Last 2 Spars Routed

 The process for routing the spars worked very well.  It's worth going back and looking at the other posts.

The First One covers the guides and basic method used.

The Second One is about the much needed dust collector.

The Third One is about planing and sanding the routed surfaces.

By the time I did these last 2 spars I had forgotten what I did.  Fortunately I had these old posts to remind me how I did it.

I used the ShopSmith as my work table with roller stands to hold the spar flat.  Fortunately my attic is 44 feet long so I have room to slide the long (15') spars in either direction.

On the first spar I forgot to lightly cross clamp the guides to the spar.  The spar started sliding with the force of pushing the router.  The cross clamps also assure the guides don't move away from the spar, so you get a very straight edge.

The vacuum hose for collecting saw dust has to be positioned so it doesn't stop the router because the hose snags on everything.  I hung it from a nail by one of my skylights.

The routing itself goes pretty easy with slow steady motion, not across the grain.  Across the grain makes a deeper cut than with the grain.  WEAR EAR PROTECTION, it's noisy.  I use my Bose headset which I wear all day in the embroidery shop.

I used 2 drill bits, 1/64" smaller than the desired cut depth, with a straight edge to set how far the router bit protrudes beyond the base.  There's a picture in the first post.

The piece of 2x4 with the corners routed to 3/8" worked very well for sanding the rear spars.

Along with the 150 grit Sandblaster I bought some 80 grit.  It worked very well for the first pass on the rear spars, where I couldn't use the block plane or my rubber sanding blocks.

The last 2 spars are done.  How cool is that?

Finished Drilling 2 Rear Spars

 

The attic is a bit crowded with the fuselage in there.  I should have turned the ShopSmith so the working side was on the left, where I had more room.  Hey it worked the holes are drilled and I'm ready to route the spars.

I only use the template to locate the drill, clamp the spar to the table, recheck the location, then move the template aside while drilling.  It's slow but the holes line up perfect.

Back To Drilling The Last 2 Wing Rear Spars

 Ok I've only drilled 2 holes, but I'm back working on the spars. The holes are the 5/16" holes which go vertically through the spars for attaching the wings.  Here are the links to go back and look at the details of how I did this for the first spars.

Aligning the ShopSmith to get accurate holes.

Positioning the drill.

Drilling the holes

After rechecking the alignment of the drill to the table and the fence we're ready to drill.  The spar is supported on 2 roller stands.  I moved the spar so the first 2 feet could be used to align it parallel to the fence.  The actual hole is 1-1/4" from the end of spar, therefore I wanted a longer edge to get it parallel.

The first pass is with a 1/4" drill.  The rear spars are 1-1/14" thick so I used a 1/2" gauge block between the drill and the table so the hole is centered on the spar width.  I center punched the holes with the optical centerpunch.

I clamped the spar to hold it flat and drilled just over 1/2 way through the spar.  Then the spar was flipped over and drilled from the other face of the spar.

The 2 halves of the hole aligned so well that a 1/4" bolt went easily through the hole.

I sort of repeated this process to drill out the hole to 5/16".  I used the 1/4" drill bit to align with the drill centerline, clamped the spar to the table, then switched the bit to a 5/16" bit and again drilled over 1/2 way through the spar, flipped the spar over and repeated.  After drilling the second side I used a letter P drill to open the hole slightly and in this case drilled all the way through, into my backing board.

Again a 5/16" bolt goes easily through the hole.

Now I need to drill all the holes for the fittings, etc.

Aileron Spars Ready to Drill

 The layout work is done on the 2 new rear wing spars.

The ailerons have 2 spars, like the wings.  The WACO NINE has ailerons on the upper wing panels only. They must Not have worked well on the 1925 version, because in 1926, with the Improved NINE, they made them longer with an Elephant Ear balance tab.  The longer ailerons would have had more power and the balance tabs would lightened the stick forces.

On the 1927 Model TEN they got rid of the Elephant Ears ears and added ailerons on the lower wings.

On the NINE the ailerons are operated by cable routed through the lower wings to pulleys hidden in the structure below the aileron control horn. You can see one in front of the aft strut and one behind it.

On the TEN they used push rods to operate the lower ailerons with the upper ailerons slaved to them by a strut between the Ailerons.

The aileron starts about 1/3 of the way along the spar and extends about 18" beyond the tip.

Each aileron is hinged with 4 hinges using an Eye  Bolt and Fork Bolt arrangement.  The fork bolt part bolts through the aft wing spar.  The eye bolt part bolts through the forward aileron spar.  I have 4 drawings showing the location of the aileron hinges, the wing assembly drawing, the aft spar drawing, the aileron drawing, and an older aileron drawing from 1926.  They all have slightly different dimensions.  There are more of these anomalies.  The aileron drawing shows the length of the forward spar is 120" but the Bill of Materials on the same drawing shows 120 1/4".

To resolve these things I've modeled the aileron in TurboCAD.  I'm using the dimensions from the drawings which work in the model.

I have all the ribs and hole locations drawn out on both sides of each spar.  I also write on the spars the size of any drilled holes.

I'll match drill the hinge bolt holes in each aileron spar by using it's wing spar as the master for the holes in the aileron spar.  Even if I measure slightly wrong the hinges won't bind.

The tip of the forward spar has a tapered tip with a gentle Ogee type curve connection the taper to the main straight section.  To layout the curves in this 8" section I clamped 2 blocks to the spar.

The one on the left is clamped flush with the straight edge, with the corner at the start of the curve.  The other block is clamped so it's edge follows the taper, with its corner at the start of the curve. 

I clamped my Starrett meter scale to the edges of these 2 blocks and drew the curve between them.  The clamps should be at the end of each block so the curve is tangent to the 2 blocks.  It was easier to do than explain.

The drawing doesn't show the taper on the aft spar so I made it such that where each rib crosses the 2 spars are the same height.  At the inboard rib the spars are 1 13/32" tall and at the outboard rib they are 1" tall.

I'm ready to start drilling, routing, etc.  We're making parts again!

Planing the Wing and Aileron Spars

 

I decided to install new knives in the planer before planing the spars.  There are 3 knives in the Shopsmith planer.  Each blade is held in by 2 wedges, with 4 screws each.  Below each knife there are 3 screws for adjusting the height of each knife and for leveling it end to end.

It takes about an hour to replace and/or adjust the knives.  They can be lightly sharpened (honed) without removing them.  The new knives are sharp, I cut myself on one.

When I packed everything a couple years ago to build the wall between the 2 rooms in the attic, I packed up the adjustment gauge and can't find it.  I ordered a new gauge and found they had changed the design.  The original had a curved edge (7) that the knife needed to just clear.  The new one has a straight edge.  They didn't send any instructions and they were closed so I winged it.

It turns out I came pretty close to how they wanted you to use this gauge.  I put a piece of tape on the gauge and marked where a knife touched it, then made sure all knives touched at the same point.  The correct instructions are to put this mark 7/16" from the bottom corner.

I have an idea to make a label to do this more accurately, more on it another day.

The attic is 44 feet long but the wall limits how long a board you can plane without working through the outside door.  The 17 foot and 18 foot boards just fit.  The 20 foot boards will probably need the door open.  I wanted to plane the full length of the board so I could cut out the best section for each spar.

I put 2 rollers on each side of the planer.  It worked out well except that the 1/2" thick aileron spar boards drooped enough that I could have used an assistant to lift the end onto the rollers.

It actually worked quite well even without an assistant.

You really need the vacuum.  This make a lot of chips and sawdust.

The board on the right is the aileron spar from the second board.  You can see where the high spot, caused by the bandsaw blade curve, has started planing first.

The picture below is the wing spar from the other side of the cut.  You can see where the low spot hasn't planed down.

You can't plane 2 boards at once, but if you do multiple boards between each thickness adjustment they will come out the same thickness.

I found I could keep it straight if before each change in height I put an X on the start of each board so I knew which ones had not been planed yet.

I set the board, waiting it's turn, to the left side where it couldn't accidently get into the planer.

The boards tended to slowly rotate as they went through the planer.  I found it only took the slightest touch with my thumb nail to hold them so they feed straight through.

I checked the thickness of each board after each pass using my Vernier calipers.  The planer adjustment wheel has markings for every 1/128" (0.008").  You can easily plane to whatever thickness you want within a couple thousandths of an inch.

All the wing and aileron spars are cut to width and planed to thickness.  The task now is to layout all the bolt holes, rib locations, routing, etc.  I've been waiting almost 2 years to get back to this point.  It took a bit to remember what I was doing with this layout process.

I've call Aircraft Spruce and cancelled my spar order.  

It's great to be back to making wings and ailerons, YEA!

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.