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Archive-Name: models/rc-cars/newbie-guide
Posting-Frequency: monthly
Last-Modified: 8 June, 2002
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:
<mailto: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 <mailto:mail-server@rtfm.mit.edu>, with the
command "send /pub/faqs/news-answers/introduction" without the quotes.
I am seriously lacking in time to give this document (and the hobby) the attention
it deserves. If anyone would be interested in taking over the maintenance of this,
please contact the author <mailto:siking@myrealbox.com>.
Subject: 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. Legal jargon
Subject: 0. Preliminaries and Introductions
I am seriously lacking in time to give this document (and the hobby) the attention
it deserves. If anyone would be interested in taking over the maintenance of this,
please contact the author <mailto:siking@myrealbox.com>.
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
sometime in 1998. At the time I started posting this I had built two cars, raced
three, and won zero races. This, by every definition possible, does NOT make me an
expert in the field, but I would like to think of my self as a successful 'graduate
from a newbie'.
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 author of this document has never touched a gas R/C car. This is strictly a
personal choice (actually my wife's), and should not in any way indicate that one
is better over the other! Therefore the rest of the discussion here will be mostly
limited to electric cars. In any case, I personally would never recommend that a
newcomer to this hobby get a gas car anyway, so the topic would actually be outside
of the scope of this document.
If anyone is interested in making up a "Nitro Guide and FAQ", feel free to contact
me and I will try to help out as much as I can, including with submissions to
*.answers groups.
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
<rec.models.rc.land">http://groups.google.com/groups?group=rec.models.rc.land>; this place has an
archive of older postings, much older than what your newserver 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
diskspace, 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://ripperd2.dhs.org/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!
Subject: 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.
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
<rec.models.rc.land&as_usubject=review">http://groups.google.com/groups?as_ugroup=rec.models.rc.land&as_usubject=review>.
- 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.
Subject: 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.
Subject: 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.
Subject: 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
- elastics
- 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.
Subject: 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."
Subject: 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. 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 3000mAH, which range anywhere from US$5 to US$60 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>
<as_umsgid=893ee903.0105271726.1222d70b@posting.google.com">http://groups.google.com/groups?btnG=Google+Search&as_umsgid=893ee903.0105271726.1222d70b@posting.google.com>
<as_umsgid=ql7g7.5720%24xb1.2523383@news1.rdc1.ne.home.com">http://groups.google.com/groups?btnG=Google+Search&as_umsgid=ql7g7.5720%24xb1.2523383@news1.rdc1.ne.home.com>
<rec.models.rc.land%2C%20uk.rec.models.radio-control.land&as_usubject=batteries">http://groups.google.com/groups?as_ugroup=rec.models.rc.land%2C%20uk.rec.models.radio-control.land&as_usubject=batteries>
<http://www.schumacher.clara.net/charging.htm>
Subject: 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 ...
Subject: 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?
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 Radiocommunications 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/>
Subject: 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 <//groups.google.com/groups?selm=news:9ep918$41q$1@news8.svr.pol.co.uk" target="new">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
This is still quite new, or at least not very widely accepted concept as of yet.
The idea is something like an electric motor with no brushes and no speed
controller. Read all about it here:
<http://www.gtdodd.demon.co.uk/brushless/intro.htm>
<as_umsgid=a8mod3$28p$1@reader06.wxs.nl">http://groups.google.com/groups?btnG=Google+Search&as_umsgid=a8mod3$28p$1@reader06.wxs.nl>
<as_umsgid=20010225001710.04970.00002026@ng-cd1.aol.com">http://groups.google.com/groups?btnG=Google+Search&as_umsgid=20010225001710.04970.00002026@ng-cd1.aol.com>
<as_umsgid=19980129044301.XAA29614@ladder02.news.aol.com">http://groups.google.com/groups?btnG=Google+Search&as_umsgid=19980129044301.XAA29614@ladder02.news.aol.com>
<as_umsgid=uOIwO9qlBHA.227@net037s.hetnet.nl">http://groups.google.com/groups?btnG=Google+Search&as_umsgid=uOIwO9qlBHA.227@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
<//groups.google.com/groups?selm=news:jx_j8.48632$y76.5834820@news6-win.server.ntlworld.com" target="new">news:jx_j8.48632$y76.5834820@news6-win.server.ntlworld.com> offered the following
advice: With pinions you use a larger one for more top end speed (the reverse for
the spur), but only change either the spur or the pinion not both. Most people
change the pinion and leave the spur at the factory supplied size, if you change to
a smaller spur and start to use small pinions you might find trouble meshing the
gears (the motor won't reach the spur). Same thing goes for a larger spur than
standard.
There are different sized teeth on the gears. This is called the 'pitch'. Lee Cao
<//groups.google.com/groups?selm=news:a24aqn$gjv$1@lore.csc.com" target="new">news:a24aqn$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>.
Subject: 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':
<rec.models.rc.land&as_usubject=paint">http://groups.google.com/groups?as_ugroup=rec.models.rc.land&as_usubject=paint>
<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/>
Subject: 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.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.wildhobbies.com/> Hobby resource site for high power rocketry, r/c
cars, rc planes, mini 4wd, and much more.
<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
Subject: 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/>
Subject: 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 <//groups.google.com/groups?selm=news:2oES5.429$6p6.520@news.world-online.no" target="new">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.
Subject: 14. Legal jargon
Comments about, suggestions about, and especially corrections to this document are
welcomed and greatly appreciated. Send <mailto:siking@myrealbox.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
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