Model Forum / Radio Controlled / Land Models / July 2004

This is the most recent I found on google groups, so here goes:  I did make a
single change, regarding my archive at ripperd.com of the binaries group.  I no
longer use ripperd2.dhs.org, and it contains a placeholder forwarder so the FAQ
needs to get updated in this respect. I updated the last-modifed date also.

=========BEGIN FAQ====================================

Archive-Name: models/rc-cars/newbie-guide
Posting-Frequency: monthly
Last-Modified: 26 July, 2004
Disclaimer: Approval for *.answers is based on form, not content.
The most recent version of this FAQ list is posted by the author monthly to
the Usenet groups <news:rec.models.rc.land>,
<news:uk.rec.models.radio-control.land>, <news:rec.answers>, and
<news:news.answers>.
Several servers around the World Wide Web, NONE of which are maintained by
this author, store a copy of this document. It can be obtained by anonymous
ftp from <ftp://rtfm.mit.edu/pub/faqs/models/rc-cars/newbie-guide>; or by
e-mail: <mail-server@rtfm.mit.edu>, the body of the mail must contain the
command "send /pub/faqs/models/rc-cars/newbie-guide" without the quotes. A
relatively decent HTMLized version of this document can be found at
<http://www.faqs.org/faqs/models/rc-cars/newbie-guide/preamble.html>. For a
complete list of world wide mirrors, see the document "Introduction to the
*.answers newsgroups", which is posted frequently to <news:news.answers>; or
retrieve it through e-mail by sending <mail-server@rtfm.mit.edu>, with the
command "send /pub/faqs/news-answers/introduction" without the quotes.
The official home of this document is maintained by the author at
http://www.wildhobbies.com/newbie-guide.html.
------------------------------
TABLE OF CONTENTS
0. Preliminaries and Introductions
   0.1. What is this?
   0.2. What other FAQs are there?
   0.3. What will you NOT find here?
   0.4. Usenet
   0.4.1. NETiquette
   0.4.2. Posting binary attachments
   0.4.3. Posting sales / auctions
1. What car should I get first?
2. What radio should I get first?
3. What motor should I get first?
4. What other stuff will I need?
5. What else do I need to know?
   5.1. Ready to Run - RTR
   5.2. The controlling bodies of R/C racing
6. What about batteries?
   6.1. Battery care
7. What are the different types of cars?
8. What are the different kinds of radios?
   8.1. What is all this stuff on the radio?
   8.2. Radio interference
   8.3. Using a 4-channel radio with a car
   8.4. Too much Information on radios
9. What about motors and stuff?
   9.1. How to speed up electric motors?
   9.2. Brushless motors
   9.3. Speed controllers
   9.4. Gear ratios
10. Painting
11. Some useful links
12. Links to links to manufacturers and stores
13. Legal frequency - channel tables
14. Document Changes
15. Legal jargon
------------------------------
0. Preliminaries and Introductions
I am Kerry Garrison and I have just taken over the maintenance of this
document. This is no small task considering what has to be done every month
to keep it posted to all the right groups. Please bear with me as I get the
hang of this. Who am I? I am the publisher of WildHobbies.com
(http://www.wildhobbies.com) which is an online magazine. A discussion forum
on WildHobbies exists to discuss changes, additions, and deletions to this
document.
0.1. What is this?
Answers to some common questions and some suggestions for people wishing to
join, or just starting out in, the remote controlled (R/C) cars hobby.
Contains information useful for beginners, as well as directions where to
get additional information.
It is an attempt at collecting / organizing / sharing some of the
information (dare I say 'wisdom'?) that I have managed to acquire since I
got involved in this hobby. At the time I took over maintaining this
document, I had been involved in the hobby for several years, race on a
regular basis in both electric and nitro and off-road and on-road. I have
also been publishing WildHobbies.com online magazine for several years. This
is not meaning I am the end-all beat-all expert and I often defer questions
to people much more knowledgeable than myself.
0.2. What other FAQs are there?
First off, let me stress that in no way do I intend for this document to
replace or supercede any other FAQ on this or similar subject found anywhere
else. Different people have different experiences / opinions, and those are
generally relayed through their FAQs. I recommend that you have a look at
all that you can find, in order to gain as much practical information as
possible.
Further, almost every single manufacturer that has a web site has some type
of FAQ or some variant of "Getting Started in R/C" type of document; those
are just way too numerous to list, and, unlike me, they have an actual
advertising budget. Therefore I will not list any of those here - see the
section "Links to links to manufacturers and stores", below.
There are, however, a few FAQs maintained by individuals, such as myself,
whom I would consider more 'my competition'; although AFAIK mine is the only
one posted to Usenet. Here are the ones I have been able to find so far:
FAQ for R/C electric off-road racing
<http://www.geocities.com/MotorCity/2314/rc-faq.html>
The rec.models.rc.land Frequently Asked Questions archive
<http://burnt-kat.streetracing.org/rcfaq.html>
0.3. What will you NOT find here?
The original author of this document has never touched a gas R/C car and
thus currently contains no information specific that nitro at this time. As
the new author, I will begin to include relevant information.
I do not want to have specific car reviews and comparisons. Further, I do
not intend to address questions of the type 'car A vs. car B, which is
better?' A better question would perhaps be 'car A vs. car B, which is more
popular?', because it is often a popularity contest! But the answer to this
you will not find here either, since within a year BOTH car A and car B will
be replaced by something new and more popular.
See "What car should I get first?", below, where to get this information.
0.4. Usenet
When I got involved in this hobby, one of the first places that I went to
was the Usenet. Surely, no surprise, there is a newsgroup dedicated to this
hobby. If your computer is set up properly, then you should be able to go to
the URL <news:rec.models.rc.land> and just start reading. Alternatively, you
could go to <http://groups.google.com/groups?group=rec.models.rc.land>; this
place has an archive of older postings, much older than what your news
server probably carries, so it is an excellent resource for searching past
information.
If you got this document through means other than Usenet, and want to find
out more about it, a good place to start is
<http://www.geocities.com/nnqweb/>.
There are several R/C Usenet groups of similar interest; the descriptions
are not mine, they are taken directly from the group's charter (bad
formatting and spelling error included):
<news:rec.models.rc.air> RC controlled air models.
<news:rec.models.rc.helicopter> Model helicopter flying, construction, and
tips.
<news:rec.models.rc.land> RC controlled land models.
<news:rec.models.rc.misc> RC controlled miscellaneous items.
<news:rec.models.rc.soaring> Building and flying radio controlled gliders.
<news:rec.models.rc.water> RC controlled water models.
<news:alt.binaries.radio-control> Newsgroup for radio contol related
binaries (software and pictures).

Most countries have a Usenet hierarchy of their own. There might be a group
specifically for local discussions. For example, United Kingdom has the
following groups:
<news:uk.rec.models.radio-control.air> UK Radio Control Aero Modelling
<news:uk.rec.models.radio-control.land> UK Radio Control Cars, Buggies,
Trucks

Before you start posting to any of these groups, there are some things you
should be aware of:
0.4.1. NETiquette
There are certain assumed rules when posting to Usenet. If you break these
rules, you will be mercilessly ostracized by the rest of the group. If you
are not familiar with this 'code of conduct' there are numerous articles on
the subject. One good one is at <http://www.lynnsland.com/Netiquette/>; a
second source of numerous articles is at <http://www.faqs.org/faqs/usenet/>.
If you still have questions or doubts, then the appropriate place to ask is
in <news:news.newusers.questions>.
The denizens of rmrl are willing to tolerate off-topic posts, as long as
they are marked with "[OT]" in the Subject. Every so often someone suggests
(mostly as a joke) starting a rec.models.rc.land.ot group. If you don't like
them, create a filter; if you do post them, please mark them in the Subject!
The sad truth is that a lot of people have problems expressing themselves
through the written word; I myself am certainly no expert. Further, a lot of
people easily take offence. Please keep both of these points in mind when
you are reading or writing posts, and take everything with a 'grain of
salt'.
There are a lot of acronyms that are used throughout the Internet,
especially on Usenet. Try here for a little help:
<http://www.gaarde.org/acronyms/>.
0.4.2. Posting binary attachments
No! I will attempt to justify this, but make no mistake; the answer is a
definite no!
Binary attachments are normally restricted to the Usenet hierarchy
alt.binary.*. This is done so that people who do not wish to receive binary
attachments can easily avoid them. These people often include system
administrators with limited disk space, and users with a slow Internet
connection such as a dial up modem. If people post binary attachments in a
non-binary group, they will quickly get alienated by that group. If a lot of
people post binary attachments to a non-binary group, then system
administrators will simply stop carrying that group and the group will die.
If you insist on distributing binaries, the correct procedure is to find
diskspace someplace on the Internet - there are plenty of sites that offer
this sort of a service for free - and then post a link with an appropriate
description to rmrl. Alternatively, you could post the binary to
<news:alt.binaries.radio-control>; just keep in mind that most servers set a
very low expiration time for all binary groups, usually on the magnitude of
a few days. This means that very few people will get to see your post. A
private archive of binary postings can be found at
<http://www.ripperd.com/alt.binaries.radio-control/>.
HTML messages (almost) fall in the same category, especially if you insert
pictures into your messages. Some systems automatically imbed pictures into
the signature for each post! I know that the actual method of transmitting
the pictures in this case is different from attaching binaries to a message,
and I do not want to discuss that here. Let's just say that a significant
portion of Usenet considers HTML messages on Usenet impolite and ignorant.
0.4.3. Posting sales / auctions
This is one of those gray areas. If you cross-post an auction or a sale to
the entire rmr* hierarchy, then most people will probably consider that spam
and will get upset at you. If you must post a sale or an auction, then post
only to one or two relevant groups, and make sure that in the subject of
your message you include an unmistakable description of what the message is.
For example, the subject "rad buggy" would not be acceptable, but "[eBay]
XXX buggy with extras" is fine. You could also use the acronyms "[FA]" to
indicate 'for auction' and "[FS]" to indicate 'for sale'; please do not
confuse these two. People also use "[WTB]" for 'Want To Buy'. Not everyone
is interested in buying stuff, and yes, people will use these indicators to
make up filters. Please respect that!
------------------------------
1. What car should I get first?
There are several questions that most beginners will have, that are somewhat
difficult to answer. This is usually the first one! In order to give any
kind of a meaningful answer, several things must be known first. These
include, but are not limited to:
- how much money do you have / want to spend?
- where do you mostly intend to drive this car (street / off-road)?
- do you intend to race in sponsored races?
- do you want to build your car or not (kit / RTR)?
- do you want a car to 'learn on and graduate from', or a car that you will
'grow into'?

There are numerous answers to each of these points, and, therefore, there
are numerous answers to this question.
[Kerry]
As you will see, this is no easy question and different people will have
different answers. My first good R/C car was an HPI RS4 Pro2. I began racing
in novice stock classes and when I had the driving down pretty good I wanted
a newer car. From there I picked up an Associated TC3 Team Kit. I have been
racing the TC3 for almost two years now. Since then I have ran tons of cars
for reviews and my opinion is that you really need to look at what you will
be doing with the vehicle. There is a reason why the Associated T3 is one of
the best selling vehicles. You can run it on-road, off-road, race with it,
get good air with it, and it is easy to maintain. Would I recommend against
nitro for beginners? Even a year ago I would have said "no". These days,
with a lot of excellent Nitro-based Ready-to-Run vehicles, I don't say "no"
so easily. If you want the thrill of Nitro, and are willing to put up with a
little more maintenance and the noise of a nitro motor, then there is no
reason not to start off with a good nitro RTR vehicle.

[SiKing]
Still, in an attempt to give some sort of an answer, I can offer a personal
experience: the car that I myself bought first and some of the reasons for
my decision. Personally, I did not want to spend a lot of money, but I
normally do try to balance quality and quantity. I knew that I was mostly
going to race my car in my parking lot, which is quite beaten up, but I also
wanted to enter into some of the local races, most of which were clean
parking lot races. I wanted something that is going to be fairly easy to
maintain and build, and also get spare parts for. Initially I was
considering the HPI RS4 Pro2. But I thought this kit is somewhat expensive
as it needed a lot of additional stuff; also this car would have problems
with clearance on my broken up parking lot. I eventually ended up with the
HPI RS4 Rally. I had every intention of learning on this car, and then
moving up to something 'hot'. Eventually my interests changed though, and
now I drive mostly off-road cars. Looking back on it now, I still feel this
was a good decision on my part. The Pro2 would have been a bad purchase for
me. I have to stress the "for me" part in that last sentence; I know a whole
bunch of people who own the Pro2 and are very happy with it.
If you are still unsure, which you probably are, then read the rest of this
document, read some magazines, get informed. Here are several places that
you want to check:
- Past posts to rmrl
<http://groups.google.com/groups?as_ugroup=rec.models.rc.land&as_usubject=re
view>.
- Post a message yourself to the group, get the opinions of several people.
With your inquiry, try to be as specific as possible with what you want.
- Go to your local hobby store (LHS) and a local track (find one from your
LHS), and talk to people there. See if someone will let you drive their car
(they probably will not, but you can still ask).
- Check the "Radio Control Car Action" magazine
<http://www.rccaraction.com/>; check for back issues at your local library
or from your friends online.
------------------------------
2. What radio should I get first?
To initially get into the hobby, you will probably have to purchase
everything since you are starting from nothing. This fact will probably
limit your budget. Many stores offer some sort of a combo deal, which
contains a whole bunch (or all) of the stuff you will need, as a package
deal. This is normally, due to financial constraints, the best option for
you. In all likelihood, the radio that comes with a combo will be a low end,
2-channel, AM, pistol grip radio. The radio will have very few features,
which is probably good, as it will not overwhelm a new user. The minimum
features that you should look for are 'throttle trim' and 'steering trim',
which almost all radios today have. These two features will help with
fine-tuning of the center point for throttle (car is standing still) and the
center point for steering (car goes straight), respectively. For a more
detailed description of radios, see below "What are the different kinds of
radios?"
One rule of thumb that I have heard and also like, is to match the quality
of your radio to the quality of your car. In other words, do not blow 90% of
your budget on the hottest car out there and then cheap out on an old used
AM radio.
------------------------------
3. What motor should I get first?
Fortunately there is a little more help on this one. Check any or all of
these places:
- As mentioned above, stores often offer package deals. If a package deal
comes with a motor, it will often be matched fairly well for that car.
- Once you decide on a car kit that you want, check the manual that comes
with it. Stores often have a copy on hand, or you might be able to get a
copy on the manufacturer's web page (see "Links to links to manufacturers
and stores" below). The manufacturer will often recommend a motor for their
kit.
- If you intend to enter into sponsored races, a motor is usually one of
the items that might be restricted - you are allowed only certain motors.
Check with the organizer of the race.
- If you did post to the newsgroup asking for a car recommendation, ask for
a motor suggestion as well. Again, expect several (sometimes contradictory)
answers.
What you will end up with probably, is a some sort of a spec for a motor.
See "What about motors and stuff?" below, for an explanation of what this
spec means. Go to your LHS with this spec, and ask the salesperson to show
you one of those.
------------------------------
4. What other stuff will I need?
First you will need enough parts to build a complete car. As mentioned
above, most (or all) of this is often available as a complete combo. In
order to go from nothing, to a running car, you will need the following:
- car chassis
- car body (shell)
- car motor
- model car battery*
- speed controller
- steering servo
- receiver
- wheels (tires and rims)*
- radio
- radio batteries
- battery charger
- crystal set*
*All the items that are marked with an asterisk, you will probably want to
have multiples.
To put everything together, that is to build the car, you will need tools.
Looking around my own garage, here is what I have lying around:
- assorted small screwdrivers
- assorted small wrenches
- tapered reamer
- sharp (X-Acto) knife
- scissors
- needle-nose pliers
- sandpaper
- rubber bands
- small wire ties
- body (Lexan) paint
- CA (cyanoacrylate) glue
- thread lock
- gear lubricant
For a better (exact) list, again, consult the manual that comes with your
specific car kit. Often car kits come with few basic tools, and then the
manual will tell you what else you will need.
------------------------------
5. What else do I need to know?
5.1. Ready to Run - RTR
There is a new trend increasing in popularity: "Ready to Run" or RTR, and
"Almost Ready to Run" or ARR. These are essentially car kits that are
completely or mostly pre-built right out of the box. These are especially
popular with nitro cars, but electric RTR kits are also available. The price
is often not that much higher compared to the non-RTR equivalent (sometime
even lower), and spare parts usually have the same availability as the
non-RTR counterpart. Again, check into everything before you commit to a
purchase.
5.2. The controlling bodies of R/C racing
There are several bodies that control 'professional R/C racing'. You only
have to really worry about their rules if you are going to enter into a race
that is sanctioned by one of these authorities. You will need to contact the
organizer of the said race to find out if it is.
IFMAR <http://www.ozemail.com.au/~ifmar/> - International Federation of
Model Auto Racing. This is taken directly from their web site: "IFMAR's sole
responsibility is to organize rules for World Championship events."
EFRA <http://www.efra.se/> - European Federation of Radio operated model
Automobiles. "...the European Federation of Radio Operated Model Automobiles
(EFRA) exist to promote International links within the sport of Radio
Control Model Car Racing."
ROAR <http://www.roarracing.com/> - Remotely Operated Auto Racers. "ROAR is
the official U.S./Canadian sanctioning body for racing R/C cars."
NORRCA <http://www.norrca.com/> - National Organization for Racing Radio
Control Autos. "The main purpose in forming NORRCA was to give tracks/clubs
and racers much more than they were receiving from their existing
sanctioning organization. NORRCA is here to help the tracks/clubs promote
their existing facilities, develop their existing operations, give them
direction on future endeavors and give the racer an organization that is
truly built around the racers needs."
BRCA <http://www.brca.org/> - British Radio Car Association. "It oversees
all aspects of the sport, from setting construction rules to organising
British championship events, to selecting the British team for International
competitions."
------------------------------
6. What about batteries?
The batteries used for car racing are made up of cells, which are
individually little smaller than standard C size cells (they are referred to
as 'Sub-C' cells). . A battery pack consists of 4 to 7 cells, most common
are 6 cell packs. You can build your own pack, or buy an already assembled
one. If you purchased your car kit as a combo deal, the battery pack that
came with it is probably going to be a 6-cell 'stick pack' (the cells are
assembled nose-to-tail three in a row, in two rows side by side, sealed with
shrink-wrap). This type of pre-assembled battery pack is a good starting
point for beginners. Racers often assemble their own packs into a 'saddle
pack' configuration (three cells side-by-side, in two groups connected by an
electrical wire), or side-by-side configuration (all the cells
side-by-side). The important point to note is that some car kits (especially
high-end performance ones) can only accept certain battery configurations.
This is often done for performance reasons - to allow fast battery changes,
or to have a particular weight distribution. Again, check the manual that
comes with the car.
An average battery pack will charge in about 15 to 30 minutes, and give you
5 to 15 minutes of run time. For this reason people often get several packs.
A good starting point is to get the same number of packs as the number of
races you want to run in one day; this is especially important if you will
run in sponsored races.
The batteries are rated in mAh: milliAmpere-hours. This is a measure of how
long the battery will last before it needs recharging. To get an estimate of
run time, take the rating and divide it by 300 to get a VERY approximate
estimate of run time in minutes; mileage WILL vary! Currently on the market
you can get batteries that range anywhere from 1000mAH to 3300mAH, which
range anywhere from US$5 to US$120 per pack of six cells.
If you are going to be running at a sponsored race, batteries might be one
of the restricted items. Check with the organizer of the race.
6.1. Battery care
An entire document could be written - actually has been - on this topic
alone. The best and simplest advice that I have seen so far is from Tom
Younger: "The people who have poor battery life are those who re-charge when
their batteries are still hot, and who spend far too much time, money, and
effort trying to discharge their batteries after using them."
I am not going to repeat what has already been covered very well. If you
need to know more, check Dennis Clark's "The Care and Feeding of NiCd
Batteries" page at <http://www.verinet.com/~dlc/battery.htm> for a
discussion of battery care. At the end of that page you will find a link to
"The R/C Battery Clinic" <http://www.rcbatteryclinic.com/>; this site has
more info, more detail, and more stuff on batteries.
Also, do a search for past posts at rmrl on this topic. This is a very FAQ.
Here are a few links, follow them to the threads:
<http://groups.google.com/groups?btnG=Google+Search&as_umsgid=Pine.SUN.3.96.
1010526082947.109A-100000@valdes>
<http://groups.google.com/groups?btnG=Google+Search&as_umsgid=893ee903.01052
71726.1222d70b@posting.google.com>
<http://groups.google.com/groups?btnG=Google+Search&as_umsgid=ql7g7.5720%24x
b1.2523383@news1.rdc1.ne.home.com>
<http://groups.google.com/groups?as_ugroup=rec.models.rc.land%2C%20uk.rec.mo
dels.radio-control.land&as_usubject=batteries>
<http://www.schumacher.clara.net/charging.htm>
------------------------------
7. What are the different types of cars?
As the hobby increases in popularity, so will the different categories of
cars. It is difficult to easily categorize every single car out there. Here
are the big three, most agreed upon, categories:
Surface: off-road, on-road (also called 'street'). Hopefully this does not
need any further explanation.
Scale: 1:4, 1:8, 1:10, mini, micro. This refers to the size of the model.
The first ones are referred to by their scaling factor; in the 1:8 size, for
example, any feature that is 1 inch on the model car would be approximately
8 inches on the real thing. Note that this is VERY approximate (when is the
last time you have seen the same length VW Bug and a Dodge truck)! Same
thing for the other scales, just a different scaling factor. The minis and
micros vary in scale depending on the manufacturer; they range from 1:18 to
1:30. There are other scale models besides the four listed here. The 1:10
scale is probably the most popular today. Note also that the micros use
different size motors and batteries.
Nitro / Electric: I don't know what to call this category (power, fuel?).
This essentially talks about the motor inside the car. Nitro, also called
'gas', cars are powered by a combustion engine and some mixture of a
combustible fuel. Electric cars are powered by an electric motor and
electrical batteries. Generally the nitro cars require a bit more
maintenance compared to the electric cars, and therefore the electric are
preferred by first timers in the hobby. Although this is strictly a
suggestion as there is absolutely nothing preventing you from buying a nitro
car right from the go!
After that the categories get little more sub-divided. Here is a sampling of
the different categories and classifications that people generally talk
about:
Drive: 2 wheel (front / rear), 4 wheel. This is pretty much the same thing
as on a real car.
On-road types: touring, pan. Touring cars are probably the most popular type
of car of all the categories. They are optimized for racing on a fairly
clean surface. Anything from a clean parking lot, to perfectly swept and
sprayed with some sticky substance (cola will do) lot. With a slight
modification to the tires, these are also raced on an indoor carpet surface.
Pan cars are similar to touring cars, but they are optimized to be raced on
an oval shaped track (i.e.: only left turns!). They often have the shell
similar to NASCAR type of cars, but this obviously varies with personal
preference.
Off-road types: buggy, truck, rally. Some people will argue that rally cars
also should have a mention in the on-road category, and justifiably so.
These are essentially touring cars with modified suspension parts. They have
a higher clearance, longer shocks, and often rough thread tires. They are
intended to be raced on very rough street conditions, such as a broken up
parking lot. Trucks generally resemble ... well, trucks. They are often a
little more sturdy and have a narrower wheelbase, as compared to buggies.
Buggies resemble the real-life dune buggies. They are often a little more
nimble, with a wider stance. In the off-road arena, trucks are probably more
popular with first timers and back-yard bashers, as they can 'take a beating
and keep on ticking.' Buggies are a little more popular with off-road
racers. Some people would argue that monster trucks are a category all of
their own. I am not one to make that decision. But basically, just like
their real life counterparts, they are generally 4-wheel drive, big, and you
can run them over top of stuff! Did I mention big?
Specialty vehicles: dragster, tank, semi-truck, motorcycle. Like I said, as
the hobby becomes more popular, there will be more ...
------------------------------
8. What are the different kinds of radios?
There are two ways of looking at this:
The first way of approaching this topic is from the physical characteristics
of the radio. In this case there are two types of radios. The most common is
a 'pistol grip' type radio. This is the type that you hold in one hand,
kinda like a hand gun. On your trigger finger you have a lever that controls
the speed: the throttle, with the other hand you hold on to a little wheel
that controls the direction of the car: the steering. These radios mostly
come in right hand configuration - you hold the radio in your left hand, and
steer with the right - left handed radios are also available, but there are
fewer to chose from. The second type is a 'stick' or 'paddle' type. This
type of radio you generally hold with both hands, and with your index finger
or thumb you hold on to two levers sticking out of the top. One level is the
throttle and the other is the steering. The stick type of radio, in car
racing, is decreasing in popularity in favor of the pistol grip, but there
are still few around.
There is apparently a single-stick radio out there. This works similarly to
a joystick. I have never seen one, I am only spreading the rumor ... If
anyone has an URL to a manufacturer, please send it my way
The second way of looking at this topic is the type of communication, the
radio uses. I will, unfortunately, have to use some electronics terminology
to be able to describe this. The radio transmits a radio signal which is
picked up by a receiver in the car. So that more than one person would be
able to race their car at the same time, each radio is assigned a particular
frequency - this frequency is referred to as the 'carrier frequency'. Out of
convenience, each carrier frequency is assigned a 'channel number' (see
"Legal frequency - channel tables" at the end of this document). Almost all
radios today can have their channel changed by changing a 'crystal' in the
radio - this is a small electronic device which generates the appropriate
carrier frequency. The radios are intentionally manufactured to make this
relatively easy to do. The receiver must have a matching frequency crystal
as well. Normally people get multiple crystal sets, so that when they get
together with friends or for a race there is less likelihood that several
people will have the same channel. In fact, if you enter into a race they
will require you to submit three channels that you can race on, and just
before your race they will tell you which of your three you must use.
There are different methods to generate the carrier frequency, this is
called 'frequency modulation'. There are three types of modulation that you
will see when shopping for a radio. AM - Amplitude Modulation - is the
simplest, least expensive method of signal transmission. The next type if
FM - Frequency Modulation - which has inherently slightly better range and
is less susceptible to radio interference. The last type is PCM -
Pulse-Coded Modulation - which is a type of AM or FM modulation, but it has
a greater range and resolution. PCM signals are coded in such a way that
interference is almost nonexistent.
8.1. What is all this stuff on the radio?
When you drive your car, the radio will impress information onto the carrier
wave. The type of information that is impressed onto the carrier is: going
left / right and how far to the left / right, go forward / backwards and how
fast forward / backwards. Unfortunately, each of these functions is also
referred to as a 'channel'. So a radio that can control steering and speed
will be a 2-chanel radio. These channels are different than the channels for
the carrier frequency; it is just a confusingly similar label. The receiver
in the car then decodes this information, and generates appropriate
electrical signals for the devices that are connected to it: the steering
servo and the speed controller. These devices then transform those signals
into the physical: your car moves! The term 'proportional radio', which
might pop up while you're shopping, means that as you press more on the
throttle the car moves proportionally faster; same goes for the steering.
This is opposed to simple on-off control: the car is either standing still
or going full blast - most toy R/C cars use on-off radio control. Check
<http://www.howstuffworks.com/rc-toy3.htm> for a different explanation of
the same thing, and with pictures. ;)
All of this is quite simplified here. If you want more (technical) detail
you can look up how a radio works in any electronics communications
textbook.
The method used to generate the radio signal (the modulation) is pretty
standardized. The way to impress the information onto that carrier signal is
different for each manufacturer. This means that radio made by company A
will probably not work with a receiver made by company B, even if you have
matching frequency crystals. The whole set: radio, receiver, and crystal set
come as a matched set. There are third party manufacturers that make
receivers that are compatible with first party manufacturers. Check with the
manufacturer of your equipment before you commit to a purchase!
One thing worthy of note is that crystals (channels) are interchangeable
between AM and FM radios made by the same manufacturer. However, the radios
are built so that crystals are not interchangeable between manufacturers -
you need to buy crystals made for your brand of radio.
There is also something called a 'synthesized frequency module'. This is
referred to differently by different manufactures, for example: 'spectra
module', 'synthesized transmitter', etc. The idea is rather simple (to the
end-user anyway). There is an extra piece of electronic built into the radio
that will allow you to dial in the desired frequency: no more crystals to
swap. You can (but do not have to) get a receiver with the same thing in it.
Another feature is something called Battery Elimination Circuit - BEC.
Normally you need a battery pack connected to the speed controller which
drives the motor, you also need a separate battery pack to power the
receiver itself. Most receivers today have a BEC, which eliminates the need
for the battery pack going to the receiver. The receiver gets its power from
the motor battery pack. Less weight for your car to carry, less run time
though; the tradeoff is worth it however.
8.2. Radio interference
There is a whole bunch of stuff that can cause radio interference. How you
detect it is very simple: your car goes crazy. If interference is a problem
for you, go through the following list and see if you can eliminate any of
these. I tried to put suggestions as to what you could do to fix the
problem; some of these are simple and inexpensive, while some others ...
- As stated before, from most to least susceptible types of radio
transmission: AM, FM, PCM. The less susceptible you get, the more it will
cost you.
- Some people experienced a lot of interference when standing close to
their car, especially with AM radios. This is especially a concern for nitro
cars, when starting their car up.
- Some people claim that the 27MHz band is more susceptible than the 75MHz
band (in the US). The reasoning here is that the 27MHz band has the channels
spaced further apart, this leaves more room for error. R/C toy
manufacturers, who are not very concerned about making quality equipment,
take advantage of that. Unfortunately, you cannot simply change the crystals
to the 75MHz band - you would need to get a whole new radio.
- Sparking (arcing) coming from the motor. Get new brushes; clean your
motor; install noise capacitors on your motor: check the manuals that came
with BOTH your motor and your ESC on how to do this correctly.
- Bad (bad = old, defective, or possibly cheap) servos.
- People standing next to you are using channels that are next (or close)
to yours. Change your channel.
8.3. Using a 4-channel (or more) radio with a car
Most radios used for R/C cars are 2-channel: direction and speed. There are
also 3-channel radios; the third channel is used for fancy stuff. For
example, some people wire up lights on their car to the third channel.
Higher number of channels (up to 8) is intended for aircraft, but can it be
used for cars?
The Novak XXTRA Synthesized FM receiver for example supports 5 channels and
the Multiplex Profi Car radios have up to 7 channels of operations.
This will work, but there are a few things you must keep in mind. Different
radios are designed for different applications. You might have to use some
trial and error to figure out which channel you want to use for the throttle
and which for the steering on your car. Also, multi-channel radios are
intended for airplanes and other flying R/C models. The throttle for a car
radio is spring loaded, but for an airplane it is not. This means that on a
car radio when you let go of the throttle, it will return to the neutral
position. On an airplane radio the throttle will stay, by design, wherever
you had pushed it to. It will require some getting used to, but it can be
done.
Yes, there are also legal issues as well! You must use the correct frequency
for your radio. Certain frequencies are reserved for air use only, and some
others are for ground use only. At the end of this document, see "Legal
frequency - channel tables", there is a list of legal frequencies for ground
vehicles only.
I personally am no lawyer, and as such I am not familiar with all the legal
subtleties! In North America the government authority responsible for this
is the FCC - Federal Communication Commission - which controls everything
transmitted trough the air. They have a web site, and the relevant pages can
be found at: <http://www.fcc.gov/wtb/prs/radcntrl.html>, and
<http://www.access.gpo.gov/nara/cfr/waisidx_00/47cfrv5_00.html>. In the UK
it is The Radio Communications Agency; here is the best link I have been
able to find: <http://www.radio.gov.uk/publication/ra_info/ra60.htm>. Good
luck!
8.4. Too much information on radios
Someone posted a message asking for plans to build his own radio. This topic
is way too advanced for the scope of this FAQ. However, Rudie Shepherd
provided the original poster with some very excellent URLs to sites with
this type of information. For those truly into way too much information,
here are the links:
MicroPro8000 Users <http://mp8000.rcclubs.com/>
Radio Modelisme (in French and English) <http://home.nordnet.fr/~fthobois/>
RCMICRO: Microprocessor based radio control encoder
<http://www.eagleairaust.com.au/encoder.htm>
Here are a few more links describing how to build your own electronics, or
modify your electronics. Please note that modifying your equipment will most
certainly void the warranty on your equipment. :)
The 7 channel hack: <http://www.teamtornado.co.uk/7channel.htm>
PC-to-R/C Interface: <http://www.mh.ttu.ee/risto/rc/electronics/pctorc.htm>
Micron Radio Control: <http://www.micronradiocontrol.fsnet.co.uk/>
------------------------------
9. What about motors and stuff?
Electric motors EXTREMELY simplified: An electric motor has basically two
parts: a 'can' and an 'armature'. In reality it has a whole bunch of other
parts, but those are important mostly to hold everything together. The can
is what you see on the outside; it is made of two (sometimes more) magnets.
The armature is on the inside; you can usually see it if you look through
the went holes in the can or if you take the motor apart. It is made of some
magnetic substance like iron and has wire wrapped around it; this makes it
an 'induction coil'. When electricity is run through the wire, it creates a
magnetic field. This electro-magnetic field is opposite to the magnetic
field provided by the permanent magnets; the two repel each other, and the
armature rotates.
As a user, you are generally concerned about how fast the armature spins
when a given voltage is applied to it, and how well it can retain those
revolutions when a load is applied to it. The first is normally given by the
manufacturer in 'RPM' (rotations per minute), and the second is referred to
as 'torque'. Two motors (even the same make and model) can have wildly
different values. Therefore motor specs have been generalized in terms of
'turns' and 'winds'. Turns is the number of times a wire is wrapped around
the armature; winds is the number of strands the wire has. For example, you
will see motors specified as "17T2"; this means the wire is wrapped
seventeen times around the armature, and the wire is made of two strands.
Assuming that everything else on the car is kept the same lower number of
turns translates to higher RPM. Winds deal with torque. In simplest terms, a
single wind will give you generally more punch and a higher wind will give a
progressively smoother pickup and a bit more top speed. Both winds and turns
also affect run time - higher number of turns and single wind will give you
more run time.
Note that RPM does not always translate directly to speed! There are other
factors, plus a better driver will always beat out a faster motor with an
unskilled driver.
In R/C car racing motors come in two categories: 'stock' and 'modified'.
If you enter into a stock race, you will need to do it with a stock motor.
The idea of stock races is that all the motors will perform the same, so the
winner of the race is determined by: 1) the skill of the driver, and 2) the
setup of his car. This is not necessarily always true, but that is the idea
anyway.
Modified motors come in wide range of winds and turns, and are usually made
so they can be rebuilt and therefore are modifiable. They are generally (but
not always) higher performance motors as compared to the stock.
Significantly more detailed information can be found at Tom's R/C Page
<http://www.csc.uvic.ca/~tyounger/hafh/rc/>.
9.1. How to speed up electric motors?
Keep in mind that several factors contribute to the speed of your vehicle,
the motor is only one of them. Following is a post to rmrl, slightly edited
for grammar and legibility:
From: popeye <news:9ep918$41q$1@news8.svr.pol.co.uk>
Tuning modified motors is not that easy, first of all clean the thing.
1. Mark the end bell and case so as to keep timing position.
2. Remove brushes and springs.
3. Remove the top screws twist end bell and pull up; be sure to not loose
the small shim washers.
4. Pull the armature out of the motor again, look for the small shim washers
at the bottom.
5. Clean the inside of the case and end bell with motor cleaner.
6. Wash the armature with the cleaner, do not touch the armature com (copper
bit) with your fingers.
7. Use bearing oil to oil both case and endbell bearings. Reassemble motor.
8. Don't forget to put the shims back in; if you have them right then there
should be a very small amount of play when reassembled.
9. Brushes should be replaced when about 1/3 worn.
10. Line up the timing marks, and hay presto one clean efficient motor.
Sounds difficult to some but it is not. If you want to get more speed etc,
then get com skimmed, put softer brushes, better springs, renew bearings
when armature feels gritty (to test bearings before reassembling place
armature in housings from the outside and spin). Also as motor gets old
timing may need adjusting. Never throw away a motor, it can be reused
remagnetised even 15T4 turned in to 12T2 or any other motor is usually
cheaper than the cost of a new motor.
For additional information on motor maintenance see:
<http://www.wildhobbies.com/news/default.asp?cmd=view&articleid=412>, and
<http://rcvehicles.about.com/library/rc101/blackbook.htm>.
9.2. Brushless motors
Several companies are manufacturing brushless motors now. The primary
difference is that in a brushed motor the armature has the windings and the
magnets are mounted in the motor can. As power is supplied to the brushes,
the armature turns. In a brushless motor, the armature contains the magnet
and the coils are in the motor can. As the coils are energized in sequence,
the armature turns. Brushless motors require their own speed control and the
speed controls are not interchangeable between brushed and brushless motors.
<http://www.gtdodd.demon.co.uk/brushless/intro.htm>
<http://groups.google.com/groups?btnG=Google+Search&as_umsgid=a8mod3$28p$1@r
eader06.wxs.nl>
<http://groups.google.com/groups?btnG=Google+Search&as_umsgid=20010225001710
.04970.00002026@ng-cd1.aol.com>
<http://groups.google.com/groups?btnG=Google+Search&as_umsgid=19980129044301
.XAA29614@ladder02.news.aol.com>
<http://groups.google.com/groups?btnG=Google+Search&as_umsgid=uOIwO9qlBHA.22
7@net037s.hetnet.nl>
9.3. Speed controllers
There are two types of speed controllers:
1) Mechanical Speed Controller, MSC - This type of a controller is basically
a big variable resistor, controlled by a servo. It can normally achieve
three different speeds (three-steps), and does not have a reverse option.
Advantages: there is only one that I am aware of: cost!
2) Electronic Speed Controller, ESC - This type of a controller is a
mysterious black box (to the end user). This means that it has a lot of
electronic components, all of which are not visible to the user. It supplies
the motor with pulses of the appropriate voltage. Since it is electronic,
and the insides are digital, it has many more steps / speeds (up to 255),
which makes the running the car seem much more life-like. These also do come
with a reverse option. Advantages: better control of the car; runs much
cooler; can handle higher battery cell packs; can handle hotter motors
without melting. Most drivers today run with electronic controllers. It is
actually quite rare to see a car with a mechanical one today.
Most manufacturers will have an explanation of all the terms that go along
with the ESC; unfortunately each manufacturer uses a different term to name
the same thing, and further, each manufacturer will stress a different thing
on their product (it's called 'marketing'). The things that you should
concentrate on, to start of with: reverse (this is a yes / no type of
thing - for off-road go with a 'yes', for on-road you could go either way);
number of cells (this is generally a range - you will want one that can
definitely handle 6 cells, which is almost all ESCs on the market today);
motor limit (the number of turns on the motor that an ESC can handle -
remember: the lower the turns = the hotter the motor).
Way detailed info on ESCs:
<http://www.math.niu.edu/~behr/RC/speed-ctl.html>. Wanna build your own? See
Mike Norton's Hobbies at <http://home.HiWAAY.net/~mjn/>, or Stefan's
Electric R/C Web Site <http://www.capable.on.ca/rcstuff/escbec.htm>
<http://www.capable.on.ca/rcstuff/esc.htm>.
9.4. Gear ratios
There are two gears on your car. A 'pinion' is generally the smaller gear
attached to the shaft of the motor. A 'spur' is the bigger one connected to
some drive mechanism of the wheels. A 'gear ratio' is the number of teeth on
the spur divided by the number of teeth on the pinion. This ratio represents
the number of rotations the pinion makes per every rotation of the spur.
Note that one rotation of the pinion is equal to one rotation of the motor,
since the two are attached by a shaft. Depending on the drive mechanism in
your car, there might be additional geared wheels (like differentials)
between the spur and the tires - this is almost a certainty for 4WD cars.
The manufacturer will generally supply you with the 'final drive ratio'.
This is the number of rotations the pinion makes per rotation of the wheels.
If you have a two wheel drive car and the spur gear is connected directly to
the wheels, then your drive ratio is going to be the same as the final drive
ratio.
Taking the circumference of your wheels, divided by the final drive ratio,
multiplied by the RPM of your motor, would give you the theoretical top
speed of your car - the units will be same as your circumference per minute.
This is only theoretical since it does not take into account friction, and
other factors such as how well your tires stick to the pavement, and the
skill of the driver.
So what gear ratio should you use? Chris Dugan
<news:jx_j8.48632$y76.5834820@news6-win.server.ntlworld.com> offered the
following advice: With pinions you use a larger one for more top end speed
(the reverse for the spur), but only change either the spur or the pinion
not both. Most people change the pinion and leave the spur at the factory
supplied size, if you change to a smaller spur and start to use small
pinions you might find trouble meshing the gears (the motor won't reach the
spur). Same thing goes for a larger spur than standard.
There are different sized teeth on the gears. This is called the 'pitch'.
Lee Cao <news:a24aqn$gjv$1@lore.csc.com> offered the following definition
(edited for spelling): Pitch is the number of teeth a gear has per inch of
circumference. So a 32 pitch gear would have the tooth sized and spaced in a
manner such that if the circumference of the gear is exactly 1 inch, the
gear would have exactly 32 teeth. Similarly, a 16 teeth gear would therefore
have a .5 inch circumference.
Also have a read through S. Varah's info on gearing:
<http://www.schumacher.clara.net/gearing.htm>.
------------------------------
10. Painting
The question of painting (as well as removing paint) seems to come up quite
often, enough to warrant mentioning it here; actually someone even
specifically mailed me about adding a section on this. Personally I rather
suck at it, so I will just direct you to the 'experts':
<http://groups.google.com/groups?as_ugroup=rec.models.rc.land&as_usubject=pa
int>
<http://freespace.virgin.net/bodyshells.uk/faq/faq.htm>
<http://groups.google.com/groups?q=remove+paint+body&btnG=Google+Search&meta
=group%3Drec.models.rc.land>
<http://www.rcxotic.com/pkg-how/000002/>
------------------------------
11. Some useful links
The links below, are to sites that contain technical information that mostly
pertains (but not exclusively) to R/C cars. The descriptions (if any) are
the webmaster's own and not mine; it is taken from the META - DESCRIPTION
tag if there is one, and secondary consideration is given to the TITLE tag
(because after all, that is what they are meant for!). The order presented
is not any kind of a rating system, it is simply the order that I happen to
add these to the list.
<http://www.wildhobbies.com/> On-Line Magazine for R/C vehicles featuring
monthly articles, reviews, technical information, forum, and much more.
<http://www.rcracing.com/> RC Racing, Local RC Racing in Northern
California, Yokomo, Losi, Kawada, HPI RS4, Tamiya Mini Cooper, Kyosho and
other touring cars, RC Cars, RC Racing, RC Electric Cars,RC Racing,R/C
Racing.
<http://gallery.uunet.be/heremanss/> This site describes the function and
importance of various suspension components, as well as their effects on the
car's handling. Its purpose is to give you some insight in elementary
vehicle dynamics.
<http://www.csc.uvic.ca/~tyounger/hafh/rc/> Tom's R/C Stuff.
<http://www.verinet.com/~dlc/rccars.htm> DLC's RC Cars.
<http://www.geocities.com/MotorCity/2314/> Mark Brown's home page.
<http://moe.intelos.net/~rpm/> R/C Headquarters.
<http://rcvehicles.about.com/> Find everything you want to know about rc
cars, rc trucks, rc aircraft, rc boats and other types of radio control tips
& tricks. You can get information about electric and nitro powered Kyosho,
Associated, Trinity, DuraTrax, Tamiya, Losi, Traxxas radio controlled cars
and trucks in all scales.
<http://www.rccaraction.com/> Radio Control Car Action is the world's
leading RC model car and truck magazine.
<http://www.rcnitro.com/> Radio Control Car Action is the world's leading RC
model car and truck magazine.
<http://www.maxxtraxx.com/> T-maxx news/reviews/discussion! The most timely,
reliable, service on the web for up to the minute T-maxx news, hot tips,
reviews, and message board community about the T-Maxx!
<http://home.kc.rr.com/grayghost/> The Gray Ghost's Homepage.
<http://www.rccentral.com/> RC Central - Remote Control RC Cars and Trucks
<http://www.rcxotic.com/> Best Resource for 1/10 scale Touring RC Cars on
the web. Here you will find TIPS that actually help,links, Canadian RC
EVENTS, Inspiring RC Pictures and much much more!
<http://www.rcmt.net/> Welcome to the new Radio Control Monster Truck
Network Your Guide
<http://www.rcrally.com/> RC Rally - Proud Sponsor of the World Scale Rally
Championship and home of all things Rally
<http://www.rcdesign.ru/> Electronic devices for modelling. Pictures,
descriptions, schematics, documentation. Everything for RC models:
tachometer, speed control, motor heater, battery indicator, piezo gyro...
<http://www.rccartalk.com/> RC Car Talk is your complete guide to electric
and nitro gas powered rc cars and trucks with hot tips for buying, building,
tuning and racing popular remote control cars, trucks, magazines, and more.
<http://www.rc10gthobby.com/> Manufacture of the Crescenzi rc10gt Brake
System for, radio control RC10 GT and Nitro DS. Aftermarket Hop ups like,
MIP, RPM, Robinson Racing, Racers Edge, DuBro, Crescenzi Racing. gallery,
Best 50 nitro RC Off Road Sites, Links and more.
<http://www.BlueMaxRC.com/> Blue Max R/C Flying Club
<http://www.schumacher.clara.net/> Viper RC - The definitive guide to Radio
Controlled cars
------------------------------
12. Links to links to manufacturers and stores
There are just too many manufacturers, and this section started to get out
of hand. The following links already have pretty good lists, so no point in
wasting more bandwidth than is absolutely necessary. You should be able to
find almost anything from any one of these:
<http://homepages.ihug.co.nz/~atong/>
<http://www.sandland.ws/links/>
<http://www.cse.unsw.edu.au/~waleed/rc/>
<http://www.rcyellowpages.com/>
------------------------------
13. Legal frequency - channel tables
USA and Canada:
<http://www.rcxotic.com/frequency.shtml>
UK:
27 MHz (general R/C use) band: <http://www.gjctech.co.uk/misc/27mhz.htm>
40 MHz (surface use) band: <http://www.gjctech.co.uk/misc/40mhz.htm>
From: Orjan Sandland <news:2oES5.429$6p6.520@news.world-online.no>
Here are the frequencies for Norway:
For ALL sorts of remote control
26.995 MHz
27.045 MHz
27.095 MHz
27.145 MHz
27.195 MHz
27.255 MHz
40.665 MHz
40.675 MHz
40.685 MHz
40.695 MHz
Only for R/C cars and boats
35.310 MHz
35.320 MHz
35.330 MHz
35.340 MHz
35.350 MHz
35.360 MHz
35.370 MHz
35.380 MHz
35.390 MHz
40.705 MHz
40.715 MHz
40.725 MHz
40.735 MHz
40.745 MHz
40.755 MHz
40.765 MHz
40.775 MHz
40.785 MHz
40.795 MHz
From: Stipus <news:00e901c1c06a$317d34c0$bb01043e@JMJOUDRIER>
Here are the authorized R/C frequencies for France:
26.815 to 26.915 MHz = All sorts of rc activities
41.000 to 41.100 MHz = Only flying r/c models
41.100 to 41.200 MHz = R/c cars and boats
72.210 to 72.490 MHz = All sorts of rc activities.
------------------------------
14. Document Changes
04/11/2003
Fixed numerous links
12/11/2002
1. What car should I get first?
+ Added my own opinion to original author's opinion

8.3. Using a 4-channel (or more) radio with a car
+ Added sentance about Novak XXTRA and Multiplex multi-channel radios

9.2. Brushless motors
+ Added technical information on brushless motor design
------------------------------
15. Legal jargon
Comments about, suggestions about, and especially corrections to this
document are welcomed and greatly appreciated. Send
<mailto:kerryg@wildhobbies.com> to reach the author.
This article is provided as is without any express or implied warranties.
While every effort has been taken to ensure the accuracy of the information
contained in this article, the author / maintainer / contributors assume no
responsibility for errors or omissions, or for damages resulting from the
use or misuse of the information contained herein.
This FAQ may be posted to any Usenet newsgroup, on-line service, web site,
or BBS as long as it is posted in its entirety and includes this disclaimer
statement. This FAQ may be distributed as class material on any printed,
magnetic, or electronic medium as long as there is no charge (except to
cover materials). This FAQ may not be distributed for financial gain. This
FAQ may not be included in commercial collections or compilations without
prior express written permission from the author.

--
Kerry Garrison
WildHobbies.com - The #1 On-Line Hobby Magazine
http://www.wildhobbies.com

=====================================================
---
Proud owner of:
Associated RC10GT <the other basher>
Team Losi XX "CR" <the basher>
Team Losi XXX KE  <the racer>
http://ripperd.com
email: dean (at) the above domain