Coordination of Supercharger Speed to Manifold Pressure

THE control discussed here is used with engines having two engine-driven superchargers; one being driven at constant ratio; the other being driven through a fluid coupling at a variable degree of slip, and called the auxiliary stage.

The auxiliary supercharger fluid coupling control consists of:

1. 1.
   Engine power control.
2. 2.
   Auxiliary supercharger control.

The engine power control maintains the selected manifold pressure by automatically operating the carburetor throttle. The supercharger control is altitude responsive, operating the scoop of the hydraulic coupling.

It is possible with this device to limit the manifold pressure below detonation independently from the pilot's selected pressure. By means of this device it is possible to control manifold pressure 2 in. of mercury below borderline detonation on engines without inter- or aftercooler.