1/10th Electric Off Road
2 Wheel drive
This formula has exploded in popularity in the last couple of years, with club meetings being popular (typically running 5 heats) and regional meetings attracting 120 cars for a days racing.
These cars are driven by the rear wheels only, with the front only being used to supply steering. A lot of the cars are very similair in design, with most being based on the original Associated B2 etc.
The cars traditionally started with the drive motor behind the rear wheels, but it has recently become more popular in the UK to move the motor in front of the rear wheels (known as a mid motor). The mid motor seems to work better on high grip tracks with rear motor being popular when the track is slippy.
4 Wheel drive
Four wheel drive cars are slightly more complex than the 2wd cars. These cars tend to be more popular in numbers, possibly because the power available to them can typically be applied far quicker.
All off road vehicles require a servo to control steering. This is plugged into one channel of a receiver. The second channel on the receiver is used for the electronic speed controller, this allows proportional control of the motor. This means you can either move the car very slowly for corners, or flat out for the straight. Motors can be either brushed or brushless. Brushless is by far the most popular just now due to the extra power available and almost zero maintenance. Most drivers also use a third channel on the receiver for a lap counting device. These are purchased by the driver, the advantage being they are fitted to the car permanently. For those that choose not to invest in a personel transponder, the club supplied hand out transponders that must be returned after each race.
The electric power cars are typically now powered by LiPo batteries. These can potentially be dangerous if not handled correctly and therefore must be charged in a fireproof lipo sack, this helps to contain any problem. Previously cars were powered by NiMH cells, and although these could still cause problems, they typically had a problem and then it was over, unlike the LiPo cell which can last longer with an issue.
A guide to safe use of Li-Po Batteries, from the British Radio Car Association. Any rechargeable battery that is currently on the market has a risk of explosion, fire, and smoke emission if not handled properly. Despite the stories that have made the press, Lithium (Li-Po) batteries are not fundamentally unsafe, but they need to be treated with a lot more care and respect than NiCd or NiMH cells. Just because a supplier of a Li-Po battery does not label or warn of the dangers of their product does not make that product safe.
The principal risk is fire, which can result from improper charging, crash damage, or shorting the batteries, and this can be difficult to extinguish. Fire occurs due to contact between lithium and oxygen in the air. It does not need any other source of ignition or fuel to start, and burns almost explosively. A lithium battery fire is very hot (several thousand degrees) and is very good at starting additional fires that can result in loss of models, cars and other property. Homes, garages and workshops have also burned.
Here is an example of what could happen (do NOT try this):