About Gas Powered RC Cars
Gas powered RC cars are a fun and easy alternative to electric RC cars. Gas powered RC cars do not depend on a short-lived battery pack, so while others are waiting for their batteries to charge, you will be outside having fun. With some basic information and a trip to a local hobby store, anyone can enjoy the rewarding hobby of gas powered RC cars.
-
Gas vs. Electric
-
Both gas and electrically powered RC cars have their advantages and disadvantages. Gas powered RC cars typically run longer than electric RC cars because they are only limited by the amount of fuel you have on hand. Gas RC cars can run for hours if properly cooled, while electric RC cars must have their batteries changed and recharged between runs. Electric cars are somewhat easier to maintain and are much quieter than gas cars; however, their electronics are sensitive to water, ice and snow, limiting their use in fair weather only.
Cars, Buggies and Trucks
-
Gas RC cars come in various shapes and sizes, though there are a few common vehicle types. On-road cars are a popular choice, because they are faster and more maneuverable than off-road vehicles. On-road cars have stiff suspensions and can be geared for high speed, making them a great choice if you live near wide, open expanses of asphalt and pavement. Off-road vehicles like buggies, trucks and monster trucks can be driven almost anywhere, on-road or off-road, and have long travel suspensions that allow them to handle trails, climb hills and launch off jumps. Choose a vehicle that best suits the terrain it will be driven on most often.
-
Two-Stroke Nitro Engines
-
The engines used in gas RC cars are two-stroke nitromethane fueled, single cylinder engines. The fuel used is the same fuel used in nitromethane top-fuel drag cars, giving gas RC cars loads of power. Two-stroke engines burn fuel that has an oil mixture mixed right in with the fuel, so when the fuel burns, it also lubricates the engine. Two-stroke RC engines do not have a spark plug; rather, they have a "glow-plug" that ignites the fuel mixture. Like full-size diesel engines, the glow plug is heated first by an electric "glow-plug igniter." The glow plug is then heated directly by the combustion in the cylinder, remaining hot enough to ignite the fuel mixture with each stoke of the engine. Gas RC engines come in a variety of sizes, though the most popular engines range from .12 cc - .21 cc depending on the scale of the RC car. Bigger engines have more power, but will use more fuel.
Drivetrain
-
The drivetrain of a gas RC car is much more robust than those in electric RC cars. Gas RC cars depend on a centrifugal clutch that engages the clutch bell when the throttle is opened. The clutch is made up of two- to four-clutch shoes attached directly to the flywheel/crank-shaft assembly. Each clutch shoe has a high tension spring that disengages the shoes from the clutch bell at low RPM. When the throttle is opened, the flywheel/crank-shaft spins more rapidly, causing the clutch shoes to spin outward, engaging the clutch bell and powering the drivetrain. Gas RC cars also have a disk brake incorporated into the drive train. Unlike the brakes on a full-size car, the disk brake slows the rotation of the entire drivetrain, not just the wheels. When the brake is applied on the transmitter, an electric servo closes the brake pads on the disk brake, slowing both the drivetrain and the car itself.
Tuning
-
Just like full-size cars, gas RC cars use a carburetor to properly mix fuel and air and feed the mixture into the engine. The carburetor mixes the correct ratio of fuel and air to give the car enough fuel to produce power, but not so much as to flood the engine. Some common terms used when adjusting gas RC car carburetors are "lean" meaning more air than fuel and "rich" meaning more fuel than air. If an engine is run with a "lean" fuel mixture, it will not get enough fuel (and lubrication), causing it to run hot, damaging the engine. If an engine is run with a "rich" fuel mixture, it is being flooded with fuel, causing it to lose power, run erratically and produce large clouds of blue/white smoke.
Tips
-
Read the manufacturers recommendations on tuning your carburetor, and be sure to always run a little on the "rich" side. Gas RC cars should always produce a light trail of white smoke from the exhaust. If yours is not, it is running too "lean" which will quickly damage the engine.
-
