Archive for July, 2014

Mounted ELT

Saturday, July 26th, 2014

While I was contorting myself back into the baggage compartment to work on the autopilot pitch servo, I went ahead and installed the new ELT also.

For those of you keeping track at home, you might be confused because I already mounted the ELT a long time ago. In fact I did it twice. Well, I didn't like either of the two previous arrangements, and also new and improved ELT technology has come along in the meantime. I wanted the benefits of having a 406 MHz ELT, so I bought an ACK E-04. That's the least expensive one on the market, although they are still not what I would call cheap.

Anyway, does this look like a happy face or what?

You're supposed to mount the ELT in a more or less level orientation, as far back in the fuselage as possible, and attach it to something strong enough to resist deforming in a crash. I attached the mounting bracket to the F-729 rib, using structural screws for the top two holes that go through the reinforcing angle. It's plenty strong.

Here's what the ELT looks like popped into its bracket:

I still need to connect the power and GPS inputs, not to mention mount and connect the antenna, but first I have to go to Oshkosh to work…

Posted in Fuselage |

Autopilot upgrade

Friday, July 25th, 2014

I sold my Trutrak autopilot system and changed over to the Garmin G3X autopilot instead. Fortunately the GSA 28 servos fit into the same bolt holes as the old servos, so installing the new pitch servo was straightforward. And it's a bit lighter too.

The electrical connections were surprisingly not that hard to retrofit either. Of course the wiring is very different between the two systems, but the servos use a similar number of wires, so I was able to repurpose existing wiring for new tasks. The old stepper motor drive and torque sense wires became CAN and RS-232 lines – luckily I had the foresight to use shielded wire. The only new wire I had to run was a single conductor for the autopilot disconnect line; in the old system the red button was connected to the control head in the panel, whereas in the new system it connects to both the servos. The power and ground wires stayed the same.

I'll have to come up with something to do with this oddly-shaped hole in the panel, which used to be occupied by the Trutrak autopilot control head. I'll figure it out.

I haven't installed the new roll servo yet, since I need to redo some wing wiring, but the wiring that goes out through the side of the fuselage is now all prepared for the Garmin autopilot.

Posted in Electrical/Panel |