abgd, I have tried this, as I described earlier. Establish the aircraft in a stable, full power, Vy climb, properly trimmed and all. This is about a 20-25 degree nose up attitude. Release the stick altogether and chop the power.
The aircraft got into a wild speed/pitch oscillation and had not sorted itself out after 1000' of altitude loss so I called it quits. However, the aircraft did indeed NOT stall. (Although I don't remember if it got close enough to the stall for the stall warner to go off.)
Furthermore, even though Vbg is equal to Vy in this aircraft, the trim settings were completely different. With full power there is a lot of airflow over the all-flying tailplane, with zero power there is not.