Floorboards
Floor boards
The standard Javron kit comes with pre-cut ¼” Baltic birch plywood floor boards. There is a good diagram of these in the Backcountry Super Cub build manual (figure #78). The diagram shows a notch in both the rear baggage panel and the front baggage panel to fit the dogleg tube – you’ll need to make this as discussed below. Also, there is a 6[SUP]th[/SUP] board not shown on the diagram. This is the back of the rear seat. When I was in Brainerd, Jay tossed a few pieces of scrap plywood into my kit. These scraps have been extremely helpful for: testing stain colors and testing out various drill techniques. If you’re ordering a Javron kit, you might ask Jay to do the same for you.
Staining boards
The first thing I did to the boards was to stain them. The Backcountry manual helpfully points out that the untreated boards can easily be marked or stained. I guess the safest approach would be to varnish them as well, but I knew I’d be drilling and sanding them to fit. So I split the difference and just stained them. For the stain, I used Minwax Cherry stain and followed their directions. One of the smaller cans covered the top of all the boards and the backs of the two seat boards. Before staining, I sanded the boards smooth with 220 sandpaper.
![IMG_2456[1].webp IMG_2456[1].webp](https://www.supercub.org/forum/data/attachments/32/32244-0f651293233afa1acb6be3e6148f6214.jpg?hash=k2hFOyekGg)
Fitting rear baggage panel: starting in the back, I sanded a slight bevel in the rear edge to better match the angle of the rear end. Throughout, you’ll notice that I hand-sanded the boards to get the proper fit. I could have probably used a different technique and saved a lot of time. But if I’m saving time that means the process is faster which also means that I can screw something up much faster! So I stuck with sanding. So far, I’ve found that these kinds of manual tasks (e.g. sanding or filing) don’t really seem to add a lot of time to the build. And they're nice distractions at the end of a work day. Best yet, they can be safely performed while enjoying a beer. (There’s a saying in the wine country that it takes a lot of beer to make good wine. I’m finding that it’s taking a lot of beer to build a plane.)
The sides of the rear panel were in pretty good shape. I will talk about the aluminum side panels in a later post, but I had them installed for fitting the floorboards to ensure there was good clearance. The front edge required a notch to be cut out for the dogleg tube. Using my trusty calipers, I got an idea of the size of the required hole and marked where it should go on the board. I removed the board and attempted to drill the hole with a hand drill. Guess what? Drilling a partial hole at the edge of the board with a spade bit and a hand drill is darn near impossible. That bit REALLY wants to walk. So, I bought a drill press off Amazon and was able to drill a proper hole.
Front baggage panel: this was fit similar to the back panel with a corresponding notch to fit the other half (approx.) of the dogleg tube. The dogleg tube is farther forward at the base than at the tube. Therefore, the hole in the front board needs further work so that the dogleg tube can “tunnel” under it. Using a round file from the file kit noted above, I angled the hole until the tube fit in nicely.
![IMG_2559[1].webp IMG_2559[1].webp](https://www.supercub.org/forum/data/attachments/32/32279-385888a0ad1d8349d1fbde2176138b9d.jpg?hash=CFGIVZWrtj)
Seat panel: The next board forward was the bottom board for the rear seat. Since I will have underseat storage for this seat, the bottom board will be hinged to the front of the front baggage panel. Therefore, when fitting this board, I also needed to make sure there was appropriate clearance on the sides through the range of motion of the seat panel.
Securing baggage panels: Unless I overlooked it, the kit does not come with hardware to secure the rear baggage panels (Keep in mind, Jay is constantly improving the kit. Accordingly, any comment I make about what I got may not be applicable to new kits). However, the kits does come with hardware to secure the front floorboards. So, I just ordered more of the truss head stainless steel 10-32 screws from Aircraft Spruce (Part# AN526-1032R10). By the way, not only does Jay provide a fairly complete hardware kit in neatly arranged plastic cases, he also provides a detailed inventory sheet of exactly which hardware should be in those cases. This makes confirming the inventory helpful (hey, they’re human and might miss packing a screw among the hundreds of pieces of hardware). And if you want to order extras of anything, you know exactly what the parts are.
To locate the proper spot to drill the holes, I measured the width of the “trays” that the boards sit in. If I recall, it was about 2 cm. So, I evenly spaced 3 holes down each side of the rear panel, 2 in front, 2 matching holes on the rear of the front panel and two on the sides of the front panel. I center punched the spots and then drilled out the holes (top down). These holes will get nutplates. I just need to decide between countersinking and dimpling.
Now that the baggage panels were secured, it was time to fabricate the hinge connecting the baggage panel to seat panel. I purchased the 1.5” aluminum hinge from Aircraft Spruce (part MS20257P4-3). Then I shamelessly copied the layout of the model Javron that was at Oshkosh.
![IMG_2481[1].webp IMG_2481[1].webp](https://www.supercub.org/forum/data/attachments/32/32250-c389592e072f2291238b4d7d9879ef9a.jpg?hash=aR8h449AMp)
This gave me both the length and the screw pattern. I used a hacksaw to cut the hinge (cutting the wire separately) and then cleaned up the edges. Using the calipers, I located the holes in the middle of the hinge. I center-punched the holes then drilled and deburred them with the hinge out of the aircraft. I also closed the hinge and redrilled to mirror the hole pattern on the other side. Finally, I placed the hinge back in the plane on the floorboards, secured it with clamps, tested the hinge action and then drilled holes in the boards.
Now the dilemma. Underneath the hinge and boards is a crosstube (which is covered by underseat storage if you have it). If you just put screws through the hinge with nuts on the back, I think you will dig into that crosstube over time. Instead, I’m using this marvelous invention known as the t-nut.
![IMG_2561[1].webp IMG_2561[1].webp](https://www.supercub.org/forum/data/attachments/32/32255-61d6127b81d26b45b17801de28fd9e01.jpg?hash=BweaQ5UWD1)
This nut sits flush with the board. I ordered some ¼” 6-32 t-nuts off of Amazon (https://www.amazon.com/gp/product/B07HYPWCQ7/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1) Once they arrived, I measured the size of the “base” (1/2” if I recall) and also the outside diameter of the barrel (using my…say it with me…calipers). I up-drilled the holes to accept the barrels and countersunk them for the bases.
At this point, I think I had messed with the boards enough and it was time to varnish them. First, I used a tack cloth to get the boards as free from any debris as possible. I used Minwax Polycrylic Clear Gloss and brushed three coats on the boards. Between each coat, I sanded with 220 grit sandpaper working on removing any brush marks. I also put one coat on the bottom of the boards to seal them. I also put a couple of coats on the back of the rear seat board.
The last challenge was that the t-nuts were actually slightly longer than ¼” and would be a little proud of the board thickness if I did nothing. So, I filed them down slightly (making sure the threads still worked after modification).
![IMG_2579[1].webp IMG_2579[1].webp](https://www.supercub.org/forum/data/attachments/32/32262-0988b0be8bd2b050b901110d8fd6976a.jpg?hash=6rKsOfsaQT)
![IMG_2580[1].webp IMG_2580[1].webp](https://www.supercub.org/forum/data/attachments/32/32266-febe9c123f7fe1ccca6ebdd2ba03b545.jpg?hash=VpWFmBv5n0)
![IMG_2581[1].webp IMG_2581[1].webp](https://www.supercub.org/forum/data/attachments/32/32271-3087d1aa35894cf32e2d4b80127fec7b.jpg?hash=HkwFVWTas2)
I installed them by placing scrap floorboard pieces above and below the board and squeezing the t-nut in with pliers.
![IMG_2578[1].webp IMG_2578[1].webp](https://www.supercub.org/forum/data/attachments/32/32258-8b7944255d88b703dd2bfa66b98f6769.jpg?hash=BPIiRcGu4w)
And this is what everything looks like in place
![IMG_2562[1].webp IMG_2562[1].webp](https://www.supercub.org/forum/data/attachments/32/32274-6880e5a48049d47898f908d679b61bb3.jpg?hash=UwadQv-sNL)
I’ll cover the front floorboards in a separate post.
Floor boards
The standard Javron kit comes with pre-cut ¼” Baltic birch plywood floor boards. There is a good diagram of these in the Backcountry Super Cub build manual (figure #78). The diagram shows a notch in both the rear baggage panel and the front baggage panel to fit the dogleg tube – you’ll need to make this as discussed below. Also, there is a 6[SUP]th[/SUP] board not shown on the diagram. This is the back of the rear seat. When I was in Brainerd, Jay tossed a few pieces of scrap plywood into my kit. These scraps have been extremely helpful for: testing stain colors and testing out various drill techniques. If you’re ordering a Javron kit, you might ask Jay to do the same for you.
Staining boards
The first thing I did to the boards was to stain them. The Backcountry manual helpfully points out that the untreated boards can easily be marked or stained. I guess the safest approach would be to varnish them as well, but I knew I’d be drilling and sanding them to fit. So I split the difference and just stained them. For the stain, I used Minwax Cherry stain and followed their directions. One of the smaller cans covered the top of all the boards and the backs of the two seat boards. Before staining, I sanded the boards smooth with 220 sandpaper.
![IMG_2456[1].webp IMG_2456[1].webp](https://www.supercub.org/forum/data/attachments/32/32244-0f651293233afa1acb6be3e6148f6214.jpg?hash=k2hFOyekGg)
Fitting rear baggage panel: starting in the back, I sanded a slight bevel in the rear edge to better match the angle of the rear end. Throughout, you’ll notice that I hand-sanded the boards to get the proper fit. I could have probably used a different technique and saved a lot of time. But if I’m saving time that means the process is faster which also means that I can screw something up much faster! So I stuck with sanding. So far, I’ve found that these kinds of manual tasks (e.g. sanding or filing) don’t really seem to add a lot of time to the build. And they're nice distractions at the end of a work day. Best yet, they can be safely performed while enjoying a beer. (There’s a saying in the wine country that it takes a lot of beer to make good wine. I’m finding that it’s taking a lot of beer to build a plane.)
The sides of the rear panel were in pretty good shape. I will talk about the aluminum side panels in a later post, but I had them installed for fitting the floorboards to ensure there was good clearance. The front edge required a notch to be cut out for the dogleg tube. Using my trusty calipers, I got an idea of the size of the required hole and marked where it should go on the board. I removed the board and attempted to drill the hole with a hand drill. Guess what? Drilling a partial hole at the edge of the board with a spade bit and a hand drill is darn near impossible. That bit REALLY wants to walk. So, I bought a drill press off Amazon and was able to drill a proper hole.
Front baggage panel: this was fit similar to the back panel with a corresponding notch to fit the other half (approx.) of the dogleg tube. The dogleg tube is farther forward at the base than at the tube. Therefore, the hole in the front board needs further work so that the dogleg tube can “tunnel” under it. Using a round file from the file kit noted above, I angled the hole until the tube fit in nicely.
![IMG_2559[1].webp IMG_2559[1].webp](https://www.supercub.org/forum/data/attachments/32/32279-385888a0ad1d8349d1fbde2176138b9d.jpg?hash=CFGIVZWrtj)
Seat panel: The next board forward was the bottom board for the rear seat. Since I will have underseat storage for this seat, the bottom board will be hinged to the front of the front baggage panel. Therefore, when fitting this board, I also needed to make sure there was appropriate clearance on the sides through the range of motion of the seat panel.
Securing baggage panels: Unless I overlooked it, the kit does not come with hardware to secure the rear baggage panels (Keep in mind, Jay is constantly improving the kit. Accordingly, any comment I make about what I got may not be applicable to new kits). However, the kits does come with hardware to secure the front floorboards. So, I just ordered more of the truss head stainless steel 10-32 screws from Aircraft Spruce (Part# AN526-1032R10). By the way, not only does Jay provide a fairly complete hardware kit in neatly arranged plastic cases, he also provides a detailed inventory sheet of exactly which hardware should be in those cases. This makes confirming the inventory helpful (hey, they’re human and might miss packing a screw among the hundreds of pieces of hardware). And if you want to order extras of anything, you know exactly what the parts are.
To locate the proper spot to drill the holes, I measured the width of the “trays” that the boards sit in. If I recall, it was about 2 cm. So, I evenly spaced 3 holes down each side of the rear panel, 2 in front, 2 matching holes on the rear of the front panel and two on the sides of the front panel. I center punched the spots and then drilled out the holes (top down). These holes will get nutplates. I just need to decide between countersinking and dimpling.
Now that the baggage panels were secured, it was time to fabricate the hinge connecting the baggage panel to seat panel. I purchased the 1.5” aluminum hinge from Aircraft Spruce (part MS20257P4-3). Then I shamelessly copied the layout of the model Javron that was at Oshkosh.
![IMG_2481[1].webp IMG_2481[1].webp](https://www.supercub.org/forum/data/attachments/32/32250-c389592e072f2291238b4d7d9879ef9a.jpg?hash=aR8h449AMp)
This gave me both the length and the screw pattern. I used a hacksaw to cut the hinge (cutting the wire separately) and then cleaned up the edges. Using the calipers, I located the holes in the middle of the hinge. I center-punched the holes then drilled and deburred them with the hinge out of the aircraft. I also closed the hinge and redrilled to mirror the hole pattern on the other side. Finally, I placed the hinge back in the plane on the floorboards, secured it with clamps, tested the hinge action and then drilled holes in the boards.
Now the dilemma. Underneath the hinge and boards is a crosstube (which is covered by underseat storage if you have it). If you just put screws through the hinge with nuts on the back, I think you will dig into that crosstube over time. Instead, I’m using this marvelous invention known as the t-nut.
![IMG_2561[1].webp IMG_2561[1].webp](https://www.supercub.org/forum/data/attachments/32/32255-61d6127b81d26b45b17801de28fd9e01.jpg?hash=BweaQ5UWD1)
This nut sits flush with the board. I ordered some ¼” 6-32 t-nuts off of Amazon (https://www.amazon.com/gp/product/B07HYPWCQ7/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1) Once they arrived, I measured the size of the “base” (1/2” if I recall) and also the outside diameter of the barrel (using my…say it with me…calipers). I up-drilled the holes to accept the barrels and countersunk them for the bases.
At this point, I think I had messed with the boards enough and it was time to varnish them. First, I used a tack cloth to get the boards as free from any debris as possible. I used Minwax Polycrylic Clear Gloss and brushed three coats on the boards. Between each coat, I sanded with 220 grit sandpaper working on removing any brush marks. I also put one coat on the bottom of the boards to seal them. I also put a couple of coats on the back of the rear seat board.
The last challenge was that the t-nuts were actually slightly longer than ¼” and would be a little proud of the board thickness if I did nothing. So, I filed them down slightly (making sure the threads still worked after modification).
![IMG_2579[1].webp IMG_2579[1].webp](https://www.supercub.org/forum/data/attachments/32/32262-0988b0be8bd2b050b901110d8fd6976a.jpg?hash=6rKsOfsaQT)
![IMG_2580[1].webp IMG_2580[1].webp](https://www.supercub.org/forum/data/attachments/32/32266-febe9c123f7fe1ccca6ebdd2ba03b545.jpg?hash=VpWFmBv5n0)
![IMG_2581[1].webp IMG_2581[1].webp](https://www.supercub.org/forum/data/attachments/32/32271-3087d1aa35894cf32e2d4b80127fec7b.jpg?hash=HkwFVWTas2)
I installed them by placing scrap floorboard pieces above and below the board and squeezing the t-nut in with pliers.
![IMG_2578[1].webp IMG_2578[1].webp](https://www.supercub.org/forum/data/attachments/32/32258-8b7944255d88b703dd2bfa66b98f6769.jpg?hash=BPIiRcGu4w)
And this is what everything looks like in place
![IMG_2562[1].webp IMG_2562[1].webp](https://www.supercub.org/forum/data/attachments/32/32274-6880e5a48049d47898f908d679b61bb3.jpg?hash=UwadQv-sNL)
I’ll cover the front floorboards in a separate post.
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