Pantera Scientific Information Site
A servey of model aeroplane motor types.
Model aeroplanes use more or less the same type or motors as real sized aircraft, but because of the small size, they are oftem much simpler built than their real sized counterparts.
1. Piston motors
Piston motors are divided in one stroke, and two-stroke motor, both principles are in use for models, although the smallest are nearly always one-stroke-motors.
1.1 Glow motors
In a glow motor, there is a glow-plug that is constantly glowing and that ignites the fuel. The plug has to be warmed up by electrisity beforte the motor is started. Glow motors mostly use metanol-nitro mix as fuel.
1.2. Diesel motors
In a diesel motor, the fuel-air-mixture is ignited and detonated when the piston compresses it to a high pressure so that it gets very warm. Diesel motors was once popular for model airplanes, but is not used less by now.
1.3. Gazoline motors
In the gas (gazoline, petrol) motor, the fuel is gazolinean it is ignited by a spark plug. These moters are mostly used in greater models.
2. Wankel motors
Wankel motors for hobby models use glow-plugs for fuel ignition and use metanol-nitro mix as fuel.
3. Turbine motors In a turbine motor, air and fuel is mixed, and the combustion makes a great pressure. The rear end of the chaber is open so that only the pressure at the front end of the chaber has an effect upon the motor, and therefore this pressure is throwing the motor and aircraft foreward. The motor has a pivot going from one end to the other. In the front end of the pivot there is a fan that presses the air into the motor. At the part of the pivot situated in the combustion chaber, there is another fan that the pressure in the chaber drives
3. Electric motors
An electric motor for aircraft models is driven by batteries, of which these types are on the market:
Nicad batteries (NiCad)
Nickel Metal Hydride batteries (NiMH)
Lithium Polymer batteries (LiPo)
Lithium Iron Phosphate and A123 (LiFePO4)
These motors are usually direct-current motors. They have a rotor on the axis with rotating magnets and a stator with magnets around. One of these magnet assemblies, usually the rotor, is an electromagnet while the other consist of permanent magnets.
The magnets attract each other so that the anchor goes around until the fields in the anchor and the stator are aligned.
There is also an alternator arrangements that shifts the direction of the current, with that the magnet polarity, and hence the power of one of the magnet assemblies each time the position of the magnets are so that the magnet fields are in the same direction in the two assemblies. Then the magnet fields get in opposite directionand the rotation contimues.
The alternator can be mechanic consisting of rotating electrodes on the rotor and brushes touching these electroes, or it can be electronic.
It is also possible to make alternating current motors for aircraft models where an electronic alternator makes that kind of current.