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##  Fuel System Components 

The WSC aircraft is equipped with fuel tanks usually ranging in capacity from 5 to 20 gallons. As with any aircraft, knowing how much fuel the tank holds is crucial to fl ight operations. The LSA definition has no limitations on the size of the fuel tank, unlike its ultralight vehicle predecessor. 

Generally, the fuel tank is located close to the CG, so fuel burn does not affect the balance of the carriage. Some fuel tanks are clear for visual inspection of the amount of fuel on board  [Figure 3-50], while others have tanks that are not visible and require fuel level probes for instrument panel indication of fuel. [Figure 3-51] 

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Fuel lines exit the fuel tank, and may incorporate a primer bulb, fuel filters, fuel pump, and/or a primer system, all of which must be integrated into the carriage. A fuel venting system is also required, which can be a hole in the fuel fi ller or lines running to vent at an appropriate location. 

A fuel shut-off valve may be installed and can be located anywhere in the fuel line. Some designs have a fuel tank sump drain valve to remove water and solid contaminants. 

##  Engine and Gearbox 

The typical WSC aircraft engine can be two or four stroke, liquid or air cooled, and normally ranges from 50 to 100 horsepower. Some engines have electric starters and some have pull starters. Most WSC aircraft engines have reduction drives that, when attached, reduce the propeller rpm from ½ to ¼  the engine rpm. [Figure 3-52] 

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A significant amount of the total aircraft empty weight is determined by the powerplant (engine, gearbox, and propeller) and mounting configuration. When trailering the WSC aircraft over bumpy terrain or over long trips, the bouncing of the carriage in the trailer can put extreme stress on this mounting system. In addition, repeated hard landings of the carriage can also stress the welds of the engine mount. Consistent detailed inspections of the engine mount should be an important part of every preflight and postfl ight inspection. 

The powerplant systems are as varied as the WSC aircraft they power. Modern technology has allowed these systems to become lighter, quieter, more efficient, and, most importantly, dependable. 

##  The Propeller 

Propellers are “power converters” that change the engine horsepower into thrust. Thrust is the force that propels the aircraft through the air by pushing the WSC aircraft forward. Aerodynamically speaking, a propeller is a rotating airfoil and the same principles that apply to the wing applies to the propeller, except the propeller provides a horizontal force of thrust. 

