FAQ for R/C electric off-road racing


[Document Version: 1.01] [Last Updated: Oct_8_1995]

1. Introduction

  1.1) About the Author

Author: Mark R. Brown
E-Mail: mbrown@OpenMarket.com

This document is meant to answer basic questions about R/C electric off-road racing. My aim is to help people get started in the hobby.

I'd like to keep improving this memo. If you have a basic question that isn't answered here, please send the question to me. I'm happy for anyone to reproduce the entire memo freely provided they don't alter it. Some newsreaders can't deal with a posting this long (around 100,000 bytes); I will email the FAQ to you on request.

This memo is full of my personal opinions, based on experiences in five years of racing. Your opinions may differ. My employer doesn't have any opinions about R/C racing; I don't work in the R/C hobby industry and I am not sponsored by any hobby shop or manufacturer of R/C racing equipment.

  1.2) What is R/C electric off-road racing?

R/C electric off-road racing is a scaled-down version of the Mickey Thompson off-road "stadium races" that many people have seen televised on ESPN. Racing takes place on a closed dirt course featuring a variety of turns, jumps, bumps, and straightaways. Because the races are run on dirt the racers brake- and power-slide through turns, and a certain amount of bumping goes on among the cars. The two most prevalent classes in R/C electric off-road racing in the USA correspond directly to two Mickey Thompson classes: R/C buggies are scaled-down Super 1600 open-wheel racers, and R/C trucks are scaled-down Grand National trucks.

Although R/C electric off-road racing resembles Mickey Thompson racing, R/C electric off-road racing actually came first. R/C electric off-road racing was born when Tamiya, a Japanese model manufacturer, created its radio-controlled model dune buggies, the Rough Rider and Sand Scorcher. These models were not designed for racing, but "mini-Baja" competitions soon developed in Southern California. Mickey Thompson's idea of bringing Baja-like competition to a stadium came years later.

R/C electric off-road racing really came into its own with the introduction of the Associated RC-10, the first buggy engineered well enough to survive the rigors of competition. Improvements to racing technology have continued year after year, making it easier for newcomers to come up to speed.

R/C electric off-road racing is less expensive and safer than full-scale automobile racing, but just as real. Winning requires a combination of skills: building, set up, and driving. Nearly any tuning parameter available for setting up a full-size racer is also available in R/C electric off-road racing. Organized R/C electric off-road racing events now take place at the local, regional, national, and world levels.

  1.3) How do these cars differ from what I can buy at Radio Shack?

An R/C electric off-road racing car bears some resemblance to an R/C toy that you can buy at Radio Shack. Both are radio-controlled, are powered by an electric motor, and use a rechargeable battery.

At a deeper level there are big differences. The racing car has a four-wheel independent suspension, oil-filled shock absorbers, and fully proportional steering, throttle, and brake. The racing car goes much faster and is built to survive high-speed collisions. When the racing car breaks, replacement parts are available so you can always fix it without replacing the whole thing.

  1.4) What other classes of R/C racing exist?

If a type of auto racing is done with full-size autos, it is probably done in a scaled-down version via R/C. Paved oval, dirt oval, road course, drag race, truck pulls, monster truck car-crushing, ice racing, ... you name it, people do it.

This memo deals specifically with R/C electric off-road racing in the USA. You may find that some of the information here applies to other forms of R/C electric racing, to gas powered (really fuel powered) off-road racing, and to R/C electric off-road racing in other countries.

  1.5) What are the pluses and minuses of R/C electric off-road racing compared with other classes of electric R/C racing?



  1.6) What are the pluses and minuses of electric versus gas power?

Electric power is both reliable and easy to use, and electric racing is much more prevalent than gas racing. For these reasons alone, electric power is the only way to go if you are a beginner interested in racing.

As you get experience in racing you will form your own opinion about gas power. By all means attend some races and drive some cars if you get the chance. In my opinion gas power is wonderful for outdoor road racing. Gas powered road racing cars travel at 70 MPH (actual), and major races last an hour with short refueling stops. Clubs exist all over the USA to race 1/8 and 1/10 scale gas road racers. I believe that fuel is less well matched to off-road, largely because of the high maintenance created by mixing oil and dirt. Manufacturers are trying to generate interest in 1/8 and 1/10 gas off-road racers, but with only modest success (as measured by actual racing activity) so far in the USA.

  1.7) How are races run?

In the USA, off-road races are four minutes long. In the rest of the world (and in international competitions held in the USA), the standard is five minutes. Even five minutes is not a long time, so bad luck or bad driving early in the race can put you in a seemingly hopeless position. But anything can happen in racing. At the really big races they run the main event (top ten drivers) two or three times and combine the results to determine the overall winner.

Generally there are more entries in a given class than can run together on the track, so there is a qualifying phase followed by the main events. Qualifying is done by dividing the entries into qualifying groups, then having each group run some number (often two or three) of races. A driver gets some score for his performance in each race; drivers are then sorted into main events according to their best qualifying race score. The "A" main contains the ten (or eight, or whatever the track will bear) top qualifiers, the "B" the ten next, etc. Everybody runs a main event.

The most common system is to run each race to the time limit, then it is "finish the lap you're on." The score is a number of laps and an elapsed time. For instance, ten laps in four minutes, four and three-tenths seconds -- written 10/4:04.3. You want the most laps and then the shortest time.

The technology used in timing off-road races varies a lot. For small races you can do it by hand with a sheet of paper, using a watch for timing the last lap to the nearest second. These days it is more common is to use a program running on a PC, with an operator to punch in the car number each time a car goes by. The most common system uses radio transponders to count the cars automatically. Transponders are not preferred over a good human operator, except at big competitive races when the tenths of seconds count during qualifying, because transponders are less reliable than a good human operator and fussing with transponders always slows down the racing program.

Another system is sometimes used when no timing computer is available. In this system the track is divided into some number of sections, say ten. The race runs four minutes; during the four minutes somebody counts laps by hand. When the four minutes are up, you stop your car and count the number number of sections. The score is the number of laps and the number of sections. You can run a fine race using this low-tech method. The main drawback of this method is that it doesn't produce lap-by-lap results at the end of a race, so it doesn't help you understand why you finished where you did (were you slow every lap, or did you have a couple of very slow laps due to crashes?) and it doesn't permit easy correction of lap counting mistakes.

When there's only going to be one main in a class, it may seem silly to run all the qualifiers just to determine the starting grid for the main, but that's how it is done. Even when there's only one main, the qualifiers give people a chance to work out their set-ups and generally have fun. And being on the pole can be a big advantage in the main.

Some tracks run the mains on a bump-up system. Rather than filling the mains strictly according to qualifying scores, the race director leaves one or two spots open in each main except the lowest. Then the top one or two finishers in the lowest main start at the back of the next higher main, and so on up through the "A" main. This system is not often used in big races because it takes extra time for the bumped-up cars to get ready.

At some tracks the heats are not packed as tightly as the mains - say 8 per heat and 10 per main. Really small heats are bad because the drivers from one heat are the turn marshalls for the next heat. A small heat means poor turn marshalling or delays in trying to scrape up volunteers.

If the track has narrow lanes or is very short then it will usually run fewer drivers per heat and also in the mains.

Prizes vary a lot. Some places give hobby shop certificates as prizes -- you can buy a new set of tires (or make a down payment on a set) if you win. Other places give plaques or trophies. Sometimes the only prize is bragging rights until the next race.

A typical entry fee these days is around $8-10. Often there is a discount for the second class you enter, so it might cost $14 or $17 to run both a buggy and a truck, or to run one buggy or truck with both stock and modified power.

  1.8) How is racing organized at a national level in the USA?

There are two national sanctioning bodies for electric off-road racing: ROAR and NORRCA.

ROAR is the original, largest, and most powerful sanctioning body. ROAR's power derives from its membership in IFMAR, the international sanctioning body for R/C racing. Because ROAR is a member of IFMAR, ROAR has a voice in setting international rules, and ROAR has control of US entries in international championship events. Internal struggles and mismanagement have reduced ROAR's effectiveness over the past five years. The current ROAR president is Mr. Bob Novak of California, founder of Novak Electronics; he is trying to get ROAR back on track.

NORRCA is run by Mr. J.R. Sitman of California. He casts NORRCA as the organization that cares about racers, in contrast to ROAR which (in this view) cares more about equipment manufacturers and their financial well-being. Certainly NORRCA has been more innovative than ROAR over the past several years. NORRCA has created racing classes that separate pro drivers from the average guy, and recently has experimented with tire limits at major events to hold down costs. NORRCA's national championship events are considered less important that ROAR's national championships, but major teams contest them both.

  1.9) What's the difference between stock and modified classes?

The stock class is meant to give all cars limited and approximately equal power at low cost and low technical sophistication. When these goals are met, the result is an interesting class of racing that's very accessible to beginners. The cars are easier to drive because of the limited power, and with equal power the emphasis shifts to setting up the car and driving clean lines.

In the early days of racing, the Mabuchi 540 was the stock motor. If you ran a six-cell battery pack and a Mabuchi 540, you were legal for stock class. The Mabuchi 540 had limited power and was very easy to use -- it did not allow much if any "tuning". You would just bolt it in and run.

Today's stock class is not so simple. There are many stock motors to choose from, and these motors allow tuning through the replacement of brushes and springs. The motors are much more powerful than a Mabuchi 540 but have a correspondingly shorter life. And because of advancing technology driven by the economic competition between motor manufacturers, a stock motor can become obsolete overnight.

So it is apparent that in many ways today's stock class is inferior to the original. Yet it is still the best class for beginning racers, so you need to understand it.

To run in stock class, you must use a ROAR stock motor and a six-cell battery pack. A ROAR stock motor

  1. has an armature that spins in bushings (not ball bearings),
  2. has a non-removable endbell,
  3. has an armature with at least 27 turns of wire that's no larger than 22 gauge, and
  4. has at most 24 degrees of timing advance, with a motor design that makes it difficult to alter the timing.

(These are the main points; the actual rules are considerably more detailed.) A ROAR stock motor has "ROAR 91" stamped on the can near the mounting holes. ROAR stock motors are used in both ROAR and NORRCA sanctioned events.

A key restriction on stock motors is the non-removable endbell. This feature means that the armature cannot be removed from the can for servicing when the comm goes out of round, as it will after four or five runs in competitive racing. A stock comm lathe will true a stock motor's comm while it is still in the can; however the use of stock comm lathes is illegal at ROAR events. (Your local track may be less picky, even if it demands the use of ROAR motors.)

Some tracks allow "outlaw" stock motors in their stock class racing. These are typically motors that resemble ROAR stock motors in having bushings and a non-removable endbell, but violate ROAR rules in some other way -- usually by having more timing advance. Outlaw stock motors became popular when ROAR's timing restrictions first went into effect, because the first crop of 24 degree motors gave lower performance than the stock motors they replaced. Also, NORRCA didn't embrace the ROAR rules at first. But today's ROAR stock motors are much higher in performance than any of the old stock motors, and NORRCA has unified its stock motor rules with ROAR, so there is little excuse for the continued use of outlaw stock motors.

  1.10) What is the atmosphere like at races?

R/C car races generally have a fun, relaxed atmosphere. Even at big events most people don't take themselves too seriously. The racing is competitive, yet most racers are not secretive -- if you ask, they will tell you exactly how they've got their rides set up. (Often they will tell you even when you haven't asked.)

Most race venues have strict rules against the consumption of alcohol and illegal drugs on the premises, and against any sort of abusive behavior.

  1.11) Is this a hobby suitable for young children?

The driving part of R/C electric off-road racing is definitely suitable for young children. The building and maintenance part of racing is not so suitable, due to the limited attention spans of youngsters. If somebody older can be the pit crew, the child can be the driver. At the age of eleven or twelve the child can start taking on more of the pit jobs.

Organized racing is competitive in nature. Some kids would rather play than compete. The Tamiya 1/14 scale QD (quick drive) series of cars and trucks are a good choice if the goal is recreation rather than competition -- good performance, rugged, long run times. They are a step up from what you'll find at Radio Shack, for about $100 (includes everything needed except batteries and charger.) If you are getting into racing but your child isn't ready, think about getting the child a Tamiya QD. A race car would be overkill.

  1.12) How do I find a place to race, and how do I learn more?

One way to find a place to race is via the Internet newsgroup rec.models.rc. This newsgroup includes racers from all over the USA and the world.

Try calling local hobby shops to find shops that know about (or preferably sponsor) racing.

Radio Control Car Action magazine is the largest-circulation magazine on the R/C car hobby in the USA. Every other month it includes a track listing with tracks all over the USA. There are three other smaller magazines on R/C cars in the USA, and more in other countries around the world. I've seen locally-produced magazines in England, France, and Italy.

By far the best way to learn more is to find a race track and show up during a race. Wander around, look at what's going on, and ask questions. Most racers are happy to share what they know.

Please check attribution section for Author of this document! This article was written by filipg@repairfaq.org [mailto]. The most recent version is available on the WWW server http://www.repairfaq.org/filipg/ [Copyright] [Disclaimer]