Mailing List lml@lancaironline.net Message #70065
From: Gary Fitzgerald <gbfitz@prodigy.net>
Sender: <marv@lancaironline.net>
Subject: RE: MkII tail trim servo
Date: Wed, 28 May 2014 07:39:14 -0400
To: <lml@lancaironline.net>
Rob,

I'm sure somehow, somewhere, there's a MkII tail section where the servo,
clevises, and trim tab fit according to the picture in the plans. But it's
definitely not the one I'm building. You actually have more of your clevises
remaining than I did.

Just a few other things that may help in this phase of building:

1) Make sure to mock up the location of that servo bracket on the upper
elevator skin, temporarily attach it, put the upper elevator skin in place,
and make sure you can install the servo through the opening in the lower
elevator skin, and over the screws. Also, make sure you can get a wrench or
something into that opening to tighten the nuts that hold that servo in
place. You mak have to change the location of that bracket from where the
book says to mount it, which, naturally, will change the length of your
actuator rod.

2) Attach that servo bracket before you close out the elevator.

3) I installed the forward spar and inboard rib for the trim tab before I
closed the elevator. It seemed to make the trim tab construction go faster.

4) I can't tell from your picture if you've installed them yet, but the
location of the elevator inboard ribs is pretty important. If they're too
far inboard (as in you didn't apply enough tape to your elevator actuator to
properly simulate the 4 BID layup that covers the inboard side of these
ribs), you'll have problems with the elevator binding and not travelling
freely. Don't ask me how I know this. I think it happened to a friend. Yeah,
that's it.

Gary Fitzgerald
LNC2 ~70%
St. Charles, MO
(Still) Looking for a good deal on a rebuildable or used (I)O-360



-----Original Message-----
From: Rob Murawski [mailto:rob@robmurawski.com] Sent: Friday, May 23, 2014 11:12 AM
Subject: MkII tail trim servo

Hi everyone,

I'm getting ready to close-out my elevators on my MkII tail, but I also
wanted to have all of the innards in place to balance the elevator properly.
I made the bracket with the pocket for the trim servo, but with the clevises
for the Ray Allen servo, I'm not convinced it actually fits in the elevator.
Per the latest rev of the instructions, I was planning on cutting the trim
tab out after the elevator is closed, but trying to do the mock-up looks
like a tight fit.  I made a test rod which allows me to put the two clevises
right against each other and it seems like there is barely enough room to
reach the appropriate place where the hinge would be.  I think my trim tab
is the right size--it is 2" from aft to forward at BL24 which matches the
plans and drawings.

I added a picture as to what I'm talking about.  The servo is approximately
halfway to represent a neutral trim and have equal upward and downward
movements.

Is my trim servo bracket wrong?  Is my trim tab too big?  Or am I
over-thinking this?

Thanks,

-Rob


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