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The aircraft fuel system is paramount for standard flight operations to be carried out, ensuring that fuel and air is properly mixed and combusted for driving systems and creating propulsion. Two of the most important aspects of an aircraft fuel system are aircraft engine fuel and fuel metering systems, both of which pilots need to understand for proper operations to be carried out. In this blog, we will discuss aircraft engine fuel and fuel metering systems, allowing you to understand the various types that benefit aviation.
Depending on the model of an aircraft, whether it features a reciprocating or turbine engine, and other various factors, there are a number of fuel types that one may take advantage of. Generally, these include jet fuel (Jet A-1), kerosene-gasoline mixtures (Jet B), avgas, and biokerosene. Jet A-1 aircraft fuel is most often relied on by those who operate jet engine and turboprop aircraft, and it is considered to be a refined, light petroleum that is highly regulated due to its demand. Jet B fuel, on the other hand, is primarily used for military jets as it requires a suitable aircraft engine for optimal performance.
Since the rise of turbine engine aircraft, avgas has decreased in popularity, regularly being used for older piston engines and some private aircraft. In the present, the primary form of avgas that one may procure is the 100 LL variety, though low-lead types can be found in the United States in some instances. It is important that avgas is only used with a gasoline engine, due to the fact that diesel engines require kerosene. Biokerosene is another alternative to jet fuel, and it serves as a renewable option to meet the rising prices of jet fuel. To manufacture biokerosene, algae or biofuels are processed and mixed with kerosene.
While choosing the correct type of aircraft fuel is paramount for proper thrust generation, there must be a fuel metering system to manage the flow of fuel as it is delivered to a combustion chamber or cylinder. Similar to aircraft fuel, metering systems will often vary based on the type of aircraft and its engine. For reciprocating engines, the fuel metering system will be tasked with atomizing and disturbing carburetor fuel into the mass airflow. It is crucial that the metering system provides equal amounts of fuel to each cylinder, ensuring the same fuel-and-air ratio in all. As the qualities of atmospheric air change based on the altitude, reciprocating fuel metering systems will make changes to compensate.
For aircraft that have a turbine engine, fuel metering will often be hydromechanical or hydromechanical/electronic. With hydromechanical fuel controls, the engine’s gas generator gear train will drive the controls, allowing them to detect engine speed for properly actuating cams, servo valves, fuel pump components, and other elements that assist in management. As engineers began to experiment with the addition of electronic based control for increased computing, the purely hydromechanical fuel metering system began to fall in popularity. Nowadays, many modern turbine engine fuel metering systems take advantage of vane fuel pump components, hydromechanical fuel control assemblies, a remotely mounted electronic fuel control unit (EFCU), and other such elements to optimally manage fuel.
As you carry out standard flight operations, it is important that your engine fuel system and engine assembly are regularly maintained to ensure airworthiness and safety. At Just Parts Limited, we provide customers access to over 2 billion new, used, obsolete, and hard-to-find components, all of which have been sourced from leading global manufacturers we trust. With our Instant RFQ services, we can also ensure you receive competitive quotes for your comparisons with rapid turnaround times. Get in touch with a Just Parts Limited representative at your earliest convenience and see how we can serve you!