Well, it was worth it heading south.
Took a side trip before a concert at the casino and met with my new friend Jim who was selling off some aircraft parts inventory.
Managed to pick up a bunch of stuff that I'll need for my build and at excellent prices.
From the top row, 2 bottles of EkoEtch and cleaner used for prepping aluminum for primer/paint.
Next row down from the top, 2 master brake cylinders for the rudder pedals on the pilot (left) side and a single master cylinder for the right side rudder pedals (I'll need a second one to match, this one I think was used as a hand brake).
On the white tissue paper and hard to see, 2 clear plexiglass window vents and associated hardware.
On the bottom row, 2 Matco axles and matching brake calipers. These were the model used on early 750 aircraft, but have since been superseded by a larger diameter version. Ron can use these on the 701 build which they are still the standard.
Very happy with my purchases!
Earlier this week was the 16th anniversary of the September 11th terrorist attacks in North America. I say North America vs. New York and Washington because even though these are the locations of the actual attacks, they had profound impacts all over North America including here in Canada.
I'm not going to go into a long story about where I was, or what I remember, but I think it's important to remember what happened that morning and how lucky we are to have the freedom to pursue what makes us happy, despite the efforts of others in the world who turn to terror in the furtherance of their beliefs. You can see more of my thoughts in a video I posted on my Facebook page.
Okay, time to move onto happy thoughts!
Spent a fair amount of time in the shop this week. Managed to get a bunch of parts cut out and ready for bending.
This week I also spent some time in the wood shop prepping my plywood forms for final sizing. The scroll saw is excellent for this fine work:
The important part is to make sure both sides of the forming block pairs match. So I started by cutting and sanding one side to perfect size, then used it as the guide for making the second the same size.
I didn't get all of them done in this session, but a got a good start. I focused on the ones I need for the horizontal stab and elevator, the current section I'm working on. I think I'm going to wait on the others and see if these work well and what improvements may be needed before cutting out the others.
That's it for today's update. There isn't really any easy way to capture all the work that goes into these but I hope this blog is somewhat east to follow along with. If you have any questions, please don't hesitate to ask by leaving a comment below.
Heading south today to go check out an inventory of parts that a gentleman has in a barn. It looks like I may be able to pick up some hardware for my build and possibly for Ron too. More details to come!
The last week of summer has come and gone. We made a family mini vacation to southern Ontario and took in the Brantford Community Charity Airshow among other things. It was an awesome airshow with quite the collection of warbirds, aerobatics and of course the Canadian Forces Snowbirds!
Also located at the same airport is Aircraft Spruce, one of the biggest suppliers of aircraft parts, pilot gear and building supplies. I had placed an order the week before and was able to pick up 3 rolls of aluminum sheet to be used in my build. Ron and Donna were also at the airshow and were kind enough to bring the rolls back north with them to the shop, saving us having to drag them around on the rest of our family trip.
I also stopped at KBC Tools in Missisauga and picked up a couple of really handy items. First, I've been reading about how to cut long straight edges on aluminum sheet. Some of the spars and doublers I have to make for my airplane are too long to be easily cut by shears. Even local machine shops in my area are either unable to handle the widths or too expensive.
One of the solutions on the Zenair builder's forums caught my eye. It involves making a aluminum cutting knife out of a carbide machine shop grooving insert attached to a handle, in this case a old crescent wrench.
I found the grooving insert at KBC tools. It's expensive for it's size, but is able to make very thin cuts in aluminum. For a couple of dollars more, I opted for the Titanium nitride coated insert making it more durable:
For a donor handle, I used an old crescent wrench with a seized head. I cut the head off at a 110 degree angle at the narrowest part of the handle using the chop saw:
Cleaned it up on the grinder.....
Next I used a combination of Dremmel tools and hand files to carve a shallow groove in the handle for the insert to rest in:
I made a test cut on a scrap piece of aluminum and this tool cuts it nice, clean and straight and only requires a couple of passes to score the aluminum enough for breaking. MUCH faster than using a laminate blade like an Olfa.
The other tool I picked up at KBC Tools was a NOGA Rotodrive countersink/deburring tool:
This is a much quicker and simple way to deburr dril holes. It is a rotating "dog-leg" countersink and with a very light touch and two turns will remove drilling burs without countersinking the hole. Lightweight and fast, it will be super handy as I progress through building. Much better than rolling an oversize drill bit between the fingers.
I continued work on the wing tip extension. I fabricated two (one for each wing) spar web doublers out of 0.032 sheet on the bandsaw. These will be the bread of the sandwich where the tip extension and spar web meet:
Laid out the proper rivet spacing and matched drilled them together:
Mounted the assembly to the wing spar web and match drilled the par caps, then clecoed everything together to confirm alignment:
With the assembly temporarily in place, the next problem needs to be solved. How to match drill to the original holes in the spar web (inclunding the orginal outer wing rib) without any access inside this part of the wing? As you know, the previous builder just eyeballed things so measuring what is already there won't be accurate enough. I could pull more of the wing skins off and back drill through the new doubler, but there is an easier way!
Introducing the "rivet hole duplicator". This ingenious tool allows you to match drill to holes behind the sheet aluminum. It consists of two straps of spring steel, one with a hole locator and the other with a drill guide:
With this tool, it's simple to find the right spot to drill each pilot hole. The pin tang slides in behind the panel you are drilling and the guide lines right up to where your new pilot hole should be..... GENIOUS!
Duplicate holes on web spar (right side of joint centreline) are complete awaiting final rivets. We'll need to figure out what we are doing on the back side to extend the spar caps and sandwich everything together but for now, this should be easily repeatable on the second wing:
With that complete, I took some time to fabricate the wing slat ribs from some spare 0.016 sheet.
There are 12 of them required, 6 in each wing slat. So I traced them out from the template, trying to use up as little real estate as possible. This will become more important later on when cutting other multiple items from full sheets:
One of the lessons learned earlier when I was making tail ribs was to centre punch and drill the relief and tooling holes before cutting out the metal, so I did that here first:
I discovered that the elevator tip rib form I traced out was undersized by about 2%. So I corrected the form and made the tip ribs with the correct aluminum template. Glad I caught this now, not later when I begin assembly. Here they are awaiting bending:
Very please at the progress I'm making. Coming up this week, I'm going to the woodshop to final trim and sand my plywood form blocks and I'll start tracing out the longer spar and doubler pieces for the horizontal stabilizer and elevators. Then I can start the assembly process!
As the summer draws to a close and the kids head back to school next week, I'm getting prepared to get moving in the shop on my build.
I'm hoping to finish up the 701 wing repair and make the updates necessary to the other wing. This will free up some bench space for tracing out my parts on the the aluminum sheet.
I got the wing spar tip extensions made and bent this week and added the stiffener angles:
All ready to be fit and installed, leaving just he skins and extra ribs.
I used some of the spare space on the bench to pin and tape my wing form templates together:
After tracing this out on the plywood, I got to work rough cutting out each of the form templates. These will become the final forming blocks once I final cut and sand them to proper size. I think I have most of them cut out with the exception of a few that I need to find from the 701 which may match (why make them if Ron already has them made?):
We are heading south in the next couple of days to catch the Brantford Community Airshow (see www.communitycharityairshow.com for details). Bonus news.... aircraft building supply store Aircraft Spruce is co-located at the same airport and I'm planning a little shopping :)
Next up, laying out some part templates on aluminum sheet and finish sizing the forming blocks.
LETS BEND SOME METAL!!
A while back I saw the following quote which really sums up building a big and sometimes overwhelming project like an airplane is....
How do you eat an elephant?
I have a lot of time on nightshifts at work to study my 750 plans and as I think of all the things I need to make, decisions on features I think I want to incorporate and how I'm going to make all these the parts, I get a bit discouraged. It is indeed a massive undertaking.
But as I keep being reminded both by others and myself, it's all the small bites that add up.
I find myself spending more time focused on completing tasks than taking pictures of my build which is both good and bad. I'm probably getting more done this way, but it doesn't leave a lot to add to my blog for you readers. Most of what I've done in the last couple of weeks is really just repetitive steps that I've already shared. But here is some of what's been happening.
In my last post I said I was headed back to the "drawing board". Here is the correct plywood I should have been using for my form blocks. Much smoother and knot free!
Each form template gets traced twice in opposite (flipped over), creating left and right side forms. These will be cut out in rought form using a hand jigsaw then cut close to final size using the scroll saw (more on this later).
Ron and I continues on our discussion regarding the wing extensions for the 701 wings I'm helping repair. Now that the main repairs at the root end are done, I can focus on this. Ron wants a 18 inch extension, so that's what I'll work towards.
First we have to remove the "factory" wing spar tip extension. I say "factory" because like a good majority of other "factory" items on this plane, it's really not to "factory" plans. Not the right thickness and missing two critical rivets at the upper and lower spar caps.... sigh. At least this time it's coming off to be replaced with longer ones, not just coming off to be fixed or replaced as original.
The wing spar tip extension isn't considered structural per se, but it is an important component of the wing. It supports the fiberglass wing tip and completes the outer structure end of the wing. Here it is close to it's original position on the end of the spar (I had already removed it at this point but forgot to take a picture):
....and removed from the spar. There appears to be a small wrinkle in the wing skin behind the joint, but that can be fixed easily and will be underneath the new skin extension:
Next we had to decide on how to handle the new wing skins extensions and how they would attach to the old skins. We believe at this point we can get away with a simple overlap with a double row of rivets, but we'll probably add a doubler strip underneath for strength, or even another wing rib. We trimmed the lower and upper wing skins to a convenient length and made sure to leave enough skin outside the last full wing rib. Where the trim line ended up (defined by green frog tape below) is actually a good place for a new rib:
The upper wing skins were trimmed back in the same fashion. Then, using the original plan dimensions I cut a new wing spar tip extension web (actually two, one for the other wing to match), by adding a full 18 inches to the inboard end. I was very important to get these right as they need to be perfectly straight to match the wing spar. After careful measuring, they turned out perfectly! This was also good practice making the long scoring cuts from a full 4 x 12 foo sheet of 0.025 aluminum. I'll be doing the same for my 750 wing spars and tips too:
With a little thinking and practice on a scrap piece of matching 0.025 aluminum, the top and bottom flanges were bent to a perfect 18mm width, leaving the total top to bottom dimension of 209mm, exactly as the plans call for!
We are going to wait on putting in the lightening holes until we see where the new ribs end up. The flapperons will also need to the extended, making another pick up point necessary which in turn will determine where one of the new ribs goes.
Ron keeps reminding me to continue working on my stuff too. So I took some time to make some of the smaller parts needed from some of the "scraps" left over from the 701 wig repair.
It's paying off studying the 750 plans when I can too. For example, I new I had to create 6 full length flapperon ribs and probably had enough cut-offs lying around from the repair I was doing to complete them. But then I recalled that the plans call for 4 full flapperon ribs made in 0.016 thickness and 2 full flapperon ribs in 0.025. I referred back to the plans and remembered that the two thicker ribs are "root ribs" meaning they are where the control rods for the flap actuators attach, requiring something more robust. The other 4 thinner ones are distributed elsewhere in the flapperon assembly. Glad I noticed nd didn't make them all the same!
They use the same templates, so I traced out the other four flapperon ribs on the 0.016 aluminum:
Although almost any thickness of aluminum can be roughly cut out on the bandsaw, a standard office paper cutter works great for cutting 0.016 aluminum sheet. Here I cut as close as I can to the template trace lines, then I use the grinder and hand sanding to bring them to final shape/size:
I'll store these in inventory as they are for now as I don't have the bending forms ready yet and wont be building the flapperons for a while.
To continue towards starting my tail section, I found another couple of little parts I could make up while I had the scrap out. I'm also learning that it sometimes pays to bend multiples of the same part where required. The tail section call for two of these 35 x 40mm bent angles from 0.025, and I had the perfect piece to make it from. After cutting and deburring, into the bender they went:
This way they end up being perfectly matched!
I got several other small parts made as well that aren't pictured here, but like the quote says.... "One bite at a time".
Wonder what's for dessert?
Although I haven't been in the shop as much as I like the past couple of weeks, I continue to get there when I can. It's hard to be inside when the sun is shining so much outside (which means more stuff to do around the house), but the shop sure is nice and cool when it's too hot to be outside!
The wing root repair/rebuild is now complete, just need to clean up all the Sharpie marker notes:
Progress also continues on cutting some of the smaller template parts that I need for my 750 STOL build. These are wing parts (strut attachment brackets):
Yesterday, I finally completed the wing tank rear channel. Ron decided he wanted to return the fuel tank size to factory specs, so this necessitated moving the channel rearward and cutting down the original shorter to fit inside the tapering wing chord. This is the location where it should be according to the plans, the previous builder had half of this space for his wing tanks. Maybe that's why he purportedly ran out of fuel?
I don't have many pictures of the process, but here is the completed item riveted in place:
With this done, we'll be moving on to the wing tip extension that Ron wants done. While we plan that out, I started tracing out the templates in preparation of cutting out the plywood forming blocks required for my 750. It starts with a piece of plywood which Ron purchased for me as part of another project he is working on. We had discussed the need for only half a 4 x 8 sheet as some of the forms that I need Ron has already made and interchangeable with the 701. So I grabbed a half sheet from the woodshop:
Each form template gets traced out twice to make out each half of the forming blocks:
As you may recall from previous posts, it took a fair amount of time working in CAD and with Adobe Acrobat to print full size templates onto card stock. Some part templates are fairly large and don't fit on a single piece of 11 x 17 inch cardstock, making it necessary to break the template into 2 or more pieces. For the most part, it's long pieces like wing ribs that are the issue, like this wing root rib form template which is shown here taped together:
It's also helpful to pin larger templates down to ensure an accurate trace:
Just as I was pondering whether all my templates would fit on this piece of plywood and how to make that happen while trying to avoid placing cut lines on places with wood knots, Ron arrived back in the shop. He quietly asked how I was making out and I explained my dilemmas. Ron quietly grinned and told me the piece of wood I was using was actually scrap flooring from the other non-airplane project he was working on. My piece was still up in the woodworking shed.
Guess it's a good thing I didn't trace everything out yet and I haven't thrown out the templates, otherwise it would be back to the drawing board. Hehe... drawing "board"... I kill me.
Back in a few days.... :)
I apologize to my regular followers that I haven't posted much lately. End of June and beginning of July are a very busy time for our family, between the kids finishing the school year, birthdays, anniversaries, fireworks shows.... there hasn't been much time for shop.
I did manage to make some progress yesterday when I freed up a full day in the shop.
The work continues on the 701 wing repair. I finally got the final riveting complete on the rear channels, root rib and tip and fuel bay area. All squared up ready for a modified (again) fuel tank support channel:
Getting everything lined up and square is a real pain when working within the bounds of what the previous builder left behind, but it eventually went together okay. Lots of tight places to try and fit the pneumatic riveter!
The tip rib is fastened to the spar and through to the root rib by two A5 rivets. According to the plans, the top most hole also uses the same A5 rivet, but the plans don't seem to account for the extra thickness created by the wing attach point. I'll have to have another look at the plans and check with Ron. I'm almost of the mindset to buck a solid rivet in there - always go better than the plans in any modification made.
With this section repair almost complete, we'll be moving on to the wing tip extension Ron has planned for this 701.
In addition to the 701 repairs and modifications, I've been slowly making parts for my 750 in anticipation of starting my tail group in a couple of weeks. Lots of tracing, rough cutting, trimming and final debur/sanding.
Seat belt attachment brackets and flapperon splice plates complete and ready for inventory. These aren't tail group parts, but it often makes sense to complete items as they fit on the sheet of raw aluminum of the same thickness. You are already tracing and cutting anyhow, why not get stuff done at the same time.
There won't be any shop time for the next couple of weeks as we head east on a camping trip. I've made contact with a guy in Quebec who is selling a bunch of aluminum sheet and angle extrusions. I hope to stop at his place on the way home and pick up a bunch of materials at a discount rate.
Thanks for reading, back in the shop soon!
I made some excellent (small step) progress on my airplane build this past week.
Before I get into details, I want to share a bit of scrounging advice. Don't ever be afraid to ask around when you are looking for something, be it materials or tools.
While building, Ron and I often get to talking about ways to save on costs. One of the things that costs a bunch of money when getting it done by others is powder coating parts. Powder coating is a dry finishing process that gives various materials a durable coating that can be much tougher than paint alone. It's particularly good on non load bearing parts that may be handled regularly or exposed to friction. Control columns and rudder pedals come to mind.
Powder coatings are based on polymer resin systems, combined with curratives, pigments, and other additives and ground to a fine powder. A process called electrostatic spray deposition (ESD) is typically used to apply the resin to the metal substrate. The process uses a spray gun which applies an electrostatic charge to the powder particles which are attracted to the grounded part. After application of the powder coating, the parts enter a curing oven where, with the addition of heat, the coating chemically reacts to produce long molecular chains, resulting in high cross-link density.
That's the long way of saying "it sprays on and sticks really well after being cured in the oven".... ha!
Ron and I both figure the majority of the parts we might want powder coated should be able to be done ourselves. Ron has a source for the powder coating gun and resins, we just need an oven. Baking resins can generate a fair amount of unpleasant fumes, so we won't be using the kitchen!
I've been real fortunate over the course of the last few years to have several people I know come to me with leads on "airplane stuff" and I owe a bunch of that to talking to everyone I know about my project and plans. Opinions regarding my sanity range from "wow, that's cool" to "you are bat-s%$t crazy dude!" However, even if the vast majority consider me closer to the slightly crazy side of the scale, they do come to me when they hear of something.
In this case, when I mentioned that we were seeking an oven, Brenda noticed a Facebook post from a friend of a friend who was remodeling their kitchen. Turns out they were giving away a built in Jen-Air oven! Free! Brenda messaged them, I hopped in the truck and 10 minutes later, it was in our possession. We really don't need the stove top portion for baking parts so this is perfect:
We'll build a simple stand and wire it for power. It will require some calibration tests to ensure the temperature settings are accurate as they need to be for the powder coating. Not every oven is created equally as far as accuracy is concerned and oven temperature can drift as much as 25 to 50 degrees over time.
As for my airplane, I started to put the templates I made to use and traced out my first parts with them.
They worked real good. A thick Sharpie marker leaves a good line for rough cutting:
Before making the rough cuts of individual pieces from the sheet, now is the time to drill the corner relief holes where reuired. Here are some that I remembered to drill before cutting them out. Much easier to do this before hand I've learned!
Once the parts are rough cut out (thicker pieces on the bandsaw), further fine cuts are made using hand tools. By always leaving a bit of the thick marker line, we can see where the part will be trimmed down with the grinder, a file or hand sanding when taking of the burrs.
I made several parts over a couple of hours:
I took a good idea from Ron and taped the template to the parts when they were done. That way I don't have to write the part numbers on the aluminum. These completed parts will be stored until I need them later. I'm keeping a massive spreadsheet to track parts made, where they are stored and what inventory of materials I have on hand:
I know I have a TON of parts still to make, some simple, some complex.... but there is something so motivating about making these first parts for my 750 that makes me want to be in the shop full time. Unfortunately without spending at least some of my waking hours at my paying job, I can't afford the materials to make parts, so I guess I'll have to get back to the shop when I can.
Next up, further repairs to the 701 wing and I'll finish the sub assembly parts I need for the tail group on my 750!
As I work away on the repair of the 701 wing I'm caught in a bit of a conundrum.
The spar cap repair I'm ready to rivet is all fit and ready to go, but in order to solid rivet the spar cap inside the nose skin, I need to take that nose skin off in order to have the room required for the rivet gun. Not a huge deal and not difficult to do, but as with everything else in this repair, we're scared to discover more of the original builders follies.
The other side of the coin however is do we want to take that chance? Forego opening the nose skin section and we might miss something important, but we can't leave it in place if we expect to complete the spar cap repair. Eventually the MDRA inspector will need to see inside the wings anyhow, so off it comes.
First steps, drill out all the nose skin rivets on the bottom edge and rib noses:
Gently unroll the nose skin which can very easily be creased when not secure:
Thankfully it came apart very easy. It actually looks decent and proper inside. Some minor issues with rivet lines on the nose ribs, but certainly better than what we've seen so far.
With the nose open, I finished solid riveting the spar root doubler. Nice to see this part close to being done - really happy how it turned out, the solid rivets are not too difficult to set:
I also finish riveted the spar cap repair. It too turned out real nice:
While all this has been going on, I've been working on printing and cutting out the templates I need to make my forming blocks and shaped aluminum blanks for my 750 build. It was lot of work but now I can start cutting and bending metal for my project!
Next up, continue the 701 wing repair (almost there!) and start tracing out the parts for my 750 horizontal stabilizer.
One of the new skills I'm learning is how to "buck" rivets.
Bucked rivets, also referred to as driven or solid rivets, have been used as the primary fastener type in the construction of aircraft for decades. These solid rivets are light-weight, strong and inexpensive fasteners. That’s why they and pulled rivets were chosen for aluminum aircraft construction.
A bucked rivet is a round fastener that attaches two or more pieces of metal together. The rivet is driven by a pneumatic rivet "gun" with an attached rivet "set" shaped according to the shape of the manufactured head of the rivet. The rivet's "tail" (blunt end) is backed up by a "bucking bar" that acts as an anvil while the rivet gun and set are acting as a hammer.
As rivets are driven the tail of the rivet is transformed (technically called “upset”) and two things are accomplished. First, the rivet shortens in length and the exposed tail bulges outward to morph into what is called the shop head. Secondly, the shank diameter swells in the hole to fill it entirely. A bucked rivet holds the metal pieces in compression (like your thumb and forefinger holding two pieces of paper together) and in shear (does not allow the pieces of metal to slide around in relationship to each other. Typically multiple rivets are used to hold objects together and the combined strength of all of the rivets have tremendous holding power. Although riveted construction is permanent in nature, it can be easily repaired by drilling the existing rivets out, making any necessary repairs and re-riveting with the same or a slightly larger size of rivet.
Although it will take some time and practice to learn how to do this, it really isn’t a terribly difficult skill to acquire.
First thing is the rivet gun. The rivet gun is like a hand held pneumatic jack hammer for driving rivets and could easily be confused with an air hammer. However, there is a significant difference between these tools as the rivet gun’s impact can be controlled by varying the amount of squeeze on the trigger, whereas an air hammer is on full or off. The gun incorporates a removable coil spring that both holds and retains the rivet set securely to the rivet gun and acts as a return spring each time the rivet gun drives the rivet set outward:
The rivet set is the business end of the rivet gun. You can have one rivet gun and any number of rivet sets to accommodate the shape required for the contour of the manufactured head of the rivets being used. From what I can gather in the plans, the vast majority of bucked rivets in the Zenair aircraft are of the domed head type, so the rivet set I need looks like this:
The bucking bar is the other half of the equation. Just about anything of a hardened material can be used and like the rivets themselves they come in all shapes and sizes, allowing access into tight or blind spaces where required. The brass cylinder on the left in the photo above can be used as a bucking "bar", as can the red cylinder propping up the rivet gun for the photo. Sometimes they are a square block, it doesn't matter as long as it can be held firmly and flat against the tail of the rivet being driven.
Like any fastener, rivets come in any shape and size you desire, and the plans are very specific about the specs required at each location. Usually, the length is measured from the flat underside of the rivet head to the tail and is noted in sixteenths of an inch.
Sometimes, rivets that are too long can be trimmed to the correct length using a rivet cutter. A rivet cutter is like a scissor or shear that can cut rivets of various sizes to specific lengths. The 1/4'” length rivets cannot be cut any shorter with this tool as this the minimum length of cutting. However, the rivet cutter can cut longer rivets (like the 1/2” rivets) to 4/16” (AKA ¼”), 5/16”, 6/16” (or 3/8”) and 7/16”. The rivet cutter has a series of length setting spacers that can be rotated above the selected hole that is appropriate to the rivet diameter being cut. Then, tighten the knurled knob to keep the length setting you desire while cutting a number of rivets:
As with any new skill, practice makes sense. I took a couple of scrap pieces of aluminum, match drilled some holes and got right to bucking some practice rivets.
Because this is a two handed job (sometimes a two person job) it was impossible for me to get pictures of the rivet gun and bucking bar in action, and I forgot to get a picture of the after bucking. I'll post some soon, but I'm happy with my first attempts and Ron says my results are to an acceptable level for construction. Again, it's not a hard skill, but an important one to get right.
Setting aside the rivet gun for a bit, I focused on match drilling and fitting (and of course deburing) the ring root assembly in anticipation of final riveting (both pulled and bucked rivets).
With everything clamped temporarily in place, I noticed that the wing root rib upper flange wasn't matching up properly:
As always, when something doesn't look right, refer to the plans.
The plans sometimes don't describe things as well as they should. Part of that is on me as a new builder. In this case, the plans advise that the flange is only bent to 30 degrees at the front, gently increasing to 90 degrees towards the rear. This makes sense as the wing root skin that it supports curves in the same way. So I'll have to bend it back. Hammering it isn't an option, but using another of Ron's custom made tools is:
With a bit of gentle work and some minor trimming, the root rib now fits as expected:
Next step was figuring out how to drill the rib, spar web, web doubler and nose rib in prep for final riveting.
Much like the wing attach fitting, this involved back drilling the top hole through the web into the rib, cleco, drill the bottom hole, cleco and finally the middle hole, being very careful not to ruin the previous holes:
Remove the root rib, debur and repeat the process for the root nose rib, back drilling from behind the spar. Remove, debur and fit everything together again:
Final riveting of the root ribs will be done once the rear spar fitting is complete and test fitted. I made progress in this regard too by match drilling the rear spar doubler to the rear spar:
As I stated before, the vast majority of rivets used in Zenair aircraft designs are pulled rivets as the sheet metal construction fastener of choice. The spar web doubler was ready for final pulled rivet setting.
The larger A5 rivets are called out in the plans for this assembly. Although they can be pulled by a hand rivet tool, it is much easier and consistent to use the pneumatic rivet gun. It uses the same mechanics as the hand riveter, but is much quicker and completes the "pull" in one shot, alleviating potential issues with partially completed rivets (where the rivet isn't fully pulled before the mandrel breaks off).
The pneumatic rivet gun made short work of setting the A5 rivets:
Backside of spar web doubler - looks like a crop of mushrooms. It's pleasing to see how much rigidity this gives the structure, something ignored by the previous builder. If you look close you can also see the tails of some of the yet to be bucked solid rivets where they poke through the spar cap:
Progress... Bucking and pulling rivets is fun (that opinion may change after doing thousands of them). I'll post some pictures and maybe even some video when I get a chance. Stay tuned :)
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.