Monday, January 26, 2015

Dynon SV32 Autopilot Roll Servo Installed

Continuing with the punch list of to do items prior to mating the tail cone with the fuselage brought me to the autopilot roll servo. The Dynon SV32 autopilot roll servo would be much easier to install now while access is still good.
Dynon SV32 autopilot servo motor … this one will be used for roll control.

Before the SV32 servo can be installed, the wires coming out of it require some attention. First the wires from the SV32 servo motor need to be cut down to 7" and female .093 Molex connector pins need to be crimped onto the ends of the wires .... then inserted into a 9 pin Molex connector body. Also, two pushrods need to be fabricated and adjusted lengths of 5 1/4" and 6 1/4 " they will be used for the roll and pitch servos respectfully.
Dynon SV32 servo and parts to make up the roll and pitch pushrods.

The .093" Molex connector pins that came with the autopilot servo kit are a little harder to work with than usual. Instead of being individual connector pins they are on a long strip and the individual pins need to be cut out from the strip.  These strips are usually used in assembly line machines … preparing individual pins from these strips requires a couple of extra steps prior to crimping the pins. For builders not familiar with working with these pins, I hope you find the following helpful in preparing the pins for use.
Strip of .093" female Molex connector pins prior to separation.

Separate the pins from the strip by cutting through the eyelets between the pins using wire cutters.
Separated Molex connector pins ready for final trimming.

After all the pins have been separated from one another, use a pair of wire cutters to remove the remaining portions of the eyelet …. This should leave you with pins having two tabs or “wings” coming out from each side of the pin.
Trimming off all the eyelet material from the pins with side cutters to create tabs or “wings”.
After removing the eyelet material, the tabs should look like the ones in this photo.

The next step is to bend both tabs up with pliers to match the shape of the “U” the wire will sit in before being crimped. I find that bending each tab upward a little first with pliers … followed by squeezing the entire pin with pliers to finish bending the tabs upward, results in nicely forming the tabs into a “U”.
Bending the tab on the connector up a little with pliers to get the bend started.
Finished Molex .093" connector pin after being squeezed with pliers to form the tabs into a “U”.
Pin on the left is finished  and ready for crimping … pin on right still has the tabs or “wings”.

When crimping small diameter wire such as the 22 gauge wire Dynon used on the SV32 servo motor, I like to strip the wire twice as long as usual and fold it back on itself prior to inserting the wire into the connector pin. I find this method insures very tight crimps when using small diameter wires with Molex connector pins.
One of the servo wires stripped twice as long as necessary … approximately the length of the “U” on the connector pin. This bare wire will be twisted tight and folded back on itself and inserted in the connector pin for crimping.
Using a Tool Aid crimping tool with appropriate dies to crimp the .093" female Molex pins onto the SV32 servo wires.

After crimping the connectors, I used a hand crimping tool to tweak the strain relief area on the connector pins then inserted them into the nine pin Molex connector block. (Used the yellow handle tool just above the red handled wire strippers in the above photo).
Finished … now all the servo motor wires have .093" female Molex connectors attached to them and are ready to be inserted into the nine pin connector body.

Now that the Dynon SV32 roll servo motor is ready for instillation, the instructions call for attaching the fabricated F1291 pushrod into the middle hole in the SV23 servo arm. Next the whole assembly is attached to the fuselage with four bolts along with some blue Loctite 242 and the Molex connector is secured to the body of the servo motor with a wire tie.
Using a torque wrench to tighten the F-1291 push rod hardware on servo arm.
Tightening the mounting bolts for the Dynon SV32 auto pilot roll servo motor with a torque wrench to finish the install.