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. 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.

Next month, a look at gyros!