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## Metal Versus Plastic Fuel Containers 

There are advantages to using both metal and plastic containers. Metal cans will not allow the sun’s ultraviolet rays in to harm the fuel. It also will not develop static charges that a plastic container develops. However, a metal can is more prone to sweating when going from cool to warm temperatures on humid days. Metal cans and gas tanks are best kept either empty or full of fuel to leave no room for moist air. 

Plastic fuel containers are easy to handle, inexpensive, available at discount stores, and do not scratch the fi nish on airframes. Plastic cans also do not sweat, and do not need to be stored topped off. However, fuel does deteriorate a little faster in plastic. Also, plastic containers can get charged with static electricity while sliding around in the bed of a pickup truck, especially if the truck has a plastic bed liner. [Figure 4-19] 

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Many states now have laws prohibiting people from fi lling plastic containers unless first placed on the ground. Static electricity can also be formed by the friction of air passing over the surfaces of a WSC aircraft in flight and by the flow of fuel through the hose and nozzle during refueling, if fueling at a pump. Nylon, Dacron, and wool clothing are especially prone to accumulate and discharge static electricity from the person to the funnel or nozzle. To guard against the possibility of static electricity igniting fuel fumes, a ground wire should be attached to the aircraft before the fuel cap is removed from the tank. The refueling nozzle should then be grounded to the aircraft before refueling is begun and should remain grounded throughout the refueling process. 

The passage of fuel through a chamois increases the charge of static electricity and the danger of sparks. 

The aircraft must be properly grounded and the nozzle, chamois filter, and funnel bonded to the aircraft. If a can is used, it should be connected to either the grounding post or the funnel. Cell phones should not be used while refueling due to possible fi re risks. 

## Mixing Two-Stroke Oil and Fuel 

Two-stroke engines require special two-stroke oil to be mixed into the fuel before entering the engine to provide lubrication. In some engines, an oil injection pump is used to deliver the exact amount of oil into the intake of the engine depending on the throttle setting. An advantage of an oil injection system is that pilots do not need to premix any oil into the fuel. However, an important preflight check is to ensure the two-stroke oil reservoir is properly fi lled. 

If a two-stroke engine does not have an oil injection system, it is critical to mix the oil with the fuel before it is put into the tank. Just pouring oil into the fuel tank does not allow the oil to mix with the gas, and makes it difficult to measure the proper amount of oil for mixing. 

To mix two-stroke oil: 

• Find a clean, approved container. Pour some gas into it to help pre-dilute the two-stroke oil. 

• Pour in a known amount of two-stroke oil into the container. Oil should be approved for air-cooled engines at 50:1 mixing ratio (check the engine manufacturer for proper fuel to oil ratio for the WSC aircraft). Use a measuring cup if necessary. Shake the oil-gas mixture to dilute the oil with gasoline. 

• Add gasoline until the 50:1 ratio is reached. If using a water separating funnel, ensure the funnel is grounded or at least in contact with the fuel container. 

• Put the cap on the fuel can and shake the gasoline and oil mixture thoroughly. 

## Starting System 

Most small aircraft use a direct-cranking electric starter system. This system consists of a source of electricity, wiring, switches, and solenoids to operate the starter and a starter motor. The starter engages the aircraft flywheel or gearbox, rotating the engine at a speed that allows the engine to start and maintain operation. 

Electrical power for starting is usually supplied by an on-board battery. When the battery switch is turned ON, electricity is 

