Abstract: The plenum of an engine air manifold, coupled to engine cylinders, is provided with a fuel injector. A solenoid prevents supply of fuel to the plenum fuel injector during normal operation of the engine. Upon failure of the primary fuel system, solenoid opens to provide a fuel/air mixture via the manifold, to the engine cylinders, converting the manifold from a dry manifold to a fuel/air mixture manifold. The fuel bus of the primary fuel system preferably receives fuel from, and returns fuel to, a header tank, rather than directly from and to one or more fuel tanks.

Abstract: The plenum of an engine air manifold, coupled to engine cylinders, is provided with a fuel injector. A solenoid prevents supply of fuel to the plenum fuel injector during normal operation of the engine. Upon failure of the primary fuel system, solenoid opens to provide a fuel/air mixture via the manifold, to the engine cylinders, converting the manifold from a dry manifold to a fuel/air mixture manifold. The fuel bus of the primary fuel system preferably receives fuel from, and returns fuel to, a header tank, rather than directly from and to one or more fuel tanks.

Abstract: The plenum of an engine air manifold, coupled to engine cylinders, is provided with a fuel injector. A solenoid prevents supply of fuel to the plenum fuel injector during normal operation of the engine. Upon failure of the primary fuel system, solenoid opens to provide a fuel/air mixture via the manifold, to the engine cylinders, converting the manifold from a dry manifold to a fuel/air mixture manifold. The fuel bus of the primary fuel system preferably receives fuel from, and returns fuel to, a header tank, rather than directly from and to one or more fuel tanks.

Abstract: The plenum of an engine air manifold, coupled to engine cylinders, is provided with a fuel injector. A solenoid prevents supply of fuel to the plenum fuel injector during normal operation of the engine. Upon failure of the primary fuel system, solenoid opens to provide a fuel/air mixture via the manifold, to the engine cylinders, converting the manifold from a dry manifold to a fuel/air mixture manifold. The fuel bus of the primary fuel system preferably receives fuel from, and returns fuel to, a header tank, rather than directly from and to one or more fuel tanks.

Abstract: A propeller is controlled to change pitch at at least two different rates. In one embodiment, an electric motor is provided with a high or low voltage for driving a pitch change mechanism at a high or low change rate. Preferably the rate is selected automatically. Preferably, the high rate is not used unless the current pitch is below a threshold.

Abstract: A redundant ignition system for an internal combustion engine is provided. When the internal combustion system is a waste spark system, opposite ends of first and second secondary windings of first and second coils, are coupled, respectively, to first and second sparkplugs, for igniting first and second cylinders. In one embodiment, a diode or similar structure prevents feedback from one coil to another coil.