Restarting yet again - a year and half later

 Hard to figure out exactly where to start this Blog again. Recap - I screwed up the inner and outer skin of my left wing LE Mode in April of 2019. Tech Counselor came out and we discussed using a planishing hammer and dolly to reform the damage to the outer LE skin and inner subskin. I bought the hammer and the dolly, and was about to attempt the task of re-forming the skin, when I had yet another epiphany. 

1. I realized that positioning the dolly had to be done exactly right in a very tight spot inside the LE, and I determined that this would just be next to impossible for me.

2. After having a very honest conversation with myself, I also realized that even if I managed to reform the skins correctly, this mod went wrong almost from the start where I did not create the wood form blocks for the sub skin properly. This meant that curve of the LE of the subskin has NEVER been formed exactly as it should, and leaves a gap between the outer Le skin and the subskin that then causes issues with how the removeable plate would sit when screwed onto the subskin. It also puts additional stress on the rib flanges underneath. IOW, the removable plate will NEVER sit flush the outer skin because of the subskin deformity, and the added stress in the rib might lead to other structural problems later. I should have taken much more care and ensured that the wood form blocks I used to bend the subskin EXACTLY matched from the curvature of the LE Rib so that the radius would have mated with the LE skin correctly.

3. The final straw for me was the realization that, after seeing it all come together, there was a much easier way to approach this whole thing, without the need to use the massive subskin and all the forming, measuring, bending, cutting, laying up, and riveting that was involved. I also realized that I could still attempt this mod AFTER the plane was built per the plans that would take very little time, and could be done using much simpler techniques than my original design.

As a result of this, I decided to abandon the entire mod and order the necessary new parts, including a new left wing LE skin and some ribs to build a stock LE. The only thing I will still do differently is order a left wing LE skin from Vans WITHOUT the cutout for the stall warning vane service access plate. 

It is sad to have spent so much time and effort on this, only to reach the conclusion that I need to abandon it. It is even more sad to come to this decision only after assembling and almost completing it.  However, I am not sad about having made the attempt, as I learned tons about airplane design in the process, and I now have a very deep appreciation for those that undertake the challenge of designing airplanes from scratch. So my only regret is the time I have lost, but nothing else. Basically it was not until seeing entire mod coming together to figure out that there was a much easier, simpler, less invasive and less time-consuming way to do this. I'll keep the details of that to myself for now.

So what happened after all that?

Instead of working on the fuel tank as I previously stated in my last post, I spent the next couple of months working on some mods for my 14 inch RIGID bandsaw.  This saw became notorious for not being very well built to the point that it vibrated so badly that it was difficult to make fine, accurate cuts. With the forming of the forward Fuel tank mounting brackets looming in the distant future that would require the use of my bandsaw, I decided to spend the time to perform several well-documented mods to reduce the vibration and turn it into the tool that it should be. There are numerous You Tube videos on the subject and I watched all of them.  

I needed to purchase some new Neoprene tires for both wheels, some longer mounting bolts for the motor as well as the saw base itself, a custom cut piece of 3/4 inch plywood to fit over the top of the mounting stand, and some new composite saw guides. After much work on this, I ended up with a good saw that passes the "nickel" test, where you place a nickel on the saw table on its skinny edge, then turn the saw on. If the saw is balanced properly, the nickel will stay on its edge without falling over. I was able to achieve this to my satisfaction. 

The end result was that I could now cut the 1/4 inch thick Fuel Tank Angle Mounting brackets with reasonable accuracy on the bandsaw to reduce the amount of forming work to do after the initial cuts. One of the most challenging parts of the saw mod was the need to trim the 1 inch wide neoprene tires down to about 7/8 inches so that they fit in the wheel tracks properly. This required making a special wood frame and using my belt sander to trim the edges accordingly. That, balancing the wheels, and adding the 3/4 inch plywood base and a new composite "link" belt all contributed to solving the vibration problems with the saw. Unfortunately this was yet another delay in the build.

Then, my wife and I needed to take a much needed vacation together, so spent the next couple of months focusing on a multi-faceted trip the New York for the first time. We spent one week in New York City and did all the NYC things a newbie would want to do - Statue of Liberty/Ellis Island, 9-11 Memorial and Museum visit, which I highly recommend to any red-blooded American, went to a Broadway show, Times Square, Stood outside during a Today Show airing, had a real New York Pizza slice, learned how to ride the subway, went to Grand Central Station, Went to Battery Park, the Fashion district, visited the famous toy store FAO Schwartz, and much more.

Then we flew off to Buffalo and took a shuttle to Niagra Falls, Ontario to see the falls for the first time. We had so much fun there, and the falls were so beautiful, that we both want to go back someday. this all happened in early September of 2019. As the whole world now knows, only a few short months later all of New York and the rest of the world would be shut down and fighting for its life due to the COVID pandemic. I have not been back on the build ever since May of 2019 as the the wind just went out my sails after coming to decision about the mod, and too many other things got in the way. After  our vacation, winter and the cold set in yet again, and I still had no heat in my garage. 

Then COVID showed up in the spring of 2020, and the massive wild fires in Colorado soon followed, and it was a struggle to stay alive and to breathe through smoke and ash all at the same time. I almost lost relatives in the Troublesome Fire in Grand County - very scary. So airplane building was not on my list of things to do throughout that entire period.

I endured multiple furloughs and layoffs at work last year, only to find myself working 15 hours days, 7 days a week, for at least a couple of months. So you could say that yes, I kept my job, which was a good thing, but at great personal cost to my overall health and well-being.  Now we are in 2021, where winter is once again upon me, and still with no heat in my garage. What a wildly exhausting time it has been over the past year and a half. 

Is there a plus side to any this? Well, in the interest of counting my blessings, both kids have graduated college, have jobs, and are out of the house and successfully on their own. Several major financial burdens have ended, I have not contracted COVID nor have any of my family members, and COVID vaccinations have begun. Aside from politics and some extremely idiotic people in this world, it seems like the sun may be trying to shine on the world again. So I decided it is also time for me to re-engage with the plane project again. I need to order parts from Vans and finish the wings.

More to come..... Sorry for the long hiatus. Stay safe, respectful, and peaceful everyone. Life is too short. I'll have pics of the bandsaw mod, planishing hammer and dolly, and some other stuff in the next post.

Busy Preparing for the Fuel Tanks and Tech Counselor Checks out my LE

My Technical Counselor and former long time EAA Chapter 301 President Jim Elliot has been mentoring me through all this LE mod fiasco. I had to wait a couple of weeks for him to become available to come and visit the "almost" finished LE work, and he was finally able to come out last Saturday and take a look. He is a Mooney aircraft owner and has helped several people build different makes and models of experimental airplanes. He definitely knows his way around an airplane, and with evaluating potential affects of modifications such as mine. More on that in a bit.

Since I knew I had to wait for a bit for him to be able to come over, I started preparing (for about the third time now) to get back to work on the fuel tanks. So although I have not posted in while, I have still been very busy thinking, reviewing, and planning for re-engaging on the fuel tanks to get those behind me as soon as possible. his started with a review of many previous posts where I actually started on the left fuel tank because you needed to match it up with the LE to check alignment and drill some holes in the T-712 mounting brackets for the wing spar and the rear tank baffle. This little journey took me clear back to posts from the Fall of 2017. About the last thing I remember about the tanks was fabricating the tank stiffeners for the bottom of the fuel tank skin, and countersinking skin-to-rear baffle holes per the plans.

After reviewing the stuff from the past, I ended up coming up with a list of new additional questions that required answers from Vans. As a side note, to date I have order at least 2 proseal tubes, a small sized can of proseal, and a full sized quart of proseal - ALL of which have shelf lives that have long since expired, so they will not be used to seal any part of my fuel tanks, and I will need to put in an order for more proseal yet again. Sucks to be me I guess - that's about the only way I can sum that up.

Many of these additional questions are questions that you do not see either asked or answered by others, but I find it quite strange that others are not asking the same questions. Anyway, to make sure that I don't lose the content, I am posting them here for myself and anyone else following my blog that might also appreciate the info:

385b and c SW fuel senders - for left and right - is it correct that the potentiometer scale/meter on c version for the right tank will be reversed (facing forward instead of to the rear, when installed on the side of the tank, or should the scale for both still appear toward the rear of the tank when installed correctly.

Vans says this backwards orientation is normal - important thing is that they both point down when installed either on the end rib or the rear baffle plate.

Am I supposed to scuff the back side of the sender flange of each sender if I am going to proseal it directly to the tank rib (NOT use the rubber gasket or cork as recommended by many who have been there before.)

Vans says not needed.

The left sender seems to have a dead spot at the end of travel of the arm (empty indication) - either no ohms reading at all or much higher (300 ohms or more - much higher than expected 240 ohms per the plans.) The right sender seems to be indicating correctly per the palns info. Ordered both SW senders from Vans on 4-16-18 order # 74191. SW says has a 2 year limited warranty - how do I proceed with a replacement. Go through Vans or direct with SW?

vans - Contact SW directly to replace it

Left tank will be flop tubed, so sender will be in bay #2 in rear of baffle.
1. Did I do a lot of extra unnecessary work by cutting the big hole in the aft of the end rib, when I found out that the sender needed to be placed in the second bay via the baffle in the first place.

Vans   -still good to have access t that bay due to the trap door and the flop tube/anti hangup bracket attachments.

2. With the sender in the secnod bay of the rear baffle, that means that the only way I can service that sender if necessary is to pull the entire tank, correct?

Vans - correct - you will have to pull the tank to service the sender that is mounted this way

3. For tank baffle mounted sender, do I need to cut another big round hole in the second bay AND use a reinforcement ring (T-407) as well, or just the hole big enough for the sender to fit in?

Vans says nope - no reinforcement ring or big hole needed - just a hope big enough for the sender to be inserted/mounted directly onto the rear baffle plate web. No reinforcement ring needed because the baffle plate is thicker/stiffer than the rib web.

4. Do I need to use another reinforcement stiffener ring for the T-411 cover plate on rib T-703 if no sender is being mounted in that hole, or can I just mount the cover plate, with nut plates mounted on the rib web itself instead of the combo of the rib web and the reinforcement ring?

Vans - would still use the stiffener ring here as the rib is not very thick and alot of strngth is removed by cutting that big hole.

5. Depth of tank for SW sender specs to determine what size to cut the rod - what dimension should I use for that (tank depth so I cut the rod to the correct length?

Vans - just clamp the sender in place and measure to determine based on the area where the float will be traveling.

6. Since the left tank sender will go in the rear tank baffle, do the dimensions of the float wire change from original plans for mounting in the rib on the side? Any issues with clearance of the bottom stiffeners when mounting the sending in the rear tank baffle?

Vans - measure to be sure, but should not be a change or a problem as far as they are aware.

7. Do you know a part number for a more malleable proseal for access plates that is not as hard as normal proseal to remove??

Vans - they do not use it and did not know the part number of hand - said to check Spruce and others.

8. Grounding the sender - how is this grounded to the airframe if you have the tank baffle or rib web, proseal, and the flange of the sender on the thin later of proseal. Are we supposed to run an additional ground wire from one of the sender mounting screw holes to one of the tank attach bolts or something similar?

Vans - Use a lock nut with the cut flanges that bites into the metal on the underside of the screw head and on the sender flange as it gets mashed down during screw tightening to establish contact for a good ground - so additional wire should be needed, even if screws are prosealed. Do it on all screws or just one or something in between?

As far as the tech counselor visit is concerned, Jim took a look at my unfortunate demise on the LE. Said that it is a dent and not a crease, but that it did deform the outer skin and the subskin. Then we had a conversation about acquiring an autobody or planishing hammer and a dolly that may have to be customized to try to pound (actually TAPPED) out to try to reform the skin back to the shape that it was in before. Unfortunately I can see where my unbelieveably STUPID idea t just keep pounding on the skin with the rivet gun when the rivet was not setting properly has indeed flattened it out a bit. So as a result, if I want to continue with the LE mod using what I have done thus far, I now get to learn a new skill that involves removing dents and reshaping metal, and I probably have to custom-make yet another tool = more wasted time.

So I went to local NAPA store, found a planishing hammer with a rounded head (NOT the kit you find at Harbor Freight, that only has flat headed hammers), and a Toe dolly that, when I fitted it up against the curvature of one of my LE ribs that I took with me to the store, looks like it will almost perfectly conform to the curvature of the LE skin/subskin/rib as long as it is held in the correct position. This is probably going to require a helper to hold the dolly in position while I tap the outer skin and hope like hell that I don't just deform everything beyond reasonable repair.

The last part of our visit was spent having a heart to heart about the possible structural impacts of what I am trying to do, and if I should go ahead and contact a DER (Designated Engineering Representative) to come and look at my invention and provide some further experienced insight on what I am doing. I wanted to go ahead and finish this mod regardless of the ultimate decision about its feasibility, just to see what it would take. At the end of the day I am not certain that this is a safe thing to do, and may still decide to abandon it all together. But I'm not throwing in the towel on the mod just yet.

I've got some parts to order from a number o different vendors so I am also putting that list together. I'll have some pics on the next post that show the damage from the F'd up riveting job  more clearly, and the tools I am going to attempt to use to fix it.

More Nutplate Hell and Creative Clamping

After several days I was finally able to finish riveting all 20 nutplates to the subskin. Man did that turn into a royal pain in the ass. As of the previous post I had made it to the last side and had messed up the rivets on the last, most-forward nutplate along the edge. This is where the skin starts to curve at the very front, which makes trying to set straight rivets with a rivet squeezer a bit of a challenge. I think I managed to finally get it after drilling bad rivets out a couple of times.

With the side nutplates installed, it was now time to tackle the hard part - the remaining rear-most nutplates on the top and bottom sides of the subskin. I could not use a rivet squeezer on these because they are too deep into the center section of the subskin for any of my squeezer yokes to reach. SO that meant that it was time get out the rivet gun and the bucking bar - something that I have not done for a very, very long time.

I decided I did not think I needed to practice on anything, because I was able to get the air pressure setting correct for the rivet gun. Looking back I wish I would have been more experienced about that when I riveted the horizontal stabilizer skins onto the frame. It hangs up on the wall in my garage so that every time I walk in I have to look at it, and I cringe every time that I do. That is because I literally beat the shit out those skins because my pressure was too high, and almost every rivet attaching the skin to the forward spars has this large skin dimple from over hammering the rivet gun on the skin. By the time I got to the elevators I had pretty much figured that out, but I literally pounded the HS skins almost to death..

Anyway, with the air pressure set on the gun, the next step was to figure out how to clamp everything down tight. I ended up deciding that using my bench vise should allow me to set everything up to use both hands to buck these rivets without needing to worry about securing or holding the part. Here are some pics if what I came up with. IT involved the bench vise, a small 2x4 for the smooth front side of the skin, and a custom sized much smaller piece of 3/4 inch plywood for the back side. All of this had to be positioned very carefully to ensure that there was enough space for the rivet gun and bucking bar, and to allow everything to be clamped tightly down without deforming any dimples in the skin. With so many dimpled rivet holes in this custom part, this became a challenge at times.

The top part of the skin was easier because there were not as many holes to dodge while clamping it all down:

I used a bar clamp to provide stiffness and resistance on the top part of the skin. This was the difficult part of trying to use the bench vise for this large piece of aluminum. The vise only provides a small amount of depth, so the top part of the skin remains very flimsy unless it reinforced with something such as the wood that I used.

On the front side I had to make sure there was enough room for the rivet gun:

And here is shot of the back showing how I had to be careful about the size of he wood  used and how it was positioned to avoid smashing or deforming any existing dimples. The other concern was of course making sure that I had enough room to use the bucking bar. This did not prove to be much of a problem until I got to the corners where the first side nutplate is located relatively close to the rear-edge nut plate in the corner. 

And here is yet another creative clamping method where I was able to use the access plate hole on the bottom side to insert another bar clamp for added stiffness. 

The stiffness is needed because, regardless of who you may talk to or what you may read in a book, you HAVE TO apply some pressure on the rivet gun and the skin to ensure that it will NOT bounce when the rivet gun is activated. This is what directly causes badly set manufactured rivet heads where they sit noticeably proud of the dimple because the underlying skin was allowed to flex and bend each time the rivet set was pounding against the skin. The part needs to be clamped in such a way that any movement of the part is severely restricted. This is the only way that you are able to buck good quality rivets. Sometimes the temptation is such that you do not take the necessary steps to ensure that everything is properly clamped. Then you basically pay the price for the mistake, and you have to drill out bad rivets and try again.

I was able to get all of the nutplates riveted in place, except of course for the very last one, which was a corner nut plate on the bottom side of the subskin. This one proved to be so difficult that I think I drilled the rivets at least 4 times and replaced the nutplate once because it was deformed beyond acceptable limits on one side or the other. I think I must have drilled out no less than a dozen rivets and replaced 3 nutplates during this whole exercise. The top side ones went pretty well, but the bottom side was another story. In fact, I had screwed up the rivets on the last nut plate so many times that the shape and condition of the dimples in the subskin. it was so bad that I was now unable to secure the nutplate in place with a cleco so that the flange on the nutplate would sit flush against the skin. I had to start using tape to hold it in place. When this did not even work, I had to take out my other arsenal of tools. Luckily I was able to use my 4 inch no hole yoke on the bad nutplate on the bottom of the skin. I mounted it on the hand squeezer because I was not having any luck with the gun and bucking bar, and the pneumatic squeezer was too bulky to fit as well. 

So my only choice was to use the hand squeezer so that I could position it and take my time to set the first rivet to make certain I did it correctly. I was able to set the first rivet on one flange just enough to hold it in place where I could then finish it up with the gun and bucking bar. The manufactured head of the rivet ended up sitting just proud of the skin on one side, but I had a plan for addressing that. Part of the plan was to try to use the rivet gun to move it a bit more flush to the skin - this only partially worked.

With the first rivet set as well as could be expected, I then was able to properly set the second rivet with the rivet gun and bucking bar. The corner rivets only allowed just enough room to insert my small tungsten bar in between the two nutplate flanges on the corner. One slip and the rivet, skin, and nutplate would be history. In fact, he bar did slip one time and slightly creased the skin, but I deemed it as OK since it was a dull crease with no apparent stress risers, which means I just barely stopped the rivet gun in time. Had I not done so this entire subskin and the planned project would have come to a screeching halt.

Here re the pics of the finished nutplate rivets on the ear side of the skin. First the nicely set ones on the top side:

And then the less-nicely set ones on the bottom side. Some of the primer was knocked away from all the repeated pounding from multiple attempts to set the rivets, and if you double click on the pic you can see it in more detail and tell very easily which rivets caused me the most trouble. 

And here is the back side of the nutplates all riveted together.

Now, remember that slightly proud rivet I mentioned earlier? Well, here was my solution for that. A long time ago I was at Harbor Freight, an I just happened to stumble on this next little gem - a watchmakers hammer. I used the round headed side of this hammer to lightly tap on the edge of the rivet that was sitting proud, and I was able to get it to sit much more flush after just a few taps with this hammer. This hammer was critical for this because the small size and weight of the ball end of this hammer was just about perfect for ensuring that it only contacts the surface of the rivet head and not the surrounding skin. If it was too large it would dent the surrounding skin, but I found this little hammer to work exactly as I thought it would:

And finally, here is just a small sampling of all the tools  ended up using to accomplish this seemingly small task. As I said before, most of this was pleasant to work on, but those few times when things got difficult, they got VERY difficult. I could not risk damaging or screwing up the subskin because it has required so much customization that there was no way at all that I would be able to take the time to try to fabricate a new one, nor would I even want to. If that part were to be compromised beyond use or repair, I would abandon the entire modification and return to a stock LE without even looking back. Too much time and too many delays with this to even think about starting it all over again.

And here is he pile of drilled out rivets and damaged nut plates that I had to drill out and replace, sometimes repeatedly:

So yeah, I got really good at drilling out AN426 rivets again, too. Anyway, I was able to pound some rivets again, so that is always good. And, more importantly, that step is now complete, which allows me to move on to the next step. 

So next up s to remove all the remaining internal sections of vinyl covering on the inside of the LE skin that I have left in place all this time. Unfortunately this is proving to be difficult, because some of he overspray from the epoxy primer that I used has hardened the vinyl in those areas, and as a result is very difficult to pry up a corner of the vinyl and keep it going so that I can remove the entire thing without it breaking apart. That vinyl has also been stuck to the skin since 2010 when I ordered the wing kit, and I already know that the longer it stays on the glue makes it harder to remove as it gets older.

After that vinyl gets removed it is finally time to rivet the left wing LE together. Great  - more curved surfaces t deal with. I can hardly wait...….

KPR

More LE Prep and Other Stuff

Been busy doing several things since the last post. For starters, I finally replaced the stupid hydraulic jacks with a proper screw jack assembly. I already had one of these from a previous builder/s wing stand, but I could not find the other one, so off to HD I went to get some hardware. To make these you need a 12 inch long by 3/8  x 16 threaded rod, one 3/8 inch nut, and I chose use 2 3/8 x 1.25 inch wide washers. then you need a wood base that is tall enough to ensure that you can adjust the rod without over extending it too much.

I already had my wood base, and that did not change, except that I had to drill a 3/8 inch hole in the base wood to allow the rod to freely rise and fall inside as the nut is adjusted. Here are some pics. The first is of both the old hydraulic (worthless) jacks now sitting on the shelf doing nothing:

These have been replaced by 2 screw jack assemblies using the previously mentioned parts. After the holes were drilled in the base wood, I needed to drill and tap the piece of wood I have been using in order to secure the other end of the rod. I used a 5/32 drill bit to drill a pilot hole not all the way through the support wood, and then I used a 3/8 x 16 tap to create some threads. then I screwed the rod into the the support wood until is was securely in the hole.

When everything is done all you have to do adjust the height is screw or unscrew the nut to raise or lower the threaded rod, which raises or lowers the support wood resting against the rear spar web. No more having to keep re-pumping up the hydraulic jack every time I go out to the garage. SO why did I not do it this way a long time ago? Well, if you look at the drawing from Vans plans that shows this assembly, they show a rather simplistic but OBVIOUS picture of what looks like a bottle jack holding up the middle of the frame while it is on the stand. So I thought OK, I'll do that too. What a crock. Anyway, it's done now, and the left wing assembly was checked for level again by running the fish line across the holes in the main wing spar flange and adjusting the nut until the line runs through the middle of the spar flange rivet holes. Here is the left and right assembly in place:

Since I intentionally set my frames to rest a bit high in  the stand, I have to use quite a bit of wood to raise everything up to the correct level. I did that so that I could suspend the flaps or the ailerons from the trailing edge of the wing and still clear the floor.

the next thing I did was take a mirror to check the clearance of the joiner strip and the outboard fuel tank rib. I have reported in several prior posts that my "strip" did not exactly end up being 11/16th of an inch from the LE rib web as called for in the plans. In some places it ended up slightly less, and in others slightly more. This seems to have been confirmed after I was able to set a flashlight inside the new access hole and used my mirror to check the gap between the rib and the joiner plate. On the top side I ended up with more than enough clearance, but on the bottom side the clearance is just barely there, meaning that the joiner plate edge just about touches the fuel tank rib flange.

The reason that this is important is that at some point that fuel tank rib flange is going to be sealed with proseal and riveted in place. A combination of excess proseal in this area where the joiner plate is supposed to be flush with the fuel tank skin might be interfered with from the excess proseal. There is supposed to be a 1/6th inch gap all the way around, but mine obviously are not that way. I don't have pics of it but will try to get some for the next post. it is always interesting trying to use the mirror to check certain things. You could give a demo class on this subject alone, because it is more of an art than a science to figure out how to position the mirror just right so that you can see exactly what you want to see.

My plan for this is to continue with all the other stuff I need to do on the LE, and then when I am ready to take it off the wing again I will leave that LE rib and the plate attached, while I remove the rest of the LE (You know, the way I SHOULD HAVE done it the last time I tried to take it off), so I can more easily check the clearances of the joiner plate with the fuel tank rib. Trimming excess material is never a problem, but I want to better understand the reason why there is such a difference between the top and bottom sections first.

The other reason why it was important to double check this was because this may also have been contributing to the gapping problem between the outer LE and fuel tank skins that was giving me fits the other day. Need to check clearance with skins, ribs, Z brackets, and the baffle plate to make sure nothing is interfering with the fit.

Now that all that madness was done, it as time to remove the blue vinyl from the first bay of the LE so that I could make some final measurements and draw the final lines on the skin that will be used to mark the rivet lines, cut lines, and nut plate lines for this lovely time-consuming mod of mine. taking pics of bare metal is always a challenge, so these dd not come out exactly the way I wanted them to, but they will suffice for now.

Here is the bottom of the LE skin with the basic drawing of the planned cutout. I decided to use .75 inches as the rivet line mark from inside each existing rivet line for the rivets that will attach the ribs to the skin. The next decision was to use 5/16ths of an inch as the edge distance from the new rivet line. This will become clearer when I start drilling the new holes for everything. I decided on 5/16th of an inch because in other areas that could be construed as a "splice joint" per AC 43.13, such as the main wing skin overlap, the vertical edge distance of those wing skin rivets is 5/16ths of an inch. What's good enough for the goose is good enough for the gander, as they say.

I am using a 1/2 inch radius for the rear side of the removable LE, similar to the same radius used for the new access panel cover. In  fact, I took one of those covers that already had that radius built in to it to trace it onto the LE skin.

These last couple of pics show a line that drew on the top side of the LE skin between the 5th rivet hole from the front of the LE. After spot checking the rivet hole layout of the LE ribs on the top and bottom flanges, I discovered that the 5th rivet hole on the top is almost directly vertical to the 4th rivet hole on the bottom. The concern about using the 5th rivet hole on the top as the line where I will make the cut, is that there is still a pretty substantial amount of bend in the skin at that point. one of things I need to be careful about is to make sure that the removable part and the remaining LE skins will retain that curvature after they are fastened with screws or rivets to the subskin. I can perform some tricks that will apply a slight curve to the edge of the removable part if I need to, but I was hoping not to have to perform too much of that sort of magic.

The other, much more important concern about this, is if a crack forms or a screw come loose from a nut plate on the top of the LE. If this happens, and the skin is allowed to rise up into the slip stream, it basically turns into a spoiler, that will disrupt flow over the top of the wing, and, at best, will cause me to loose lift. At worst it can cause that part of the wing to stall, or for part of my aileron authority to be lessened, or lost entirely. (THIS is that part of the safety concern about this mod that I have been talking about ever since I thought it up.) Needless to say, my pre-flight inspections  will always consist of a significant amount of time devoted to checking ALL of the rivets and screw attach points on the top and bottom of this area, before I even think about getting in the airplane. All screws will be checked for tightness and the overall condition of this area will be scrutinized heavily.

I need to finish drawing more reference lines on the top and bottom side of the LE, and then I will mark all the additional rivet holes that will need to go through both the outer skin and the subskin and drill those. Then I need t make some final decisions about the number of screw holes along the sides and trailing edge of the areas in question, and drill #30 pilot holes through the outer skin and the subskin. Right now I am thinking about 4 screws along the back side, and 2-3 screws along the inboard and outboard edges of the bay. So I am finally and literally at that crucial point in all this prep work. If I screw any of this up now, there is no turning back. I may ask a tech counselor to come by one more time now that I have made some decisions about edge distance and rivet spacing.

Till next time,

KPR

Finalizing the Scarf Joint and remounting the LE to the Wing Frame

Been a while since I last posted. Snowblower repairs, bad weather, and a wonderful cold have kept me at bay for a while on the project. Finishing the scarf joint turned out to be royal pain in the butt. I thought I had finished the joint, had a pretty good fit between the wing skin edges and the fuel tank skin edge, and then I final sanded everything with 320 grit aluminum oxide sand paper to remove the deep scratches. Then I took both wing skins off of the frame set all the remaining dimples with my squeezer, masked off the sanded areas of the wing skins where I formed the scarf joint, and primed them all with NAPA 7220 self etching primer.

Then I reapplied both wing skins to the frame to check the fit, since this was the first time that the dimples were added to that entire area. To my utter disappointment, the skins looked like they had not even been touched. The edges stuck out like sore thumb. My friend Mike had warned me about this a while back, but I thought that was because of the skin edges not being slightly bent, which I had already addressed. However, it became apparent real fast that the newly dimpled skins and the added primer were both causing the skins not to ft very well against the wing spar flange.

SO I called Vans about this. they said that you really can't judge how they will go together until you actually rivet them to the spar, and not to worry about it too much. Well, I decided to try to alleviate at least some of this ill-fitting issue, so I took off the inner skin, noticed that the edges of the skin were quite thin, but that the rest of the metal moving away from the edges still seemed to be a bit thick - indicating that I had not removed enough metal on the inner portions of the wing skin. So out came the file one more time. This time I focused ONLY on the inner portion of the skin, staying away from the edges as much as possible.

Then I re-sanded the deep scratches from the file and re-primed the small 1 inch square area that I was working on. Then I rechecked the fit and decided that enough was enough, and it was time to move on. I think I pretty much realized at that point that it was the dimples and how they were fitting into the countersunk hole of the spar flange, that as causing the fit problem, even though the hole has been countersunk a little bit more than flush per Van's instructions.

When this areas gets riveted to the spar that metal will be forced into the spar flange hole and hopefully will smash down a bit more with the force from the rivet gun. If I don't like the fit after that, I can drill the rivets out and figure something else out. OH - but wait -  by the time you get to this joint in the wing for riveting, you have already done the rest of the holes in the skin, because per the plans you save this lovely area for last. So I'll be damned if I am going to rivet everything else just to find that this area is still not seating properly. Others don't seem to have problems with any of this, so why the hell am I?

Time to move on. The scarf joint is as done as it is going to get. I am pretty certain that all that I will get for my efforts on this is a cracking wing skin in this very area once I start flying. If I do, you can bet that I will be asking myself why I even bothered with this stupid scarf joint - which some builders have also decided not to do, since it is "only cosmetic" per Vans.

I re-inspected the state of the leading edge assembly after my near disastrous and stupid attempt to force it off of the wing spar with the fuel tank mounted next to it. (See my Stupidity label to find the post). I tweaked the rear flange of the inboard 408 rib a bit more with the handseamer, and I checked for cracks or fatigue, and did not see any evidence of that. I removed the fuel tank assembly from the wing spar and remounted the LE assembly, all the while having flashbacks to my stupidity from before. I re-secured the LE assembly to the wing spar with clecoes and then added the fuel tank assembly. That's when I got my next head scratching moment - when the edge of the fuel tank skin and the LE skin did not line up correctly.

Initially I had a situation where there was no gap at the very tip of the LE and the fuel tank skins, but as you went further aft, this turned into at least a 3/64s inch gap. WOW! I thought I had everything here all matched up nice and neat - so once again I foud myself asking what the ^&*O&%$^! Obviously this was some sort of angular issue between the wing frame and the LE and Fuel tank assemblies, which I had verified long ago were butting up to each other with no gap whatsoever - so I knew that something just "wasn't right."

So I'll cut to the chase. There were two things that found that I needed to do. The first is a long standing problem that I have had ever since I put the frames on the wing stands. I used a hydraulic jack to support the center of the wing frame, which does sag under the weight of the wing assembly when mounted on the stands at both ends. I thought that this would be a great method - but found out long ago that these jacks do NOT hold their pressure forever, and they start to slip. As a result, I have had to continuously reapply pressure to the jack to lift the center section to keep everything aligned.

This time I wanted to be sure to recheck the "level" state of the frame by using a fish line strung across the rivet holes of the spar flange and held in place by two clecoes - one at each end. Then you apply the pressure from the jack until the fish line cuts through all the rivet holes evenly. Works great, and I found that I needed to apply more pressure once again to level everything out. The only problem with this is that to do it correctly you need to remove the wing skins from the frame. I did all this in warm weather, before the cold snap hit over the past couple of days. Seemed to level everything out again.

Today is the first day since I got sick that I have been able to go out and check on things in the garage. What I found this time was even more shocking. This time the gap between the LE and fuel tank skins was consistent from top to bottom, and was quite large on both sides. So once again I am asking what the ^&%^%#%$!. I rechecked the jack, but after leveling the center again I still had this huge gap.

The Le had been firmly reattached to the wing spar several days ago, so it was not moving. That meant that something was up with the fuel tank for some reason. When I put both assemblies back on the wing spar, the fuel tank was butted up against the LE skin and then I clecoed the inboard-most holes in the baffle and Z bracket on that end. Then I put #30 clecoes back in each screw hole through the nut plates, just as I had done many times before. None of the other fuel tank ribs, including the outboard-most rib, were clecoed, because at the time I did not think I had access to those holes since the LE an fuel tank are now butted up against each other.

So while scratching my head about this latest quandary, I came up with a plan, based on the only thing I could think of that was causing this gap problem - the clecoes I used to attach the fuel tank assembly to the spar were not allowing the skins to line up correctly for some weird reason. So I came up with a brilliant idea - make absolutely sure that the center of the wing frame was level (again), remove all the fuel tank attach clecoes, slide the fuel tank assembly over till the skins are snugged up against each other, and re-clecoe the fuel tank to the spar again. Then check the fit and go from there. I was skeptical about this whole thing, because I thought that the rib to Z bracket holes would now be out of alignment after sliding the skins together to "make" them fit. I found myself asking - "did I really mess up the whole fitting process and drilled the wrong holes in the wrong places, and that is what is causing all this?" Could I really be that stupid - again?

However, much to my surprise, after I re-clecoed the inboard rib to the inboard Z bracket, and then started carefully applying #30 clecoes to the screw holes through the nut plates again, the skins magically all lined up like they were supposed to, and they stayed that way as I added each cleco. Thank goodness for that is all I can say. Then I saw that I could still apply the clecoes to the outboard fuel tank rib and Z bracket through the access panel opening of the LE. And the skins stayed flush together after I did that. How bazaar is that!

The only thing that I can conclude from this is that I think there was some misalignment of the inboard and outboard ribs when the rest of the fuel tank assembly was removed to match drill the baffle to Z bracket holes for the remaining fuel tank ribs. It could also be that the sagging center section of the frame, combined with some slight shifting of the screw hole clecoes, may have caused the misalignment occur. Putting #30 clecoes in the holes intended for the screws in the fuel tank skin, which have yet to be dimpled, is a bit out of the ordinary. Normally you put clecoes through matching holes in two or more pieces of metal.

However, in this case, until the fuel tank skin holes are final drilled to size for a #8 screw, and dimpled, you are inserting a clecoe into a hole in a flat skin, and then in turn the rest of the cleco must extend further than normal, all the way into the end of the nut plate on the inside of the spar flange. This results in a clecoe that is under higher spring tension than usual, since it has to be extended more than usual, and the flat skins are then being pulled slightly into the large countersunk hole in the wing spar flange, causing some uneven tension on the fuel tanks skin. When you combine all this with an unsupported center section of the wing frame, it is not hard to see how things might not line up correctly.

The lesson learned from this is to make sure that parts that you know are supposed to fit together are actually mated that way first, and THEN you cleco everything in place - NOT the other way around - i.e. clecoe everything and then check the fit. Clecoes that are inserted into places where they may be allowed to shift or distort the assembly a little (flat skin screw holes into countersunk holes  nut plates for example), can cause such a mis-alignment of closely fitting parts like skins. The second lesson learned here is that I need to replace the STUPID hydraulic jacks with a 3/8 inch threaded shaft with a small wood support on one end, and a large washer and nut assembly on the other end, inserted into a solid wood base with a hole slightly larger than 3/8 inches for the rod to freely insert into, and adjusted so that the center section of the frame remains level ALL THE TIME! Don't use stupid hydraulic jacks unless you want to feel my pain.

So I already have one screw jack assembly from another builder, which I obviously never used, and I'll need to fabricate another one for the other wing stand. That is my mission for tomorrow. SO in short I have been on a bit of wild ride ever since the time came to remove the LE from the frame to start working on the fuel tank assembly on the wing spar. It's been one wild thing after another ever since.

The last thing for tonight is that I finally have the LE back on the wing frame, which is the point that I was trying to get back to ever since this latest round of madness began. I needed to get the LE back on the frame one last time for it is final-assembled so that I can get down to business and make those final decisions about cut lines and new rivet holes and locations for nut plate and screw holes, all in preparation for the big "cut your LE to pieces" exercise. I worked out some final measurements tonight and will elaborate more on all that in my next post. I am very close to being ready to make the cut in the LE skin once these measurements are finalized.

Almost ruined the LE yesterday....

This is where I get to rant once gain about those that do not provide enough information to ensure that things get done properly. As a result of this lack of information, and my own shear stupidity, I almost ended up destroying my inboard leading edge rib while trying to get the damn thing off the wing spar per the instructions you get from all these web sites using the "Checkoway" method.Well, now that I have experienced the "Checkoway" method first hand, which actually mirrors a similar useless instruction from Vans, I am here to tell you that for this little part of the procedure - the method sucks!

To understand this, I'll review what is going on here.

1. You are trying to mate the LE skin to the fuel tank skin and the top wing skins to ensure that all the skins have a nice fit up against each other with no gaps, and that the joiner plate is properly positioned for match drilling the screw holes in the fuel tank skin to the joiner plate extension from the LE.
2. This means that the LE is clecoed to the wing spar nice and tight, and the fuel tank is clecoed to the wing spar using the #30 clecoes in the fuel tank skin holes through the nut plates for the screw holes - also nice and tight.
3. The other reason why you want this joint to be tight and straight is that there is a joiner plate that connects the fuel tank skin to the LE skin, and there is not a lot of room on this joiner plate for the nutplates and #8 screw holes. So the holes for the screws and nutplates for that thing also have to be drilled in just the right place.
4. Once you match drill the #30 holes in the fuel tank skin and the joiner plate of the LE, the Checkoway instruction tells you to "REMOVE the Leading Edge from the wing spar."
5. The other important thing to note is that the fuel tank is supposed to remain fully attached to the wing spar while you "remove" the LE assembly so that you can properly position the rear baffle plate and drill all the rib to baffle to Z bracket holes, starting with the inboard rib, followed by the outboard rib. SO you can't remove any clecoes or anything else from the now-secured fuel tank to allow you to remove the LE, or you defeat the purpose of mounting everything together in the first place.
6. The joiner plate extension sits UNDERNEATH the fuel tank skin. So with everything clecoed together you cannot just lift the LE assembly straight up off the wing spar with the fuel tank still secured to the wing spar, as the joiner plate will interfere with that.

SO I did all the above, and it was working out rather well. Then I removed all the clecoes holding the LE to the wing spar, and tried to "remove it from the wing spar" per the instructions. The problem was that something was not "letting go" as I tried to remove it, and at first it felt like a cleco was still holding it to the wing spar.  Three full repeated checks later, I confirmed there was NO cleco holding the LE to the wing spar. SO why was the LE hanging up, and on what?

Like an absolute idiot, I decided that maybe I just need to pull harder because the fit of the LE joiner plate to the fuel tank was very tight. The reality, and the truth to this situation, is that in order to get the LE off the wing spar you have to slide it out toward the wing-tip side of the spar, to try to clear the joiner plate from under the fuel tank skin. Then you should be able to lift it straight up and out. Well, all these idiots seem to forget to tell you that their are two problems with this:

1. The edges of the rear flanges of the LE ribs sitting flush against the wing spar web when the LE assembly is on the wing spar sit VERY CLOSE to the shop heads of the forward flanges of the main wing ribs that are already riveted to the wing spar web.

2. In order to slide the LE toward the wing tip part of the spar, you must lift the LE skins up and over your support bracket that holds the wing spar onto the wing stand. This is because the LE skins extend downward past the mounting stand bracket so they can be attached to the wing spar flange along each flange of the wing spar. This puts the LE at an angle, which unfortunately results in the inboard rib flanges of the LE digging into the wing spar and angled toward the shop heads of the rivets even further.

At one point I pulled so hard that "something" finally gave way. Upon removing the LE assembly I found out what that "something" was. One corner of the rear flange of my most-inboard 408 rib had been folded back to about 120 degrees, as it got caught on the edge of one of the shop heads of the main wing rib rivets as I tried to pull it away from the secured fuel tank assembly harder and harder. This also distorted several bends in that entire rib flange, and even bent the rib web slightly out of alignment.

I think I was able to repair the rib by bending everything back in place as much as possible, but Lord only knows what may have happened to my already enlarged rivet holes for that rib, subskin, and outer skin with all that tugging that I did.. I used pliers and my metal straightening/bending tool to try to flatten out the edge of the rear rib flange. It did not crack as far as I an tell, but it was obviously severely stressed.

I just can't believe how stupid I was. Note to self - if the part won't move, it is hung up on something! Stop what you are doing and figure out what it is hung up on, and then figure out how to solve the problem intelligently.

SO here is that "something else" that NOBODY seems to mention in their builders logs or posts to their blogs when they get to this step. I submit this in the event that my stupidity might prevent another builder from making the same mistake that I did.

I reasoned that "normal builders" that only use the small 1.5 inch wide joiner strip per the plans, end up with some "give" in the 1.5 inch wide strip when they lift up on the LE and start sliding it off of the wing spar. This also allows the rear flanges of that first LE rib to lift up high enough to clear the shop heads from the main wing spar rivets as it starts to move away from the fuel tank, and off it comes. OR.......

What probably REALLY happens is that they remove the clecoes that hold the first inboard 408 rib to the LE skin and the joiner strip, and this frees up the entire LE assembly so that it can be lifted STRAIGHT UP instead of OUTWARD. Then the joiner strip can be removed from the fuel tank, and all is well.

But try to find that little blurb in someone's build log - it never exists, and why that is, I will never know.

SO in my case, I would have needed to remove clecoes from both inboard ribs to release the LE skin from the modified joiner plate/subskin that spans the distance of both of those ribs (12 inches wide). Had I done that, all of this would have been avoided, and I would not be stressing further over the integrity of this stupid part of mine.

I'm pretty frustrated over my own stupidity, and I'm absolutely mystified about how others that work on this phase of the build do not comment on any difficulty with removing the LE assembly after the fuel tank is secured to the wing spar. I guess they must be smarter than me.

I think I escaped this stupid mistake without too much damage, but I won't know for certain until the time comes to rivet the LE to the wing spar for the final time.

On a more positive note, I did some more work on the fuel tank baffle and Z bracket rivet holes tonight, but I'll update that work tomorrow with some pics.

460 hours - finish trimming excess HS skin and check elevator alignment

Every so often during the build, probably more frequently than I am willing to admit, I have an episode of utter stupidity. Such an episode was experienced when I was trying to perform a preliminary alignment check of the elevators the other night as I described in my previous post. Short story is that I think everything is alright now, and my elevators may only be off by about 1/16 of an inch or so. So it is not as bad as I made it out to be in my previous post, and I will explain why as I work through the pics from today's activities.

I may wait to drill the center bearing hole in the control horns  until the tech counselor comes over to inspect my work, to see if I should go ahead and ajust one of the elevators to ensure that the trailing edges are completely aligned with each other.

I have a feeling that this is one of the things that may cause what some people end up describing as a heavy wing on their first flights - misaligned control surfaces or stabilizers, or both. This can result in differential lift between the two surfaces, and the plane will react to that condition accordingly. The question that I must eventually answer for myself is if a 1/16 inch difference is enough to warrant the adjustment, or if I can proceed "as is" with little or no potential impact? I am not after perfection, but I also know that misalignments ultimately result in increased drag as a result of the counter measures that are required to correct them. This, then, will also affect the overall performance of the aircraft.

So with that, here we go with today's exciting adventure....

First pic is of the elevator/HS assembly on the table. I got rid of the foam underneath, replaced that with my drill board, put  a couple of rubber tool box liners on the board, and then set the HS on top of that. I then put another piece of tool box liner over the top of the HS, followed by a long 2x4. Then it just worked out that one of my 4x4 padded blocks, standing on its end, was just about the right size to allow me to clamp it in place to keep the HS from flipping over backward.

Remember that you can click on the pic to make it bigger to see more of the details. So why did I need to do all this special clamping? Well, previously I had the HS turned upside down. The control horns are facing up in this case, making it easier to work with the entire assembly on the table without worrying about everything tipping over. Unfortunately, when everything is turned right side up, the control horns are now facing down. This makes it somewhat difficult to safely position the HS so that both elevators can swing  up and down freely, which is what I needed to do today.

You have to allow the HS trailing edge to hang over the edge of the table or bench, to allow the control horns of the elevators to acheive their entire range of motion. The elevators are then mounted completely off of the table. This raises concern that the weight of the elevators may cause the whole thing to come sliding off of the table, so I wanted to be sure to prevent that from happening.

The above pic also shows the top edge of the HS skin at the tip where the counter balance arm of the elevator is located. So I marked and drilled and cut the same way that I did for the bottom skins, and now the elevators can swing freely through their entire range of motion, limited only by the orientation of my temporary hinge pin placement (top or bottom):

The first pic above shows the completed trimming of the right side top HS skin. The clearance with the counterbalance arm per the plans is a minimum of 1/8 inches. The second pic above shows the 1/4 inch hole drilled on the left side, just prior to using the dremel cutoff wheel to cut the excess aluminum away. This pic is also a bit deceiving, because the elevator is actually in the up position, and therefore the counterbalance in the pic is tipped downward toward the floor.

The elevators are actually overbalanced right now because there is no primer, paint, or clearcoat applied, and the fiberglass tips and hardware to attach them are also not present. This actually made it easier for me to finish the top side trimming of the excess HS skin near each counter balance arm, because it kept the counterbalance arm out of the way without having to remove the elevators, like I hd to do the first time a couple of days ago, because the excess skin was still on both sides of each arm.

And another pic showing the clamping arrangement of the HS. The only other thing I still need to do to make this work perfectly is to clamp some additional blockes to the leading edge tips of each side of the HS to keep it from sliding to one side of the other while mounting the elevators. It takes a small amount of initial force to get the bearings to slide in between the hinge brackets, and this can be just enough to cause the HS to move with my current clamping arrangement.

Next are some pics that show what I needed to do to get the elevators to balance themselves in the almost "in trail" position with the counterbalance arms. I used a screw driver and a punch as counterweights and played around with the location on each elevator until they balanced.

Next is a shot of my digital smart level I used to check the range of motion on each elevator

Results from the top side were that I have plenty of range both up and down on both elevators. Plans state that the max travel is 30 degrees up and 25 degrees down. I found that the elevators would travel as far as about 35 degrees up, and I have clearance for about 32 degrees of down before the horns hit the edge of the trimmed bottom flange of the rear HS spar. At about 35 degrees up you encounter a bit of rubbing on the inboard LE of the elevator skin against the extended portion of the HS skin edge. This serves as a gap seal and seems to be quite effective, but the tolerances are very close between the HS skin and the elevator LE, so this needs to be carefully checked and adjusted if necessary.

While checking the elevator LEs during the range of motion tests, you can also see how well your elevator LE rolling exercise worked out by checking the gap line between the extended HS skin edges and the LE of each elevator. It's not very appealing seeing all the uneven bend lines in the elevator compared with the straight line of the extended HS skins. But what is important here is the freedom of movement of the control surface and clearance between all the skins, regardless of how ugly or non-linear the lines might be.

If you have achieved that, but the elevator LE roll has left some uneven or unsymetrical lines, I read a post that suggests that you can take a rubber mallet or perhaps a wood dowel and continue to reform the closed LEs enough to correct the uneven appearance. As far as I am concerned, both elevators swing freely with no binding or resistance. So unless someone more knowledgible than me tells me that I should try to "pretty up" the uneven LE rolls in a couple of places, I will probably keep them as is for now.

I was quite pleased with the movement of each elevator - very smooth and quiet and solid, with no play or slop in the hinges at all.

Next are some shots of attempting to place the elevators "in trail" by clamping the now freely moving counterbalance arms flush with the HS top and bottom skins. This was the first step in checking the alignment of the elevators.

The next step was to take something rather long that is truly straight, and lay it across both elevators, and then measure the angle or gap between the elevator skin that the bottom of the straight edge. This is done on both elevators. Then you compare the measurements. If they match, then you are golden. If not, then one elevator is not aligned with the other one, and you have some decisions to make.

Here is the pic of a piece of angle that used that is 36 inches long x 1/8 inch thick x 2 inch sides. I confirmed that this piece of aluminum is absolutely straight and true. I drew a center line on the angle, and lined it up with the cetner bearing on the HS. Note the gaps between the ends of the angle and the elevator skins on both sides.

And from the front:

This is where I got confused the other night. I originally thought that the straight edge was supposed to sit flat across both elevators. So when I saw the gap on one side, and pushed down on that side of the straight edge, I ended up with about a 1/2 inch gap on the other side, and completely freaked out, because for some stupid reason I was expecting the traight edge to lay flat across both elevators.

So, stupid me has since realized that the elevators are tapered, being wider at the root end and narrower at the tip end. So of course a straight edge is not going to lay flat across both elevators. DUH! Once I got that sorted out in my head, I took the correct measurements,and determined that I am only about 1/16 of an inch out of alignment, depending on where you place the straight edge. That may be acceptable or it may not, so we'll see.

Next is a pic of the control horns. One elevator is balanced and the other is not, which is why the horns appear to be out of alignment. I took the bolt that is supposed to be used to attach the horns to the center bearing once the holes are drilled, and laid it across the top of each horn. I am concerned that this bolt may not be quite long enough to cover the distance between the two horns,esecially after all the required washers are added to it. I believe I have also read some posts from other builders about this problem as well, so I may need to do some research to find out how to handle this one.

And lastly is a pic of the elevators in their overbalanced condition. It is really cool to see this assembly in place and moving as expected. So things are not quite as bad as I made them out to be the other night. Just another day on the build......

I will make a few more checks for alignment, and record my findings and specfic measurements. I also need to flip it over and perform the same checks from the bottom side. One note about the Avery tools temprorary hinge pins: I had to take them out and reposition them from the bottom in order to check the range of motion for the UP position. This is because the threads of the hinge pins are still a bit too long for the opening in the elevator at the tip to allow for full range of movement both up and down. The one at the root is almost completely underneath the HS and elevator skins when installed, but the one at the tip still sticks out a bit far to allow movement of the control surface on the side where the threads of the pins are sticking up.

So your choices are to grind or cut off the excess threads, or to take them out and reinstall them on the other side of the elevator to allow free movement of the surface in the opposite direction.

All for now...