Welcome to the
SUNCOAST MODEL FLYERS Inc.
Radio Control Flying At Coolum On The Sunshine Coast - Queensland, Australia
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Radios Please note the section below on frequency control, it is one of the most important aspects of the hobby
Brand Names Like engines, there are all types of radio control units with a huge variety of features and gadgets. The most common names you will come across in Australia will be JR (Japan Radio), Futaba, Hitec,and Spektrum. The JR and Futaba sets are reputed to be the better of the brands but the others are quite okay too. There is a new brand on the market is Spektrum, this radio has the new technology which is becoming common in radio control modeling. This technology uses the 2.4ghz range of frequencies and operates very differently to the usual 36mhz radios, more on this later. A complete radio set consists of the transmitter, the receiver, servos, switch and battery packs. Not all radio sets come with batteries, these are called DRY sets. Manufacturers sometimes do a crazy thing by giving you one less servo then you need. Basically speaking, all the servos and the battery pack plug into the receiver via the switch and are mounted in the model. The transmitter stays on the ground with you and transmits the inputs you give it to the receiver, these are fed to the servos which are connected to the control surfaces of the aircraft. One question that everyone asks is how far will the signal go before transmitter won't talk to the receiver. Well, the answer is 'out of sight'… about one kilometer. You will lose sight of the model before it loses signal, obviously if you can't see the model you can't control it so it flies directly to the crash site. You will hear people talk about the number of channels a radio has. Each channel is used to control one function on the plane. In aero modeling most radio control the four flight controls… Elevator, Aileron, Rudder and Throttle, so you need a minimum of a four channel radio for the standard plane. If you want to control things like Flaps, Retractable Wheels, Bomb Doors, Smoke etc you need an additional channel for each feature. Obviously the more channels you have the more expensive the set. In the main, radios can be divided into two categories, Computerised and Non-Computerised. With technology becoming so affordable nowadays computerised radios are more and more common. Many of the smaller radios (2 channels) are not computerised and are used in models like gliders, cars boats etc. So what's the big deal with a computerised radio ? They allow you to electronically adjust many different behavior aspects of the servos and hence the controls of your plane. For example, if the controls are too sensitive and your plane is ducking and diving around the sky you can simply go into the menu and back off the 'travel rate' of the servos, or, after you have installed the radio in your model you find one of the controls are back to front, simply go into the menu and reverse the throw on that servo. These are just a couple of the basic things you can do, they do more complicated stuff which I will not go into here.
Frequencies FREQUENCY CONTROL IS THE MOST IMPORTANT PART OF OUR HOBBY. There are 3 legal frequency bands available for modeling in Australia, 29mhz, 36mhz and 40mhz. You will find cheaper toy cars, boats etc on 27mhz but beware as this band is shared with CB radio and your model could go berserk. We also use the AM and FM types of modulation. There is a third modulation called PCM (pulse code modulation) which is a digital signal… very good but of course more expensive. As mentioned above, there is also the new 2.4ghz radio technology now available and should be considered before buying a radio. (See below for more on 2.4) Each band is divided up into several channels, for example (29.795) (29.820) or (36.190) (36.450) There are quite a few available in each band. You will hear people talk about 619 and 645, this is just an abbreviation for that frequency. You get it by covering the first and last number of the whole frequency. So with 619 we have dropped the 3 and the 0 from 36.190. The 29mhz channel are referred to by channel numbers e.g. channel 20 or channel 32. These are just numbers allocated to those frequencies for ease of use and you can see them on the frequency board at any field. Not many radio nowadays are on 40mhz… (Having said that my helicopter is on 40mhz) The frequency within each band is designated by the crystal in the transmitter and receiver. These crystals can be easily changed if you want to be on a different frequency. You should not move a 29mhz crystal to at 36mhz radio and visa versa, the radio is tuned for that band.
Frequency Control. To control the frequency use we use
a frequency key and a frequency board. The frequency board has a
number of slots in it, one for each legal frequency. Everybody has
a rectangular piece of plastic called a key. On this key you write
your name and the frequency of your radio. When you want to use
the radio, FOR ANY REASON, you take your key to the frequency board
and slip it into the slot marked with your frequency number. If
there is already a key in that slot someone else is using the frequency
and you MUST NOT turn your radio on. If someone is on your frequency
you return your transmitter to the 'pound' with it's key All radio transmitters at the flying field are kept in the transmitter pound for safe keeping. As soon as you arrive at the field you place your transmitter with it's key on it into the pound. It stays there until you leave the field.
2.4ghz Radios. Around 2006 a whole new radio control system became available on the market. This system uses the 2.6ghz frequency range. It was first released by a manufacturer called Spektrum. It has become so popular that most of the other manufacturers have now also released radios using the 2.4ghz technology. As mentioned above, with the current system if two transmitters are turned on and they are on the same frequency they will interfere with each other have cause serious problems. With 2.4 you can have as many radios turned on as you like and they will not interfere with each other.... actually there is a limit but it is a huge number. You can instantly recognise a radio using 2.4ghz as it has a short fat aerial out of the transmitter.
What happens with 2.4 is when you first set the radio system up in your model you 'bind' the transmitter and receiver together. Once you have done this, that receiver will only accept instructions from that transmitter. When you are ready to fly and turn on your transmitter it instantly scans for a free channel. It does not transmit until one is found, this all happens instantly, well very very quickly. When a free channel is found the transmitter and receiver lock onto it. Remember, the receiver has been previously 'bound' to that transmitter and will only accept a signal from it's own transmitter. This means you can safely turn on your radio without the fear on interfering with someone else's radio. You also have the peace of mind that someone else is not going to turn on and interfere with your radio. Now having said all this, different manufacturers are using the 2.4ghz technology in different ways. Some find one frequency and lock onto it, others constantly (and very quickly) switch channels while in use. The concern with this type of system is if there are a lot of 2.4ghz radios in use, and they are constantly changing channels, it can take a while for a radio that is just turned on to find a free channel.... I know I said there were a lot of channels available but they are not infinite. Be very careful when buying 2.4 radio systems from overseas. The U.K. for instance has very strict controls on how much power (signal) a radio can put out and their radio systems actually put out HALF the signal as the Australian radios. There are other countries in the world that that have the same regulations. The 2.4 system is rapidly taking over and should be considered before buying a new radio. I certainly now have my helicopters and good models on it.
Modes There are two modes that you will commonly come across, Mode 1 and Mode 2. The difference between the two is that the controls are in different positions. Mode 1 has the throttle and aileron on the right hand stick and the elevator and rudder on the left hand stick. Mode 2 has the elevator and aileron on the right hand stick and the throttle and rudder on the left hand stick. You can see that they do not simply have the sticks crossed over but the controls are also mixed up a bit. So the $64,000 question is... which is better ? This the source of many an argument at any flying field and always will be. Basically it boils down to what mode your radio is on when you buy it and what mode the person who is going to teach you to fly is on. About 70% to 80% of Australian flyers are on Mode 1. It is almost the opposite in the U.S.A. Many people in the UK are on Mode 1 but most people in Europe are on mode 2. Personally, I recommend people go mode 1 (You can see I'm a mode one flyer) because with more people being on that mode in Australia the more chance you have of getting someone to teach you. Also if your instructor is not at the field the day you want to have a fly there is more chance of finding another mode 1 flyer to help you for that day. Now that statement is grounds for a real argument at any field but it seems to make sense to me. Never attempt to change the mode of a computer radio yourself, there is a lot more to change then just swapping the sticks.
Bandwidth testing
2.4ghz radios do not need to be band width tested but they are required to have the 'Austraslilan C Tick' sticker on the back.
Buddy Box System This is where both the instructor and the student have a transmitter and they are connected by a cable. The instructor has the master radio and the student has the slave. The instructor holds up a switch to give control to the student, if the student gets into trouble he just releases the switch and he has control again. A great system but both radios must be from the same manufacturer and you need the cable which comes as an accessory. Usually the base model radios do not have the plug for the lead.
Okay,What To Buy Certainly JR is very good, so too is Futaba, Spektrum and Fly Dream. You only have to look at what all the world champions are using. Have a chat to whoever is going to teach you to fly and see what they are using. Not only for the prospect of using the buddy box system but they can also help you with the menus and jargon of the radio. Although most radios have the similar features different manufacturers use a different languages in their menu system. Put your radio on rechargable batteries it will save you a fortune in the long run, the most common batteries are Nicads and Nickel Metal Hydrides, although many people are using lithium batteries in their transmitters too. Go for the highest amperage batteries you can afford, the longer the charge lasts the better. Expect to pay around $300 for your radio and go up in $100 lots as you move up the models. Non computerised radio will be slightly cheaper but not really recommended. With the lower models expect to have to buy an additional servo. You will probably buy better if you are buying the whole package of radio, plane and engine. Be careful of mixing and matching servos from other manufacturers as the polarity and plugs can be different. The polarity of a JR transmitter charger is opposite to that of a Futaba and Hitec, beware of mixing your chargers. If you can't afford new certainly look around for a second hand unit. Like everything else, get someone who knows what they are looking at to look over the set BEFORE you pay out your dollars. Buy it on the condition that it passes a bandwidth test. Check the condition of the batteries, a complete new set will cost you around $50. Check that the servos don't have any broken gears or mountings. They are the first things to strip in an accident. Be particularly careful that the radio does not have 'Blackwire Syndrome' This is where the black wire (negative) from the battery gets that greeny look to it and eventually flakes away. This will definitely mean a new battery pack and definitely an internal inspection of the radio. Range test it. Beware that some 'helpful' modeler is not trying to unload his junk on to you. Don't leave your computer radio in direct sun for too long, it can effect the LCD screen.
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