Gary said,
Without - 134to 136kts, with 132/133 kts.

Thanks Gary,
I'm curious if you have numbers at higher MAP and higher IAS where the drag
would tend to kick in more.?

re: why they work.  I'm not an aerodynamacist.   but one observation is that
at high angles of attack, the bottom of the vstab may be in cleaner air than
the top.

Colyn