The first mechanical element to be fitted are the servos. I used Hitec HS55 which are a direct fitment without any form of modification to the chassis.

Aileron and pitch servos fit easily in predrilled holes. It is best to leave fitment of elevator servos until the heads are assembled as they need positioning and fixing in place with double sided tape.

Next stage is to make up the heads, these are standard Hornet heads which are relatively easy to put together.

If you cant get hold of uprated damper rings place a small amount of thin CA on the lower ring being careful not to get any on mechanicals, this stiffens up the damping.

It is vital that the distance between the base of the anti rotation arm and the base of the locking collar is 30mm exactly on each head. If you have a set of calipers use these, I used a pair of springbow dividers.

It is imperative that both heads are made up to the same dimensions

Note that the two heads are made up to the opposite direction of rotation. The rear head is the normal clockwise direction.

This is done by reversing the blade holders, flybar seesaw and the flybar paddles. In addition of course the main blades are also reversed.

The front gear can now be attached using the set screw which is tightened against the flat on the mainshaft.

Care should be taken by adjusting the motor mount / bearing block up or down to get the right amount of backlash, the motor and gear should run freely with no noise or binding.

The rear gear is completed in the same way again being careful to get the right degree of backlash.

The two rotors are meshed at 90' to each other, align the front flybar with the chassis and set the rear at 90', ensure the grub screw on the gear aligns with the mainshaft.

Spin the motor by hand to ensure correct alignment.

Front head complete

Rear head complete, ensure all linkages are moving freely.

The rear elevator servo is positioned using servo tape.

To position, get the servo horn as level as possible put in place all three servo links and position with the swashplate as level as possible.

Only cut off the other side of the servo horn once you are happy that they are positioned correctly. I used the centre hole on the larger of the two servo arms available which appears to work fine.

Similarly complete the front rotor elevator servo.