The Center Spar is installed, meaning that all the holes are drilled and it all fits. This post includes the Center Spar Installation Template I posted earlier as an idea. Scroll to the bottom for the new stuff. I added some additional detail to drilling the spar bolt hole.

First I back drilled through the bottom doubler.


Next I set the proper width for the wing spar using the new uprights as shims.



Measured the edge distance for the Center Spar front rivet line.

I decided to use a 30 pitch instead of the 40 pitch on the Upgrade drawing. This will allow me to place the new rivets between the existing holes that were set at a 30 pitch. Should have made the Center line a No Rivet zone and back drilled after installing.

Template ready to be drilled, except I should have waited to drill the new center line/doubler holes.

But I came up with a solution, another template.

Cleco and drill the four missing holes.

Measure 84 times, drill once. Verified that the Wing Spar will fit just right.

Drilled a couple of holes on each end to lock the Center Spar in place.




The competed template ready to be installed. I rounded the corners and the edges to make installation easier. I will have to remove to deburr and corrosion protect.

Template installed using the existing holes for the rear Center Spar.

Back drilled every other hole on the front Center Spar and front doubler rivet line. Time to install the Center Spar for another trial fit.

A view from the bottom.

Success!! This was way to easy ;-)


I need to finish drilling the remaining holes and then I will remove the Center Spar and fit the Front Wing Uprights using the procedure I posted earlier. That's my story.

Center Spar removal and installation. I deleted this post, here are the pictures. Remove the Wing Attachment Uprights. Drop the Center Spar in over the console bottom first and lay flat with the bottom facing forward. You might have to do a slight twist to get it in. Move forward and drop over the seat pans. To remove, lift straight up and reverse the procedure.


Nothing major so far, but here are a couple of issues I've had. I noticed the Spar bolt holes didn't match up with the Rear Wing Attachment Upright, Center Spar was sitting high. Most of that was attributed to the 6B10-4 gusset. It sits on top of the Rear Center Spar flange, so I had to work the original spar flange under the gusset. Now it is sandwiched between the old and new flange, will probably do some trimming. I thought the Rear Wing Attachment Upright slid under 6B10-4, maybe not. Here is a requested picture. The dark line in the upper right corner of 6B10-4 is the area the Rear Bottom Angle overlaps 6B10-4. I'm either going to trim this off or the corner of the Rear Bottom Angle. Not sure it is necessary, but will make the installation easier. The straight black line is the overlap area of the Rear Spar flange. This could be different on your airplane, but if the Center Spar sits high, this is the culprit.

Time to reinstall the Center Spar and get some reference point for the Front Wing Uprights. This is the view down the back side of the Center Spar. I found it was easier to use bolts to align the Wing Attachment Uprights before clecoing to the fuselage.

Trimmed 6B10-4 to make installation easier.

Test fit the Front Wing Upright. I put a slight bend in the flange to compensate for the fuselage.



Setup is similar to the Spar Upright. I measured up 30mm and bent approximately 4 degrees.

Here are my reference points marking the top of the Center Spar and the existing holes in the fuselage. The horizontal lines are machining marks.

Set my rivet line at 12.5mm and the rivet pitch to miss the existing holes.

To the Drill Press. Clamped a block so I could slide the Upright across and just have to hit the mark.


Clamped the old Uprights to set the reference lines


Reference lines for the rivets.



Next I setup and drilled the rivet line.

Verified my edge distance.

Reinstalled the Center Spar to drill the fuselage sides.

But first, need to make sure I have the right gap for the Wing Spar, I used the Wing Jig, and then drilled.

I drilled the holes above the Center Spar first.

And then removed the Center Spar to drill the remaining holes in the fuselage.


Time to take apart the Center Spar and drill the 5/16" spar bolt holes through the Front Wing Uprights.

This should look familiar. I had to modify the drill guide base, cut off about 15mm to use on the upper Spar Cap. After clamping I turned the drill bit over and spun it to mark the center on the Front Wing Uprights. I then removed the Upright and used a center punch and tried to be exact. I used the Drill Press to remove most of the material starting with a 3/32"/#40 drill bit, #30, #20, and 3/16". Then I clecoed the Upright back onto the Spar to make sure I could continue with a 1/4" bit, it was almost perfect and I drilled out to 1/4". This left a 1/32" shoulder and I used the drill guide with a 5/16" drill to finish the hole. This took a bit more time and WD-40 to get through the 1/8" Upright. It was worth the effort, the holes were perfect.

Spar bolts holes drilled, Center Spar ready to install, again.


This is out of sequence. I want to use the existing holes for the XL "T" doubler, so I need a template, hmm ...

So, I slipped the "T" behind the fuselage skin and marked the holes, I will actually drill. This is just a test.

To reinstall the Center Spar I used short bolts to position the Wing Attachment Upright and then clecoed to the Spar and then to the fuselage.

Same procedure for the front, but I used long bolts to go through the Center Spar.

I've started installing clecoes from underneath, it's a bit easier.

A view of the bend in the Front Upright.

That's it. I need to drill out the holes to final size and then remove the Center Spar one more time. I still need to install the seat angles, side doubler and rear attach plates. I'm working on a Console control gust lock and am hoping to incorporate an aileron stop control. If all goes well, I should be done with the fuselage this weekend and then it's onto the wings!

Not sure if I will be able to do my version of the Aileron Control Stop. Talked with the DAR and the current interpretation of the SAIB and EAB's without an Airworthiness is that the Upgrade is "Mandatory", not "strongly recommended". No Upgrade, no Airworthiness. So, it looks like I have to comply with the AMD Safety Directive exactly, or better, and I am no longer an Independent Manufacturer able to pick and choose what modifications I choose to do. Any components that AMD is installing will probably be required, unless you can convince your DAR otherwise, but it's up to your DAR.

So, the goal is to finish the Upgrade as quickly as possible and get my Airworthiness before AMD issues any other Safety Directives that might be forced upon me.

Live long and prosper!

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Comment by Paul Hammond on January 23, 2010 at 1:15am
yeah ;jake I just had ano ther look and I am still waiting for the rest of the upgrade, phill says it all
Comment by Phill Barnes on January 21, 2010 at 3:38am
Hi Jake
Everytime I read your blogs, I get more out of them. They say a picture tells a thousand words but your pictures just don't shut up.

Awesome Jake
Comment by Paul Hammond on January 13, 2010 at 6:07pm
very helpfull; keep up the good work ,
now al I have to do is wait for the centre spa kit to arrive, very slow air freight from USA to Australia expenisve too.
but my wings are finnished
Comment by Jake Reyna on January 13, 2010 at 6:57am
Hoping that the Upgrade kit has been worth the wait.

I will be adding some additional information and links later today or tomorrow. David Gallager's Adventures in Riveting and my Bucking Station and Center Spar Upgrade, stuff like that.

A job worth doing is worth doing well.
Comment by Phill Barnes on January 13, 2010 at 5:55am
You da man. Thanks.

Comment by Alex Roca on January 12, 2010 at 10:13pm
Excellent pictures ! thanks for sharing. Can't wait until I get my upgrade kit.

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