WW1 planes have two problems. The high angle that a WW1 sits on the ground. Lots of change of the toe from 2 point to 3 point. Wihen the Tail comes down, it can induce steering as the relative toe to the ground changes. Also when the tail comes down, the rudder, as most are small, gets blanked out giving no directional control. Both cases happens when the tail comes down. Getting the plane stopped fast is the best thing to stop ground looping.