Tail Rotor Setup

• Detailed setup
• Short overview on the setup of your gyro

Detailed setup

A lot of first time builders have problems getting the Tail Rotor to work correctly. The following shows the steps I use to set mine up.

The first things to look at are the obvious mechanical things. When you look at the tail rotor blades from the right side of the heli you should see the Ikarus logo facing out. Pay attention to the direction of the blade grips as well. See the Photo below.

The next thing to check is the direction the T/R spins. Spin the main gear clockwise (the normal direction of rotation) by hand and the T/R blades should turn counter clockwise up into the main rotor when viewed from the right side of the heli. I reversed the direction of the belt when I first assembled mine and I could not keep the heli from spinning around as I powered up. Don't forget to check the belt tension, Ikarus suggests that you should be able to compress the belt together 5mm for the belt to be tensioned correctly.

Disconnect the gryo when first checking the T/R movement, you don't want it to confuse things. You'll need to turn on the radio and the receiver to perform the following checks. With the rudder stick centered the T/R servo lever should be perpendicular to the servo body, remove the lever and reseat it or use the Sub-Trim if necessary to accomplish this. It is also important that the lever that moves the tail slider is perpendicular to the tail boom when the servo is centered. Center it on the edge of the tube where it meets the tail drive body. It is easy to see this by looking thru one of the unused holes on the lever. If your servo is mounted on the Tail boom like mine you will need to move the servo assembly back and forth to correctly position the lever. Once it is positioned correctly tighten the clamp. See the pictures below. You should also notice that I am using the outer holes in the levers for maximum throw.

The next thing to check is to make sure that the T/R servo moves in the correct direction. Look at the following picture to see how to position the T/R blades for the checks.

Look at the T/R blades from above and behind the heli. When you move the stick to the left the pitch should decrease (blade twists counter clockwise) as shown in the following series of pictures.

When you move the stick to the right the pitch should increase (blade twists clockwise) as shown in the next series of pictures.

I have to assume at this point that you have followed the manufacturers directions as to the correct mounting of the gyro. Because there are so many available I can't tell you how to do this. Please note if the gyro direction setting is wrong it will not change the way the stick moves the T/R blades, it only adds to or subtracts from the stick movements.

Turn the receiver power off and plug the gyro in, reconnect the servo and turn on the receiver again. Put the blades in the same position as before. Lift the heli holding the tail in your right hand and quickly push the tail away from you in a rotating motion simulating a turn to the left. The gyro should move the T/R blades as if you had moved the stick for a right turn. You can look at either the servo arm or the blades to see the movement, use whichever is easier to see. If it moves the blades like a left turn command then reverse the gyro direction. Refer the previous series of photos to be sure of the normal movements.

Now all you need to do is setup the gyro following the directions supplied by the manufacturer and at this point you should have a well behaved tail.

One final note, Ikarus has 3 different gear ratio's available for the T/R. A 40t gear is supplied with the kit, it provides a 4.5:1 ratio to the main rotor. There are also 35t and 45t gears available for 5.15:1 and 4:1 ratios respectively. In my experience the 40t gear works very well and you will probably have no need to use the others. Unless you make substitutions to the T/R assembly like perhaps different T/R blades that might provide more or less thrust.

Short overview on the setup of your gyro

1. Hook up your tail servo directly to your Rx
2. Make sure all trims, ATV and centering is at normal position (0 or 100%)
3. With the stick centered, mount a pretty big servo horn to your servo and make sure it's exactly centered (it's more accurate to say it needs to be perpendular to the tail control rod though).
4. Connect the tail control rod to the servo at a distance of 18 to 20mm from center (if possible). The longer servo horn will give you a faster tail movement and better gyro control
5. Adjust the control rod on the tail bell crank so you have a full deflection from the tail slider when moving the yaw stick full left and right.
6. Make sure your servo moves in the right direction. Check the tail setup page on the Dream Models site for this.
7. Set you gyro gain to 50%, centered and throw to 100%. Hook it up in the system. Chances are you don't need any other adjustment regarding throw.
8. Make sure your gyro compensated in the right direction. You can do this by watching the tail blades move, or by spinning up slowly without the main blades and holding the tail. When moving the tail, you should feel the gyro compensate. It's best to have somebody move the throttle stick while you hold the heli.

Keep in mind that heading hold gyros take control of the tail. Only in normal mode will the tail slider directly respond to stick movement. Heading hold gyros take from 5 to 30 seconds to "set". When switching on your Rx, wait for a little while before moving the tail stick or teh heli! It's pretty normal for the tail slider to move one way totally when initialised. Wiggling the tail stick and letting it go should recenter it.

Heading hold does not need revo mixing (pitch to tail mixing), so keep it at 0% when in HH mode. Normal mode requires between 10 to 30%.