1. What are Proportional Control and Digital Proportional?
Proportional Control means the position of the control surface in the model is proportional to the position of the control stick on the transmitter.

Digital Proportional is a computerized digital bitstream signal to the receiving device, instead of analog type pulse modulation.

2. What are kit, RTR, ARR, RTF and ARF?
A kit usually refers to an assmebly kit which you need to build the whole thing yourself and is no radio control system inside.

RTR is a short form of Ready-to-Run but can also stand for Ready-to-Ride and Ready-to-Race. It means there is little or no assembly required to operate the RC.

ARR stands for Almost-Ready-to-Run. It is essentially a kit that is mostly pre-built right out of the box.

RTF stands for Ready-to-Fly. An assembly airplane or helicopter kit that is factory pre-assembled and is ready to operate out of box without the need for any construction.

ARF stands for Almost-ready-to-Fly. A reduced size model assembly airplane or helicopter kit that is partially prepared. The kit requires some construction skill to complete and may require some alteration and adjustment to achieve completion.

3. What are Nitro, Nitro engine and 2-stroke engine?
Nitromethane often refers as Nitro which is an organic compound. It is a slightly viscous and highly polar liquid using as a racing fuel.

A nitro engine generally refers to an engine powered with a fuel that contains some portion of nitromethane. Nitro engines used for rc models are highly advanced engines that can turn in excess of 50,000 rpms. With this much movement, a lot of friction is generated and the fuel used for these engines usually contain between 12-18% oil content depending in the nitro methane percentage.

2-stroke engine is the engine which takes two strokes of the piston to complete the engine cycle. On the first stroke as the piston tavels downward, a mixture of nitro and oxygen is sucked into the crankcase, from the carburetor and travels into the induction port and finally into the combustion chamber. As the piston travels upward the mixture is compressed and ignited by the glow plug which causes the fuel to explode forcing the piston down. As the piston travels downward the spent exhaust gasses escape out of the combustion chamber through the exhaust port, and the cycle starts over by the fuel mixture being again sucked into the induction port.

4. What are the difference between Onroad, Offroad and Monster engines?
Onroad engines are designed to come into their powerband from mid to high rpm. They are normally used in onroad sedans where very high rpms and high speed is required. Offroad engines have a less abrupt power curve compared to onroad engines. Offroad engines have a powerband that extends through most of the rpm range.

Monster truck engines generate much of their torque and horsepower at low to mid range rpms. They are usually used in large and heavy trucks.

5. What are gear ratio and timing belt?
The gear ratio is the relationship between the number of teeth on two gears that are meshed. The first number in the ratio is usually the gear that power is applied to.

The term "timing belt" is used for the more general case of any flat belt with internal teeth. Such belts are used for power transmission or to interchange rotary motion and linear motion.

6. What are fail-safe and glow plug?
A device which, if (or when) it fails, fails in a way that will cause no harm or at least a minimum of harm to other devices or danger to personnel.

A glow plug is a part of a glow engine which produces the heat needed to ignite glow fuel. Glow plugs provide heat; spark plugs spark ignition in gasoline engines.

7. What are highspeed needle, lowspeed needle, idle, lean and rich?
A highspeed needle tunes how much fuel is allowed into the carburetor at mid to high rpms, and a low speed needle determines how much fuel is allowed into the carburetor at low to mid range rpms.

Idle is set by an idle screw which allows the engine to receive a very small amount of fuel to keep the engine running when the vehicle is at a stop.

Lean describes the amount of oil the engine is being lubricated with. To a point this will make the engine run faster with better performance, but once too lean the engine will overheat, and wear out prematurely due to too little lubrication.

Rich is the opposite of lean, it means more oil is entering the engine. If the engine is too rich, it will run poorly. The engine will run very slow and seem to have no power and possibly cut out from being flooded with fuel.

8. What are carburetor and crankshaft?
The carburetor also called carb for short, is a device that blends air and fuel for an internal combustion engine. The crankshaft, sometimes abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation.

9. What is displacement for an nitro engine?
Displacement refers to the volume of space a piston displaces, and implies an engine’s ability to produce thrust. It may be measured in cubic inches (cu. in) or cubic centimeters (cc). For example, a .40 size engine is with a displacement of around 0.40 cu. in.

10. What are AM, FM, AM radio and FM radio?
AM is the short form of Amplitude Modulation. It works by varying the strength of the transmitted signal in relation to the information being sent.

FM is the short form of Frequency modulation. In analog applications, the carrier frequency is varied in direct proportion to changes in the amplitude of an input signal. Digital data can be represented by shifting the carrier frequency among a set of discrete values.

AM radio is broadcast on several frequency bands - Long wave(153–279 kHz), Medium wave(520–1,710 kHz) and short wave(2,300–26,100 kHz).It has a susceptibility to atmospheric interference and generally lower-fidelity sound. AM radio signals can be severely disrupted in large urban centres by concrete bridges with metal reinforcements.

FM radio is broadcast on the bands between 87.5 to 108.0 MHz. Japan is the only exception, using exclusively its own unique 76 to 90 MHz band with 0.1 MHz channel spacing.