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Old Jul 21, 2006, 05:53 AM
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Now we're going to install the RC equipment. Make a 40 mm wide strip of 2.5 mm plywood or similar that fits into the space between the rotor mast, the support strut and the tail boom support. If you are using bigger servos, make this strip a little wider. Epoxy in place. Fill up the remaing space up to the
motor support with 3 mm Depron. Mount the servos on the plywood, their bottoms parallel with the rotor mast and the servo arms at the top (first picture). Put the pivot hinge into the top of the rotor mast and fix it with the grub screws of the wheel collar. Out of 2 mm cf rods make yourself two push rods with ball links at the top and servo arm links at the bottom. Adjust the length of the push rods so that - when the servos are in neutral position - the upper part of the pivot joint is in line with the rotor mast. Use self-locking nuts to fix the ball links to the control arm (second picture).

Use some velcro strips to fix the Rx and the ESC to the Depron part above the servos. Try to mantain a little distance between those two devices to minimize possible interference. What kind of motor mount you need depends mainly on the motor you are going to use. The only thing that is a must is that it ends in a wooden rod with an O.D. of 6 mm and a free length of about 12 mm. This rod goes into the cf tube of the motor support and is fixed with the wheel collar's grub screw. The third picture shows you how I did it. This picture shows you another thing, the thrust vector of my motor is pointing to the right of the gyro, we'll come to that later.

Use a rubber band to fix the battery to the front end of the bottom plate. Then lift the gyro by the top of the rotor axle - or use a bit of string to lift it - and move the battery until the rotor mast is slanting 8 to 10 backwards (hanging angle, fourth picture).

Cut out the pilot from 6 mm Depron and use velcro strips at its back, bottom and the soles of its shoes to fix it to the support strut and the bottom plate (fifth picture).

To be able to fly this gyro you need to program a mixer in your Tx. The basic mixer you need is of the delta type, which distributes the aileron and elevator signal to the two servos. But as the gyro has a tendency - due to motor torque and coning - to turn to the left, a mixer with inputs for aileron, elevator and motor is your best choice. First program your Tx so that full aileron causes the pivot hinge to tilt about 15 to the left and right and full elevator causes the hinge about 8 forward and backward. Then program the Tx that at full speed of the motor the rotor gets tilted a further 6 to the right while staying neutral when the motor is off. Use about 50% of exponential on aileron and elevator.

Finally you have to adjust the thrust vector of your motor. As the rudder is situated directly behind the motor, the wash of the prop is hitting the right side of the rudder very hard, causing the gyro to turn right while taxiing on the ground (and while flying, of course). Use some quiet spot with a flat surface and try taxiing at full speed. If the gyro turns right, put some shims under the left side (seen from behind) of the motor mount until the gyro runs straight. I had to usea 6.5 mm shim to get right.

When all this is done, put the rotor on the pivot hinge and secure it with a self-locking nut. You're ready to fly.

To be continued.

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