Gliders with unreal speed

Hi!
I've installed some glider addons. The ASK 21, DG100 and Bergfalke III.
The Bergfalke III seems to behave good and realistic.
But the other two, ASK 21 and DG100 is getting far to much speed.
I maintain 150 Km/H with full airbrakes at level flight.
When I realeas the airbreaks it rapidly accelerates to more than 200 km/h.
Does anyone have the similar problem??
I've installed some glider addons. The ASK 21, DG100 and Bergfalke III.
The Bergfalke III seems to behave good and realistic.
But the other two, ASK 21 and DG100 is getting far to much speed.
I maintain 150 Km/H with full airbrakes at level flight.
When I realeas the airbreaks it rapidly accelerates to more than 200 km/h.
Does anyone have the similar problem??