Introduction to Aircraft Internal Combustion Engines

The internal combustion (IC) engine is the powerplant used on almost all light general aviation aircraft today. Electrical aircraft motors promise a new and cleaner aviation future but are still a way off, powering prototypes but, have not yet entered mainstream adoption. We will therefore focus on the internal combustion engine in this series discussing light aircraft propulsion.
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The Four Stroke Engine Cycle

Most internal combustion engines work on one of two principles of operation: a two-stroke cycle or a four-stroke cycle. Four-stroke engines are the predominant type seen in general aviation and form the topic of this post.
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Aircraft Piston Engine Operation

In the previous post on the topic of piston aircraft engines we discussed the four-stroke cycle, digging into the details of what happens inside the engine block once the engine is fired up. Now we move from under the cowling to inside the cockpit and discuss the engine instruments and controls you are likely to encounter as you take to the skies.
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Introduction to Aircraft Engine Systems

In a light aircraft, the power and torque generated by the engine while it is running is not only used to produce the thrust necessary to propel the aircraft forward. The engine is also used to power several systems necessary to keep the engine running and to safely operate the aircraft.
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Aircraft Magneto Ignition System

In a previous post we introduced the various engine systems found on a light airplane. We now focus our attention to the ignition system, and specifically discuss the design and basic operating principles of a magneto.
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Aircraft Oil and Cooling Systems

Internal combustion engines must be adequately lubricated and cooled while running in order to provide safe operation and to function as the manufacturer intended. In this post we focus on the lubrication and cooling systems of a typical internal combustion aircraft engine.
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The Aircraft Fuel System

An aircraft’s fuel system must be capable of providing a consistent delivery of fuel at the flow rate and pressure established by the manufacturer to ensure proper engine functioning under likely operating conditions. This includes any manoeuvre which forms part of the aircraft’s certification envelope.
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The Aircraft Carburetor

The carburetor forms a part of the engine’s induction system and is responsible for bringing together and mixing the air and fuel. This mixture is then routed to each cylinder where it is ignited as part of the four-stroke engine cycle.

The carburetor is still the most commonly used device in light aircraft to atomize and mix the fuel and air required for combustion. The alternative is a fuel injection system. Fuel injected engines use a pump and a fuel distribution system to inject fuel directly into the induction system through a set of fuel injectors. Fuel injection has largely replaced carburation in the automotive industry but not so in the engines of light piston aircraft.
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Aircraft Propeller Theory

An internal combustion engine is designed to convert the reciprocating motion of the pistons into rotational motion at the crankshaft. This rotational motion is then be converted into a forward thrusting force by the propeller which powers the aircraft forward and is required to balance the drag produced by moving through the atmosphere.

This post will focus on the propeller and should provide a good overview of all aspects associated with light aircraft propellers. We will discuss the forces generated by, and acting on a propeller, the variables associated with propeller design, the types of propellers in use, and how the propeller should be operated and managed in flight.
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