Abstract: An internal combustion aircraft engine comprising a cylinder head having a cylindrical head bore formed therein, a piston, and spark plugs, the cylinder head bore and piston designed to reduce engine knock. The cylinder head is fixedly attached to a top end of a cylinder barrel formed with cylindrical walls, the cylinder head bore and the cylindrical walls defining a cylinder. The cylinder head bore has formed therein an outwardly protruding cavity with respect to the top end of the cylinder barrel. The piston has a piston crown, and the piston contained within the cylinder, the piston crown, the cylinder walls, and the cylinder head bore define a combustion chamber. The piston crown has a concavity formed therein, and the piston is constructed and arranged to reciprocate within the cylinder. The concavity of the piston crown and the cavity cooperate at a top dead center position of the piston to form a swirl chamber.

Abstract: An internal combustion aircraft engine comprising a cylinder head having a cylindrical head bore formed therein, a piston, and spark plugs, the cylinder head bore and piston designed to reduce engine knock. The cylinder head is fixedly attached to a top end of a cylinder barrel formed with cylindrical walls, the cylinder head bore and the cylindrical walls defining a cylinder. The cylinder head bore has formed therein an outwardly protruding cavity with respect to the top end of the cylinder barrel. The piston has a piston crown, and the piston contained within the cylinder, the piston crown, the cylinder walls, and the cylinder head bore define a combustion chamber. The piston crown has a concavity formed therein, and the piston is constructed and arranged to reciprocate within the cylinder. The concavity of the piston crown and the cavity cooperate at a top dead center position of the piston to form a swirl chamber.

Abstract: A plate-type annular heat exchange cylinder which has increased resistance to cracking under the stress of heat gradients. The invention comprises providing the cylinder in the form of two or more longitudinal segments, such as hemi-cylinders, spaced by axial narrow expansion slots, sealing the spaces between adjacent pairs of the plates of each segment and each expansion slot, uniting the segments by attaching radial coupling plates over the slots at each end of the segments, and blocking the inner peripheral entrance of each axial slot by attaching a narrow gas seal strip thereover.