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Lycoming Engine 320 Series: A Versatile Powerplant for General and Utility Aviation

## Overview

The Lycoming Engine 320 Series is a renowned family of four-cylinder, air-cooled, horizontally opposed aircraft engines renowned for their reliability, durability, and fuel efficiency. Designed and manufactured by Lycoming Engines, a subsidiary of Avco Corporation, the 320 Series has become a ubiquitous powerplant for a wide range of general aviation and utility aircraft.

## Design Features

The 320 Series engines incorporate a robust crankcase and cylinder assembly, featuring a precision-machined aluminum crankcase and forged steel cylinders. The cylinders are equipped with cast aluminum cylinder heads with integral cooling fins, ensuring optimal heat dissipation. The engine's crankshaft is supported by three precision-machined roller bearings, providing smooth and reliable operation.

## Fuel System

Lycoming 320 Series engines employ a pressure-type fuel system, with a fuel pump supplying pressurized fuel to a fuel injection system. The fuel injection system utilizes fuel nozzles positioned directly into the combustion chambers, ensuring precise fuel metering and efficient combustion.

## Ignition System

Ignition in the 320 Series is provided by a dual magneto system, ensuring redundancy and enhanced reliability. The magnetos produce high-voltage sparks to ignite the fuel-air mixture in the cylinders, delivering consistent and predictable engine performance.

## Lubrication System

The engine's critical components are lubricated by a pressure-type lubrication system, which circulates oil throughout the engine to reduce friction and wear. The lubrication system employs a wet-sump design, with a reservoir of oil in the engine's lower crankcase that is continuously pumped to lubricate the moving parts.

## Cooling System

Lycoming 320 Series engines utilize an air-cooled cooling system, featuring an integral oil cooler and a fan-driven airflow system. The cooling fins on the cylinder heads dissipate heat from the engine, while the fan mounted on the crankshaft draws air over the cylinders and oil cooler to maintain optimal operating temperatures.

## Performance Characteristics

The Lycoming Engine 320 Series is renowned for its exceptional performance characteristics, delivering reliable power and fuel efficiency. The engines are available in a range of power ratings from 150 to 180 horsepower, catering to different aircraft weight and performance requirements. The 320 Series engines are characterized by their smooth and responsive operation, providing pilots with precise control and excellent maneuverability.

## Applications

Lycoming Engine 320 Series engines have found extensive applications in a diverse range of general aviation and utility aircraft, including:

- Cessna 172
- Piper Cherokee
- Beechcraft Bonanza
- Mooney M20
- Diamond DA40

In addition to powering fixed-wing aircraft, the 320 Series engines have also been used in rotary-wing aircraft, including helicopters, gyrocopters, and autogyros.

## Conclusion

Lycoming Engine 320 Series engines are a testament to the engineering and manufacturing prowess of Lycoming Engines. Their combination of reliability, durability, fuel efficiency, and performance characteristics has made them the preferred choice for aircraft manufacturers and pilots worldwide.
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Lycoming engine operators manual 320 series O-302, IO-320, AIO-320, LIO-320 103 pages