• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

Golden Oldie Scratch Build

#1
After the wall of text below, I promise to be less wordy!

It is my hope to inspire others to build something to fly, not necessarily with balsa. I think if a person enjoys flying model airplanes, then the attempt to build one should be made at least once, because I want everyone else to experience the peculiar satisfaction that can be found in flying something that was self-constructed.

Back in the day, successful builders and pilots existed at about a 1:1 ratio. “Build threads” existed in the form of print magazine construction or kit review articles. Photographs of the important stuff were small, grainy, greyscale, and lacked sufficient detail to be helpful.

Most internet build threads I see tempt me to be secretly ashamed of myself at my lack of skill. Hopefully, as I truthfully depict my journey through this build, I will learn a lot from those who chime in, but I want anyone who doesn’t think they have “what it takes” to perhaps reconsider. I am about to show you how I make mistakes, fix them, ignore them, miss them entirely, and still end up with an okay-looking, fine-flying machine.

My choice for this project came about because I wanted a rickety-looking 1918-1925 era biplane with docile but sporty flying characteristics that could feasibly use a currently unemployed Saito .45 MKII for power. Having recently completed one of Fred Reese’s later designs, a Cloud Dancer 40, his Golden Oldie seems a natural choice.

I have some personal self-imposed challenges for this build, mostly to reduce expense or increase efficiency:
1.) No physical printed copy of full-size plans. Accomplished by importing PDF into Gimp or Inkscape and using the measuring tool to help plot major dimensions like rib spacing, or to trace templates for printing onto letter paper or card stock.
2.) Keep a log of time and materials used for the build. I am working from a stock of balsa that I have on-hand, and I would like to maintain the size of the hoard, so I need to keep track of what goes under the knife.
3.) Do not let the build space expand beyond the 8-foot folding table. If the extra table comes out, it gets put away within 24 hours. (Prevent “project sprawl” and “project blending“ with other unrelated projects.)
4.) Stop and clean up every 1 hour of build time in anticipation of interruption. If interrupted while building, take 10 seconds to leave my future self a note, no matter how seemingly mundane. Sometimes what seems like a quick interruption ends up lasting weeks!
5.) Take lots of pictures as the project progresses and post them on the internet.
****
Here’s the first photo I took. I’ve generated 3D printed templates for the wing ribs, which was sort of worth the trouble. I’m tracing and cutting wing ribs:

DB6A9DE8-6EB8-4D46-9322-447FF5E573F4.jpeg

Also visible in the picture is F-2. I failed to photograph the process. I traced it on a “new layer” in Inkscape (freeware) and printed it on letter paper. I roughly cut the template out with scissors, pasted it onto lite-ply, and cut it out on the scroll saw.

Below, I’m preparing ribs for gang-sanding. I want them as perfectly stacked as possible on the leading edge and bottom, so I’m using that right-angle-corner doodad and the table top to align before pinning. Then they get dressed up along the curved edges and trailing edges with a sanding bar. I don’t go crazy trying to make them all perfectly identical, but get rid of humps and bumps and obvious defects.
7C09EDAA-5277-449A-941D-72FB4A0282D9.jpeg


More to come, but I can’t find the pictures showing how I do spar notches. Edit: here are some quick photos after the fact. First, while still pinned from gang sanding, shallow v-notches are cut at the spar notch location on the scroll saw. Then, I use this tool:
F11B9D20-45A0-4136-966B-4D8222157584.jpeg

36F4C985-2B1F-401A-ABB0-74E5B72B1074.jpeg

It’s a piece of sheet of the same thickness as the spar, with sandpaper glued along the edge. It makes quick work of a nice tight-fitting spar joint that is uniform to all the ribs. I use a piece of actual spar stock to check the depth.

I should add that balsaworkbench.com has a laser-cut short kit available for this model. It is very well-priced, and I can attest that his products are top notch! If I hadn't had all the wood I needed, I would have had him send me all these pieces cut out for me.
 
Last edited:
#2
This flat-bottomed, bottom-spar, sheetless wing begs to be constructed flat on a building board with pins. Unfortunately, my building table is visibly bowed. Besides, I don't have printed plans, so I'm using a jig. Here I'm drilling out the jig rod holes. I should have spent the extra five seconds adding these to my templates in Fusion360. Do not ever try to drill all the holes out in one shot. That's not what I'm doing here! I've picked the spot for my rod holes, and am carefully drilling one or two ribs at a time, using the rib on top as a template, unstacking as I go. It worked out this time, but I'll probably add holes to the templates in case anyone wants to use them. The Ajusto-jig drilling guide probably wouldn't work well for the shorter ribs that don't have a pronounced trailing edge.
IMG_0443.JPG
IMG_0444.JPG

Then, started setting up the wing jig.
IMG_0446.JPG

The next day, I came down to continue the build to discover a note from my former self:
IMG_0445.JPG

It was far worse than that. Not only were my two top wings not the same length, but neither was very close to the design span as depicted on the plans. I ended up ditching half the jig, and very carefully setting up the rib stations to be as close to perfect as I could muster. Now, all four wing panels will be built on the same jig. I just need to make sure I don't build four right wing panels!!
****
Here are the machinations I resort to for stripping spar stock from sheet balsa. Actually, this is how I *used* to do it before I got a bandsaw, but I figured it would be worth showing. I have these 3D-printed c-clamps and an aluminum yardstick/meter stick. I clamp the straight edge along the sheet balsa as a cutting guide and take several passes with a sharp #11 blade. Once the cut is complete, I leave the wood clamped to the straight edge and dress it up with a sanding bar. The result is not quite as uniform and dimensionally perfect as purchased stock, but once the plane is done nobody will know if it's a tiny bit wavy.
IMG_0447.JPG
IMG_0448.JPG
IMG_0451.JPG
IMG_0449.JPG


Here, I have the old jig set up in half-size configuration. I've never done it this way before, but I think I'm going to from now on. I always join wing panels off the jig anyway. I have most of my spar stock pre-cut and ready to go, it's just a matter of gluing things on. I like to use rubber bands and pop-sickle sticks to keep pressure on things when needed. I think my leading edge stock is waaaaay too big, but I think I'll be able to take the whole panel through the band-saw to get myself a strip of triangle stock and have a lot less sanding. After this panel is done, I'll probably pre-shape the other leading edges a little bit.
IMG_0453.JPG

According to the build article, the ailerons and wing panel are built together, and then the ailerons are "cut away." I'm sort of following that plan. First, I had to cut out a bunch of W-5's and W-6's:
IMG_0461.JPG

Then, I added "filler" balsa to the top of the trailing edge where the aileron will hinge:
IMG_0463.JPG
IMG_0462.JPG

I clamped the aileron leading edge to the wing panel's trailing edge and commenced to adding parts:
IMG_0464.JPG
IMG_0465.JPG

IMG_0468(1).JPG

As you can see, I'm not interested in doing a lot of "cutting away" of the ailerons. Anyway, the next day I notched a trailing edge and glued it on:
IMG_0472.JPG
IMG_0473.JPG

And that pretty much brings us up to speed. Next, I'll pull this panel off the jig. I'll build-up the wing tip on the bench, and build the other three wing panels. When I report back, it will be to show building the center sections and joining the panels.
 

SquirrelTail

Well-known member
#3
This flat-bottomed, bottom-spar, sheetless wing begs to be constructed flat on a building board with pins. Unfortunately, my building table is visibly bowed. Besides, I don't have printed plans, so I'm using a jig. Here I'm drilling out the jig rod holes. I should have spent the extra five seconds adding these to my templates in Fusion360. Do not ever try to drill all the holes out in one shot. That's not what I'm doing here! I've picked the spot for my rod holes, and am carefully drilling one or two ribs at a time, using the rib on top as a template, unstacking as I go. It worked out this time, but I'll probably add holes to the templates in case anyone wants to use them. The Ajusto-jig drilling guide probably wouldn't work well for the shorter ribs that don't have a pronounced trailing edge. View attachment 183204 View attachment 183205
Then, started setting up the wing jig.
View attachment 183206
The next day, I came down to continue the build to discover a note from my former self:
View attachment 183207
It was far worse than that. Not only were my two top wings not the same length, but neither was very close to the design span as depicted on the plans. I ended up ditching half the jig, and very carefully setting up the rib stations to be as close to perfect as I could muster. Now, all four wing panels will be built on the same jig. I just need to make sure I don't build four right wing panels!!
****
Here are the machinations I resort to for stripping spar stock from sheet balsa. Actually, this is how I *used* to do it before I got a bandsaw, but I figured it would be worth showing. I have these 3D-printed c-clamps and an aluminum yardstick/meter stick. I clamp the straight edge along the sheet balsa as a cutting guide and take several passes with a sharp #11 blade. Once the cut is complete, I leave the wood clamped to the straight edge and dress it up with a sanding bar. The result is not quite as uniform and dimensionally perfect as purchased stock, but once the plane is done nobody will know if it's a tiny bit wavy.
View attachment 183209 View attachment 183210 View attachment 183212 View attachment 183213

Here, I have the old jig set up in half-size configuration. I've never done it this way before, but I think I'm going to from now on. I always join wing panels off the jig anyway. I have most of my spar stock pre-cut and ready to go, it's just a matter of gluing things on. I like to use rubber bands and pop-sickle sticks to keep pressure on things when needed. I think my leading edge stock is waaaaay too big, but I think I'll be able to take the whole panel through the band-saw to get myself a strip of triangle stock and have a lot less sanding. After this panel is done, I'll probably pre-shape the other leading edges a little bit.
View attachment 183214
According to the build article, the ailerons and wing panel are built together, and then the ailerons are "cut away." I'm sort of following that plan. First, I had to cut out a bunch of W-5's and W-6's:
View attachment 183215
Then, I added "filler" balsa to the top of the trailing edge where the aileron will hinge:
View attachment 183216 View attachment 183217
I clamped the aileron leading edge to the wing panel's trailing edge and commenced to adding parts:
View attachment 183218 View attachment 183219
View attachment 183220
As you can see, I'm not interested in doing a lot of "cutting away" of the ailerons. Anyway, the next day I notched a trailing edge and glued it on:
View attachment 183221 View attachment 183222
And that pretty much brings us up to speed. Next, I'll pull this panel off the jig. I'll build-up the wing tip on the bench, and build the other three wing panels. When I report back, it will be to show building the center sections and joining the panels.
Awesome! I've been looking at the Golden oldie 20 for awhile. Seems like a nice little flier
 

speedbirdted

Well-known member
#4
I think this might be the hardest I've ever seen someone try to avoid just building over a plan. :ROFLMAO: Why not go to Staples or something and print one out? It doesn't cost much. A lot of airplanes have zero ability to jig themselves together without the help of a plan, and you really need it to help align things right a lot of the time. No idea how you're going to do the fuselage straight and true with no plan...

Here's a shortcut to cutting out tons of wing ribs at once. If you have a scroll saw, get some Super 77 and spray just the edges of the balsa so that you can stack several pieces but still pull them apart afterwards easily. It's long been my preferred technique. Works flawlessly for basically any size range, for reference here are 8 stacked 1/16" ribs I cut and sanded in one go for a tiny sailplane I built a while ago. They are about 3" long.

P_20200817_225743 (1).jpg
 
#5
I think this might be the hardest I've ever seen someone try to avoid just building over a plan. :ROFLMAO: Why not go to Staples or something and print one out? It doesn't cost much. A lot of airplanes have zero ability to jig themselves together without the help of a plan, and you really need it to help align things right a lot of the time. No idea how you're going to do the fuselage straight and true with no plan...

Here's a shortcut to cutting out tons of wing ribs at once. If you have a scroll saw, get some Super 77 and spray just the edges of the balsa so that you can stack several pieces but still pull them apart afterwards easily. It's long been my preferred technique. Works flawlessly for basically any size range, for reference here are 8 stacked 1/16" ribs I cut and sanded in one go for a tiny sailplane I built a while ago. They are about 3" long.
Nice tip on the Super 77 and stack-sawing, I’ll try that next time, thanks!
 

rockyboy

Skill Collector
Mentor
#6
Love this project! A classic biplane, and neat new jigs & clamps! Couldn't be more awesome for me :love:

I've just recently learned about the Ajusto-jigs and have held off eBaying one while I think about making one from scratch. Very interested to watch you build using this (especially the fuselage phase of the jig).

Thanks for sharing this build!
 
#7
Love this project! A classic biplane, and neat new jigs & clamps! Couldn't be more awesome for me :love:

I've just recently learned about the Ajusto-jigs and have held off eBaying one while I think about making one from scratch. Very interested to watch you build using this (especially the fuselage phase of the jig).

Thanks for sharing this build!
Thanks for the kind words, Rockyboy. Every time I see your screen name, I mentally complete the phrase “...this is a showdown.”
There are alternatives to the a-justo-jig or however it’s spelled. I’ve had mine for a few years and several builds now. There is extra work involved in setup versus pins on a board, but in my opinion it is worth it, especially with symmetrical airfoils and D-tube wings. There is something satisfying about constructing a ramrod-straight wing panel on a rotisserie, and removing it when it’s complete or nearly so. Any other wing jig I consider would have to be able to be rotated on the fixture, and there are options if you have access to aluminum extrusion and a 3D-printer...the old A-Justo’s are getting rather long in the tooth, and expensive! There’s a very bloated discussion about alternatives on RCgroups that begins with the original Ajusto’s designer’s son(?) investigating the possibility of reviving manufacturing at least replacement parts. So between that discussion, and thingiverse, unless you can get a mint Ajustojig for less than $100, I’d go that route. There’s just too many parts of these old things that don’t age well, like the particle-board center brace that’s designed to allow you to build the entire wing with dihedral. I tried that feature once and decided it’s just easier to join wing panels on the bench for me.

I do have the fuselage jig too, but I’ve never tried it. Maybe I will this time.

More build photos to be posted by the end of this upcoming weekend. There has been progress, but not quite enough to report on.
 

rockyboy

Skill Collector
Mentor
#8
Thanks for the kind words, Rockyboy. Every time I see your screen name, I mentally complete the phrase “...this is a showdown.”
I'm drawing a blank on that quote - curious about the source? :unsure:

There are alternatives to the a-justo-jig or however it’s spelled. I’ve had mine for a few years and several builds now. There is extra work involved in setup versus pins on a board, but in my opinion it is worth it, especially with symmetrical airfoils and D-tube wings. There is something satisfying about constructing a ramrod-straight wing panel on a rotisserie, and removing it when it’s complete or nearly so. Any other wing jig I consider would have to be able to be rotated on the fixture, and there are options if you have access to aluminum extrusion and a 3D-printer...the old A-Justo’s are getting rather long in the tooth, and expensive! There’s a very bloated discussion about alternatives on RCgroups that begins with the original Ajusto’s designer’s son(?) investigating the possibility of reviving manufacturing at least replacement parts. So between that discussion, and thingiverse, unless you can get a mint Ajustojig for less than $100, I’d go that route. There’s just too many parts of these old things that don’t age well, like the particle-board center brace that’s designed to allow you to build the entire wing with dihedral. I tried that feature once and decided it’s just easier to join wing panels on the bench for me.
Yeah, I think I'm going to go down the custom-build-a-jig path probably :) Just need to clear a few other projects off the pile and fix the darn 3D printer again... (cheap filament blocked up the nozzle real bad again - don't buy cheap filament, not worth the headache)
 
#9
Now she and her man
Who called himself Dan
Were in the next room, at the ho-down.
And Rocky burst in, grinning a grin, said
"Dannyboy, this is a showdown..."

Okay so I got it wrong in my head. I see Rockyboy and I think of the song off the Beatles' White Album, "Rocky Racoon."
 
#10
Now she and her man
Who called himself Dan
Were in the next room, at the ho-down.
And Rocky burst in, grinning a grin, said
"Dannyboy, this is a showdown..."

Okay so I got it wrong in my head. I see Rockyboy and I think of the song off the Beatles' White Album, "Rocky Racoon."
Saw this post and looked up the song. Never heard it before, but its nice.(y)
 

rockyboy

Skill Collector
Mentor
#11
Now she and her man
Who called himself Dan
Were in the next room, at the ho-down.
And Rocky burst in, grinning a grin, said
"Dannyboy, this is a showdown..."

Okay so I got it wrong in my head. I see Rockyboy and I think of the song off the Beatles' White Album, "Rocky Racoon."
I haven't heard that song in years! A golden oldie for sure! :cool:
 
#14
Build Update

The upper wing is nearly complete. As I write this, I’m waiting for glue to dry so I can put on the last two inboard trailing edge pieces, and then I’ll sand the whole thing, at which point it will be ready for cover and aileron hinging. My level of satisfaction with the quality of the build is about a 5.5 out of 10. Hopefully that will increase after sanding and shaping.

All four wingtips were built-up on the bench, one at a time. I printed wingtip patterns on letter paper and slid them under a piece of glass, taped the wing panels down, cut the excess spar lengths off, and cemented on the wingtip parts:
52937071-A189-4331-9EAF-335322DED82D.jpeg

68D5DF32-00E2-4FB2-B75A-0C2CFB07F968.jpeg
C5B21ABB-8304-47E9-B946-5FA3E2FC5DE8.jpeg


After the four wing panels were essentially framed up, I set about building the top wing’s center section. This was a comedy of errors. First, I edge-glued some sheeting, and cut it to fit between the trailing and leading edge:
55A51D31-8C7F-4F03-9847-CEABEE1266D5.jpeg
294F5715-BDD7-42EE-B7F2-055DCFB45428.jpeg
FC861B14-D11F-4621-98F7-6AA709E04096.jpeg


After I marked the sheeting for the positions of the ribs, I cut out the ribs for the cabane attach blocks:
C967639A-2677-48EB-8857-CE05AAE17EF9.jpeg


Then, I checked how everything was going to fit, and saw the evidence that I was in the process of making a mistake:
1F83936D-2BF8-42E0-B712-8B03A50579AC.jpeg


Fred Reese explicitly describes the process for building the center sections in his build article. As you can see in the screenshot below, the bottom sheeting goes between the spars, not under them:
E79E4F8E-033E-4CB0-9939-1D3FB1F6ED76.jpeg


So, disaster averted I guess. Here, I have used some glue stick to tack the sheet down to the glass, and am gluing the spars to the edges of the sheet:
F18B930C-D530-4267-ABD0-750738AA4603.jpeg


Then I decided I better make sure the outer panels were going to fit properly. Aaaack!:
900A00A7-3201-4CA0-9BC6-56052834F3D5.jpeg


This is why I don’t use CA! In fact, I have found that solvent-type cements are very forgiving of pulling glue joints apart for adjustments. Anyway, I did some trimming:
4D861E73-54AF-4194-BCC4-DBD6E8F923F5.jpeg


And checking:
60A6E154-D442-46D8-A750-406B804E424C.jpeg


And sanding:
4F1D959C-B965-4634-8803-353FD53DDCBB.jpeg


And after I was satisfied with the fit of things, I glue in a couple of ribs and called it a night. So much for cleaning up:
20F2EB90-CF17-4664-841D-E53E83173AC0.jpeg


As the center section took shape, I started really fitting the wing panels. I trimmed back the excess spar lengths and did some sanding to account for interference with the bench top when glued together with dihedral. I took too darned much off the spar centers to make a butt joint, but I’m not all that concerned because of the generous overlap with the center spars.
BEDD33D7-ADDB-439E-A9EE-D746B3981627.jpeg
E2A11E45-14D8-435C-AD15-3FF35F4DF0B1.jpeg


I really wanted the center leading edge spar to have decent butt joints, even though I can work some magic with micro balloons. So I mocked up the wing with dihedral, and marked the angles for cutting:
3F14351A-2CB0-4F57-A381-95D5E816C3DF.jpeg
39A9C5C0-BDE6-45D8-846C-27997BE15DE0.jpeg


That should get me reasonably close: (And yes, I repaired the broken rib.)
1A2A6567-A808-436A-A4C0-910F80ED2DD6.jpeg


The next morning, after having epoxied the wing panels to the center section, I propped the assembly up for a picture:
272F1F91-91F7-457D-9F78-76A0F928DFB4.jpeg


Here, I have epoxied in the cabane mount blocks and wrapped it with cellophane packing tape to keep epoxy from dripping out and making sanding work later: (I have some scrap balsa dry-shimmed in there to keep the rear block in place.)
64B139ED-914A-4179-9CB8-26E587A4BEAD.jpeg


In this last pic, I have the front bottom sheet cemented in, and also the final ribs (W-2’s) glued in. I saved those two ribs for last because of complications that may arise from setting dihedral.
FDB00969-39EB-44B6-A50E-726201757C7D.jpeg


After I finish with the trailing edge and sand it, I will move on the the lower wing.
 
#15
Good work. Remember: The interior of the wing doesn't need to be Michelangelo quality. Just needs to be sturdy. The covering film will hide it; just make sure the covering goes down nicely :p That is, as long as you don't use transparent film...

I wonder how cement stacks up strength and weight-wise to CA or aliphatic glues? I've never used the hobby stuff. When I was really young I once tried to put together a Guillows kit with some Elmers rubber cement I'd stolen from school. As one can imagine the strength was not really up to the task but I'm assuming this stuff is a bit different. CA has always been fine for everything I've tried to do - It's like drawing a picture with a pen, as in requires you to check whether things line up correctly before you glue it all together, which will make you a better builder and save you some time from having to re-glue stuff.

How will you hinge the ailerons? Mylar CA hinges would probably be the lightest but they can be a pain to install and get to work well sometimes. Nylon creased hinges or pinned ones are better as they will not allow the control surface to move laterally nearly as much if there's any gap, therefore also making the installation somewhat easier. But, they can sometimes bind if they aren't all lined up correctly. My personal favorite are the Robart hinge points, but they take the aforementioned alignment problem and make it hell to deal with because they're round and can literally go in with any orientation you want (or don't want) them to...

On another note... is that a Sophisticated Lady I see hanging up there? :unsure:
 
#16
Good work. Remember: The interior of the wing doesn't need to be Michelangelo quality. Just needs to be sturdy. The covering film will hide it; just make sure the covering goes down nicely :p That is, as long as you don't use transparent film...

I wonder how cement stacks up strength and weight-wise to CA or aliphatic glues? I've never used the hobby stuff. When I was really young I once tried to put together a Guillows kit with some Elmers rubber cement I'd stolen from school. As one can imagine the strength was not really up to the task but I'm assuming this stuff is a bit different. CA has always been fine for everything I've tried to do - It's like drawing a picture with a pen, as in requires you to check whether things line up correctly before you glue it all together, which will make you a better builder and save you some time from having to re-glue stuff.

How will you hinge the ailerons? Mylar CA hinges would probably be the lightest but they can be a pain to install and get to work well sometimes. Nylon creased hinges or pinned ones are better as they will not allow the control surface to move laterally nearly as much if there's any gap, therefore also making the installation somewhat easier. But, they can sometimes bind if they aren't all lined up correctly. My personal favorite are the Robart hinge points, but they take the aforementioned alignment problem and make it hell to deal with because they're round and can literally go in with any orientation you want (or don't want) them to...

On another note... is that a Sophisticated Lady I see hanging up there? :unsure:
I really thought I replied to you, Speedbirdted, but either that was a figment of my imagination or it disappeared. Thank you for the vote of confidence. Even if the bones were my masterpiece, I don't think this design lends itself to transparent film. If I was feeling more adventurous, I might try dying silk in tea and covering with that for the surplus Jenny look, but I'm thinking of a fairly conservative approach with painted doculam. As far as hinges, I do have some CA hinges here, but if I manage to get the surfaces beveled properly with a nice straight hinge line, I'll probably use covering material for the hinges, as I have had good success with that in the past. I also prefer the Robart hinge points, but man, with four ailerons on top of the rudder and elevator, the law of averages is against me and I'd be sure to get at least one clocked wrong.
The Sig-Ment that I am using is, in my opinion, easily comparable to CA and aliphatics in terms of strength. I think it is like the old Ambroid, basically celluloid dissolved in acetone. It sands like a dream. Joints can be re-glued with impunity. The weight is negligible. I've never squirted any out on a scale and measured how much weight is lost during evaporation, but a 4 fluid ounce tube of this stuff easily lasts through an entire project (without clogging the nozzle) and I'd wager it's measurably lighter than aliphatics. It dries rapidly compared to aliphatics, but it is hardly comparable to CA in terms of cure time.

Yes, that is a Sophisticated Lady you spied in that pic.

The build is progressing, the lower wing panels are about to be joined to the center.
 
#17
Build Update

The upper wing is nearly complete. As I write this, I’m waiting for glue to dry so I can put on the last two inboard trailing edge pieces, and then I’ll sand the whole thing, at which point it will be ready for cover and aileron hinging. My level of satisfaction with the quality of the build is about a 5.5 out of 10. Hopefully that will increase after sanding and shaping.

All four wingtips were built-up on the bench, one at a time. I printed wingtip patterns on letter paper and slid them under a piece of glass, taped the wing panels down, cut the excess spar lengths off, and cemented on the wingtip parts:
View attachment 183938
View attachment 183940 View attachment 183941

After the four wing panels were essentially framed up, I set about building the top wing’s center section. This was a comedy of errors. First, I edge-glued some sheeting, and cut it to fit between the trailing and leading edge: View attachment 183943 View attachment 183944 View attachment 183945

After I marked the sheeting for the positions of the ribs, I cut out the ribs for the cabane attach blocks:
View attachment 183946

Then, I checked how everything was going to fit, and saw the evidence that I was in the process of making a mistake:
View attachment 183947

Fred Reese explicitly describes the process for building the center sections in his build article. As you can see in the screenshot below, the bottom sheeting goes between the spars, not under them:
View attachment 183948

So, disaster averted I guess. Here, I have used some glue stick to tack the sheet down to the glass, and am gluing the spars to the edges of the sheet:
View attachment 183949

Then I decided I better make sure the outer panels were going to fit properly. Aaaack!:
View attachment 183950

This is why I don’t use CA! In fact, I have found that solvent-type cements are very forgiving of pulling glue joints apart for adjustments. Anyway, I did some trimming:
View attachment 183951

And checking:
View attachment 183952

And sanding:
View attachment 183953

And after I was satisfied with the fit of things, I glue in a couple of ribs and called it a night. So much for cleaning up:
View attachment 183954

As the center section took shape, I started really fitting the wing panels. I trimmed back the excess spar lengths and did some sanding to account for interference with the bench top when glued together with dihedral. I took too darned much off the spar centers to make a butt joint, but I’m not all that concerned because of the generous overlap with the center spars.
View attachment 183955 View attachment 183956

I really wanted the center leading edge spar to have decent butt joints, even though I can work some magic with micro balloons. So I mocked up the wing with dihedral, and marked the angles for cutting:
View attachment 183957 View attachment 183958

That should get me reasonably close: (And yes, I repaired the broken rib.)
View attachment 183959

The next morning, after having epoxied the wing panels to the center section, I propped the assembly up for a picture:
View attachment 183960

Here, I have epoxied in the cabane mount blocks and wrapped it with cellophane packing tape to keep epoxy from dripping out and making sanding work later: (I have some scrap balsa dry-shimmed in there to keep the rear block in place.)
View attachment 183961

In this last pic, I have the front bottom sheet cemented in, and also the final ribs (W-2’s) glued in. I saved those two ribs for last because of complications that may arise from setting dihedral.
View attachment 183962

After I finish with the trailing edge and sand it, I will move on the the lower wing.
Looking good!