So back to the shop on yesterday, looking forward to flanging the root rib lightening holes.
When I set the flanging die up on the bench, I noticed that although my lightening holes are cut to a perfect 65mm diameter as per the plans, the outside diameter of the flanging tool above the shoulder (the one on the left) is also exactly 65mm, making it too tight a fit in the hole, and impossible to work correctly:
This means the holes I cut in the rib will need to be expanded just slightly.
There are a couple of ways I could accomplish this. To sand/grind the aluminum away to make the hole bigger would be quicker, but next to impossible to maintain a perfectly round circle.
Going back now with the flycutter set slightly wider presents an issue because there isn't any metal in the middle of the hole to centre the flycutter on and there is an increased risk of tearing.
I really didn't like the idea of ruining the perfectly symetric holes by grinding and hand sanding would take forever. Flycutter it is then!
To make another cut, I needed to add a piece of scrap aluminum to the back of the rib. Luckily, I have just the piece left over from the damaged rear channel (always save stuff you might use later). Here the sacrificial piece is riveted in place on the back side of the rib:
With slow and careful application of the flycutter, the new diameters are cut, maintaining the centricity of the circles. Now I know to make the lightening holes slightly larger to fir the dies. I'm pleased it worked okay, I was real concerned removing such a small amount may lead to a tear in the rib:
A quick drill out of the attachment rivets and voila, one rib ready for deburring (again) and flanging:
Deburring the lightening holes is very time consuming. I think I'm going to investigate what 3M Scotchbrite wheels will work on them.
The process to flange the holes using a die is much quicker than working them by hand tools. First, set the rib on the male side of the die:
Place the female side of the die on top, making sure the flange will press out in the correct directions according to the plan (in this case the same as the outside edge flanges):
Although it would be much faster in a hydraulic press, enough force can be exerted using a C-clamp and the bench top edge to accomplish this. For this size die, one clamp is enough, but on larger dies, multiple clamps would be used:
Squeezing of the clamp leaves a wonderfully even and clean flange:
Now that understand the process, making the ribs for my 750 will be much quicker.
I finished the day by doing further final work on the missing wing root doubler. Lots of back drilling of pilot holes, final match drilling and thinking about what can be riveted ahead of other items etc. I'm to the point of having everything ready for final fitting. I flipped the wing over to get better access to the doubler. The wing attach fitting in the lower left is the bent original with the terrible out of round bolt hole. I've clecoed back in place as a guide for backdrilling out the web doubler and new wing attach bracket:
So far so good. I'm really getting a handle on what it means to pilot drill, cleco, match drill, cleco, take apart, deburr, cleco again and final drill.... just to take apart again for deburring, cleco and final rivet. All important steps that mean a well built airplane.... something that the previous builder didn't seem to understand.
Got to the shop this morning for a couple of hours. Trying to squeeze in a bit of time here and there before going to sleep before nightshifts.
First thing I finished off was the fuel tank bay inboard wing rib cap repair. Finished deburring the holes, both the old bad ones and my new ones to prevent any further cracking. The new cap repair is really stout and should give a great surface to attach the wing skin back on compared to the original rib flange which was mangled by the previous builder:
The missing wing root doubler has been drilled according to the plans and is clecoed in place. I've yet to decide which order to rivet this in place, but I'm going to wait until we have all the other items (nose rib, root nose rib, root rib, wing attach bracket, etc) gathered so I can test assemble and measure everything. This took a lot of careful back drilling through the spar web to get it right, and I'm happy with it so far:
In a lot of places of any given airframe, the designers of light aircraft take advantage of the inherent structural strength of aluminum to lighten the overall structure of the aircraft (lighter is better). A common method is the use of lightening holes. You can see them (the large circles) in the spar web of the above picture.
Lightening holes serve a number of purposes besides weight reduction (obvious). Wiring, hydraulics and or fuel lines can be passed through these easily. It also provides an opening for inspection of control linkages that might be inside otherwise closed cavities without having to remove the skins. The most common place they are used is in wing ribs, including the replacement root wing rib I'm currently making for the 701.
Lightening holes are also flanged which provides even more rigidity to the part (more on this in a future post).
Making lightening holes is where the fly cutter tool really shines. Cutting perfectly round holes by hand is near impossible.
So what is a fly cutter?
I particularly like the quote from the machinist that it's like "running a lawn mower without the deck". After drilling my into my hand a week ago (I'm fine by the way), I'll take this as a warning!
The fly cutter I used is a single arm one. It's like a high speed compass that cuts metal:
Adjusted to the right radius/diameter required using the set screws and placed into the drill chuck. When spinning it clearly will hurt you if it's not respected! Here it is with the root rib:
The only safe way to use the fly cutter is to clamp the part being cut down to the drill press table and keep you hands well clear. Trying to stop a piece of spinning aluminum should the cutter jam would be foolhardy. I used wooden blocks to prevent marring the aluminum with the C-clamps. It was also important to make sure the clamps were clear of the rotating fly cutter arm (that also would be very bad):
The secret with any machine tool cutting is to go slow and steady and use lots of lubrication. Once lined up correctly, I began to make the cut, adding a little WD40 as I went. Here is the cut well into the process (yes, the drill was stopped for the picture):
As soon as the cutter breaks through, pressure is lifted to prevent a chance that the cutter tearing the remaining aluminum.
Re-position and cut two more holes without issue. It takes a bit of time and I'll have a ton to do for my 750 parts, but it's worth it to have nice clean holes. Here is the root rib with all three holes cut and the cut out discs. They are sharp, I wonder if that's how they make pizza cutting wheels for the kitchen!:
All cleaned up and waiting for deburring and flanges. Looks great!
Next up, flanges! Stay tuned and thanks for reading :)
Got into the shop for a couple of hours on Friday afternoon. Busy week working around the house and cabin now that the nice weather is here.
First order of business was to finish making the new wing root rib for the 701 wing repair. When I last left the shop, I'd prepared the aluminum rib cutout by placing it into the wood forms. Now it's time to bend! Tools of the day... workbench board, plastic dead-blow hammer and fluting pliers.
Ron has made many wing ribs over the years and has developed some great ideas to make the work easier. One of his ideas is a wooden two-by-four with a channel cut down the middle. This workbench board is screwed to the tabletop and gives a great surface to bend against from many angles.
Next tools needed are a plastic headed deadblow hammer and fluting pliers. The hammer is plastic coated to avoid damaging/scratching the aluminum and the deadblow properties (non bounce) prevent leaving tooling marks.
Fluting pliers are used to slightly crimp the rib edges to take up the extra aluminum that bunches up when corners are bent. Pliers can be bought at a tool supply shop, but Ron prefers to make his own from re-purposed tools.
So lets bend!
Forming aluminum around a form takes equal parts of patience, gentle hammering and finesse. Starting at one end I used the deadblow hammer to start bending the rib flanges over, a little at a time all the way along and back again.
As the flange starts to conform to the curve of the form, fluting pliers are used to "take up" the extra aluminum in strategic locations. This is more of a do as you go type of thing, adding a little crimp here and there. The fluting pliers are just the thing:
One nice thing about the Zenair plans is that they take some of the guesswork out of deciding where to place the crimps. It still takes some experimenting to decide how much is required for each bend.
Once all the flanges are bent, the rib is removed from the forms.
Looks great.... until I laid it on the flat table! That's not right.... hmm...
The cause? Crimping depth wasn't enough. Flipping the rib so the web side is face down and the flanges face up allows one to adjust the crimps slightly, completely flattening out the rib. Perfect!
This was great to practice with and a big step to getting the 701 wing repair complete. I'll have a ton of ribs and other formed parts to bend for my 750.
The next thing I managed to do was finish rivet the fuel bay rib cap repair. Real happy with how good the repair looks:
In the closing moments of the afternoon, I started drilling apart the damaged slat ribs and brackets. I wanted to get these done as they are the next repair up after the main wing.
The title of today's blog entry refers to finesse and a stupid move. I've covered the finesse part with the wing root rib creation. But no day is complete without a stupid move....
While drilling out the rivets on the damaged slat ribs, my smart brain apparently took a coffee break without the rest of my brain knowing. Holding onto one the slat ribs in my left hand and drilling with my right I managed to remove the rivets fairly easily. However, one of the rivets required more pressure on the drill. Well... too much pressure and yup... through the rivet, through the rib and into the palm of my hand.
Ouch! I immediately thought "oh-oh" but considering how much it hurt, there wasn't much needed to stop the bleeding. Two days later, after much consideration about a weekend trip to wait in the understaffed ER, my hand is finally starting to feel better and I'm getting the flexibility back in my index finger. Hopefully no permanent damage. No pictures either, too hard to hold the tablet camera and take the photo with only one hand!
Who knew building could be so much fun!
Where did March go?
Work, family vacation to Florida and a week away from home for a work conference left little time for any shop work. It was difficult to be away so much, but it was a much needed break and I'm making up good shop time again this past week.
Took an hour and started comparing my CAD drawings to the templates already made for the 701. Ron and I had previously sat down and compared drawings and it was a great exercise in determining the commonalities between the two aircraft.
For example, I pulled out Ron's form block for the 701 slat rib and compared it to my CAD drawing for the 750 slat rib form (top right CAD drawing in the picture above). It's a perfect match, which means that is one form I won't have to make for manufacturing my part:
Every form has a matching template for the aluminum that needs to be cut for the specific part (that's the slat rib template CAD drawing directly below the form in the picture above). So somewhere the template already exists for this part, another thing I won't have to create for myself.
On the same track, I pulled a good number of templates and compared them to my plans. Every template has a matching form (where a form is required). What an amazing amount of time and labour this is going to save me:
Next up, I worked towards finishing the fuel tank bay repairs on the 701 wing. As you may recall, I've been working on repairing the spar, rib and channel tops using a "L" doubler. Working inside the nose skin is a challenge!
I made a spar cap doubler repair and test fitted it along side the new spar root doubler:
The only way to get this tight to the existing spar cap is to remove the rivets holding the spar cap to the web. As I indicated, the room to work inside here is really tight and I don't want to remove the nose skin any further than it is and risk creasing the thin aluminum.
Right angle air drill to the rescue!
With the required spar cap rivets removed, I back drilled from the rear of the spar into the new spar cap doubler and clecoed it in place. Another parallel row of rivet holes will be drilled between where the clecos are and the lightening holes of the spar web. This will be very solid when rivetted later:
Finished off fitting and match drilling the rib repair caps as well. Other than some final drilling and riveting, the fuel bay repair is complete and waiting for the new fuel tank.
The next thing to do is replace the root rib with a brand new one. Like a lot of the other repairs needed, it has less to do with being bent from the crash and more to do with poor workmanship by the original builder. Holes that missed centre line, cracks from forgotten de-burring and the like.
Ron and I pulled out the root rib forms. Root ribs are the same length as the wing ribs, but much shallower in height as the wing chord narrows dramatically as it approaches the fuselage.
Forms are what are used to shape flat aluminum into ribs or other structural components. The flanges created by folding the aluminum edges over create rigidity in the part being formed. It starts with matching forms:
Between these, the aluminum that is cut from the matching template is placed:
Before fastening the two forms togther, it's important to check the forms are oriented the correct way. The forms have a beveled edge. This is too allow the aluminum to be bent past the 90 degree mark and spring back to 90 degrees once removed from the form. My first look at the orientation showed I had the forms backwards:
The next important thing is to remember which way the rib flange is to be bent. Often the same parts are bent either left or right, depending on what side of the airplane they are on. It's about symmetry. In this case I have the advantage of looking at the part being replaced and comparing. Then I make a note on the part which way to bend it in case I get sidetracked on something else and button it together with through bolts and wing nuts:
Also needing replaced is the wing root nose rib. The original builder cheaped out and used non standard aluminum and again wasn't very careful with the drill. I found the template for this piece and the form.
Comparing my 750 plans to the 701 plans indicates that this part is identical, so while making the new one for the 701 wing, it made sense to make my two at the same time. My first manufactured parts.... YAY!
So cool to make some parts for MY airplane. Many, many more to come :) Time to go buy some plywood for the remaining forms unique to the 750.
Oh look, my build time log has 1 hour for the wings!
Remember how I said I was manually entering all the drawings from my plans into CAD? I've completed most everything and very happy about what I've learned.
I spent several hours trying to figure out how I'm going to print these items to scale for templates which will be used to trace out my aluminum parts. It's a careful balance trying to print the items to scale and within the borders of what a printer will print on a 8.5 x 11 sheet of card stock. I haven't decided yet if the card stock will be sturdy enough, or that I might transfer the patterns from card stock to a light gauge aluminum like an eaves trough flashing. This will be particularly important on multiple pieces where repeatable results are key.
LibreCad is the free program I used to digitize my plans, but like anything free it has some drawbacks such as a limited ability to print to scale right from the program. It does however export to PDF. There doesn't however seem to be any rhyme or reason to what scale the drawing end up in when exported.
To solve this problem, I found an online program that takes DXF files (the LibraCad file type) and converts them to PDF. It automatically scales them to the best size paper, not 1:1 scale (which I need).
I figured out however, that if I print the PDFs as is and hand measure them, I can calculate the scale percentage I need to up or down scale the PDF. The it's just a matter of entering that percentage in the final print and voila! 32 Perfectly scaled 1:1 drawings printed direct to card stock!
I'll be limited to those templates that fit on letter or legal card stock for now. Most of the larger parts are strait cuts anyhow. I'm more concerned with the complex curves of nose and wing ribs and some of the smaller parts. Maybe I'll do some research and see what size I can get card stock I can get.
The other item I've been trying to determine is the specs on my Corvair crankshaft. I've mentioned before it will need to be magnaflux tested for cracks, heat treated (nitride) for strength and the rod journals ground for bigger should radii. I happy to see the crank I have is within a couple of thousandths of stock meaning there is lots to room to have it ground properly.
Progress. Back into the shop I go!
To make up time I missed last week, I did back to back days in the shop this week.
The next step in the rebuild of this 701 wing is making new aluminum caps to reinforce the damage done by the original builder to the tops of the two fuel tank ribs. As you can see here, the holes are kinda randomly spaced and most aren't even clean:
We'll be doing a cap along the front edge as well for the same reason. This will strengthen the upper spar cap angle and make a much cleaner (and stronger) assembly. Before doing this, I did a test fit of the infamously missing replacement wing root spar doubler before measuring it for the bending of the flanges, and I'm really happy with the result of the fit:
Or at least I thought I was until I remembered the small bend in the upper spar cap that needs to be repaired. Looking along the top of the spar cap angle you can see the "wow" (bend) I'm talking about. It's not enough to change the fit of the spar root doubler, but it will affect how squareness of the wing to fuselage join-up::
So, using a bit of my recently learned knowledge about how aluminum "springs back" some when bent, I had to come up with an easy way to take this bend out. First, I taped some mahogany shims on opposite side of the spar cap and to either side of and equidistant to the bend:
Once these were in place, I carefully clamped a 2x2 piece of wood to act as a surface to leverage against:
Unfortunately, you'll have to use your imagination to visualize the next step as I don't have a picture.
Another C-clamp placed directly of the centre of the bend is gently tightened drawing the bend towards the gap and slightly beyond. Once released, "spring-back" takes over and the spar cap returns to the straight position. It took a couple of tries to get it perfect, but it worked. This wouldn't work if the spar cap was broken or kinked - it would have to be replaced at that point, a very time consuming and expensive process. Here is a picture of the now straightened spar cap. Very pleased how this worked out:
Next up, bending the spar root doubler and installing the new caps around the edges of the fuel tank bay. Progress!
I had hoped to get to the shop last week, but an unseasonably warm weather forecast was causing me some concern at home. With all the snow we've had through January and early February, we had about 3 feet of accumulation on the roof. Rather than go to the shop, we thought it better to remove the bulk of snow before the positive temperatures arrive and make the snow weight too much for the roof. It took several hours, but I got it done. Didn't feel like going to the shop (ok, actually I couldn't lift my arms for a couple of days).
Back to the shop today. Got right to work creating two new wing root spar doublers. These will be installed where they should have been in the first place. Using a template, I traced out the rough shape on the 0.032 aluminum:
I cut out the shape in rough and used a file and the grinder to get the final shape exactly right:
I repeated the same steps for the second one. The process is fairly simple as you can see from the wing root attachment brackets below. From top to bottom, a finished piece from inventory, a rough cut piece to be ground and the template from the plans:
First you trace the template onto the stock, and use (in this case) a bandsaw to cut it out close to the line. Comparing the two after the bandsaw, use a sharpie marker to trace it again, leaving a line showing the remaining material to remove by sanding or grinding:
Next, use the grinder or file to remove the balance of the material as defined by the trace line:
Last step, hand sanding all the edges to a satin smooth finish. Here is the stack of eight I finished (two for this repair and 6 for inventory) and below that the stack of wing root doublers for inventory:
More rain tomorrow, so back to the shop to start working these items into the repair.... and find more things wrong with this wing..... probably :)
Those that know me also know that I tend to stew on things. It's a trait I've always had and as I grow older, I've tried turning the energy that is wasted away worrying about the little things and more towards solving the problem or fixing the mistake. It doesn't always work, but sometimes, with a little thought and time to ponder it does.
I got to thinking about the Rear Wing Root channel that I made the "oops cut" on last week. Looking over the plans, not all is lost. I'd already made the flange end longer than what the plans called for. Beefing things up in this manner is an accepted practice. This larger flange means that I still have room to correct my mistake and salvage the piece.
Here is the damage I did. You can clearly see where the cut extended beyond the relief hole:
By trimming the flange end a little bit narrow and creating a new relief hole, I eliminated the bad cut and still met the requirements for size on both. The corrected mistake is shown on the top in this picture and my second proper length "no damage beyond the relief hole" cut at the bottom:
Once I dressed and deburred the edges of the entire piece, off to the bending brake we went.
Unfortunately, I went a bit far with the lower edge. It ended up with a full 90 degrees of bend, but needed to be less than 90 to match the curvature of the wing skin.
No big deal, I just made up a jig to bend it back a bit (you can't undo bends in the brake). The key is to bend it all at once to maintain a consistent edge on the flange. You can see in the next picture that I placed the channel on the workbench and used a two-by-four and C-clamps to secure it. Ron has an excellent flanging tool just perfect for adjusting things (painted red):
Worked like a charm... my oops is no more!
Fit up seem good. Plenty of room for new rivet location and flange matches top of the rib:
Next I worked on making a new wing root attachment bracket to replace the damaged original. This required cutting thick aluminum with the band saw, a new experience for me (although I've cut wood many times on the bandsaw). It went well. The secret is to cut the piece out slightly larger, allowing room to sand/grind the piece smooth to it's final dimension:
Next up will be to make a replacement forward wing attachment bracket and the new wing root spar doubler that we discovered was missing on the original build. Luckily we have a traceable template for this:
With each repair and new fabrication I'm making, I'm getting the courage up to start bending and shaping metal for my own plane. I CAN do this!
Back in the shop again Monday. I got some more repair work done on the 701, but like home renovations one thing leads to another.
Talked over the latest issues with Ron. We decided we didn't like the original builders efforts on the rear wing attach point either. Damage to the rear root channel is also too much to accept as is, so we'll replace it too.
Drilled out the rivets holding the root rib and the first outboard rib, then started removing the rivets to separate the channel from the wing attach bracket:
With the rivets removed, it becomes easier to see the damage done by whomever drilled the wing root skins. The wing root skin is one of the last things to be fitted during a build and one might understand the desire to "hurry up" and get done, but this is done terribly, even if they weren't in a hurry. None of the holes are measured right and at least one critically damaged the wing attach bracket:
The hole for the wing attach bolt has a few issues too. According to the plans, it should be drilled directly centered in the channel. A random second hole on this attach bracket shouldn't even be there and look how close it is to the main bolt hole. This is a fatigue crack waiting to happen. Corrosion protection certainly wasn't considered either. Regular old white paint ain't going to cut it!:
I spent some time cleaning up the skin edges around the fuel tank bay. This will go a long way to making the skins sit flat. We are also putting L brackets over the top of the ribs and spar web in this area. This has the dual benefit or strengthening the ribs and providing a better place to rivet the tank skin on later - with the proper rivet spacing! These look like Swiss cheese.
The overriding goal of this repair is to learn the fine skills required for my build. I definitely learned one when preparing the new rear channel. I measured very carefully, and made sure to drill the corner relief holes in the correct position. This material is 0.032 thick, something I really haven't cut before with hand tools.
Reminder to self.... when cutting with hand shears, the tool will jump ahead when reaching the relief hole. A cut past the hole is the inevitable and regrettable result, ruining a well measured part:
I originally circled the excess cut and was pretty angry for making this simple mistake. Then I reminded myself the goal is learning. As long as I don't forget next time when cutting towards a hole, making a 2nd replacement rear channel isn't a big deal.
I added the rest of the word "OOPS" as a humorous reminder that life is good as long as I'm learning. I'm going to salvage the majority for other small parts and leave this part propped up on the bench as a reminder.
Back into the shop in a few days. Thanks for reading.
As regular readers will recall, I'm working on repairing a damaged Zenair 701 that shop owner Ron bought as a rebuildable scrap project. Eventually, it will be reinspected, painted and sold to fund other projects. Ron is giving me the opportunity to learn the skills I need for my build by doing this rebuild and it's been really enlightening.
We are both starting to guess that whomever inspected the original build must have either been in a huge hurry or not very aware of acceptable building practices. Through this post, I'll point out some of the more obvious clues. It's lucky no one was killed flying this airplane (I use the term loosely).
These photos were taken over the course of the last couple of weeks, but are generally in order that I accomplished them.
Ron decided that the rear tank channel needed to be moved back to accommodate a bigger fuel tank, so I worked on removing it. This first picture was from several weeks ago, when I was still stripping paint and the rear fuel channel was still in place:
Here is a more recent one. The paint strip is mostly complete and the rear fuel channel is removed. I've also removed the silicone caulking the builder used for "anti-oil-canning":
The channel came out without too much effort. It's in rough shape and covered in the remnants of adhesive from the tank mounting cork, silicone (surprise) and, get this.... crack filling foam! Ron seems to think that the plane at some point probably developed a fuel leak and the silicone and crack foam were a red-neck repair (clue # 1). Ron also let me know that the suspected cause of the crash that damaged this 701 was the plane running out of fuel. More on this later. Here is the removed channel:
As the wing gets thinner top to bottom the further to the rear you move, so does the space where the channel will go. After measuring very carefully considering what size it will be in it's new location, I cut the top edge off. Here is the modified channel, all cleaned up, cut down and straightened:
In order to bolster the strength of the channel top edge, I created an "L" flange out of flat stock using the same thickness as the channel:
Next was a series of trial fits, removal, trimming, fit, removal, and fit again to get the new channel in the right place to ensure the new flange was at the correct height to meet the wing skin. I predrilled the new mounting holes in the ribs at this time. This is where clecos earn their value!
It took some more working of the edge of the channel to remove any interference with the rib lightening flange hole and working around the rib repair piece:
Once I was happy with the fit of the modified channel, it was time to attach the reinforcement L flange. Measure two rivets per section, cleco, drill and deburr:
The new L flange really tightened everything up!
I've put it aside for now to work on the next repair item, the wing attach point.
When this plane crashed into the trees, this wing was ripped backwards, bending the wing attach bracket. No small feat, as these are obviously designed to be stout:
Even if it wasn't bent, it would need replacing anyhow for a couple of very obvious reasons. Look at the shape of that hole! There is no way this was an acceptable mount. It looks to me like someone got lazy and just made the hole bigger instead of rigging the wing properly in the first place (clue #3). Another issue is the lack of corrosion protection at this joint. The aluminum of this wing attach point was obviously in direct contact with the steel of the fuselage frame. Anytime two dissimilar metals are in contact, there needs to be corrosion protection. It's called Galvanic Corrosion, and you can read about it here.
To remove the wing attach bracket is going to take some work. These are installed using bucked rivets, not the pulled rivets I'm used to dealing with. That root nose rib is also really trashed from the accident, so it will also need to be replaced:
To make access easier, I tied back the top of the nose skin with a piece of string, being careful not to crease it. Sometimes it's the simple way that's best!
Using a centering punch and a drill bit, the heads of the rivets are drilled off. After some gentle persuasion, the wing attach bracket came off without much trouble.... hmmm. It shouldn't be that easy, should it?:
Pulled rivets have a hollow core, which means they can be drilled out and removed with ease. Bucked rivets are solid all the way through and what a pain they are to remove even after the heads are removed. Reminder to self - don't screw these up when doing mine!
Next, remove the root nose rib and it's support bracket. This is when I noticed this wing spar is missing the root doubler (clue #4)! A root doubler is another layer of aluminum plate sandwiched to the main spar web to increase the strength and integrity of the wing attach points. This is missing on this build. How it could have been omitted, I don't know. What drew my attention to the issue was the L bracket riveted on the spar web. This doesn't appear anywhere in the plans. The root doubler has this built right in!
As far as I am concerned, this was an accident waiting to happen, all the clues add up. It's a wonder this wing (or the other one as I suspect it's the same) never folded or failed in some way, even on the ground.
Running out of fuel (the actual cause of the accident), probably saved this guy's life and perhaps that of his passenger. I'm not going to even try and guess the reason they skipped such an important assembly, but I guess I'm fixing that too!
I decided to drill out the next row of nose skin rivets, as I'll have to remove everything up to and including the next outboard rib to install the missing doubler:
Next I removed the bent L that supports the root skin at the rib and I removed the slat support bracket. Next was the nose rib and the mystery L on the spar web:
Definately a ton of work (and learning) done and still more to come. I'm really enjoying this process!
During my free time away from the shop I'll continue to get the plans digitized into CAD. I've repurposed an old laptop we had lying around. I installed the Ubuntu (Linux) operating system and the CAD program LibreCad. It's really fun, easy to use/learn and best of all it's free. It's also available for Windows and OSX if Linux isn't your thing:
Back to the shop tomorrow, thanks for reading!
Time until takeoff
Husband, father and 911 dispatcher. Long time pilot with a licence that burns a hole in my pocket where my student loan money used to be. First time aircraft builder. Looking to fly my own airplane.