Abstract: A fluid coupling device, especially a viscous fan drive, of the type including an output coupling member defining a fluid operating chamber. The device includes an input coupling member rotatably disposed in the operating chamber and cooperating with the output member to define a shear space. The output coupling member defines an annular inner surface, at least a major portion of the inner surface cooperating with the axis of rotation to define an included angle between about 20 degrees and about 70 degrees. The input coupling member defines an annular outer surface, a major portion of which conforms generally to the angled inner surface of the output coupling member and is closely spaced apart therefrom. The fluid coupling device of the invention has a substantially reduced idle speed, without a loss of peak speed, as well as a greatly reduced pump-out time.