The Retro-fit Compressed Air Vehicle System of Leroy Rogers.The Rogers motor shown here makes no claims to spectacular operation, but in spite of that, Leroy did admit in an interview that this motor does indeed have a greater output than the applied input, provided that the motor is not left just ticking over. This motor is like the US patent 3,744,252 “Closed Motive Power System Utilising Compressed Fluids” by Eber Van Valkinburg shown below. However, the Rogers patent shown here has the distinct advantage that it uses off-the-shelf motors and readily available hardware and there is nothing really exotic or difficult about the Rogers engine that a person couldn’t get from a valve supplier or get a metal fabrication company to construct. However, while Leroy did state that his design was self-sustaining when going over 30 miles per hour, a key design feature is his very high performance compressor unit which he later patented as shown below. Present day vehicle engines are under-geared and run at fairly low revs. These same engines operate much more efficiently at higher revs, if they are given different gearing. With the Rogers motor, the air contained in the high-pressure tank is sufficient to drive the pistons up and down. Air can be pumped back into the high-pressure tank by a compressor which has a much higher gearing and much lower capacity per piston stroke. The expanded air exiting from the engine is at much lower temperature than the surrounding air and if it captured in a buffer tank and used as the input of the compressor, then recharging the air tank is more efficient, provided that the tank absorbs heat from the surrounding environment, raising it’s temperature inside the tank and so giving an extra boost to the tank pressure, over and above the compression provided by the compressor. One really nice feature of Leroy’s design is that he envisages it as being an adaption of an ordinary vehicle engine and he provides a considerable amount of practical detail as to how the adaption can be carried out.