The micro 4-cycle single-cylinder model airplane engine (far right engine in photo) was designed and built by Ronald Valentine, of FL. In the 1980s, Ronald, who is known for his miniature diesel engines, designed and built three miniature four-cycle model airplane engines. Two are air-cooled single-cylinder model aircraft engines, and one is a 5-cylinder radial engine measuring only 3.25 inches in diameter.
This air-cooled single-cylinder model airplane engine runs on methanol with glow ignition using custom made glow plugs by R. Valentine. These 3 are the only 4-cycle engine Mr. Valentine built. All were designed to burn methanol on glow ignition, and all required special (custom made) glow plugs that Ronald designed and fabricated. These are the only four-cycle model engines built by Mr. Valentine.