Working on the log entries for the wing lately feels like I am just regurgitating log entries I made with the right wing.  Therefore, I am omitting a lot of detail here if it is something I covered when doing my right (1st) wing.
Today, my goal was to get all the z-brackets drilled and get ready for riveting the leading edge together on Saturday.  Below, I am following the same method for z-bracket drilling I used on the right wing.  I first drilled the inboard z-bracket and rib.  You can sort of see in the picture where I marked the center of the z-bracket flange where it is clecoed to the rib and baffle plate.  Since you can slide the tank an 1/8 to the top of and/or bottom of the wing, I marked the center of the z-bracket and that is where I drilled the center rivet hole for the rib and clecoed it in place.

Within a couple of minutes, I had drilled the 5 z-bracket holes to size #30.

Then I proceeded to the outboard of the fuel tank and lined up the leading edges of the tank and leading edge.  You can see on this tank, I used a ratchet strap to put a SLIGHT force on the tank to line up the two leading edges.  When I was happy with their alignment, I drilled the tank screw attach holes to the attach plate with a #19 drill bit.

Here is my a couple of pictures of my ratchet strap set-up.  Note on the rear spar, I have a piece of scrap 4" x 4" block.  This was to prevent the strap from bending the wing skin clecoed to the skeleton.  The top skin overhangs the rear spar by a little to form part of  gap seal.  I didn't want the ratchet strap to apply any force to the skin and bend it.  MISSION ACCOMPLISHED!!!

Just my strap arrangement from the top side of the skin.  I just tried to be careful with the location of the ratchet mechanism and the hooks.

After you drill the inboard rib to z-bracket holes, then the next step is to remove the leading edge to gain access to the outboard tank rib and z-bracket.

With the ratchet strap in place, it also performed a second unintentional feature of holding the tank place and kept it from moving.  A big nylon, adjustable cleco if you will....

Once the outboard rib has been drilled and clecoed to the z-bracket, then remove the tank keeping the inboard and outboard ribs clecoed to the z-brackets.  This holds the baffle plate in place so that the rest of the baffle plate to z-bracket rivet holes can be drilled.

I didn't get any pictures of prepping and priming the leading edge and z-brackets.  As you can see below, the z-brackets are primed with the exception of the flange that will be attached to the tank baffle plate.  I didn't want the primer to interfere with the tank sealant.

Also I think that Van's has done a less than stellar job on these z-brackets.  On this tank, I got the nutplate holes almost perfectly centered on the one flange.  However, the other flange (that attaches to the tank baffle plate) results in its holes very close to the web of the z-bracket.  I checked, and I will still be able to get the pop rivets in there to attach the z-brackets to the tank.

Basically, I would think that Van's could easily move the holes on the main spar to move the z-bracket over about 1/16", the holes on both z-bracket flanges would be dang near perfectly centered.

Below, I am drilling for the nutplates by using 3 sacrificial nutplates that I tapped out when I was working on the right tank so that I could easily screw on and remove the nutplates.

After drilling out for the nutplates, it didn't take long to countersink for the nutplate rivets and rivet the nutplates to the z-brackets (that is except for the inboard z-bracket).

With a little persuasion, I got Tami to help me rivet the leading edge together.  Now when I ask her for help, before she will answer, she asks me if we are working on the tank?  She has been really good at helping me with the exception of the sealing the tank.  I guess I can't blame her.  I don't want to mess with the sealant either.

We are getting fairly proficient at riveting AD3- rivets.  Tami has decided she likes bucking more than shooting.  It doesn't matter to me as long as she helps.

On the right wing, I got in the habit of putting a piece of tape over the rivet hammer attachment.  The benefit of that is that it prevents the rivet hammer from scratching the surface of the skin around the rivet.  Well, on the leading edge, I had to drill out 3 rivets because the factory head of the rivet pinched off a piece of tape and the tape got trapped under the shop head (Yes, I changed the tape every 3 or 4 rivets).  Dag Bernit!!!  After that, I said screw the tape on the rivet hammer.  Since the plane will be painted, it really isn't a big deal to have some minor scratches resulting from the rivet hammer.  I figured that not having any scratches around the rivets would make the skin look nice until the time it was painted....

I decided to wrestle the left fuel tank together tonight.  What a pain in the ass this was.  The tank skin is fairly heavy and the ribs do not fit all that well when compared against the other parts in the kit.  The pre-punched holes combined with the relatively poor alignment of the ribs makes it difficult to cleco the tank together.  I had to tweak a number of the ribs a couple of times in order to get a half decent fit.  A little over two hours and a couple of well placed cuss words, and the left fuel tank was clecoed together.

Once clecoed together, I had to put it on the wing.  I still need to do some drilling of the z-brackets to the spar, but I couldn't resist setting it on the wing and admiring how far along I am (yeah right...  I am friggin' a long ways from done).  However, I am starting to have some big parts coming together and they actually look like parts to an airplane.  No more tripping over small parts and wing crates.  All the remaining parts sit on a couple of shelves and a table.

Just a rough placement on the wing shows me that I should be able to get a very good fit between the leading edge and the fuel tank.

Just a picture of the top side of the wing with the tank setting on the spar.  When clecoing the tank together, I ran out of clecoes (you can never have enough clecoes) so I had to scavenge some clecoes the wing skins at strategic locations.  Looking at the picture, I wonder why I ran out of clecoes???  Cripes, there is a lot of clecoes holding the wing structure together at this point.

I am also getting a good fit here on the top side of the wing.

After work, I finished up on the W-423 joint plate (leading edge side) and drilled the inboard leading edge rib, the joint plate, and the skin all to size #40.  Working on this left wing joint plate was so much easier than I remember it being on the right wing.  I set this puppy in there, took numerous measurements, drilled, checked new hole on rib, and drilled again.  Wham, bam, thank-you maam...  The joint plate was drilled and clecoed in place in about 15 minutes.

Just an view of the inboard side of the leading edge.  I think that the joint plate and inboard rib turned out better on this second wing than on the first.  It definitely went faster....  WooHoo!!!

Now, the first of the dreaded tank fabrication tasks.  The "Z-BRACKETS".  I reviewed my log entries I made for the right wing so I remember what I did and what I WISHED I DID.  The one thing I did differently is that when I measured the center of the z-bracket, I measured from the inboard side of the bracket in order to account for the thickness of the bracket web.

Right Wing Log Entry For Fabricating Z-Brackets

My drill press has a tendency to "wander" and results in inconsistent location of the holes drilled in aluminum.  Yeah, this cheap drill press is okay for wood working, but not for drilling plane parts.  In order to get a more consistent drilling location, I clamped blocks to the drill press table.  I wished I had a 'X - Y' adjustable clamp (next time I go to Harbor Freight).  To further enhance the accuracy of the drill press, I used a spring loaded center punch to start the hole.

Yeah, I know, this is some basic stuff.  For the life of me, I don't remember doing this on the first wing and I couldn't find any mention of it in my log entries for the other wing.  Anyway.... the holes on the z-brackets this time around came out great.

After drilling the one #12 hole on one side of the z-bracket flange, I used some scrap bolts and nuts I used on the right wing to secure the z-brackets to the main spar.

I have been having a difficult time getting out in the garage this week.  A hour here and a hour there is about all I have been able to muster.

Recently, there has been some discussion on the Yahoo RV-7 discussion group about whether or not to remove the vinyl from the parts prior to deburring and dimpling.  The picture below is a prime example of why you SHOULD NOT debur and dimple with the vinyl in place.  This is a picture on the inboard side of the leading edge skin after I match drilled the W-423 joint plate to the leading edge.  As you can see, there are a lot of aluminum filings trapped under the vinyl.

Not all holes will have this many filings, but it made a good example to illustrate why the vinyl should be removed prior to deburring and dimpling.

So far on this project, I have tried to leave as much vinyl on as possible, however, I remove the vinyl along all the rivet holes prior to deburring and dimpling.   Tonight I was able to talk Tami into coming out to the garage and remove the vinyl on the lower skins.  This work isn't all that exciting, but it sure helps things move along when she will come out and help me with these "low level" activities.  She was such a perfectionist on this job.  She even removed the vinyl around the curves for the inspection plate recesses.  Nice job honey...  Thanks for the help.

And finally for the night, I finished the z-brackets by riveting on the plate nuts.  I decided to sacrifice 3 plate nuts to my growing "scrap" collection.  I chased the threads of the 3 K1000-3 plate nuts with a 10-32 tap so that the AN3-4A bolts would thread with just your fingers.  This made installing/removing the plate nuts to drill the rivet hole locations on the z-brackets much easier and FASTER.  The brackets turned out okay.  I sure wish Van's would have designed them a little differently and give the builder a little more room on the rib / baffle / z-bracket flange.  It is going to be interesting to get a pop rivet puller in close enough to pull those rivets straight.

My next task will be to focus on fabrication of the first fuel tank...  WooHoo!!!

Okay, after some additional reading and clearing my head, I decided to try this again using the z-brackets for the left wing.  I will tell you up front, Dan Checkoway had the best solution I could find on this.  Here is how it worked:

• Mark all the centerlines on both flanges of the z-brackets. 
• Find the vertical center of the the bracket flanges.  When you are done, you should have the "cross-hair" you see on the z-bracket in the picture below.
• Drill a #12 hole in the center on one side of the z-bracket flange.  Set the bracket aside and do the same to the other 6 brackets.  (NOTE:  If the #12 hole is closer to the web of the bracket, that in theory, will make more room for riveting the other side of the z-bracket to the fuel tank.  I didn't try to compensate.  I tried to drill as accurately as possible to the center of the flange.)
• Get some sacrificial AN3-4A bolts, washers, and nuts to attach the z-brackets to the main spar.  I used just one bolt in the center hole I drilled in the z-bracket.  Don't get ridiculous, but make it tight enough so the bracket won't spin.  After you drill the 2nd hole, you can stick in a cleco if you are concerned about it moving.
• OPTION- You can bolt these to the bottom of the spar if you wish and then back drill from the top side of the spar.  I drilled them by mounting them to the top.  To each their own.

To ensure that the brackets are square to the spar, I used two methods:

• I eyeball'd the centerlines I drew on the z-bracket flange that is now facing down towards the spar.  The lines you drew should be visible through the spar holes and in the same location within those holes when looked at from below (aft side of spar).
• I used my machinist square to ensure the z-bracket was square to the wing spar assembly (this seemed to be the easier and more accurate method).

Repeat that exercise for all 7 z-brackets.  Ensure that your orientation is correct or the brackets will clearly not line up with the tank baffle.

Now take the time to assemble the fuel tank.  This is not as easy as it seems.  This took me about 2 hours to assemble.  The ribs fit very tight against the leading edge of the fuel tank skin.  I had to adjust the knuckles on the flanges.  I detailed my process under the leading edge assembly log entry.  Now that I knew what I needed to adjust, I just did it.  The ribs still fit very tightly, but I didn't notice any bulging on the fuel tank skin like I had with the leading edge assembly.

Okay, 2 hours of effort and viola, you have an dry-fitted fuel tank assembly.

Now this is where the wing starts looking good.  It resembles a finished wing assembly, but I am a long way from putting this together for the final time.

Tami said people at work were asking if her husband was building a plane in the garage?  This was one of the first weekends, I worked with the garage door open.  I also had a number of people ask me about it at work.  I guess that is one of the joys of living in small town USA.  Everybody knows what you are doing.

Anyway, don't get to excited here as it all has to come apart before you are done drilling the z-brackets.

ENSURE that you put the tank baffle plate under the fuel tank assembly when putting the tank on the wing.

Before drilling, position the tank so there is no clearance between the leading edge and the fuel tank skins.  Additionally, the fuel tank holes that attach the tank to the main spar should also line up.

This looks good...  A sheet of paper might fit in this seam, but I doubt if two sheets will fit. 

• Then position the tank baffle so that the tank baffle holes line up with the T-701 (fuel tank skins).
• Throw a couple of clecoes in each side of the tank so that the tank and baffle are now an "assembly".  Double check your alignment and position.
• Ensure you see the scribed sharpie marker line for the vertical center in the center rib hole.  You may or may not see the vertical centerline (note difference between my usage of vertical center and vertical centerline) you scribed.  It should be real close.
• Drill the rib / baffle / z-bracket holes on the tank end rib (T-703) and cleco after each hole is drilled.  These are the only holes you can currently access to the z-brackets.  If you drill all 5 holes and cleco, there should not be any movement vertically when you remove the leading edge.  This will give you access to the opposite side of the tank so you can drill that rib / baffle / z-bracket holes.

A right angle drill came in really handy here.  If you don't have a right angle drill, use a long bit to minimize the angle you drill from perpendicular and use a drill stop (not your hand...  see my previous log entry).

Okay, now the part you probably won't like...  Remove the leading edge assembly from the wing.  This will give you access to the outboard fuel tank rib / baffle / z-bracket.

• Double check your vertical center of the tank bracket to the center rib hole.  There shouldn't be any movement of the tank / baffle plate if you drilled and clecoed all 5 rib holes on the inboard side.
• Drill the outboard tank rib / baffle / z-bracket.  Cleco as you go.

Continue with your disassembly.  Remove the fuel tank assembly leaving the two end ribs clecoed to the baffle / z-bracket.  This will hold the tank baffle in place to drill the remainder of the baffle / z-bracket holes.

The hard part is done, now just match drill all remaining holes and cleco as you go.  Ensure you are using a properly adjusted drill stop to prevent drilling your main spar.

Another 10 minutes of drilling and all holes are drilled.  As Dan details on his web site, this is a ton of work to get 7 z-brackets drilled.  I am really happy with my second attempt.  Dan nailed the process.  I did not have to elongate any baffle holes (or any holes for that matter) and I have excellent alignment.

An impromptu inspection by Arnold, our resident aircraft and home inspector found no issues worth hocking a hairball over....  However, he had one nagging question; Where's mom?

To finish the night, I decided to mount the plate nuts that attach the root rib z-bracket.  These are flush rivets on the forward side of the spar so that you can attach the z-bracket I spent so much time drilling for. 

The trick with these plate nuts is how do you get in here to buck the rivets that attach the plate nuts?  This is in the wing walk area
so the ribs are really close together.  Additionally, the main spar assembly prevents a person from getting a bucking bar in there.   Anyhow, this situation does not give you alot of room to work.  A couple of minutes of scratching my head and I had one moment of clarity (for once).

I had Tami place the bucking bar on the factory head (flush side) of the rivets and I used a back rivet attachment for the rivet hammer to form the shop heads.  This worked GREAT!!!  The back rivet attachment has the spring loaded collar and that held the plate nut tight against the spar during riveting.

This whole process wore me out today.  I quit early so I could get cleaned up and watch the "Blue Collar Comedy Tour" on DVD.  Very Funny!!  Larry the Cable Guy is HILARIOUS.  The others are pretty good too.  Anyway, I need to veg out so I can hit the plane hard next week.  Getting close to working with the fuel tanks....  WooHooo!!!!

This is a picture of the wing leading edge and the W-423 joint plate.  The joint plate is fabricated out of strip of aluminum labeled as AS3-032x1.5x36.5. 

On the leading edge side, Van's has you draw a line 1/2" from the edge of the joint plate to align with the rivet holes on the leading edge side.  As you can see in the picture below, my sharpie marker line looks to be centered in the leading edge rivet holes.  This arrangement should then leave 11/16" from the edge of the W-408R rib so that the fuel tank can be attached via plate nuts later.

My alignment here looks pretty good.  The trick, however, is to get the joint plate properly lined.  It took me around a half dozen tries to get it to a point where I was happy with it.  I did try to pre-form the aluminum strip by bending it around the end rib and that helped.   Ensure that you have adequate hole clearance on the aluminum strip at the aft side of the rib on both the top and bottom. 

As you try to position the joint plate between the rib and the leading edge skin, it becomes very hard to move and align as it is a very tight fit.  I did have to lightly tap with a soft faced mallet in order to get everything positioned.  This is just a trial and error effort to get everything straight the way you want it.

FABRICATING FUEL TANK Z-BRACKETS
-------------------------------------------
Disclaimer-  I tried Van's method and didn't like my results.  This log entry and my next log entry detail my experience with this task.  The method I tried the second time around worked great for me, however, I can foresee if not done carefully and correctly, you will have a hard time riveting the fuel tank rear baffle / ribs to the Z-Brackets.   If misdrilled by a little bit, you won't have adequate clearance between the Z-Bracket flange and web to rivet everything together (the same goes for Van's method to).  I am not endorsing one method or another.  I am just detailing how I got through trying to get all these pieces to line up correctly.  Read at your own risk!
-------------------------------------------
Okay, the rest of this page is all about what I did the first time I tried fabricating the fuel tank Z-Brackets.  In my opinion, Van's instructions are not the best for this task.  I started by following Van's instructions and now I am ordering a new set of Z-Brackets for the left wing.  No biggie, I checked the price on their web site.  Van's gets a whopping $1.60 for another set.  I am more disappointed in how much time I ended up wasting.  I guess I am too picky.

Anyway, Van's has you draw centerlines on the flanges for the Z-Bracket and mark the exact center of those lines.

• The flange that will be bolted to the main spar is drilled to size #12.
• The flange that will be connected to the T-702 tank baffle is drilled to 1/8".

OKAY, HERE IS WHERE VAN'S INSTRUCTIONS START BECOME A PROBLEM.  Do not drill the 1/8" hole on the flange (where the red "x" is located) on any of the Z-Bracket flanges.

Let's focus on this log entry why their instructions don't work that well for me.  When I was trying to figure this assembly was going to fit together, I had a hard time picturing the end result for some reason.

If you are not careful where you put your hand while drilling>>>  Be prepared to invent new 4-letter words (multiple words).  Your hand is not a good substitute for a vice clamp, cleco clamp, or a scrap AN3-4A bolt. My hand could not get out of the way of the drill fast enough.  It should be noted that the hole in the Z-Bracket looked great.  To bad I was going down the wrong path and would have to rework the Z-Brackets the next day. 

Aahhaa, trying to out-smart the Z-Bracket, I used some large jaw vice grip clamps, I was able to better stabilize the Z-Bracket so that I could drill the remaining #12 holes.  This actually worked a lot better than my hand.

Just an picture of the clamping arrangement on the aft side of the spar.

After I drilled and bolted the Z-Brackets to the main spar, it became so clear why Van's instructions didn't work very well.  Van's has you drill the 1/8" hole in the Z-Bracket which theoretically is where you will cleco the tank baffle to the Z-Bracket and final drill the remaining rib / baffle / bracket holes to #30.

Well, as soon as I tried to line up the holes between the tank baffle and the Z-Brackets is the moment I realized I just spent a couple of hours on getting nowhere.  I had read other builders state that Van's instructions where not very good here and discounted that information.  I always try to give Van's the benefit of the doubt.  Most of the time they are right.  OOPS, didn't pay off this time!!!

The problem, was that without having access to precision milling equipment, I could not drill my holes to the exacting tolerances Van's does with their pre-punching's.  When I tried to line up the Z-Bracket to tank baffle holes, I could only get one or two holes to line up at a time.  Not to mention that when those holes would line up, there was as much as 1/8" to 1/16" left or right movement in the tank baffle to get that alignment.  Van's instructions tell you to elongate the holes in the baffle as necessary to allow the baffle holes align with the T-701 (tank skin) when the T-701 is clecoed to the spar.  (I did not like the elongate holes idea).  Again, I am to picky...  For my efforts, I was going to have to elongate 7 holes on the tank baffle to get proper alignment with respect to the tank baffle, spar, and leading edge.

• Red Arrow(s)-  Approximate illustration of where the Z-Bracket and the rows of tank baffle plate holes are.
• Yellow Arrow-  Illustrating that using Van's instructions, you may have to move the tank baffle or elongate the holes in the tank baffle to get ANY of the 1/8" holes to line up.

Okay, time to call it a day and come up with a better strategy.  I will work on this tomorrow.