HELICOPTERS

"Discover electric RC helicopters at this site. Here you will find articles, guides, product reviews, and a discussion forum dedicated to this enjoyable hobby."

Frequently asked questions

As a beginner which model should I buy?

Most 30 size models are okay to start with, it is only much later in the learning curve that the differences start to show up. The Thunder Tiger Raptor is probably the best 30-size model around at the moment, but the model, which is most widely used at your local club, could be the best bet as there will be plenty of help and possibly a good supply of spares.

Do I need to join a club?

Yes, you will need help with setting up and experienced helicopter pilots can also test-fly your model as you progress, if you know the model will do it then you know its down to you. Try to join a club, which is exclusively for helicopters, even if you have to travel, it will be worthwhile. You should also join the BMFA, which will give you liability insurance of up to 5 million pounds, as well as many other benefits.

I have been flying model aeroplanes for a few years and I would like to learn to fly a model helicopter. Will my fixed wing experience help?

It will help in that you are familiar with radio control but you will still have to learn from the ground up. Learning to hover can take some time and you will have to be determined if you want to do it.

 

Aerobatics

If possible ask an experienced member in your club to test fly your model, this way you will know that the model set up is okay for aerobatics and if you have a flight simulator practise on that first.

Before you attempt any of the following manoeuvres you need to get used to flying at a considerable height, high enough so that if things go wrong you will have time to correct it but low enough to see what is going on. It's a difficult balance but I know from experience that the ground seems to come up very quickly when you make a mistake. You will be able to gradually reduce height as you become more proficient at each manoeuvre.

Loops
The loop is probably the easiest and therefore the first manoeuvre to try. Start with the model flying at a safe height, into wind and with plenty of forward speed. When the model is passing in front of you apply up elevator (back cyclic) to start the climb into the loop, (not to much up elevator or the model will come to a stop) as the model reaches the inverted section pull a little more up elevator and keep it there until it gets to the bottom of the loop. Your first loops will probably be more like a figure 9 but if you lower the collective pitch to negative at the top of the loop you will gradually make the loop more circular.

Stall turns
As with the loop pull back on the elevator to start the climb, as soon as the model is in a vertical climb reduce the collective pitch to 0 degrees, when the model comes to a stop apply full rudder left or right. You are now in a vertical dive don't panic! This is where the safe height comes in; just apply up elevator to get the model back to forward flight.

 

What radio should I use?

The best you can afford is the short answer but anyway the transmitter must be specifically for helicopters and again the one most widely used at your club is probably best.
We recommend that you start with at least a basic computerized 6 channel helicopter radio such as the JR 652 or Futaba 6XHS. If your budget can go higher, get a good 7,8, or 9 channel heli radio with dual ball bearing servos such as the Futaba 9CH, JR 8103 or Hitech Eclipse 7. As your flying skills progress, these better radios will keep you from being limited by the basic features provided i n the entry level units.

 

Why do I need a gyro?

The gyro helps to stabilize the tail and without it the model will be almost impossible to control. Modern piezo gyros are better than ever before and it is one thing that will make the model much easier to control, however, a piezo gyro needs to be matched to a high-speed servo, preferably digital. Again buy the best you can afford and don't waste any money on old motorised gyros, they have been superseded.

When should I remove my training undercarriage?
Can you hover tail in and side on, both sides and land the model level every time?

If yes, then you could remove it but don't let anyone persuade you until you feel you are ready.

I can hover and fly circuits but how do I learn to hover nose in?

There are two possible ways to do this either: refit your training undercarriage and practise from the ground up or, fly the model towards you gradually slowing up until you can hover. I have seen it done both ways; I did it by the second method.

 

What is an autorotation?

An autorotation is an engine off landing, the idea is to make the decent with just the right amount of negative pitch so that there is enough energy stored in the rotor to flair and land the model. This is considered quite an advanced manoeuvre by some but if your engine cuts the learning will be worthwhile.

What are the benefits of a 60-size model?

A bigger model will be more stable particularly in windy conditions, the power to weight ratio is also better and the extra rotor diameter leaves more reserve for autorotations. However it will use more fuel and spares are usually more expensive.
Better quality servos are also advisable in a 60-size model.

Gyro

The purpose of the gyro is to stabilize the tail, without it the model would be almost unflyable. Early gyros had a motor and two flywheels inside and at the time worked quite well but they are no match compared to piezo gyros, which have no motor but use an electronic sensor.
Piezo Gyros
Modern piezo gyros have never been so good and are no longer an expensive alternative but an essential part of the radio system. Modern peizo gyros can cost anything from £40 to £300.
So how much should you spend and which one should you buy?
Well at the lower end of the scale the gyro will be single rate adjusted on the gyro itself and will not have pilot authority, while at the top of the range it will probably be dual rate in both normal and heading lock mode (sometimes called heading hold or AVCS), selectable from the transmitter, and it will also have full pilot authority.
Modern piezo gyros have a very fast response, and will need a servo, which can keep up with the gyro output. Servo speed is measured by the number of seconds it takes for the servo to turn 60 degrees so a digital servo with a speed of 0.12s/60 to 0.08s/60 is the ideal but you will have to pay around £60 to £125 for it.
Gyro gain
The best way to adjust gyro gain is to turn it up until the tail wags in forward flight then turn it down a little. You should be able to get near 100% gain, if you cant then try changing the length of the rudder servo arm, there is no point spending serious money on a good gyro and then only using 50% gain.
Pilot Authority
On a standard gyro when you input a rudder command the gyro will try to correct the tail back to the centre, the higher the gain on the gyro, the less tail authority you will have. With pilot authority the gyro gain decreases as you input commands so you can have 100% gyro gain and still have full tail authority.
Heading Lock
With the gyro in normal mode the tail will weathercock to some extent so when flying circuits or hovering in to wind the tail will tend to follow the line of the model. In heading lock mode the tail stays wherever you put it, so it is quite easy to fly the model sideways or backwards at speed without losing the tail position. The only downside to heading lock mode is that you have to steer the tail all the time as it will not naturally follow the model, and if you enter a manoeuvre, say a loop, with the tail offline it will stay offline throughout the manoeuvre. If you are not sure which mode the gyro is in, with the radio on and without the engine going, move the rudder control fully to one side, if heading lock is selected the servo will stay at one end until you move the stick back to the other side.
Mixing Makes
I have used Futaba, JR, and CSM gyros on JR radio systems with no problems at all but I would advise the use of a matching rudder servo in the case of JR or Futaba, as they would have been designed to work with their own servo.

 

 

Pitch & Throttle Curves

Most transmitters will have three flight modes available via the flight mode switch (sometimes called the idle up switch), this will give you three pitch and throttle curves, one for normal hovering, one for aerobatics like loops and rolls, and the third one can be set for more extreme 3D type flying.
Throttle Curves
During aerobatic manoeuvres negative pitch is used during the inverted sections so the throttle curve is set so that it will not drop below 50%, while you have full pitch control.These high throttle curves should only be switched in when flying and not before take off as the engine will over rev in this situation.The main difference in pitch curves will be in the negative section where up to minus 8% may be used for inverted flight, where as for the hovering mode minus 1 or 2% will be ideal. It is also useful, in the hovering mode, to flatten out the curve at the centre point to make the model less sensitive.
Revolution Mixin
This is available on most transmitters and is quite simply a mixer, which adds pitch to rudder to correct tail swing on adding power. However it is not always easy to set up and if you have one of the latest piezo gyros with heading hold, you probably wont need it
Cyclic to Throttle Mixing
Some transmitters have dedicated mixers for aileron to throttle and elevator to throttle but you can use any free mixers, try about 20% throttle to start with and if possible only on flight mode 3 for more extreme manoeuvres. Be aware that if your throttle is already flat out, the mix will try to add more throttle and could overdrive the servo, some transmitters (like the JR PCM10) take account of this and therefore will not overdrive the servo.

Upgrades

If you have only recently started in this hobby you probably have a 30-sized model with wooden blades and basic radio equipment, fair enough, you don't want to spend too much on a new venture, as you may not like it.  As your flying progresses you will want to improve your equipment accordingly:
Exhaust System
I mention this first, as a quiet muffler is absolutely essential, flying sites are lost due to noise complaints so the quieter the better. Avoid tuned pipes as they are generally noisier, the extra power is not needed and the engine is much more difficult to set up.
Main blades
Most carbon glass blades will be an improvement on the wooden ones that came with the model, there are 2 main types or sections, semi symmetrical which have a flat bottom to give more lift, and fully symmetrical which are the same shape both sides. Which ones you go for depend on your flying style but without getting to complicated, symmetrical blades are better for aerobatics as they give the same pitch inverted as they do the right way up, where as semis generally perform better in autorotation.
Radio
More of an essential than an upgrade is a PCM receiver, as PPM receivers have no fail-safe system. If your transmitter is a very basic one it might only have 1 or 2 pitch and throttle curves and probably only 3 point curves at that. This will be limiting, particularly if you want to progress to aerobatics. The more expensive transmitters will have a minimum of 3 pitch and throttle curves, and many more functions, which become more useful as you progress
Gyro, Servo and Tail Control
The best gyro you can afford along with a suitably fast rudder servo will probably be the most noticeable upgrade you will get, depending on what gyro you had before of course. My Raptor 30 cost a little over £200 but the gyro and servo cost nearly £300! The point is no matter how good the model it will be much better with a good gyro. The control from the rudder servo to the tail pitch control will vary from one model to the other, a smooth straight direct control is desirable, tail boom mounted servo brackets and carbon rod upgrades are available to suit most models and these tend to work best.
Servos
The latest digital servos are much more accurate and responsive and start at around £40, although if you have a 60 sized machine you may want to spend more on higher torque servos.
Fuel Header Tank
There are at least 3 good reasons to fit a header tank, it will stop problems with fuel foaming, it gives a consistent level of fuel no matter how much fuel is in the main tank or what ever the attitude of the model, and you get longer flight times.
Metal Upgrades
There are plenty of after market metal upgrades available for most makes of helicopter. They are usually anodised in purple or gold colour and even if they are not needed they do look nice on the model. A metal swash plate is probably the first upgrade, followed by the washout assembly and many more.

 

 

Autorotation

There are many pilots who advance to quite a high level of flying yet never bother to learn autorotations (autos), a comment often heard is "why stop an engine that is going perfectly well", fair comment I suppose but what if your engine cuts, chances are you will panic and crash the model. So there is one good reason to learn autos, the other reason being the shear satisfaction of landing your model time after time with no engine power. I having gone through many stages of learning to fly but I found the autorotation the most rewarding of all.
During autorotation the negative pitch will control the glide angle of decent, this will be about minus 3 degrees but will vary according to wind conditions, blades, and forward speed during the auto. I always set my negative pitch to about minus 5 degrees and then adjust the pitch with the stick to get the ideal decent angle.
Before you start, you will need to set your throttle hold switch so that it gives a reliable engine tick over when operated. If your tail is driven during autos you should set the tail blades with no pitch when the hold switch is operated, as there is no torque from the rotor head during autorotation the tail does not need any counter acting pitch. You must be able to perform a 45 degree approach and landing before any attempt at autos. Also make sure you are familiar with the throttle hold switch position on the transmitter, you will need to find it quickly while practising.
To give you an idea of how much power is in the rotor head with no engine power, from the ground, raise the throttle until the model is light on the skids, switch to throttle hold and gently add pitch, the model will hover for a short time.
Start by flying your normal circuits at a safe height, when flying into wind hit the hold switch and apply negative pitch, the forward motion of the model should keep the tail straight, if the tail kicks to the left or right return the hold switch to normal and land the model, adjust the tail trim and try again. Once you are happy with the tail trim keep practising autorotation descents but only down to a height that will give you time to abort (return the hold switch to normal). After hours of practise you will be able to descend at 45 degrees, apply back cyclic to flair (stop the forward speed) and add pitch to land. The difficult part is the timing of all this, if you add to much pitch to early (to high) you will use up the inertia in the rotor head and will not have enough to land. If you add pitch to late the result is obvious.
Autorotations are easier with a 60 size model due to the extra blade power but wither it's a 60 or 30 size model, the type and weight of the blades will have a major effect on auto performance, use glass/carbon blades like SAB or TG for best performance.
Keep practising but remember - it supposed to be fun!

 

Engine

Getting the mixture right on a helicopter is far more important than on a fixed wing model, mainly because the throttle is operating at mid range for a lot of the time and a clean response is required throughout the rev range. This can only be achieved by getting the correct balance between the bottom end (idle) needle and the main needle, most OS motors come out of the box fairly close to the correct setting, but I have found some other makes to be a long way out. Don't expect to get the mixture perfect on a new engine, it will need some running in time.
Assuming you have a new engine in your heli I would proceed as follows:
With the glow supply not connected set the throttle at high tick over, put your finger over the exhaust outlet and turn the engine over until you have fuel coming out of the exhaust. If no fuel comes out of the exhaust then either the throttle is not open enough or the idle needle is set to lean, if you have to adjust the idle needle only turn it a maximum of a quarter turn at a time. As soon as you have fuel coming out of the exhaust stop turning the engine, connect the glow supply and attempt to start it, making sure you have a firm hold of the rotor head and are ready to adjust the transmitter should the engine over rev.
If when you disconnect the glow supply, the engine slows down or stops, the idle mixture is probably to rich or the glow plug is duff or not the correct type (to cold). I wont get into the technicalities of glow plugs (cus its boring) but suffice to say that I have used Enya no.3 or OS no.8 in all my engines with no problems.
Setting the main needle can only be done by flying the model but an initial setting of 1.5 to 2.5 turns out is about right for most engines. Plenty of smoke with plenty of power is the ideal situation but some running in will be required before the ideal mixture can be achieved gradually leaning out after a few gallons of fuel.
Try to avoid using tuned pipes as these complicate the mixture set up and are generally noisier than standard mufflers. I have personally never found the need for the extra power these pipes produce, but it depends what you are trying to achieve I suppose.
On the subject of fuel, I use Model Technics Bekra 10 which is a fully synthetic mix with 10% nitro. Fuel with castor oil in the mix is okay but  it's a bit messy. Raising the nitro content does not in itself give more power, but allows the engine to run on a richer mixture and more fuel going through gives it more power and cooler running.
Hope this has helped a little but don't forget to read the instructions with your engine and again, someone with experience in your club will be a great help.

 

 

FirstCircuit

Before we get into the flying, set your lower pitch to about minus 2 degrees with 5 to 6 degrees in the hover position and 8 to 9 degrees at the top. It is also useful to set up the radio so that the throttle trim gives you tick over in the middle, idle up at the top and engine cut at the bottom. You should be able to achieve this using the travel adjustment (not the throttle curve) on the transmitter, if not you will have to adjust the throttle servo arm as required. You should now fly the model with the throttle trim at the high position; this will keep the engine revs up when in negative pitch there-by giving more control. As with learning the hover it is a good idea at this stage to get an experienced pilot to fly the model and adjust the trims as required, this will make it much easier for you.
Start with the model tail in, facing into wind, at a height that you are happy with, then hover over to your left side, back to the middle and then to the right side, keep practising this with the tail in then gradually turn the tail to follow the direction of the model and without stopping in the middle. The turns are initiated by applying lateral cyclic (aileron) to produce a bank, together with tail rotor (rudder) to make the tail follow the turn. The amount of aileron and rudder applied will vary according to the forward speed of the model and whether you are turning upwind or downwind. With practise this will eventually become a figure eight with the turns at both ends away from you and at the same height all the way round.
Do not be tempted to fly the model in a circuit around yourself; this is bad practise as most flying sites will not permit you to do this, so all flying should be in front of the pilot and anyway, you will not learn much from this as the model is in the same situation relative to you, all the way around.
Some pilots find the transition from forward flight to the hover quite difficult and avoid this manoeuvre by stopping the model at height and lowering the model vertically to land. This looks very untidy and if you are ever going to fly in a scale like manor you will have to approach at 45 degrees, you will also need to be able to do this to learn autorotations.
To return the model to hover from forward flight reduce power and apply back cyclic, adjust the amount of each control to achieve a 45 degree approach. Ideally the approach should be into wind but make sure you practise the left and right to avoid getting handed.
As you gain confidence with flying circuits try to gradually make them higher and faster. The height will be useful later when you attempt new manoeuvres, giving you more time to correct a mistake before the ground comes up! Also don't be afraid to fly on a windy day, I have seen many pilots build up a fear of the wind and you can't let the weather stop you flying, particularly if you live in the UK.
Remember, the only way to learn is stick time and lots of it.

 

Hover

Before we get into the flying, set your lower pitch to about minus 1 degrees with 5 to 6 degrees in the hover position and 8 to 9 degrees at the top. It is also useful to set up the radio so that the throttle trim gives you tick over in the middle, idle up at the top and engine cut at the bottom. You should be able to achieve this using the travel adjustment (not the throttle curve) on the transmitter, if not you will have to adjust the throttle servo arm as required. You should now fly the model with the throttle trim at the high position; this will keep the engine revs up when in negative pitch there-by giving more control. As with learning the hover it is a good idea at this stage to get an experienced pilot to fly the model and adjust the trims as required, this will make it much easier for you.
Start with the model tail in, facing into wind, at a height that you are happy with, then hover over to your left side, back to the middle and then to the right side, keep practising this with the tail in then gradually turn the tail to follow the direction of the model and without stopping in the middle. The turns are initiated by applying lateral cyclic (aileron) to produce a bank, together with tail rotor (rudder) to make the tail follow the turn. The amount of aileron and rudder applied will vary according to the forward speed of the model and whether you are turning upwind or downwind. With practise this will eventually become a figure eight with the turns at both ends away from you and at the same height all the way round.
Do not be tempted to fly the model in a circuit around yourself; this is bad practise as most flying sites will not permit you to do this, so all flying should be in front of the pilot and anyway, you will not learn much from this as the model is in the same situation relative to you, all the way around.
Some pilots find the transition from forward flight to the hover quite difficult and avoid this manoeuvre by stopping the model at height and lowering the model vertically to land. This looks very untidy and if you are ever going to fly in a scale like manor you will have to approach at 45 degrees, you will also need to be able to do this to learn autorotations.
To return the model to hover from forward flight reduce power and apply back cyclic, adjust the amount of each control to achieve a 45 degree approach. Ideally the approach should be into wind but make sure you practise from the left and right to avoid getting handed.
As you gain confidence with flying circuits try to gradually make them higher and faster. The height will be useful later when you attempt new manoeuvres, giving you more time to correct a mistake before the ground comes up! Also don't be afraid to fly on a windy day, I have seen many pilots build up a fear of the wind and you can't let the weather stop you flying, particularly if you live in the UK.
Remember, the only way to learn is stick time and lots of it.

Scale

If you're getting a little bored with throwing your model around the sky at great speed and want something different, scale may be the answer. With so many skills required it is bound to be interesting.
There are three main ways into scale helis :

  • Buy a complete kit, which includes all scale parts as well as the mechanics. (i.e.Hirobo Lama or JR Ergo Robinson R22))
  • Buy a pod and boom model,which is also designed for use in scale fuselages (i.e. Vario or Graupner/Heim).
  • Buy a fuselage and fit your chosen heli into it.

Option 1 is the simpler and cheaper one although there will be less choice of models. Option 3 will require a higher degree of design and skill to build. Option 2 is I think the best option as once you have the pod and boom model you can fly it for some time to test and get used to it before putting it into a fuselage also there are plenty of scale fuselages to choose from.
Your choice of subject for scale might be your local police helicopter or a military helicopter or maybe one that you have seen on film, like the airwolf, or it could be one that you just like the shape of. Whatever you choose remember that a full fuselage will always restrict access to the mechanics where as models like the Robinson R22 or Hughes 300 will be more accessible. This may not be a problem to you, but worth bearing in mind.
Three, four and five blade rotor heads can be fitted for more realism though they are expensive and have different flying characteristics to the standard two blade and flybar.
Also available from Vario are models like the EC 135, which has an enclosed (Fenestron) type tail rotor and the Notar which has no tail rotor but uses vectored air instead.
Flying a scale model is quite challenging and requires a great deal of accuracy to make it look realistic. Smooth hovering, slow climb outs and circuits, and nice 45 degree approaches are all part of scale flying. I prefer a model which flies well and looks realistic in the air rather than one which is accurate in every detail but is not flown due to the pilot being afraid of a possible crash, maybe the pilot lacks the confidence or has spent to long on all that detail!

 

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