Stabilator Trim Reversal

[f1rocket]

Where's the best place to switch the two white wires to change the direction of the trim? Unfortunately I guessed wrong and "Down" on the trim button produces nose UP trim motion. I'm guessing back in the tail cone cover but thought I'd ask before taking things apart. Thanks.

 

[yankee-flyer]

YEP!

Keep track of which wires you switch and color=code them when everything is right. BE SURE to check the archives for Marty's excellent post on where to set the trim bug for takeoff and BE sure to recognize that "neutral" stabilator is not horizontal. That's a symmetric airfoil and needs negative incidence to produce the required negative lift for trim.

Wayne 120241/143WM 225 hours

 

[Mike S]

May I suggest you take a look at this thread for an idea or two that may interest you.

http://www.vansairforce.com/community/showthread.php?t=68671

Also, I would do the wiring mod close to the servo, that way if it is necessary to remove the servo in the future it is much easier to reinstall.

 

[rvbuilder2002]

May I suggest you take a look at this thread for an idea or two that may interest you.

http://www.vansairforce.com/community/showthread.php?t=68671

Also, I would do the wiring mod close to the servo, that way if it is necessary to remove the servo in the future it is much easier to reinstall.

Nice job Mike.... you are starting to sound like an RV-12 expert (working on another project?)

 

[ao.frog]

Flip the switch

I don't know what kind of switches you have in the trimsystem on the -12, but if you have Ray Allen switches like these, (sub panel, each side of the thr/prop/mix) you can simply flip the switch and install a new label.
That way you don't have to mess with any wires...

 

[MacPara]

Where's the best place to switch the two white wires to change the direction of the trim? Unfortunately I guessed wrong and "Down" on the trim button produces nose UP trim motion. I'm guessing back in the tail cone cover but thought I'd ask before taking things apart. Thanks.

Had the same problem. Please see here and here.
It should work by switching pins 31 & 32 on the Fuselage connector.

 

[f1rocket]

Had the same problem. Please see here and here.
It should work by switching pins 31 & 32 on the Fuselage connector.

Thanks. That's what I was looking for.

 

[MartySantic]

Thanks. That's what I was looking for.

With that resume'. Think you would want to fix the error and not compensate. A VERY humble opinion.

 

[cactusman]

With that resume'. Think you would want to fix the error and not compensate. A VERY humble opinion.

That is the correct advice. Page 31B-04 details the procedure for install.

The two white wires are what you test with the 12v battery to determine trim up and down by reversing them, and then watching either the AST or the jackscrew in the ray allen servo.

It's easy to mix them up. It took me several back and forths as at that point I did not have the stab on because of space issues. The two white wires then go into 31 and 32. Reversing them should fix the problem.

As an aside, I plan to triple check this several times, AND treat it like a B737 trim check first flight of the day to make sure it is working right ALL the time.