[aerohead]

Sorry,I'm away from my resource materials,however,I don't remember that Hucho's book actually had a formula for that design.I believe it was merely a windtunnel excercise to investigate how far you could cheat on a boattail (get around someone elses' patent) and still realize some aerodynamic benefit.The flow immediately separates from the trailer then reattaches on the box,with locked-vortices captured in between.The surrounding flow is supposed to flow over the vortices as though they were solid surfaces,and then separate from the box into a wake that is somewhat sculpted into a form better approximating Mair's 22-degree boattail.Being flat surfaces,I suspect that in full-scale,such panels would be inherently weak structurally,and would have to be reinforced (added weight )to achieve the integrity of the more natural compound form they are trying to mimic.Good thing these people don't design rectal suppositories!