1. Gravity. Examples: falling sand turning a wheel, marble runs,
lines of falling dominoes, bagatell game, etc.
2. Pushing. Toy cars, etc.
3. Pulling. Young children especially like pulling a car or similar
toy behind them on a string.
4. Clockwork motor. A wound spring slowly releases its stored energy
to make something move. Gearing is used to increase the power available
(gearing up reduces power and increases final shaft speed, gearing down
increases power but reduces final shaft speed). Clockwork motors are usually
geared up as the wound spring stores considerable power, so much that
a governor is used to regulate its speed to prevent damage to both the
motor itself through excessive speed and the toy in which it is fitted.
The spring is wound either directly via a key, pulling a string or, in
the case of some types of vehicles, pressing the toy down to engage an
extra gear and then pulling backwards. Most toy springs are made from
a flat steel strip but some cheaper tin toys used a coiled spring wire.
5. Electric motor. Applied electricity causes an armature to rotate,
gearing is used to increase the power available. The toy either carries
its own electricity supply (batteries), is fed by a trailing wire from
a battery/control box or picks up its supply from an external supply via
the track on which it is running, e.g. a Scalextric car or train.
6. Twisted elastic. Mainly used to power model aeroplanes but is
also used in other toys such as simple cars.
7. Steam engine. Boiling water produces steam which is used to
move a piston inside a cylinder. The up and down motion of the piston
is converted to rotary motion by a crankshaft. A steam engine can be a
stand alone device powering other toys via drive belts or fitted with
wheels to move itself.
8. Petrol, diesel and glow plug engines. Compression ignition (diesel)
and glow plug engines work in a similar way where a fuel/air mixture is
compressed rapidly inside a cylinder by a piston. In a diesel engine the
rapid compression heats the mixture causing it to ignite (blow a bicycle
tyre up quickly then feel the end of the pump, it will be quite warm).
A glow engine uses a battery to heat up a small coil of wire in the cylinder
head, this ignites the mixture. The coil continues to glow after the battery
is removed due to the heat generated as the engine runs. A petrol engine
requires an electric spark to ignite the compressed fuel/air mixture,
this being achieved using a coil, the contact breaker (to ensure the spark
happens at the right time) and the spark plug which is mounted in the
top of the cylinder. The up and down motion of the piston in these reciprocating
engines is converted to rotary motion by a crankshaft. These motors are
mainly used in model aeroplanes but are also fitted in cars and boats.
For their size they produce a quite extraordinary amount of power.
9. Solid fuel jet engines. A pellet of fuel is fitted in a metal
casing that has a tiny hole at one end. A fuse is used to ignite the fuel
which burns producing a large volume of gas. As the gas escapes through
the small hole it produces thrust. The motors, made by Jetex, were popular
in the 1950's and 60's for powering model aeroplanes, cars and boats;
a modified form is still available today. Faster burning single use motors
of different sizes and power are currently used in model rockets (Note,
these are not Guy Fawkes' type gunpowder rockets).
10. Compressed air. A reservoir is filled with compressed air which
then is used to move a piston in a reciprocating engine. These motors
are mostly used in small model aeroplanes where the fuselage is also the
'fuel tank'. The piston is pushed down the cylinder by the compressed
air. Near the bottom of its stroke the exhaust port is uncovered releasing
the pressure. The piston continues back up the cylinder using the energy
stored in the crank and associated mechanism. When it gets near the top
of its stroke it opens the inlet valve to let in more compressed air and
the cycle repeats, the inlet valve closing as the piston starts its descent.
11. Compressed gas (CO2). Similar to 10 but carbon dioxide is the
gas (as used in fizzy drink makers). As the CO2 turns from liquid to gas
it expands greatly. This type of motor is mainly used to power small model
aeroplanes. Its advantage over compressed air is that the CO2 is usually
in liquid form so the fuel tank volume is very small, typically only a
12. Flywheel. Stored energy in a spinning flywheel is slowly released
to drive a mechanism. The flywheel is spun up to speed either by winding
a piece of string round the shaft and pulling sharply or by pushing the
toy so using the gearbox in reverse to spin up the flywheel. This mechanism
then uses the rapidly spinning flywheel via the gears to rotate the final
drive axle slowly. This type of motor is usually used in toy cars. A spinning
top is a simple flywheel as is a gyroscope.
13. Magnetism. Some toys use magnets and are based on the fact
that like poles repel and unlike poles attract.
14. Hot air. Hot air rises and if contained in a big enough container,
as in a hot air balloon, the lift generated will overcome its weight and
the balloon will rise. Another hot air toy looks like a steam engine but
without the water and boiler. These Stirling engines work on the difference
in temperatures in the engine.
15. Wind. Kites and yachts are examples of toys powered by the
16. Throwing. Good examples are balls or a 'dart' shaped paper
aeroplane where the force of the throw is infinitely greater than the
flying ability of the aeroplane!
17. Baking powder. A drop of water on some baking powder will make
it fizz. Simple toys such as a submarine use this principle to operate.
18. Camphor. A small piece of camphor stuck on the back of a tiny
boat changes the surface tension acting on the boat and makes it move
until the surface of the water becomes contaminated with a film of camphor.
Remove the boat, clean the water surface with a piece of paper, replace
the boat and it will sail again. Some tiny boats used methelated spirits
via a wick to do the same thing. NOTE, the meths is not lit!
19. Turning a handle.
20. Liquid fuel. Before electricity was generally available early
optical toys such as projectors used oil lamps as a source of light.