Part 14: Disassembling the Center Wing Spar Assembly and more...

As most of you know, we're now accepting orders for the Upgrade Package kit. We're not ready to ship the kits just yet, but we're getting everything organized so that we can ship as soon as the kit installation has been verified and documented, and that all the needed parts are in stock. We're prioritizing availability to first ship to those builders who are ready to install the Upgrade Package kit parts. We ask that those of you who are not ready yet to install the upgrade package to let us know (you can indicate this on the order form). One of the advantages of taking delivery later will be that better documentation will be available as fellow builders will have already done through and documented the process.... If you have not already ordered your Upgrade Package kit, you can order yours today.

Today, we've also updated the draft drawings for the Upgrade Package: 6-ZU-1, 6-ZU-2, 6-ZU-3, 6-ZU-4, and LAA Aileron Balance.

I've noticed that some builders are posting photo updates of their Upgrades as they perform them. Thanks for taking the time to share your photos and experience with fellow builders. Alex Roca has started a photo album chronicling his Upgrade Package installation.

Disassembling the Center Wing Spar Assembly:
After pulling the center wing spar assembly out of the fuselage, we now start taking it apart.

The rivets along the top of the front center spar web (6W4-1) are drilled out and we take out the AN4 bolts, nuts and spacers between the front and rear halves of the center wing spar (above), and then take the two halves apart:

These are the AN4 nuts and bolts, and the spacers (6W4-5) from the original Center Wing Spar (6W4) assembly:

The two halves of the center wing spar assembly (6W4). On the right is the front half (facing down) with the back half on the right.

Here Caleb uses a center punch to expand the dimple in the solid (conventional) rivet:

And now he uses an undersized bit to drill into the AN-470, being mindful not to enlarge the hole:

Then, using a chisel and hammer he knocks the rivet head off:

...and now he hammers the rivet stem out using a punch. This is the same procedure and tools we used earlier to drill out the top inboard main wing spars.

Here's the disassembled Center Wing Spar Assembly (on the right) with the additional new parts on the left that we'll position, drill and rivet together next:

Here's the video clip:

As many of you know, the Zenair Newsletter includes a bonus DVD with every issue (which, in my opinion, makes the Newsletter subscription an outstanding value). Jon Croke, the editor, has stated that he'll summarize my video clips on the next DVD. We'll update these video clips to make sure that they reflect the latest changes...

Views: 1670


You need to be a member of Zenith Aircraft Builders and Flyers to add comments!

Join Zenith Aircraft Builders and Flyers

Comment by Dwayne W. Price on November 25, 2009 at 1:46pm
Sebastien, just a few words of encouragement…

I very much appreciate the level of documentation you are providing and the timeliness in which it is delivered.

As a scratch builder, I finished my spars almost a year ago. More recently, I completed the center spar, but due to the NTSB letter in April, elected to leave it at the “clecoed” stage.

Since April, I felt that a recommended alterations to the spar was a real possibility, and therefore have been pondering over how exactly to proceed.

Needless to say, I am very pleased to see Zenith moving forward with these changes, and although I too now have some “redo” work in front of me, I believe that these changes will have a positive impact on re-establishing confidence in the Zodiac aircraft.

Over the last two weeks, our nightly routine has consisted of my father (a fellow builder) and me connecting via Skype, and then collaboratively dropping in on your site to follow your daily progress.

Keep up the good work.
Comment by Sebastien Heintz on November 25, 2009 at 10:51am
Ted - thanks for your comments and support!
Comment by Ted Taylor on November 25, 2009 at 10:47am
I was a dismayed at finding I would have to remove the center spar now, but I'm pleased to see the full development of the wing root doubler and the necessary changes it entailed. The upgrade looks thoroughly worth the work involved. Some of the recent developments, such as the aileron control stop, are very good additions. This is inspiring a lot of confidence that I was lacking with the original mods. Nice work.
Comment by Ian McClelland on November 24, 2009 at 7:54pm
Thanks for the enhanced strenghening updates. Am I correct to assume the latest drawings are not the final drawings?

New from Zenith:

Zenith Planes For Sale 

Classified listing for buying or selling your Zenith building or flying related stuff...

Custom Instrument Panels
for your Zenith

Custom instrument panels are now available directly from Zenith Aircraft Company exclusively for Zenith builders and owners. Pre-cut panel, power distribution panel, Approach Fast Stack harnesses, Dynon and Garmin avionics, and more.

Custom Upholstery Kits for your Zenith Aircraft:

Zenith Vinyl Upholstery Kits

Zenith Apparel from EAA:

Zenair Floats

Flying On Your Own Wings:
A Complete Guide to Understanding Light Airplane Design, by Chris Heintz

Builder & Pilot Supplies:

How to videos from

Developed specifically for Zenith builders (by a builder) these videos on DVD are a great help in building your own kit plane by providing practical hands-on construction information. Visit for the latest DVD titles.

Aircraft Insurance:


West Coast USA:

Pro Builder Assistance:


Transition training:

Golden Eagle Aviation

Pianosa Flying Farm

Aircraft Spruce & Specialty for all your building and pilot supplies!

© 2020   Created by Zenith.Aero.   Powered by

Badges  |  Report an Issue  |  Terms of Service