Sawing Spruce Boards Into Spars

 I've finally started sawing spars from my stack of spruce.  I started by inspecting all the boards and picking out the shortest ones with good sections long enough for the 2 wing spars.

The first step was to saw 2 boards to 4" wide.  The spars are 3 5/16" tall.

The boards are 17 feet long and I was able to saw them by myself with 2 sets of rollers on each side of the saw.

The next step was to re-saw them with the bandsaw.  Shopsmith makes a 5/8" blade specifically for re-sawing boards.

I split the board to have a 1 1/4" wide Aft Wing Spar and a 1/2" wide Forward Aileron Spar, plus an extra 1/8" available to plane off each.

I made a fence for the bandsaw with a piece of 3" angle iron clamped to the table.  

I used the featherboard to hold the wood tight at the bottom.  Shopsmith makes a feather board that you can stack up to 4 high just for this type work ($90).

The instructions for the 5/8" blade were to run it at 500 RPM to prevent overheating.

When sawing long boards a wedge can be useful to keep the saw cut from closing and binding the blade.  It wasn't needed with the bandsaw.

The kerf is very clean and narrow.

It measured 0.030" wide, about 1/3 the width of the 10" circular Rip blade I used for the first cut.

I went real slow and the first board came out perfect, straight down the board, and straight and square top to bottom.

The second board I must have pushed too hard and the blade curved into the wing spar, leaving extra wood to plane off the aileron spar.  In the end the wing spar would be less than 1 1/4" after planing in order to clean both sides.  

I'll plane it down for another project.  I bought enough wood to rebuild the monoplane wings for our Fly Baby.  The old ones were lost in a hangar fire.  It's licensed to use either the monoplane or biplane wings.  The monoplane wings work better for trailering to events because they fold in about 10 minutes.  This board will make a nice rear spar.

On the 3rd board I decided to try a different approach.  I've never had luck lining up 2 deep table saw cuts to meet in the middle of the board, so I tried a 3 cut approach.  I made a 1 1/2" deep cut, took the board outside and flipped it end for end, then made a second cut on the other edge.

I used the bandsaw to connect the two assuming the blade wouldn't wander so far off the cut line.

It worked perfect, 2 nice boards ready to plane down.

You can see below how the blade wandered but never cut into either spar.  They'll both plane down perfect.

I had bought a couple 10' boards to use for the aileron Aft Spars.  The rings were at slightly more of an angle than I wanted.  I got the idea to cut the board in half at about the angle of the rings.  Then I used this surface to re-saw the boards.  My first cut was along the line running almost corner to corner of the original board.

It worked perfect.  I used the wedges to cut, quarter sawn, 1 1/8" x 3/16" laminations for the wing tip bows.  I ended up with only a small bundle of tiny wedges for scrap.  I needed 8 laminations and ended up with 9.

Time to do some thickness planing.

Upper Right Wing Ready For Varnish

 Before I shaped the tip bow I added a small scrap of the lamination at the joint between the leading edge and the tip bow.  The idea was to be able to shape it to a slightly better transition.  I tapered the end so it would fit in the joint better.  I think it was worth the trouble.

 I followed the same process as the last wing for shaping the leading edge, plane, file, sand. 

The tip bow came out great using the disc sander for most of the wood removal.  I did it outside so I wouldn't make such a mess in the workshop, much better.

This wing is ready for varnish.

Now I need the remaining spars from Aircraft Spruce, help guys.

Upper Right Wing - Tip Rib and Tip Bow Braces

 Building the tip rib went about the same as the last wing.  I fit the end of the rib capstrips an glued the rib in place.  The vertical sticks were glued to the spar. 

 Once the glue was set the corner gussets, at the spars, were added.  The bracing sticks and their gussets were cut to fit, and glued in place.

The lower rib stringer and the filler blocks along the bottom of the rear spar were finished.

I still need to add the upper rib stringer and a couple filler blocks on the top of the rear spar, and carve the tip bow to shape.  I think I'll move the wing to the driveway to do that.  I made a sawdust mess in the shop last time.

Last Lamination on Upper Right Wing

Yesterday I went back to the airport and figured out the Fly Baby won't start because neither magneto is firing.  That was quick, so I went home and glued the last lamination on the tip bow.

The next task will be to install the tip rib and figure out what happened to the magnetos.

Leading Edge On Upper Right Wing, Varnishing Lower Left Wing

 It's been a busy day.  I worked on the Fly Baby first thing this morning while it was coolish at the airport.  Then I came home and glued the leading edge to the Upper Right wing.

 We mover the Lower Left wing to the tent in the driveway.  I have to push the C-140 out the other end to be able to rotate the wing all the way around.

 I started varnishing.  I did all the areas I could do with a 2" brush, wing walk, spars, etc.  I have an idea for getting into the gussets.  I need to run to the hardware store.

I'm using just over 1 quart per coat per wing.  I expect I'll be well over 2 gallons when I'm done with all for wings.  I've got about 2 hours doing the easy bits.

Back to the airport to work on the Fly Baby this evening.  It will be flying again soon.

Finish Shaping Of The Leading Edge and Wing Tip

The little block plane worked well for shaping the leading edge.  When I was routing the spars I rounded the corners on it.  That really helped with this job.  When I got to a rib the plane slid right across it without catching on it.

The plane leaves slight corners because it only makes flat cuts.  A 10" bastard file knocked the corners down nicely.

I finished up with the 150 grit sand paper I used for the spar routing.

It was quick and easy, and the shape came out perfect.

On the tip bow I found my trusty disc sander was perfect for removing large amounts of wood.  I used a 36 grit disc and a very light touch.  This is what I use for sharpening and balancing lawn mower blades, so I use it regularly.  Once I roughed it down I used the plane, file and sand paper to finish it.

I had a spot where I let one of the laminations slip out of alignment during the gluing.  I made some filler with sawdust and T-88.  It sanded down to a nice smooth finish.  The glue does clog a file, so you need to keep cleaning it with a file card.

It really does look like a wing now.

I used the band file to shape the ends of the corner blocks so they will not show through the fabric covering.

Any edge of a block which might touch fabric was chamfered to soften the corner.

The leading edge corner of the plywood wing walk stuck out slightly past the leading edge wood.

It also had a slight gap because I finished the edge flush with the face of the nose ribs.

The block plane is nice and sharp so it was easy to use it to smooth the corner flush with the leading edge.

I used the wood filler I made to fill the gap, leaving a very smooth finish.

I'm looking forward to doing all this on the next wing.