Page 44: Autopilot servos

Considering that I want to get everything that goes beneath the seats and baggage compartment panels installed in preparation for closing all that up, the time had come to make a fairly big decision: Garmin or Dynon autopilot?  I had intuitively been leaning toward Dynon rather than the 800-pound

gorilla.  Not sure why.  I knew that Dynon map updates were free for life, but a visit to Mothership's website which shows the cost of all the bits and pieces I'm going to have to buy sealed the deal.  For the single display (can't afford dual), autopilot servos, knobs panel (optional but makes setting the autopilot easier in flight), ADSB in and ADSB out, the Dynon was about $2500 cheaper.  With all the other stuff in the avionics kit (radio, intercom, etc.) the total cost for the Dynon is $18,995.  A staggering amount of money for a guy about to retire, but I have no choice.


The title of the picture above is "Two Autopilot Servos and a Meat Servo."  Each AP servo -- one in each hand -- costs over $800.  The meat servo between them is the chump footing the bill.  You can see that I've installed the canopy frame.  The rear window is hugging the tail cone, waiting for a trial fit.

One of the first steps involves stripping all the wires from the two servos, 14 wires in all, and crimping a .093 Molex pin on each.  A good crimp tool is a must for this, but even with the best available from Klein Tools I managed to screw up a few and had to re-order.  The stripper from Klein (shown) is also well worth the money.






There's definitely a technique involved in making the crimps.  There are two sets of tabs involved,

with the outer set making a bear hug on the insulator and the inner set plunging into the conductor.  After each crimp, I gave the Molex pin a fairly hard pull.  A few failed the test and had to be re-done.  The picture shows an average crimp.

When each seven-wire set is crimped, the pins have to be inserted into a 9-position Molex connector which will plug into an opposite gender plug installed much earlier in the build during the wiring harness installation.  Each pin must go into the correct hole in the connector, of course, and there's a very clear diagram to help facilitate this.  After doing it correctly, I gave one last tug and one of the wires came out!  This required removing an already-inserted Molex pin from the connector, which is an odious task.  Quite a few swear words followed this event.

Installation of the servo motors was fairly straight forward.  I was immediately able to allay my previously mentioned fears about the effort required to operate the control stick with all the AP hardware installed.  You can feel some added resistance to movement, but not much.

Pic above shows roll servo, pic below shows pitch servo.