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Note
The first thing to make clear about upgrading the Eco is that this little helicopter will really fly quite well straight from the box. However there are a couple of upgrades that will, with very little effort, turn it into a much nicer flying machine. Other upgrades will improve it's flying characteristics further, others will just make it look prettier (and there's nothing wrong with that!)
The Autoration Hub
If any of the upgrades can be considered a must then this is the one and should be carried out before any other.
As the name suggests this upgrade consists of a new main gear hub with a one way bearing installed that will allow the rotor head to revolve independently of the motor and permit autorotations. That is controlled descents without power.
However that is not our main concern. Allowing the rotor head and blades to revolve while the motor is slowing or stationary, to “free wheel” if you like, means that the headspeed is not slowed abruptly as soon as the motor speed is reduced.
In a fixed drive system the blades will have to try to turn the motor once the power is reduced. If you are lucky this will slow the head speed rapidly. If you are not so lucky it will strip teeth from the main gear. Either way you are not going to have a very smooth flight!
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Bracing the frame
 Anyone who has operated the cyclic and collective controls of their standard Eco while it is on the bench will have no doubts about the amount of flex in the frame. In fact it moves so much that I was really amazed that I had any control over the helicopter at all for it seemed that any movement of a control resulted in a movement of the frame rather that an adjustment to the flying surfaces. Thankfully the remedy is simple and effective. A brace needs to be installed between the side frames at a position just behind the motor.
Some excellent aluminium braces have recently become available commercially. In the past equally good results have been gained by making a brace from a piece of carbon fibre plate or a section of the Eco plastic motor mount (a good option if you have just upgraded to the aluminium mount and have the old plastic one laying around).
This simple upgrade will yield a dramatic improvement in control precision and make the Eco a much easier helicopter to fly. It is for that reason that I have placed it at the number two spot. Others, no doubt, will have their own ideas!
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The rear mounted tail servo and boom brace
One of the most important factors in a well behaved helicopter is good tail control. This relies on accurate control inputs from the servo to the tail rotor. Unfortunately connecting the two with a long “snake” as with the Eco is not conducive to accurate control. It is true that with careful placement of the snake and with sufficient securing the system can be made to work reasonably well but it will never be as accurate and friction free as a direct link between servo and tail.
The rear servo mount places the tail control servo at the front of the boom. From here a control rod of carbon fibre can be run directly to the tail control horn. If good quality clevises are utilised at either end of the control rod a near friction and play free control system is produced.
To make the most of our new found tail control a set of boom braces is highly recommended. All this good work is wasted if the tail can be held accurately but the helicopter still moves because the boom “gives”. Remember our flexible frame? Two braces run from the main frame to a point towards the rear of the boom will stiffen the helicopter considerably enabling us to make the most of the tail control. The gain on the gyro can now be turned up without the tail oscillating.
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These upgrades are the ones that will make the biggest changes to the flying abilities of the Eco. A well built Eco upgraded as above will prove to be an enjoyable little machine.
