My second Monday night session at the shop was a productive one. Three uninterrupted hours of build time and I got some good stuff done.
First up, I decided to go ahead and rivet the flap arms in place. The three outboard arms follow the standard rivet head on thinnest material (in this case the ribs):
The inner-most flap arm sits inside the fuel tank bay. In order to allow clearance for the fuel tank, the rivets are pulled with the head on the thick side of the joint here (the flap arm):
Rivet tails on flap side:
Rivet heads on rib side:
Fuel tank bay is opposite - rivet heads on flap arm side of joint:
All rivets double checked for correct pulled form. Lots of strength here:
I decided it was time to start trimming up the wingtip and cut it out of the moulding material.
I tested the Dremel cutting wheel on waste edge first, it makes quick work of cutting out the wingtip from the form:
Here it is, rough cut out:
Careful use of the Dremel trims it down to the flat flange edges that will eventually tuck under the wing skin tips:
There are a couple of spots where the flange narrows around the point of the nose and at the trailing edge. I was careful to leave lots of extra for fine trimming later:
I removed the skin stiffeners that were clecoed in place on the inside of the upper skin. I can't believe how much drill debris (called swarf) that can fin it's way into the little spaces between parts.
A quick vacuum with the ShopVac and a soft brush attachment cleaned up most of it.
With things cleaned up, I slid the wing tip onto the end of the spar and rear channel. I still need to make the support angles for each, but really happy how it's shaping up!
Neither the picture above or the one below capture how slanted the wing tip is. The is on purpose and is for aerodynamic reasons (more on this in a future blog):
Finally tonight, I finished deburring the upper wing skin stiffeners, cleaned them and primed them.
They will go back on the upper skin once the wing is right-side-up. For now, I'll leave them off until the upper skins are deburred, primed and not rolled up for storage.
Overall a good night. Back on Wednesday for more.
Thanks for reading :)
Full and productive day in the shop yesterday, but not a lot of pictures to share.
Started taking the nose and lower skins off the wing in preparation for deburring and priming. If I'd only known how many holes there would be to deburr, I wouldn't have drilled so many! Just kidding, but man there are a lot of holes to clean.
Lower outboard wing skin, deburred and primed. This section is small enough to store flat, so I deburred, primed and riveted the skin stiffener in place.
Inboard nose skin deburred and primed. I found it convenient to leave it on it's edge on the floor and roll along on the stool with the deburring tool. Primed the areas using a sheet of newsprint held behind. The lower edge shown will be primed later (didn't want to get primer on the carpet runner):
Lower wing skin removed and flipped over for deburring. Very pleased to see all rib holes are centered on the rib flanges and I don't have any elongated holes - bonus! Once complete and primed, I rolled it up for storage until ready for re-assembly.
At this point I can begin the final riveting of the wing skeleton. Removed nose ribs from the spar, deburred them and the holes in the spar and final riveted them to A5:
Next I finished the final rivets on the wing tie down ring (not pictured) and the rear channel, including the channel to ribs and the rear strut pickup. This joint has seventeen A5 rivets and an AN3 bolt on the face of the rear channel alone - plus another eight A5 rivets once the skin is in place. It's one heck of a stout assembly once it's in place:
Final riveting of the flapperon arms might wait until I have the lower skins on, or I might rivet them first. It's probably better to do them now while I have unfettered (today's big word) access, so I'll do that before I rivet the skins on.
I'm getting closer to fitting up the wing tip. I'll need to cut it out from the blow mold process that it is made from. These are the ones I picked up in 2019 when Dad and I went to Montreal-St Hubert
I'll probably cut them out rough with a Dremel cutting wheel and leave enough of an edge that can be trimmed, sander later. It will be easier to fit up with the wing upside down on the bench:
Still a bunch to do, but the wing is essentially ready for the skins to be added back and final riveted to the skeleton. I need to add the support Ls at the spar and rear channel tips that support the wingtip. Before I rivet the skins though, I also need to vacuum out all the drill and deburr debris so when I flip the wing over it doesn't get into any areas I won't be able to reach.
I'm also close to fuel line routing decision. I can't add the trailing edges in permanently until that gets finalized and installed, which can't happen until the tanks are fabricated and the rear channel root doubler is dilled and deburred for the fuel line passthrough. Need to start looking for grommets for that to0.
Blog posts in the coming episodes will likely be shorter but more frequent. Thanks for following along! More to come.....
Got the inboard and outboard trailing edges fit up and pilot hole drilled tonight.
The fit up was fairly easy and straight. I'll need to close up the trailing edge angle a bit before fitting up the topside. I can't rivet the bottom side until I route the fuel lines.
Notched the inboard edge at the rear channel. I'm going to wait to trim the trailing edge taper for now.
A3 pilot holes along the rear channel. Outboard half of the wing will be upsized to A4, inboard to A5
Outboard trailing edge will get trimmed to match the wingtip. I'll need to get it out of storage and prep it for fitting too.
Not a huge update tonight, but progress is progress.
Stay tuned for more, thanks as always for following along.
Although I've read it many times, watched and listened to other successful builders state it many times, one of the truisms I have really realized the value over the past couple of weeks is consistent shop time. Not leaving so much time between shop sessions leaves previous work accomplishments and next steps fresh in mind, saving tons of re-thinking everything each weekly visit.
To that end, I'm planning on adding 2 nights a week to the full Saturdays I'm currently spending in the shop. Some nights, I might be only a couple of hours, some more. The point is I need to keep at it if I ever expect to get this project done. Blogs will be more frequent too. Tonight was my first evening session.
I decided to get the strut support section done.
Like the jury strut brackets, I found the scaling of my original templates lacking some accuracy, so I did up a new template on cardstock. I left the lower end a little wider than the plans call for - that give me room to trim it after I bend the flange over to match the strut pick-up.
Found a nice piece of 063 perfectly sized for this - nice to find in scrap bin!
Bending this bracket took a fair amount of figuring out. The point of the curve needs to mate up to the curve of the strut pickup. I measured three times and used a cut-off piece of 063 as a proof piece first to establish correct angle and bend line:
Trimmed the lower flange to match the upright flange of the strut support angle - perfect fit, glad I took the time to measure thrice!
Seven measured A3 (small bit) pilot holes in the lower flange:
Some small C-clamps hold everything in place nice and tight and even:
Match drill the bracket to the angle. This is challenging, but easily do-able with a very long A4 drill bit and 90 degree air drill.
Match drill the 3/8 strut bolt hole in the support bracket by back-drilling (BIG bit) through the strut pick-up:
A5 (big bit) rivet hole as per the plans, drilled through both:
Everything comes apart, bracket to angle rivets are upsized to A5 and deburred. Scrub down with Scotchbrite and prime (I did the front jury strut brackets at the same time.
As the title says, every bit counts. More to come.
I can't believe how much work I got done in the past 3 weeks. Progress has been so good, I've been neglecting my blog in favour of keeping up the momentum on the right wing. I was off work this week for annual holidays, so was able to get four solid days in the shop this week alone.
I wanted to start on the trailing edges. Like the tops skins, they are made of two sections which join at the mid-way point of the wing in the same area as the strut pickups.
Cut the inboard and outboard trailing edge skins to width and length then I marked out the inboard edge where the trailing edge tapers and has a cutout to match the rear wing channel.
On the bender, I used the the 1/8th "shoe" to creat the trailing edge:
With all the top skins fitted and keeping the wing skeleton square I was finally able to release the spar from it's screw-down clamps and flip the entire thing over on it's back. At this point it makes sense to elevate everything up on square steel tubes:
I've temporarily added the required skin stiffener "L"s in each of the wing bays. The upper skin will need to come off for deburring later so I haven't final riveted these yet - that way I can roll the skin for storage if needed.
With the bottom side open for work, I could have a good look at the alignment of the flapperon arms in comparison to the rear channel and each other. The mid-wing joint at the rear channel and strut attachment point is quite a complex piece of joinery!
All four flapperon arms mount up correctly and line up close to perfectly. There is a bit of twist in the wing induced by the roundness of the upper wing surface, so I'm happy where the arms are at for now.
The lower inboard skin is the largest part I've made from of aluminum sheet so far - almost 3 metres long and 720mm wide. I rolled a full sheet of 020 out and made the necessary cuts - it was A LOT of cutting with shears, but at least it's a rectangle to start with before trimming the tapered inboard edge. Layout is marked on the sheet, including the areas for the cut-outs at the spar and rear channel whoch will allow access to the wing mounting bolts:
It even looks longer in the photo! No way in our shop to cut that other than by hand. We'd love a CNC or waterjet cutter for stuff like this, but where would we put it!
The wing skeleton is bolstered from below to bring the spar perfectly vertical again. With the spar both vertical and level from end to end, The lower wing skins can be added. It all begins with the first dill hole at one corner, then squaring it all up before adding more holes down the spar and rear channels:
With enough clecos to hold the skin square to the skeleton, I laid out the rib rivet lines and the lower skin stiffeners:
The skin was removed again and taken to another spot in the workshop (the floor!) to drill the A3 pilot holes as laid out. The skin is returned to the wing skeleton, re-attached by clecos and pilot holes are drilled throught the skin into the ribs, working from rear edge to front spar:
Man, there is a lot of holes to make and secure! A quick peek once in a while through the spar lightening holes confirms the rib holes are in the centre of the rib flanges and not near any rib fluting.
Eventually, all the rib line holes are upsized to A4. The spar and the rear channels remain as A3 until the nose skins and trailing edges are added. I've constantly checked the level of the wing across the spar and the rear channel, so far so good - it get better with each cleco I add as the whole assembly stiffens up:
With the skins drilled to A3 at the rear channel and the ribs brought up to A4, I removed the skin again and pilot drilled the spar. Then I re-attached the skin -again- and used the strap dupplicator to complete the skin holes at the spar up to A3:
With the inboard lower skin now firmly in place and square, I cut out the outboard skin and starting fitting it up in positiion, again using the strap duplicator where this skin overlaps the inboard one and at the spar:
The outboard skin has a very subtle curved edge on it which I was able to trace using the cardstock templates I created:
Looking ahead to the fuel line routing, I marked and pilot drilled where the fuel line will exit the rear channel - it's hard to see in the picture, but the pilot hole is just left of dead centre in the image below. This will be upsized to the required diameter once I figure out fuel lines and grommet sizes for the hole. There will also need to be holes in this area for wiring - but that can wait for now.
Next skin I prepared was the outboard nose skin. This has a very complex curve to match the wing tip insert once it is wrapped around the nose ribs. Another cardstock template I created from the plans is used here to trace the curve described in the plans:
The inboard nose skin is almost as long as the inboard lower skin, but only extends from rib number 1 to rib number 5. I cut it out from a sheet of 016 and laid it temporarily on top of the clecos to get a better idea if the length was correct and it was. According to the plans, it is a rectangle shape to start before it is wrapped around the nose ribs:
I notices in the assembly drawings however that the pictured skin they show was a triangular tab running between the 1st nose rib and the root rib (outlined in yellow on my picture):
My plans don't reference this at all. My plans do not show any rivet line layout in this location (which there would need to be) nor any dashed line to indicate this tab:
After some head scratching and discussion, both Ron and I feel a full root nose skin from top of the spar to bottom of the spar will be correct (as shown in the plans). Everything is covered, this isn't a structural piece and the plans version is actually cleaner aerodynamically, At the end of the day, the plans are always the final answer.
The procedure to fit the nose skin is multi stepped. First the skin is slid between the main lower wing skin and the spar:
Now the lower skin holes at the spar are used to back drill through the nose skin:
The same is done for the outboard nose skin:
Once all the holes are drilled along the spar of both nose skins, they are pulled out and cleco'd on top of the lower wing skins - this will be their final orientation.
I removed the outboard lower skin and using the strap duplicator, I created the A3 pilot holes in the spar tip. Eventually, there will be two rows of offset A5 rivets here (the flange die is keeping the skin flat to the nose rib below as I drill them out):
I re-attached the outboard lower skin, sliding it below the outboard nose skin - this too will be it's final position. The three clecos at the spar hold everything square, but I'll wait to drill the second row of A5 rivets where nose and lower skins overlap once I have the wingtip trimmed and in place:
Speaking of wingtip, you might recall I decided to wait on trimming the outboard top wing skin until the wingtip is in place. I decided to trial fit the cardstock template and although still in very rought layout, it looks promising!
The yet to be wrapped overhanging nose skin doesn't leave a lot of room between the workbench and the counter!
To give myself (and Ron) some room to work, I sued a couple pieces of twine and tied the nose skin loosely down and out of the way. This gave me the room to work I needed to layout and pilot drill the nose ribs:
Next up is the strut support angle. This is a piece of 032, bent in an L shape which helps transfer the load of the wing strut back and across the wing rib and wing structure.
In the picture below you can see the lateral skin stiffeners temporarily mounted on the outside of the lower skin. The eventually will be inside the wing, i just have them there to help keep everything firmly in place while I was pilot drilling the rib holes. Perpendicular to that is the strut support angle which mounts on the outside of the wing. According to the plans, the support angle is supposed to only go as far back as shown, about 40mm short of the the lateral stiffeners - this makes absolute no sense to me. Why would they leave it short of the lateral support? I double and triple checked the plans and it clearly shows it short like the picture below..... strange choice by the designer.
I decided to deviate a little here. I'll extend my support angle back to meet the lateral supports. It adds more strut support with very little work or weight penalty and I'm not adding any new holes or rivets in doing so:
Once bent, each end of the 032 strut support angle is tapered:
Before adding that support angle to the lower wing surface, I'll need to know exactly where the strut support protrudes through the wing at the spar so I can fit them together properly. So until that was done, I set it aside for the moment and focused on the jury strut angles which needed to be attached.
Jury struts are diagonal braces that run between the middle point of the main wing struts and the wing. That triangular structure adds even more rigidity to the wing structure. The jury struts attach to the wing with simple (so I thought) 025 brackets. I made the ones I needed way back when I had some scrap 025 metal cut-offs from the wing rib blanks (that was a couple of years ago - jeez time is flying by). They are the ones on the left below.
Turns out the scaling I calculated back then was skewed and the original PDF cardstock templates I created was incorrect. I tried using them and bending them as per the plans and made several bad ones before deciding it was time to re-do the templates new (shown on the right). The CriCut Maker does this so much better than manually scaling a PDF to print on cardstock!
Below, the proper size front jury strut brackets, match drilled, one pair for each wing.
One set of rear jury strut brackets get match drilled holes as well:
A pilot hole drilled in the centre of the lower flange:
Mounted in position on the wing at the main spar. The other two pilot holes are made using the strap duplicator (not shown):
A long A3 bolt is used to help line up the second bracket where i mounts on top of the lower one:
Matching pilot holes drilled from below through the upper bracket and secured by a cleco for drilling of the other 2 pilot holes:
Secured to the wing. The bolt is not the correct one that will be used here, it was only temporary to help align things:
Next up was the tie-down ring and how the nose skin needs to be trimmed at the number 5 rib to allow it to protrude below the wing (sorry about the crappy picture):
I measured the distance from the spar forward to where the tie-down ring would pass through the skin and marked everything out on the skin. The tie down ring has not been riveted yet to the rib, it is only clecoed in position for fitting at this point, that can be done later from above:
Using a Dremel wheel, I cut out the slot a little at a time until the tie-down ring fit nice and snug:
I used the same methods for the wing strut pick-up pass through point:
Now I can fit the strut support angle as I know where it meets the strut support laterally. Again the duplicator is very handy here:
I'll need to create new 063 strut support brackets which mount under the strut attachment plates. I don't show it above, but I ran into the same issue where the part I made isn't correctly scaled. More to come on that.
Next up was the flapperon arm slots at the rear channels. This time I measured and used a 1/8 drill bit to create the upper extend of the slot and used metal snips to create the slot up from the trailing edge of the lower skin to the hole. That worked very well.
The skin and fapperon arms are very well supported on both sides here - four A4 rivets in the rib and four more A4 rivets in the flapperon support angle on the opposite side of the arm:
This wing is really getting close to be ready for final debur and riveting of the lower skins. Next up is trailing edge skins and maybe a trail fit up of the root nose skin.
When not at the shop, I'm still tinkering with a way to use an Arduino and a pressure transducer to measure fuel quantity in the tanks. I picked up some fittings and some 3/8 diameter poly pipe to use for simulating a fuel tank level sensing device. I'll need to make a decision soon if this is going to work like I expect it to. I think I'm going to need a lower range sensor, bt have found a decently priced source for them online. More on this to come.
Well, I've been hacking away at this blog well past my bedtime. I'm exhausted be very happy with what I got accomplished since my last post.
Thanks for following along.
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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.