It's a 1956 V-tail. Stable? Far from it. Any kind of bumps at all and it wallows on it's yaw axis to the point of making you sick.
The straight tails, both the 33s and 36s, are very stable, nice flying planes.
That old plane of Atlantic's has the E-225 and electric prop still. I've seen it. It's like opening a modern driving school with a 1956 De-Soto with a push button transmission. It's a non-sensical airplane for a flight school.