Specifications

DCS

[P-51D Mustang]

AIRCRAFT OVERVIEW

Figure 15: Supercharger

For normal operations, the supercharger should be kept in AUTOMATIC mode. In this position, the

supercharger is controlled by an aneroid-type pressure switch, which automatically cuts the unit into

high or low blower as required. This switch is adjusted to cut the unit back into low blower mode

approximately 1,500 feet under the altitude at which it cuts into high blower. This prevents the high

blower from going on and off repeatedly with slight changes in altitude near the level at which the

high blower cuts in. If the aneroid switch fails, the supercharger automatically returns to low blower.

The LOW position on the manual switch on the instrument panel makes it possible to operate the

supercharger in low blower mode at high altitudes. This provides better range at high altitudes,

which can be used for long-range flights.

The HIGH position on the manual switch makes it possible to test the high blower mode on the

ground. The switch must be held in the HIGH position by hand, however, because it is springloaded

and returns to the LOW position when released.

An indicator light next to the manual switch on the instrument panel turns on when the supercharger

is in high blower. The light can be pressed to test its functionality.

Carburetor

The carburetor provides automatic control of the fuel-air mixture passed from the air intake to the

supercharger and onto the engine manifold for combustion in the cylinders.

The Packard Merlin engine has an injection-type carburetor and an automatic manifold pressure

regulator. The manifold pressure regulator is effective only at pressures in excess of 41 in. The

automatic pressure regulator alleviates the pilot from having to jockey the throttle to maintain a

constant manifold pressure in the high-speed range during a climb or descent. The pilot is only

required to set the desired pressure by setting the throttle lever and the pressure regulator does the