John Galloway wrote:
as an ex Duo owner I agree with Dave Nadler and Bill
Daniels; the Duo airbrakes are better than their reputation:

Well, clearly, not all current and former Duo owners agree. Perhaps I'm
used to gliders with very effective spoilers, including various DG
models, ASW20s, Ventus Bs, etc. But, after 200 or so hours in our Duo
(and a couple of others in the area), I'll simply say that the spoilers
were workable with proper approach planning and airspeed, and that it
remains the only glider I've ever felt the need to slip on a routine
basis...

Marc