Most modern RC electric helicopters use Lithium batteries. Whilst these have many advantages over older, Nickel Cadmium cells, they also have some shortcomings, not least, when it comes to safety.
Lithium batteries rely on metal oxides, typically Lithium Cobalt Dioxide (LiCoO2) to generate energy from the cathode. These chemicals have poor thermal stability, and cannot tolerate being abused. In cells that are incorrectly charged (for example, using chargers designed for different batteries) or electric helicopters that have crashed, the metal oxide becomes chemically unstable.

Although various other metals have been tried with Lithium, cobalt gives the best results. When RC electric helicopters that fly on Lithium cobalt batteries, they are flying on one of the rarest metals on earth.

The new Saphion Cells, from Valence Technology, have solved all these problems. Having spent several years searching for a safe, environmentally friendly alternative to Lithium, they have at last found the answer: a novel Olivine Lithium phosphate compound that is green, effective, and safe to use.
Olivine, is an iron rich mineral which is common everywhere, it supplies the metallic ions previously found in cobalt. Whilst the phosphate element provides the oxygen needed. The inertness of oxygenated phosphates, plus the ionic capacities of the two metals involved, provides stability with enhanced power.

Putting batteries into RC helicopters was only the start of the electric helicopter phenomenon. First rechargeable batteries such as Nickel Cadmium, then ultra light batteries like the Lithium Polymer cells arrived. RC electric helicopters leapt from being kids’ toys to being serious model aircraft.

There has now been a new battery developed called Saphion cells. You won’t have heard much about them yet, but they look set to make the current Lithium Polymer generation redundant.
These new batteries can increase flying time, increase performance and increase safety. This last aspect is mainly because fire and explosion are a worry for electric helicopters running off LiPo.

Lithium batteries are chemically unstable (owing to their ionic technology) and can be easily damaged. This does not fit well with the fact that RC electric helicopters themselves are prone to crashing.
Saphion cells make all these dangers obsolete. They are stable, in flight or in storage as well as being fully discharged without damage, and charged up in a complete safe way. In the unlikely event of the helicopter getting wet, or being crashed, they are totally immune to sudden explosion and won’t burst into flames.

When it wants to go long distance.

Which is a poor way to introduce battery power. For many years, the domain of RC helicopters was held by gas turbine and nitro power engines. The few electric helicopters there were, were too small and flimsy to be flown outdoors and would crash back to earth in the time it took to get airborne anyway.

It took the arrival of another new technology to change all that - strangely enough, the same one that is everyone’s worst enemy on the flying field.

Electric helicopters are light, powerful and often match the size of their nitro cousins. But for years this wasn’t possible. Why? Because RC electric helicopters relied on rechargeable nickel cadmium batteries to fly. These were underpowered, heavy and ran flat quickly. In fact, most of the energy was expended just lifting their weight off the ground. Then came Nokia.

Although some electric helicopters at the cheaper end of the market still do use NiMH or NiCad (predominantly micro RC helicopters, which are too small to take an Li), the majority run on lithium batteries - the same sort found in your mobile phone.

Why are they so much better? Well, firstly they are light and stable in flight - they can be slung under the body of the helicopter without affecting its flight. They are, within reason, endlessly rechargeable and each charge lasts a long time - equal to a fuel charge in a nitro helicopter.

The bad news is the batteries are hazardous and need careful handling (read the FAQs on this site for more on that). If you have switched from nickel to lithium, you may find it hard to adjust the centre of gravity (RC electric helicopters, designed to take nickel cells, utilise their bulk in the design)

Although the charge lasts longer, the current uptake is limited. This means a large electric motor will need a larger lithium battery (and often two or more) to provide sufficient power. This can make larger electric helicopters expensive to run.

Unlike NiCad, lithium batteries cannot be drained completely of juice, or they will be damaged beyond repair. Finally, you’ve had it if your heli gets her feet wet. We all know what happens when we drop our mobiles in the bath.

All the same, lithium batteries can only be a good thing for electric helicopters and with mobile phones getting ever smaller, even mini-micro RC helicopters don’t lose out any more.

The swash plate is essential to the operation of all RC electric helicopters (and, indeed, all full sized ones). Without it, there would be no cyclic or pitch control.

There are many variations on swash plate design, depending on the rotor head type (collective pitch, fixed pitch or co-axial) and the make and model. However, the main components all work in exactly the same way.

In electric helicopters, the swash plate’s job is to translate the cyclic and collective commands from the transmitter/receiver into movement changes of the fly bar and main blades. It does this via its affect on the rotor head - the construction to which the fly bar and blades are fixed.

The swash plate is attached to the main shaft, below the rotor head. On all RC helicopters, there are two discs - the lower one, which is stationary when the axis rotates and the upper one which rotates. This is possible because the lower part of the axis has an outer, non-spinning “sleeve” to which the lower disc is firmly attached.

Linkages vary between electric helicopters, but the stationary disc directly connects to the cyclic and (if present) the collective controls, via servos located underneath. These servos respond to commands sent by the pilot via the transmitter.

The servos work individually to tilt the swash plate in any direction (cyclic movement) and - in electric helicopters with collective pitch - collectively to raise the entire swash plate assembly upwards.

The two discs are attached to each other via a bearing linkage. This linkage varies between RC electric helicopters, but in all cases its reason is obvious: to transmit cyclic changes from the lower to the upper disc, whilst allowing the upper to spin freely.

The upper swash plate has linkages to the fly bar and - in more advanced electric helicopters - to the rotor blade mechanism itself. In this way the swash plates of RC helicopters cause changes in directional movement - just as with the real thing.

Once you feel competent flying electric helicopters, you will probably want to take it further, and join a club. For most keen pilots, this is as essential as their Tx.

Practically all RC clubs, whether mixed flight or specific to radio control helicopters, expect their members to have BMFA membership and Insurance in order to fly in competitions or club events. Some clubs make it a condition of membership from the outset.

The BMFA achievements award scheme for radio control helicopters is the next stage on. It allows you to participate in BMFA competitions, which require you to have a proven level of competence at least equivalent to Sportsman Grade A.

Of course, you may decide you just want to fly for pleasure – but why not take the awards anyway? They are not that difficult.

BMFA awards are a routine part of Heli Club life, with the testers most often being club members themselves. Award Test days are similar to other club events – rows of RC electric helicopters waiting with their nervous owners; pegging checks and flights in single fashion; a lot of relieved back-slapping and a trip to the pub at the end.

All RC Helicopters start with BMFA Level A. This shows you are competent in basic manoeuvring skills, although to fly in public events you will need to complete Level B.

In Level A, you must show your skills in:

Pre-flight checkups – yes, it starts before the electric helicopters are even switched on.

Stationary hovering, tail in.

Sideways hover – both directions.

Backwards hover.

“Lazy eights.”

Landing.

Two attempts are allowed per day, there is no limit to the number of “retakes” you can do, and no written work or theory is involved.

Unlike most things in life, the tests are free. So why not prove you really have arrived in the world of RC electric helicopters, and earn your (rotary) wings?

Hobby grade RC helicopters are not cheap – especially if you are a novice who has decided to throw caution to the wind, and purchase a CP model suitable for outdoors use. Even if you have flown RC planes or gliders, you will soon see how temperamental electric helicopters are, and how easy it is to crash them.

Novice pilots should invest in some kind of training aid, until they get familiar with the controls. The common ones are:

a) A training kit or stand. The kit fits under the skids, and allows you to fly as you would normally, but with more stability. They are ideal for beginners learning hovering techniques outdoors. The stand anchors the heli in one spot, whilst you operate the controls. They are suitable for indoors practice, and also for checking settings during maintenance.

b) A flight simulator program. These are often supplied with novice RTF Electric Helicopters, but can be purchased or downloaded separately. They have a dedicated Tx (which cannot be used for real flying) or you can use the digital Tx that came with your craft. They are used by all pilots, from novice to competition level, as every movement radio control helicopters make can be reproduced – some are very sophisticated. You can even program in weather changes!

c) A buddy box system. Originally the domain of Fixed Wing pilots, it allows two transmitters (Tx) to be linked in tandem to the same chopper. Either or both of the operators have full control, all the time, with the more experienced Tx holder being able to override the novice should the need arise. This is a recent development in digital Tx systems.

d) An RC Helicopter Instructor, who works in tandem with any of the three above. Most often, c)

If you belong to a club, the chances are they have at least one instructor on the crew. It’s a good way to earn extra “pennies” once you’ve taken your BMFA certificate. A buddy box and instructor, or co-pilot, is one of the best ways to learn – akin to having driving lessons in a dual control car.

RC Electric Helicopters brought the world into miniature – all the tiniest RC helicopters are electric.

The largest, on the other hand, are gas turbine or petrol powered. They’re scale models of the real thing – not much smaller than passenger craft. Nonetheless, there are plenty of big electric RC helicopters out there.

So let’s have a look at the large and the small of RC flying …

Officially, the largest commercially sold RC Helicopter is the Maxi RC Nitro. Touting a rotor diameter of 1.76m and only a little less than this in length, this monster’s blades rotate at over 1000 rpm.

But look at this - the Raptor 90 SE, the largest of the RC electric helicopters, matches the Maxi in everything except weight. In fact, this bird is actually bigger. Rotor diameter is still a blade-ripping 1.76m, but nose to tail she comes in at – wait for it – 2.16m. That’s 7ft in English.

Why is she in second place? Well, partly because every RC heli flyer likes his bird to be the biggest. But also because RC Electric helicopters weigh less. Which, as we all know, doesn’t count …

Incidentally, the Maxi also makes an electric version, with a 1400mm (55 inch) fuselage and rotor diameter of 1640mm (65 inches). Plenty big enough for the average ESky owner.

As you might expect, these are kit builds. Safe to say they’re probably not that fiddly to build. Despite the scare stories, there have been very few accidents attributed to large model electric helicopters.

Although you can enter competitions for electric helicopters at any grade, most novice flyers start at Sportsman A. This is only for official BMFA/FAI competitions, of course. Many heli clubs run their own “fun” contests, which are loosely based on BMFA rules but perhaps not quite as daunting for the first-timer.
To begin with, it is essential you are familiar with Collective Pitch RC Helicopters, and can fly one properly.

Really master your hovering technique (without your “water wings”) and have a few practice runs on your own, using a marked out box area. Download a BMFA competition plan if possible.

But flying RC electric helicopters is hardly the Red Arrow team – so how good do you have to be?

Well, in terms of flying ability, there isn’t really a lot of difference between aerobatic competitions for radio control helicopters, and doing aerobatics in the real thing. Except maybe for the giddiness …

These are a few of the manoeuvres gleaned from a recent BMFA Sportsman Competition, held at local level:

VERTICAL CIRCLE MANOEVRE:
Electric helicopters make a spiralling turn upwards, in both forward and reverse, to describe a half circle. They come down in the same manner, occupying the second half of the circle.

VERTICAL TRIANGLE WITH 360° PIROUETTE
RC helicopters rise to eye level, and then take a 45 degree line upwards. They perform a 360° pirouette, descend at a 45°angle in the opposite direction, do their second pirouette and finish the 3rd side of the triangle.

LOOP and ROLL
Self explanatory – but have you ever tried looping and rolling electric helicopters in a strong cross-wind, with 3 judges scrutinising every move

Any member of an RC heli club worth their salt enters competitions. Once you’ve had a few hours flying time with your CP chopper, it is something you should give serious thought to.

This goes even if you are not competitive by nature. After all, it’s only doing what you already do anyway; it just adds a new dimension to your sport.

RC Helicopters are flown at both show and aerobatic (3D) competitions. Show events are still considered a sport, but are mainly concerned with creativity: showing off your hand-built and airbrush painted scale model with a series of choreographed moves, often set to music.

Beautiful and breathtaking to watch, the majority of these craft are nitro or gas powered, and built from plans or kits. Electric Helicopters do take part – and win – but we’re talking individuality here, rather than RTF.

Pilots of RC Electric Helicopters are more drawn to the 3D or aerobatic side of the industry – the one with all the big competitions. The FAI is, after all, the international body for all things 3D aerobatic, with the BMFA being its UK representative.

3D competitions are tests of skill rather than looks, and all RC Helicopters in the sport are pod-and-boom construction. This means that your bird was born to take part in competitions – even if you weren’t.

The majority of Electric Helicopters sold are the pod-and-boom type (although scale models are becoming ever more popular, especially as “under the skin” they are all pod-and-boom construction anyway). Once looked down upon by the smoked-up lobby, they are now seriously respected at sports level.

Why compete? Simply put, it hones what you already have, and gives you a chance to improve on it by battling it out against others. You also get to learn some cool new moves.

The best way forward, and the most enjoyable, is to put your name down for a couple of “in house” club meets. These have looser constrictions than official BMFA/FAI competitions, but are run to the same protocol. Most clubs combine BMFA rules with a few “tweaks” of their own; giving local terms to some of the 3D manoeuvres, for example, or using an unspecified obstacle course layout.