Abstract: A full time lean air fuel mixture running spark ignited air cooled aircraft piston engine. In one embodiment, a drop-in substitution is provided for an equivalent make, model, and engine size, wherein the new, rebuilt, or reconfigured engine provides as much or more horsepower when compared to the original engine, but runs at a lean air fuel ratio condition during normal operating modes, including takeoff, climb, and cruise, thus saving significantly on fuel. In yet another embodiment, a drop-in substitution having a somewhat larger cylinder displacement volume may be provided to attain equivalent or enhanced maximum horsepower while operating at lean air fuel ratios. Enhanced engine life may be anticipated, since cylinder head temperatures (CHTs) may be reduced, compared to engines using rich air fuel ratios for climb and cruise conditions. Aircraft using such engines are also disclosed.

Abstract: A method and apparatus for modifying aircraft having a fuselage and center fuselage carry through structure that support wing structures, comprising placing a load transferring member to extend through the center fuselage carry through structure, and transferring the tension loads from the wing structures to the center fuselage carry through structure so as to provide a redundant load path that is resistant to the hazards of single point failures modes.

Abstract: A fuel injector matrix to optimize the operating efficiency of an internal combustion engine, each injector having a metering orifice sized for each of the combustion cylinders of the engine to provide a uniform fuel to air ratio to all the cylinders such that all the cylinders reach a peak exhaust gas temperature at a common total engine fuel flow.