ROLLS-ROYCE ENGINE SUPERCHARGER

The - Rolls-Royce engine which powers the P-40 F and L models has a single stage 2-speed supercharger controlled by a lever on the bottom of the throttle quadrant. The lever has two positions-HIGH and LOW. To get the best power, operate the engine with the supercharger in LOW below 1200 feet and in HIGH above 1200 feet.

To move the blower from LOW to HIGH or from, HIGH to LOW, reduce the manifold presure

to 20" Hg. and the rpm to 2000, and then quickly shift the lever into the desired position. You can shift the supercharger lever without first reducing power, but this practice is not recommended except in emergencies because it is hard on the supercharger clutch. In normal operation, first reduce power.

Except for the supercharger, there are no great differences in the power and operation of Rolls-Royce and Allison engines.

ENGINE CONTROLS and INSTRUMENTS

THROTTLE QUADRANT

The throttle quadrant consists of throttle, mixture, and propeller controls. Adjusting the friction knob on the side of the throttle quadrant prevents the three control levers from creeping. The mixture control has four positions: IDLE CUT-OFF, AUTO LEAN, AUTO RICH, and FULL RICH.

When the mixture control lever is in AUTO RICH or AUTO LEAN, altitude mixture control is automatically maintained. Always start the engine in IDLE CUTOFF to prevent flooding and to reduce fire hazard.

Note: Never use the FULL RICH position except:

1. When the AUTO LEAN or AUTO RICH rubber diaphragm breaks or the automatic compensating aneroid fails. Symptoms are spitting or cutting out of the engine. In high-speed dives from high altitudes, there may be diaphragm or aneroid trouble.

2. When engine detonates. Before you move the mixture control level to FULL RICH, reduce power as much as possible.

B. The propeller control lever is pushed forward to increase rpm, pulled backward to decrease rpm,

Note: On P40 N models with prop and throttle linkage the propeller lever cannot be moved. Throttle action automatically increases and decreases rpm.