Many people told me that I would loose directional control in my electric tail helicopter in an auto because the tail isn’t driven by the main rotor. In real life directional control during an auto is superb, I’ll try to explain why this is so.
What many people tend to forget is that in an auto the glide ratio is roughly 1:4.This means that horizontal speed is roughly 4 times as large as vertical speed. Adding to that is the fact that aerodynamic forces are typically equal to the square of airspeed, double the airspeed and aerodynamic forces don’t double but go up by a factor of 4. During an auto the aerodynamic forces due to forward speed are thus roughly 16 times as large as aerodynamic forces due to vertical speed downwards. What keeps the SCH-2A (and my electric tail helicopter straight) is an effective vertical stabiliser, and you don’t need to look very hard to find it.
A gyrocopter works the same way, once you have enough airspeed the vertical stabiliser is what keeps the nose pointing in the right direction. Taking your feet off the pedals won’t cause you to loose directional control.
When forward airspeed drops to zero everything changes of course, because the vertical stabiliser now becomes ineffective. In a gyro the horizontal stabiliser and prop wash (if the engine is still running) now play a dominant role. If the engine is not running the horizontal stabiliser causes the nose to pitch down, airspeed builds up and the vertical stabiliser starts working again.
An auto at zero airspeed in a SCH-2A will result in yaw control reversal, to get out of that it’s necessary to build up airspeed again. For a low hour pilot that might prove challenging.
The safest way to fly a SCH-2A at auto heights is to always fly at airspeeds where the vertical stabiliser is dominant, that way yaw control reversal will never be an issue.