Electric RC helicopters
- coaxial, FP or CP... huh?!
In recent years electric rc helicopters have become very affordable, very widely available and much easier to fly than radio controlled helis ever have been, making them the ultimate 'must have' rc model and bringing countless new people to the radio control flying hobby.
As a result, helicopters now make up the fastest growing sector of the hobby and this is a trend that goes from strength to strength as more and more radio control helicopters appear in the shops.
While that's great news for the hobby, it's not so great for the beginner who can quickly find himself (or herself) completely overwhelmed with which type of EP (electric powered) rc helicopter to buy. Hopefully this page will break down some barriers and clarify some differences between heli types...
Essentially there are three categories of electric rc helicopter - coaxial, fixed pitch and collective pitch, the latter two being commonly abbreviated to FP and CP respectively.
Electric rc helicopters are available here.
Coaxial electric RC helicopters
Most electric rc helicopters follow the conventional heli layout with a single main rotor and a tail rotor, but there are also helis that have two main rotors, one above the other, and no tail rotor; these are called coaxial rc helicopters, also sometimes called dual rotor or contra-rotating helicopters.
The E-flite Blade CX3, shown above, is a fine example and is just one of several coaxial helis produced by electric rc flight specialists E-flite.
Based on the real life MD-520N helicopter, the Blade CX3 is successor to the hugely popular Blade CX2, one of the best-selling coaxial rc helicopters to date and the very first RTF rc aircraft to be sold with a 2.4GHz radio system - a major milestone in itself.
On a coaxial rc helicopter, such as the Blade CX models, the two main rotors spin in opposite directions to one another. As a result the torque force that's naturally generated by one spinning rotor is cancelled out by the other spinning rotor.
Since it's this torque force that makes a tail rotor essential on a conventional single rotor helicopter, a coaxial rc helicopter doesn't suffer from the same torque effect and so a tail rotor isn't necessary. That's one less channel to worry about when learning to fly!
This type of electric rc helicopter is very stable in the air and can be flown around with little difficulty, even by someone with no prior experience. Hovering and slow forward flight is easily achieved but it has to be said that a coaxial helicopter is somewhat limited in its flight performance; banked turns, fast forward flight and aerobatic maneuvers are out of the question.
But for a gentle and easy introduction to flying a multi-channel rc helicopter a coaxial is a good choice, and their popularity speaks for itself.
Coaxial electric rc helicopters do have the big advantage of being easy to master and the good 'hobby-grade' ones such as the Blade CX helis can be flown right out the box with little or no setting up involved.
In comparison, a single rotor RTF electric rc helicopter advertised as "Can be flown straight from the box with NO experience!" invariably needs some tweaking here and there, along with some very sensible and time-consuming practice.
Fixed Pitch (FP) electric RC helicopters
The next step up from the coaxials is the single rotor fixed pitch helicopter and these, like coaxial helis, have also been very popular with beginners to the hobby.
FP helicopters such as the Walkera Dragonfly 4, Venom Night Ranger and EF Sabre for example have been big sellers but such helis still have a steep learning curve because of their inherent instability in the air - normal helicopter stuff!
More recently E-flite (who else?!) have cornered the single rotor beginners' FP helicopter market with their innovative little Blade mSR and its slightly larger cousin the Blade 120SR electric rc helicopters, both shown below:
These little fixed pitch rc helicopters are significantly easier to fly than the other FP examples mentioned above and have proved themselves to be very popular with beginner and expert heli pilots alike.
Fixed pitch electric rc helicopters are in every sense true radio control model helicopters other than they lack collective pitch control to the main rotors.
It's this collective pitch that controls altitude on a real helicopter by changing the pitch angle of the main blades, but FP helis rely on changes in rotor speed (i.e. main motor speed) to control altitude. Faster turning rotors generate more lift, and vice versa, so motor power is used to make an FP helicopter climb or descend (read more on FP vs. CP).
The downside to relying on motor power as opposed to collective pitch control is the response time. The time lag between your throttle stick movement and the change in rotor speed means that maintaining a constant height is at best very tricky, and this is where fixed pitch helicopters let themselves down somewhat. But having said that, they do sell in their thousands and make an excellent introduction to model helicopter flying for those who want more than a coaxial helicopter.
Collective Pitch (CP) electric RC helicopters
Succeeding the fixed pitch helicopters in terms of complexity, cost and difficulty-to-master are the collective pitch (CP) helicopters such as E-flite's Blade 450 (shown below) and the Align range of helicopters, for example.
The Blade 450 replaces the very popular Blade 400 and like its predecessor is fully 3D capable. The term '3D' means that the helicopter can perform very advanced and aggressive aerobatics, but this kind of flying takes many many hours (months/years) of practice and a great deal of confidence!
Above: the Blade 450 is a fairly typical advanced (CP) electric rc helicopter.
And here's the official promo video of this helicopter to demonstrate what such helis are capable of in the right hands...
But even though many CP helis like the Blade 450 are marketed as 'Ready To Fly' it's important to remember that they are serious business. Learning the co-ordination of motor power, collective pitch control, cyclic pitch control and yaw takes a lot of time and practice and the process cannot be rushed.
The purchase of a rc flight simulator such as the excellent Phoenix simulator is highly recommended as a serious training aid - it's an extra cost of course, but well worth it if you're even half-serious about the hobby.
Deciding to buy a fully functional collective pitch rc helicopter isn't a decision to make lightly and it's important that you understand what's involved with owning and learning to fly a CP heli. They're not toys but serious radio control models, and if you're unsure about the seriousness of such helicopters it's best to start off with a simple coaxial or FP model and work your way up to a CP one.
Incidentally you might like to consider buying The Beginner's Guide To Flying RC Helicopters ebook for a complete and comprehensive look at what's involved in getting in to flying rc helicopters.
Another ebook to consider if you're intent on buying a CP helicopter is Setup & Tips for Electric Collective Pitch RC Helicopters. An essential resource for anyone looking at getting in to CP helicopter flying, this ebook certainly saved me a great deal of time and money when I first started out with a CP electric helicopter!
An important point: With any single rotor electric rc helicopter of 4 channels or more it's very important to understand that they do have a steep learning curve and should never be classed as a toy; spinning rotor blades can do a lot of damage and all rc helicopters have to be treated with a great deal of respect at all times.
Only coaxial rc helicopters, talked about at the beginning of the page, are much easier to fly with no experience.
Regardless of the type of model you choose, the great thing is that electric rc helicopters are now available to the masses and at very affordable prices. And the range is such that there's a helicopter to suit just about every budget, preference and flying need.
The traditional horror stories of how expensive and difficult radio control helicopters are to fly are no longer strictly true. This is excellent news for the hobby, an improvement long overdue!
Electric rc helicopters are available here.
Related pages
The Beginner's Guide To Flying RC Helicopters.
