Trim wiring

A question for the electrical gurus, I am using two OttoTA-0096 four-way switches on my stick grips for aileron and elevator trim control. I would like to be able to isolate the passengers trim switch with a toggle on the instrument panel. There are five wire connectors labeled A - E with the first four connected to the trim governors while the 'E' is a ground wire. Am I able to isolate this switch by putting the toggle in the 'E' wire only?

All advise gratefully recieved.

Clive Whittfield
Auckland
New Zealand
RV6

Yes, you need the ground to make the circuit.

If you are using a trim controller, then route the wire;
Trim controller --------->toggle---------------> rear coolie hat sw -------------------> trim controller

if not, sub ground connection for last loop back to the controller.

Hmmm.. Not sure I follow Wade.

Trim controller --------->toggle---------------> rear coolie hat sw -------------------> trim controller ??

The wiring diagrams and instructions I am looking at show the 'E' lead going to ground, not looping back to the trim controller. I'm using Mkll Matronic governors and MAC servos if that makes a difference.

Clive

post a picture

Clive,

Post the wiring diagram. Then we can help you modify to isolate the rear stick.

Cheers,

Chris

whittfic said:

Hmmm.. Not sure I follow Wade.

Trim controller --------->toggle---------------> rear coolie hat sw -------------------> trim controller ??

The wiring diagrams and instructions I am looking at show the 'E' lead going to ground, not looping back to the trim controller. I'm using Mkll Matronic governors and MAC servos if that makes a difference.

Clive

Click to expand...

That is why I added the second line, "sub ground connection for last loop back to the controller". I didn't know if you were using one or not.

As Chris suggested, if you want to post a diag for your install we can offer you a detailed suggestion.

Wiring diagram as it is at the moment http://s456.photobucket.com/albums/qq282/whittfic/?action=view&current=SCN_0001-1.jpg

Put this together based on diagrams that came with the governors and four way trim switch (Otto).

Thoughts??

Clive Whittfield

Based on your schematic, the ground is going thru your "elevator/aileron governor".

The lay-out out for your Otto is;

____B

A___E___C

____D Is this correct?


If so, then simply wire;

Clive, kind of hard to interpret that schematic, but I think you are on the right path. I would disconnect the E (or common) wire from the pilot switch to the copilot switch to see if that disables the copilot switch. If that works then all you need is a SPST switch in the E wire between the pilot and copilot switches. Looks like the pilot and copilot switches are wired in parallel, so you should also be able to disable a copilot input by going the opposite way on the pilot switch. One of the advantages to this setup is that it can also stop a runaway trim. Most large aircraft are set up this way. I mention this in case you are worried about an accidental input on the copilot side, say by a child for example; but you can cancel any copilot input with an opposite input on the pilot switches. This might be enough to alleviate your concern, which might eliminate the need for your SPST panel switch to deactivate the copilot switches. Anyway, you can experiment with this information and perhaps it will help refine your solution. Hope this helps.

Thanks for the quick replies. Yes Wade that is the layout of my Otto and you have pretty much confirmed what I thought I would need to do.

Pat I had read up about being able to cancel the co-pilots switch input with pilot input but have decided to go with the isolation toggle on the panel anyway. You are correct, my main concern was inadvertant activation by a passenger so would like to do what I can to reduce the possibility of it happening. I'm no high-time top-gun pilot so want to avoid unnecessary distractions and potential problems as much as I can when I eventually get airbourne.

This forum is great. Being able to ask questions and tap into the wealth of knowledge that is here with such ease, even from halfway around the world never ceases to amaze me. Thanks again guys.

Clive Whittfield