is somthing to counter the torque. Having a vent on the ends of th rotors won't do i Autogyro does nto need it because i has no power to it. The problem with an Autogyro is it neds forward momentum thus is no beter than a normal airplane but slower thus the have not been made since the 1930's. Put the rotors on over the other is a simpke soulution. I saw a demo of the Helix in Oklahoma it is an awsome machine. It can fly sidways backwards because of the way the torque is neutral. Cool looking models with a hard edge. Put them in a scene to show them off. Flying at treetop level or something. the Easy waywoudl be just to duplicate the rotor and place it just above the other for a working model. For just looks they are cool keep up the modeling. Working in aviation related buisness for 12 years takes its toll. sorry for all the data. I like building aircraft in Modeling programs also.

The wit of a misplaced ex-patriot.
I cheated on my metaphysics exam by looking into the soul of the person next to me.