Nearly seven hundred thousand (700,000) non airline civilian pilots operate over 200,000 aircraft, in the United States alone. Most of these aircraft are fueled with expensive 100 octane leaded fuel. Most of the engines have anticipated life spans between overhauls of from 1600 to 2500 hours. These engines are usually constructed with separate air cooled cylinders bolted to a central core which contains the crank shaft and the cam shaft. A significant number of these engines are turbo charged.

Conventional general aviation engines range from less than 100 to over 300 horsepower; there are a significant number of larger engines. They typically consume about 0.5 lbs of 100 octane per hour for each horsepower, when properly operated. If supercharged, then usually 0.6 lbs.

Diesel engines in these size ranges will consume between 0.35 and 0.49 lbs, turbo or supercharged. The LIM type Simple Cycle engine will be at the lower end of the range.

Forced ventilated two stroke diesels, similar to the 1930s uni flow designs of Detroit Diesel, were often described in the general aviation press during the 1990s, but none were subsequently introduced. LIM intends to develop an aviation engine using its new, patented system, which is different.

LIM’s design features top down flow of forced air with a total absence of any mechanical or electronic/electrical or magnetic management of the valves. There will be no camshaft, and nearly no valve train.

The valves are only for intake; exhaust flows away through a ring of ports around the cylinder, which are exposed by the piston as the power stroke ends. Air, under pressure in the intake manifold, forces open the intake valves, which are also patented, to allow air to stream through the cylinder, displacing the prior cycle's waste gases and also cooling all internal surfaces, including the head, cylinder and piston crown.

Unlike typical two strokes, the crank case is only utilized as the home of the crank shaft, the bearings and normal lubricants. Intake air is driven to the cylinders by a separate rotary compressor. The lubricants have no other engine task, so the oil will stay fairly cool. The pistons have at least one ring around the lower piston skirt, which will intercept almost all blow by gases, protecting the oil from contamination by organic acids.

Much longer oil life and greatly extended times between overhauls are anticipated results.

The patented intake valves are of titanium, which will not ablate from friction with the valve guides, which are of another very durable material. Lightly sprung, they will be as easily removed as spark plugs, should they need to be cleaned or replaced; it may be the sort of chore owners will be permitted to perform.

By producing a power stroke in each cylinder for each revolution, nearly twice the power is available from a given displacement at the same rate of rotation as in a four stroke. This could mean that such engines will last much longer. So you could reduce displacement, cost and weight, or just get much more power.

For their power output, the LIM type engines would weigh about 1/3 less than the engines they replace. This is a weight reduction, from a conventional 300 HP engine, of nearly 200 pounds. Using diesel or jet fuel, filling the same tanks could provide range or endurance increases of more than 35 %.