Small Electric Helicopters A Good Place to Start?

Small Electric Helicopters
One thing that seems to cause a lot of uncertainty is which micro heli is the right one? Well there is no simple answer to this as they all have their own place in the market. So to help you make a choice I have laid out the basics of each model.
Currently the Align T Rex 450 followed by the Thunder Tiger Mini Titan are by far the most popular mini helis although this is a very dynamic part of the heli market so things are changing all the time.
All the effective micro / mini helis are battery powered, an IC (internal combustion) engine at this size is not very practical and is a noisy messy little thing which is not really what you want for flying around or close to the house anyway!
 
A Little History
The development pace of small electric models has been incredibly rapid, just a few years back the standard micro heli would have been the Icarus Picolo or Century Hummingbird, both are conventional single main rotor fixed pitched models, their size and slow rotor RPM made them effectively very unstable and hard work to fly, they didn’t tolerate wind at all well which means they were more suited for flying indoors, but their poor stability made flying them indoors very hard work.
At the same time if you wanted a micro heli with collective pitch and aerobatic / 3D capability then the MS Hornet was the best available but needed very careful building and set up to get the best out of it, for it’s size and time it was great but needed a good amount of skill and experience to have any really chance of making it fly well.
The two most significant things to happen to this size of models and in effect split it up into two separate types of models was:
Firstly the development of the contra rotating models like the Twister Medivac (click here to see) & more recently the Blade MCX 2 (Click here to see).
The advantage of this type of model is they are much more stable than a model of this size should be due to the very heavy flybar weights, a feature which would not work well on a conventional model. These models all come ready built and ready to fly. They are the most economical way to get into model helicopters, their stability and size mean they really can be flown inside the average house with little practice. As they are still fixed pitch type models, which run at a relatively low rotor speed, they have little energy in them so don’t tend to damage themselves much in a crash. The flip side of this low rotor speed and their small size means they do not tolerate much wind so although they can be flown outside it really does have to be truly calm.
Secondly small models got a little bigger, the 450 sized was developed of which the Align T Rex 450 (click here to see) has been the most successful and practical.
All these models feature collective pitch control of the main rotor and have significant advantages over the older collective micro models like the MS Hornet just by being a little bigger means they are big enough to use more conventional construction techniques, i.e. they are screwed and bolted together rather than glued together which means construction, maintenance and repair is a whole lot easier! That little extra size also means they are no where near as fiddly to build or set up, the stability and ability to fly in wind goes up dramatically to.
At one time there was some pretence that one model could be used for both indoors and outside flight. Whilst any small model can be used for both, anything with collective pitch will run at too high a rotor speed and be too sensitive to cyclic inputs to comfortably fly inside an average room but great for a garden, park or large sports hall. The contra rotating models like the Blade CX2 or Medivac are absolutely ideal for flying in a limited area as they have the stability and slow damped reactions you need to learn to fly and progress in a limited area. So decide what sort of model you want and where you plan to fly it, Garden, Sports field etc then collective pitch is the way to go, if it’s going to be mainly around the house, office or work shop then got with one of the contra rotating models.

How Big are they? How Long will They Fly for on 1 Charge of the Battery?
First of all these models are small.
The contra rotating models are about 340mm rotor diameter and weighs about 230grams.
The T Rex 450 is roughly 700mm rotor diameter and weighs about 800 grams.
The average 30 sized glow model like the Raptor 30 V2 which has a rotor diameter of 1245mm, is 1150mm long and weighs about 3000 grams!
Because of their small size they do not and can not have the same stability as a larger model but their low mass does allow them to bounce much better than larger models so survive a crash that would re-kit a larger model. Spares are also normally cheaper for the smaller models.
All of the later electric models use Lithium Polymer (Li-poly) battery packs, these have much better performance than the older NiCad batteries and are basically the same type as used in Laptops and mobile phones. Lithium batteries need a little more care when using and charging but are really the only practical option.
Flight times on most small electrics either a contra rotating model or 450 sized will be roughly the same at about 7 to 8 minutes depending on flying style. Recharge time is normally under an hour, it’s common to buy 2 or 3 batteries so you can have a good flying session although in the early stages of learning you will find your brains fairly cooked after one pack and you will need to take a short break anyway.

Contra Rotating Indoor Models

All these models come ready to fly out of the box, you just have to charge the flight battery and put the none rechargeable batteries in the transmitter. The transmitters supplied with most of these models can be used with a flight simulator which a very useful feature but they are non computerized basic transmitters so can’t really be used with a more advanced helicopter. They are simple models which are a very easy and cost effective way in to helicopters but are limited to hovering or slow forward flight only, can only be flown out side in calm conditions.
 
450 Class Helicopters
Most of this size models come in kit form or possibly with the airframe mostly built but the radio equipment still needs fitting.
As they have collective pitch they need a reasonably capable radio control transmitter, the ones supplied with the contra rotating type models will not do the job. The good thing about needing a reasonably capable transmitter is that this same transmitter can then be used for almost any larger helicopter or even fixed wing model in you might acquire in the future.

You will need a motor, Electronic Speed Controller, 4 small servo’s, a receiver and tail rotor gyro to finish fitting out the model, obviously you will need the flight battery and a charger for this before it can take to the air as well. Batteries and chargers are a mine field but don’t get too worried about these at this time, one thing is for sure you will need and eventually buy more than one battery and charger!
Do not be fooled in to thinking it’s a good idea to go for the cheapest model and fit the cheapest servo’s and gyro in it because your only learning to fly and that you will get something better when you can fly. This is very much a false economy as the model will be much harder to fly and will not be so robust in a crash - leading to a longer more frustrating and demanding time learning to fly it.
Always fit good quality servo’s preferably with metal gears, the best ones for the T Rex 450’s and Mini Titan’s are the Align DS415M. The Align GP790 gyro is at this time the best gyro to go for, go for a cheap gyro and you will almost certainly not be happy with it and will end up buying a GP790 or GP900 shortly afterwards anyway. The radio control (transmitter) will make up a big part of the cost of your purchase and currently the newer 2.4G radio’s seem the way to go as they offer lots of advantages to any one flying electric models in particular as they are almost immune to interferences which can be a issue with electric models. The number of 2.4G radio’s available is massive, a 6 channel radio is all you need for this size of model but if your planning to move up to bigger or glow engine powered models then you ideally need 7 channels so keep this in mind.