Flashcards on Aircraft Engine Fuel Metering Systems

Aircraft Engine Fuel Metering Systems Explained: A Student Guide

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What are the two purposes of the manifold valve (or flow divider) in the fuel injection system of a horizontally opposed aircraft engine?

1) Provide a constant discharge fuel pressure for idling. 2) Provide a positive shutoff for the fuel when the engine is shut down.

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Aircraft engine fuel systems

11 cards

Card 1

Question: What are the two purposes of the manifold valve (or flow divider) in the fuel injection system of a horizontally opposed aircraft engine?

Answer: 1) Provide a constant discharge fuel pressure for idling. 2) Provide a positive shutoff for the fuel when the engine is shut down.

Card 2

Question: How does the mixture control change the air-fuel mixture ratio on the Teledyne-Continental fuel injection system?

Answer: Full rich: all fuel goes to the manifold valve. Idle cutoff: all fuel is returned to the pump inlet. Intermediate positions vary the amount sent to th

Card 3

Question: Why must the diaphragms of a pressure carburetor be soaked before flight?

Answer: Soaking restores the diaphragms to the flexibility they had when the carburetor was calibrated.

Card 4

Question: What are the two basic types of fuel controls for aircraft turbine engines?

Answer: Hydropneumatic and electro-hydromechanical.

Card 5

Question: How does exhaust gas temperature (EGT) indicate the air-fuel mixture in a reciprocating engine?

Answer: A stoichiometric mixture produces the highest EGT. The mixture is adjusted to the highest EGT, then enriched to place it on the rich side of stoichiom

Card 6

Question: What is controlled by adjusting the orifice in the fuel pump of a Teledyne-Continental fuel injection system?

Answer: The high unmetered fuel pressure.

Card 7

Question: What do the letters stamped on the flats of a fuel injection nozzle signify?

Answer: They designate the relative size of the injector orifice: the lower the letter in the alphabet, the smaller the fuel flow.

Card 8

Question: What is the function of the de-richment valve in a pressure carburetor used with an antidetonation injection (ADI) system?

Answer: When ADI fluid flows, the de-richment valve automatically closes to lean the mixture; when ADI stops, it opens and the mixture returns to rich.

Card 9

Question: What is the function of the economizer (power enrichment) system in an aircraft carburetor?

Answer: It allows economical lean operation except at full power; when throttle is opened for full power the system automatically enriches the mixture to remo

Card 10

Question: What position should the mixture control be in for starting an engine equipped with a pressure carburetor?

Answer: Idle cutoff — the engine is started using fuel from the primer system.