RC Conversion - MK/4 Endeavour.
PART 5 - The Servo/Tiller Linkage.
Use a servo arm of a similar length to the tiller arm, longer plastic servo arms can be shortened with a hacksaw.
There are several ways of connecting the servo arm to the tiller arm, available from hobby stores are ready made connection rods with swivels, clip on connectors, etc. the choice is yours. For this conversion I am using the simplest and cheapest way, a piece of 1.5mm stainless wire, which is easy to make although a little bit of accuracy is needed when bending the wire.
First fit the servo arm so that it is pointing towards the hull side and fit the locating screw, then you will need to centralise the servo by powering up, refer to the previous section if necessary, turn the transmitter on first before the servo, then turn the power off. Next position the rudder in the straight ahead position, both the arms should point in a similar direction.
Using the photo above for reference to the linkage hole locations, you will need a similar distance from the axis of both arms, carefully measure the distance between the holes. The servo arm is typically higher than the rudder arm so an opposite bend on each end will be required. Cut a piece of the stainless wire longer than what is required and using pliers and round pliers, make a 90 degree bend about 15mm from one end, then bend back 90 degrees to form a "Dog leg", trim back excess wire to about 5mm. Using your length measurement mark the wire and make another dogleg but the other side up, as in the photo above, trim any excess to about 5mm.
Try the linkage by feeding it from above into the tiller arm first, then remove the servo arm, feed the linkage through and replace the servo arm, check for the position of the rudder, it may take a couple of goes to get the length of the linkage correct but as long as it is almost there, you can, on the transmitter "Trim" up the rudder on it's control panel. When you are happy with the fit, replace the servo arm screw. You can then power up and test the setup for travel.
Alternative linkage.
I have advanced the linkage from the simple system above and you may want to try the following version to get around having to be precise on the measurements. What I have done is incorporated a simple flexible adjuster into the linkage wire, to do this, make your first dog leg end, then at about half way along the length bend a "V" shape kink into the wire, carry on and make the final dog leg.
Now, if the rudder does not fully line up when both the arms are fitted, then it is just a case of get a pair of pliers and crimp a little at a time the "V" together thus shortening the linkage. If you adjust too far then just pull the "V" apart and try adjusting again.
This will only work if you have used a stiff wire such as the stainless one I have used.
At this point check that both arms and the linkage are below the deck height otherwise they may catch on the underside of the deck when fitted. Ideally, the servo arm needs to be more than 3mm below deck level to account for the hatch framework.
Turn on the transmitter and test the linkage for movement so that it does not catch on any other parts.