There are many springs used on radio controlled model cars, but all are variations on a few basic types. In this article that is part of our Fixings section we are going to show examples of the most common ones and give details of how they work.
Future articles may go into more details about the different applications of these springs on the various different parts of a model car.
At a basic level, a spring is any device that is capable of storing energy, either on a temporary basis or a permanent one.
The physics behind them is fairly straightforward; Applying a load (weight) to will deflect (move) the spring and removing the load will cause the spring to return to its former position. The practical side of springs is that a load applied has to be within the design tolerances as otherwise it will cease to return to its former position.
The ability of springs to store energy, which is ordinarily movement, provides the means to do many things as they can be quickly and easily made into many different shapes and sizes by the manufacturer.
Note: The springs featured in this article are are all made from a hardened and tempered material (usually steel) - we don’t intend to cover such as air springs, as they are not (yet) used on R/C model cars.
The red arrows in the illustrations below show the direction of the force/movement.
As mentioned above, there are many different types of springs used in/on the different parts of model cars and, whilst we cannot hope to cover each and every variation, we can classify them into their basic types.
By far the most popular spring used on model cars is the coil spring and this type of spring is made from a length of (usually) round steel wire that is formed into a series of loops that allow for movement to take place.
This category of spring is further subdivided into Compression Springs and Extension Springs.
Compression type springs are, as their name suggests, used in situations where the movement energy is acting to compress (squash) the spring.
You will most probably be familiar with this type of spring as it is used all but exclusively on model car shock absorber assemblies to store the movement that bumps and weight transfer cause. As this in an important aspect in understanding model cars, a future article will be devoted entirely to suspension springs.
Other uses of this type of spring would be their use in control linkages between Servos and engines/motors to provide override and return facilities.
Extension or, as they are sometimes referred to, tension springs are used where the movement energy is acting to extend (stretch) the spring.
They are not used as extensively as compression type springs and are sometimes used as return springs. Their most common usage, though, is to hold exhaust systems either together or to the engine.
A further example of an effective use for them is shown in our Model Car Plastic Bumpers - Curing the Droop article.
The next category of spring is the torsion spring and are used in situations a few different situations depending on the requirements of the application. Basically, though, they store the movement energy by the twisting of the spring in different directions.
The most familiar example to many model car drivers is the anti-roll bar (swaybar). As you can see from the illustration to the left, the forces act on the spring to try and twist it in different directions.
As with the use of compression springs in model car shock absorber assemblies mentioned above, we may produce an entire article about the different types of anti-roll bars at some point in the future.
Our second example of a torsion spring is not a very common one, but serves to show the different applications of this category. The illustration to the right shows a spring that was successfully used on some of the PB Racing range of model cars for quite a few years.
It was used as a suspension spring and pivoted the movement forces on the ends of the spring by having a suspension pivot passing through the central loop of wire.
There are other types and variations on the springs shown above and these would include leaf springs (shown right), but as these are reserved for use in one-off custom projects (e.g. on the webmasters alloy trailer) we needn’t go into any specific details.
Other examples of the spring categories previously explained are shown below.
Although not the main focus of this article, the below are springs in their own right and are worthy of a brief mention.
Spring washers (right) are sometimes used on model cars and are springs which store the energy used to tighten the nut or bolt they are under.
Whilst you may possibly not class star washers (left) as springs, they are, in some respects, an improvement upon the spring washer mentioned above, but are frequently abused by being tightened to the point the spring type material they are made becomes totally flat.