The Hobby of Nitro Powered Radio Control Vehicles
In the beginning of nitro Radio Control (R/C) Vehicles, small nitromethane-powered (Nitro) engines originally entered the market in the 1940s. At the time, there was insufficient technology to control a nitro model car other than on a tether. Tether cars or spin dizzies were capable of speeds of 70 mph. Tether cars however could only run in a circle from the tether. In the late 1960s, the first radio control models became available, which allowed a model car to have servo-controlled steering, throttle, and brake functionality which meant that they could be remotely controlled from a radio control transmitter unit. This allowed model cars to be able to run a race track, with the ability for precise control in a similar manner as with a full sized vehicle.
Nitro Powered Engines
Nitro powered R/C's use a servo for throttle and braking control; rotation of the servo in one direction will cause the throttle on the carburetor to open, providing more air and fuel mixture to the internal combustion engine. While rotation of the servo in the other direction causes the carburetor to close while also applying torque to usually a peg which causes friction with the braking material.
Nitro R/C engine sizes often range between .12 - .21 cubic inches. Overall engine size is related to the class of car. Most 1/10th scale on and off road vehicles usually are equipped with .12 - .18 cubic inch engines, with 1/8th scale vehicles using .21 - .28 cubic inch engines. While this is most common, there are exceptions, notably conversion kits that wil allow a .21 size engine to be fitted to a 1/10th scale or a .46 size engine to be fitted to some 1/8th scales.
These nitro engines are ignited by a glow plug, a small spark plug like part that heats up instead of sparking. At first the glow plug is heated by a glow ingnitor. Once the engine is running, the glow ingnitor is removed, and the vehicle is ready to be driven.
Nitro engines allow R/C cars to reach much higher top speeds than electric cars. Maximum power is generally achieved at medium to high speeds, and a slightly slower throttle response than electric R/C's. This is because in an electric motor, the torque is instantaneous and in a nitro engine, as in a gasoline engine, it takes time for the engine to spool up and for the clutch to engage.