Radio Controlled Model Car racing started over 30 years ago and has grown throughout the World. Produced mainly in Japan to begin with ,now it is probably bigger in the USA. Many other countries have also made significant contributions, including our own Cecil Schumacher (no relation to Micheal) of Schumacher racing Northampton, inventing the ball differential that we have all come to know.
Hints And Tips
Radio interference crops up at every meeting whether it be a National Meeting or a Club meeting we have lost count of the number of times we have been informed by a driver " there's someone on my band /crystal or frequency". If only some drivers took a little more care when building and setting up the Car many of the problems would never arise. ie:
When servo's, receivers, speedo's, Motors are fitted make sure they are secure and don't bounce around inside the car, Route the aerial lead from the receiver away from servo's and speed controllers, never ever shorten the aerial wire its meant to be that long "it is a tuned length". If it is longer than you would like it to be coil it up and tape it inside the car keeping the coil as large as possible.
Make sure to fit the suggested suppression to the motor,the correct capacitors are usually supplied with the motor if you need to join wires make sure they are soldered properly and insulated preferably with 'heat shrink' The only way to connect motor wires is to solder them,make sure all of your connectors are a good reasonably tight fit when plugged together.
Crystals are fragile items than can easily get damaged ,keep them in a foam lined container to protect them Always make sure they are correctly marked with the frequency number and marked RX for receiver( in your car) or TX for transmitter( in your hand set) Be very careful not to drop your transmitter and always make sure the batteries are fully charged before attempting to race,otherwise the range of you transmission will be reduced causing you to lose control at the farthest point of the track from the rostrum. The telescopic aerial on your transmitter can get damaged very easily, make sure you push it back in from the bottom, not from the top pushing from the bottom will allow you to retract the aerial without bending it.
MODIFIED / STANDARD/ MOTORS
From the very beginning drivers have always been in a rush to go faster and faster, and the usual method is to rush to your local model shop to buy the hottest motor they can supply. Many Drivers cannot fully control a model car with all standard gear let alone one that goes at least 3 times as fast. So before you "GO FASTER" can your speed controller withstand the extra amps you'll be putting through it? If you go faster your car will not run for so long, and think - if you are going Mega fast and you crash, the damage to your car could be far worse than if you were going slower. Do you really want bigger repair bills and the hassle of maybe completely rebuilding your car after one mistake. If everything is set up properly (i.e gears meshed properly, belts not to tight, bearings all clean and running freely, batteries properly charged) you'll probably find that you keep your car on the track ,and you'll probably beat the driver with the fast motor that is the fastest thing on the track between crashes and is unable to take part in his next heat because he needs spare parts he hasn't got .
BOOKING IN TO MEETINGS
When ever you decide to book into a race meeting be sure to be as helpfull as you can - make sure you fill in all the details asked for on the entry form truthfully, especially your ability/grade. When entering Crystals/Frequencies try to put them in numerical order
ie: 40 Mhz 40.665 40.675 40.995 or 27 Mhz Grey/Brown. Brown . Brown/Red. Red etc
Below are the recommendations from the British Radio Car Association (BRCA) Electric Board on how to take care and look after your cells.
BEST PRACTICE FOR USE OF NIMH (NICKEL METAL HYDRIDE)CELLS
1. Equalise cells before charging if they have been stored (with charge) for more than 2/3 days. If any of the cells in the pack show that they do not need to be equalised (i.e. the light does not show or goes out straight away) then remove the pack from the equaliser and charge for a short period (approx. 5 mins should be adequate). Then carry out the equalising process.
2. Never exceed the manufacturers recommended fast charge rate. This should be 1C max., even if the manufacturer states higher. (C being rate of charge based on capacity of the cell, e.g. a 4200 mAh cell = 4.2 amps)
3. Disregard any charge rate recommendations be the matcher if it is more than 1C.
4. Use a maximum Delta-peak setting of 3mV per cell (6-cell pack = 3mV x 6 = 0.0I8V).
5. Never repeak cells after main charge.
6. Use a temperature cut out as an additional safety feature set at 42 deg. C Max, located on the hottest cell (usually the middle cell_. If charhing on a cold day then consider reducing this to around 35 deg C.
7. Allow cells to fully cool to ambient temperature before further charges. Be aware the centre of the cell cools slower than the outer casing. Do not put them in water to cool down; in an emergency cover the cells with a damp/wet cloth if you have to quickly cool them.
8. Store cells with some charge (30/50%)
During the past year, the use of LiPo batteries for “club” racing has become more popular, as this type of battery technology allows competitors to cope easier with short intervals between races.
Previously, the Electric Section within the BRCA Electric Board has not allowed the use of LiPo cells at any of their sanctioned events.
At the 1/10th Touring Car Section AGM in October 2007, this section decided to allow LiPo cells to be used in a support class at their national events for 2008. Obviously with this cell technology being new at BRCA events, there is a lot to learn.
The BRCA Electric Board have compiled some basic guidelines regarding the safe use of LiPo cells and a set of basic rules to enable the Touring Car Section to have a degree of control on what cells are allowed at their events.
The following guidelines and rules are not a definitive copy “set in stone” and may be subject to amendments as the racing season progresses and more information is gathered. The BRCA Electric Board requires that all competitors that intend using LiPo cells study the following advice and operate strictly within the guidelines below.
A GUIDE TO SAFE USE OF LIPO BATTERIES FROM THE BRCA
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 MiMH 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.
These warning cans be a little scary and they should be as Li-Poly packs can be very dangerous if not handled correctly. However, please try and keep this information in perspective. Kitchen knives and chip pans can also be very dangerous if not handled properly and there will probably be more injuries caused by scalpels or super glue in eyes than batteries. The following precautions should help you enjoy using Li-Po batteries without having a major incident.
- Only charge Li-Po batteries on a charger specifically designed for Li-Po batteries. Li-Po chargers are available at varying prices depending upon the features, for the same price as, or lower than NiMh chargers.
- Always ensure you use the correct charging voltage for the cell count. This will be 7.4v (2S) for car packs.
- The maximum charge rate should be 1C, e.g. 3.2A for a 3200mah, pack and peak voltage must not exceed 8.4v. For best charging low charge rates should be used where possible.
- Double check the charge voltage (or cell count), mah, and current before each charge.
- Never leave charging Li-Po cells unattended (at any charge rate).
- It is best to charge Li-Po cells in an open space on a non-flammable, not conducting surface (such as a bare cement floor, brick or quarry tile) and away from flammable materials.
- Check your charge for safety. After charging, check the battery with a digital voltmeter, the voltage for a fully charged pack should be between 8.32V to 8.45V.
- Do not charge the battery inside your model, inside your car, on home furniture or wood floor/carpet, or anywhere near flammable material.
- The minimum safe discharge voltage is 5.0V (2.5V per cell) when under load, or 6.0V (3.0V) per cell when not on load.
- A number of the electronic speed controllers have a Li-Po feature built into their software; make sure that this has been enabled. Otherwise consider fitting a Li-Po cut-off device. Failing that, stop driving when the motor loses power, remove the battery from the car, and recharge it.
- If using a Li-Po receiver pack then will need to use a 6V regulator, which will supply enough current to your radio equipment.
- Use connectors that can not be short circuited, or use silicon fuel tube to protect exposed connections. Under no circumstances should the ESC wires be soldered directly to your battery.
- Do not short the battery as it may catch on fire. If you accidentally short a battery, place it in open space and observe the battery for 10 minutes. It may swell up and possibly even catch on fire.
- Have a dry powder extinguisher or a bucket of dry sand within reach on case of a fire.
Cell balancing is a way of ensuring your Li-Po will deliver the maximum performance and capacity over a prolonged period of time, although some manufacturers claim that it is not required with their batteries.
Li-Po packs are deigned for operating temperatures at 40 degrees and under no circumstances must they become hotter than 60 degrees.
You may need to add weight to your car to balance it and/or reach the minimum legal weight.
If a pack is involved in a crash or is otherwise damaged, remove the pack from the model and inspect for damage to the pack and the wiring/connections. Lithium polymer batteries do not have a hard steel case like a NiMH battery. Instead, a special aluminium foil encloses them. Therefore, they do not vent. If the integrity of the battery is compromised, swelling will occur. If the battery is damaged and the case begins to expand, discontinue use immediately.
For use in the Touring Car Pro-Stock Class Only
- Lithium Polymer (a.k.a Li-Poly/LiPo) battery packs must have a hard, protective case that completely envelopes the cell(s). The maximum case size is as follows Length 139mm Width 47mm Height 25mm (Height excludes the moudlings on the bottom of the case that help locate the battery pack in the car)
- The maximum retail price for the year stating 1st Jan 2008 is £80.00
- Individual cells used in the consuction of the barrery shall be rated at 3.7 volts nominal and the pack shall be 2 cells in series.
- The battery pack shall have leads extending form thje case for the positive and negative electrical connections using wire of adequate size to handle discharge rates acceptbale to racing applications. Alternatively, the case shall have external connexction points for those wires clearly marked positive and negative so the user can apply lead wires.
- The case must have the original suppliers label intact, stating the rated voltage and the pack capacity. Maximum capactiy is 5,000mah. The brnad name/logo shall be easily readable.
- For 2008 there will be a rolling homologation list (as per motors).
- All Li-Po packs must be charged with a Li-Po capable charger using the industry standardCC/CV (Constant Current/Constant Voltage) charge profile.
- LiPo batteries may be charged to a maximum of 8.40V +/-0.04V. Overcharging is a serious safety hazard and will not be tolerated.