The Simplex Aero Half VW Engine Conversion Plans provide a detailed, step by step guide for converting a Volkswagen air cooled engine into a two cylinder aircraft engine. The plans cover engine selection, case preparation and modification, cylinder head conversion, rocker arm and valve cover modifications, crankshaft cutting and counterweight installation, camshaft modification, propeller hub installation, carburetion, ignition, exhaust fabrication, and final engine assembly. The manual includes detailed measurements, fabrication instructions, parts and materials lists, recommended suppliers, required tools and machine work, operating specifications, propeller considerations, and illustrated assembly procedures. Engine options covered range from approximately 28 to 45 horsepower, depending on displacement and configuration. The plans also include initial startup and break in procedures, test stand recommendations, ignition and carburetor troubleshooting, a wiring diagram, and numerous photographs and technical drawings to assist with the conversion and assembly process. Originally developed by Scott Land of Pop's Props in 1995, the plans were acquired by Simplex Aeroplanes in 2011 and subsequently expanded and revised with additional information and illustrations.