My first idea was to buy a metal cutting blade for my band saw. I found a supplier, paid a nutty amount of money for the blade, and never could get comfortable with the idea of actually using my woodworking band saw to cut steel. Being a woodworking saw, it runs the blade at 2,960 fpm but I have read that the blade should run at about 240 fpm for 4130 steel. I did find a write-up on the internet of a technique for cutting 4130 steel on such a saw but it involves pushing the material hard against the blade. Since the VS-16 spacer is only about four inches long and less than an inch wide, I could not think of a way to do that safely without getting my fingers uncomfortably near the blade.

In the end, I decided that the band saw was simply the wrong tool for the job. I bought a pneumatic cut-off tool with a 3″ disc and that made short work of the cutting. It was a little tricky using a cut-off wheel to make a long-ish slot in a sheet of steel. I kept getting the wheel just slightly sideways in the slot, which would jam the wheel and stop its rotation completely. I did get through it, though, and was much happier to have the sheet of steel clamped to my workbench and all ten of my fingers safely away from the business end of the cut-off tool.

My next worry was drilling the holes for the bolts and the rivets to hold the nut plates. I had read horror stories on the internet about people who “work hardened” 4130 steel trying to drill it. Once hardened, it becomes virtually impossible to drill and turns into a great device for dulling expensive drill bits.

The internet was my savior, once again, with words to be read and even videos on YouTube. I set my drill press for its slowest speed, put a couple drops of 3-in-1 oil on the spot to be drilled, and applied a fair amount of pressure to the bit. I do have pretty good TiN plated drill bits and they cut through the steel like butter. It was very satisfying to realize the the job was much easier than I had feared and that my inexperience had blown the whole thing way out of proportion.

When I had all six holes drilled, I used the Scotch-Brite wheel on buff the VS-16 up and make it look all purdy. Once I paint it, you won’t be able to tell, but it sure looks nice today.

Spacer made from 4130 steel

I have been working my way from the control sticks back to the tail of the plane, making the brackets to hold the control systems. With the VS-16 out of the way (it was a hold-over from when I made the rudder in December), I returned to making brackets and fabricated two brackets out of 2″x2″x.063″ aluminum angle and four brackets of of a flat sheet of .063″ aluminum.

CS-25 brackets made from 2"x2"x.063" aluminum

CS-26 and CS-27 brackets made from flat .063" aluminum

Next up: woodwork, believe it or not. There are hardwood spacers which go between the two CS-26 brackets and between the two CS-27 brackets.

After scrounging around my shop, trying several things, the piece which worked the best was a scrap of 2″x2″x.063″ extruded aluminum angle. (As usual, click any picture to see a larger version.)

A piece of .063" thick aluminum in the bending brake

The result is a couple of very nice 90 degree bends in the bases of the brackets.

CS-13 brackets made by bending .063" aluminum

By the way, I am trying a new way to include photos in my blog posts. Please let me know how you like the  way the photos appear in this posting compared to the way they appear in older postings.

Before I could install the floor, I had to remove several things from the plane which were in the way. Since BedeCorp partially assembled my fuselage, they installed the landing gear so that the plane could be rolled onto a flatbed trailer for shipping to me. The main landing gear attaches to a gear box which sits on top of the floor. The nose gear attaches to several brackets which are also positioned on top of the floor. Finally, I had to remove a couple of gussets from the rear of the cabin area.

The metal for the floor, 48″ x 72″ and just 0.020″ thick, came rolled up in a box 15″ on a side. The first actual “floor task” was to trim sheet down to 46″ x 62″. I got an air shear from Harbor Freight and it made quick, easy work of the cutting.  The slow part was measuring, re-measuring, and re-re-measuring to be sure that I was not mis-cutting this large piece of metal. Had I goofed, the replacement would have been costly and the shipping more so. Fortunately, all went well and the floor fit just fine on the first try.

To insert the floor into the base of the fuselage, Candy and I gently bent it in half and slipped it through a gap near the rear of the cabin area. Think of a process somewhat like slipping a letter into a mail slot and somewhat like putting your foot into a sock and you will have the right idea.

Candy had a brilliant idea to keep the floor from sagging as we worked with it. We took a 2×4 and used my spring-loaded stool to press the board up against the bottom of the fuselage. It made a perfect support for the middle of the floor.

With the floor in the fuselage, I drew a line 1″ in from the edge, all the way around. By drilling rivet holes through this line, the rivets would be in the middle of the 2″x2″ angle of the fuselage on which the floor rests. I then used the rivet spacer tool to evenly space the rivets 2″ apart, all the way around the cabin area.

I bolted the gear box back into the fuselage. I drew rectangles on the floor for holes for the gear legs, using the holes in the gear box as templates. David and I also drilled rivet holes on 1″ spacing through the bottom of the gear box and the floor.

I had to do a little side work, installing nut plates in the angle bracket at the front of the cabin floor, so that the nose gear bracket could be bolted to the angle bracket.

I  then bolted the angle bracket to the fuselage and the nose gear brackets to the angle bracket. This locked the angle bracket in place so that I could accurately drill the rivet and bolt holes through the floor and the angle bracket. I also drilled bolt holes through the floor to match those in a couple of nose gear brackets.

With all of the holes drilled, Candy and I removed the skin from the fuselage. All of the rivets would be countersunk (flush mounted), so in addition to the usual deburring work, I needed to dimple the skin and countersink the thicker aluminum pieces.

Dimpling is easy. Start with a dimple die set, one concave and one convex with a pilot pin sticking out of it. The pin centers the convex die over the hole. Whack the die with a hammer and poof! you get a neat dimple in the sheet metal, perfectly smooth and perfectly sized for the rivet.

Countersinking the metal is easy, too. The tool looks much like a fat drill bit, or a wood countersinking bit, but it has a smooth pilot pin sticking out of the middle. The pilot pin gets inserted into the rivet hole and keeps the countersink bit centered over the hole. The countersink bit gets screwed into a micro-stop which gets adjusted to exactly the desired depth. Pop the micro-stop, with countersink bit, into a drill and hit each rivet hole.

All of the rivets were to be installed from the bottom of the plane so the “bump” would be inside the fuselage and the outside skin of the Bede BD-4C would be smooth. Around the outside edges, the floor sits on top of the fuselage so, the rivets (being shot upward) would go first through the 0.063″ thick angle and then through the 0.020″ thick floor. The metal of the angles is thick enough that it could be countersunk.

Rivet holes for the gear box and the angle bracket at the front of the cabin area needed different treatment, though, since both the gear box and the angle bracket sit on top of the floor. This means that the rivets will penetrate first the thin floor and then the thicker material of the box and bracket. Since the 0.020″ floor is too thin to countersink, it gets dimpled. The metal on top of the floor needs to be countersunk to accept the dimple.

Countersinking all of the holes in the bottom of the fuselage and the gear box was easy but I was covered in aluminum shavings, since I had to do it all on my back underneath the plane. I will probably be picking bits of aluminum out of my beard for months!

Once all of the holes were deburred, countersunk or dimpled, it was time to see if the floor would fit. We slid it back into the fuselage and was I ever relieved to find that it did, indeed, fit. I had missed a couple of bolt holes but quickly drilled them. I also needed to slightly adjust the size of the large holes for the gear legs but, again, this was a quick fix.

David did yeoman’s duty with the rivet puller underneath the plane, easily installing 3/4 of the rivets. The floor, once riveted to the fuselage and gear box, is beautifully smooth and a delightful end to a long week’s work.

The (almost) finished rudder

I have finished the rudder of my Bede BD-4C! Well, almost finished the rudder. It still needs the counterbalance on the top and the weldment on the bottom. And it needs to actually be riveted together. But, other than those trivialities, the rudder is done. The two skins are trimmed to size. The piano hinge is trimmed to length. The three ribs fit. All of the rivet holes have been drilled in all of the parts and everything has been deburred.

Getting to this point was a full weekend’s work.

I started from the happy point of realizing that my newly designed ribs did, indeed, fit properly. Installing the top and bottom ribs would be easy, since I could reach them which the rudder skins were “closed” up. The middle rib would be the challenge so I decided to install that one first.

I began by taping the rib into position in the middle of the inside of the rudder.

The VS-10 rib taped approximately in position in the middle of the rudder.

I then drilled holes through the flange on the end of the rib and the VS-17 spar (which is along the edge of the rudder skin, farthest away in the photo above) and clecoed the rib to the spar.

With the rib held in place in the middle of the rudder by the cleco and the tape, I carefully drew a line on the outside of the rudder skins  along the top of the rib.

I transferred the line along the top of the VS-10 rib to the outside of the skin.

Knowing the length and width of the flanges on the rib, I was able to measure down from the line on the outside of the skin and drill through the skin to where the rib would be. Next, I drew a line down the middle of the rib’s flange and positioned the rib so that the line showed through the holes in the skin. I then drilled through the rib and, voila, it fit. The red line on the skin in the photo below is in the middle of the flange, which is under the skin.

I closed up the rudder (attached the right side skin) and drilled through the skin and the rib using the line that I had previously drawn.

I repeated the process through the skin on the other side of the rudder and, even though I could not see the rib, everything worked perfectly.

With the middle rib held in place with clecos, and more clecos holding the trailing edge together and the leading edges of the skins to the VS-17 spar, the rudder was pretty rigid. Inserting the top VS-15 and bottom VS-9 ribs was easy compared to the middle rib.

VS-9 rib in the bottom of the rudder. This was easier to position than the VS-10 middle rib since I could reach it and see it with the rudder skins assembled.

The final steps were to trim everything to size, enlarge the holes to 1/8″, and debur all of the edges and holes.

I have more pictures, with captions, over on my photo gallery so click to see  the rest of the rudder assembly photos.

Next task: installing the floor.

Fortune smiled on me when it blocked me from making the third rib. I would have had to make it again, along with the other two ribs, and that would have required getting another piece of 0.032″ metal.

When the Bede BD-4C plans were originally drawn, in 1969, the rudder skin was to be made from a single sheet of aluminum. Since it is pretty difficult to find a shop which can cost effectively make the sharp bend in the trailing edge. BedeCorp now recommends that you build the rudder from two skin pieces with a doubler strip between the trailing edges of the two skins. Since the two skins are riveted together at the trailing edge, it pinches the skins and makes the space inside the rudder smaller than originally planned. This means that the ribs need to be both shorter and taper at sharper angles. Because of the change in geometry, you cannot just take an original, long rib and shorten it. Were you to do so, it would be too fat at the trailing edge.

Here is a photo of the parts that I have so far. Click any of the photos to jump to my photo gallery where you can view larger versions of the pictures.

6 rudder pieces: VS-17 front spar, right side skin, tailing edge doubler, left side skin, and two of the three ribs.

Since the rudder skins are oddly shaped, it is hard to imagine how these fit together so the following pictures should help.

The spar and two of the ribs sitting in position on the right side skin. The leading edge of the rudder is on the left, the trailing edge on the right.

The bottom rib is short enough to let the trailing edges of the skins come together. The middle rib, farther away in the picture, was made from the original plans. You can see that it is too long.

To continue assembling the rudder, we lay the doubler strip, visible on the right side of the photo above, onto the trailing edge and then put the second skin on top.

The left side skin (top) clamped to the top of the spar. You can see the doubler between the trailing edges.

Here is a picture with the trailing edges clamped together. You can see that the new VS-9 rib fits neatly into position.

The trailing edges are clamped together and the VS-9 bottom rib inserted into position.

How far off, you may be wondering, was the size of the original bottom rib? Quite a bit.

Two versions of the VS-9 bottom rib. The original (on top) is too large for the new rudder. The new VS-9 is underneath.

Since there are no drawings for the new ribs, I designed my VS-9 by measuring the rudder. I put the two skins and the spar together with clamps and then used a caliper to measure the thickness by the spar. I wanted the narrow edge of the rib to be 0.25″ so I used the caliper to find the point where the skins were 0.25″ apart and then I marked that point on the skin. Finally, I measured the distance, 10.1″, from the spar/fat end of the rib to the narrow end.

I sketched that, added some more metal around the edges for the flanges, and then drew it neatly onto a sheet of aluminum. I cut it out, bent it, and voila, it fit perfectly.

I have the measurements for the other two ribs so I will spend the next couple of evenings fabricating them.

Strap duplicator

Fortunately, there is a tool for that: a strap duplicator. It has a pin which fits in the (hidden) hole and a bushing that you stick your drill bit into. The bushing stays aligned with the pin so the new hole that you drill is perfectly aligned with the existing hole. If you look at the picture to the right, it worked like this: The skin, with the pre-drilled hole was on the far right. The right-hand strap of the duplicator, with its pin (not really visible in the photograph) sat on the left side of the skin with the pin in the pre-drilled hole. The piece the I needed to drill, the TC-2, went between the two straps. Then the drill bit was inserted into the bushing in the left-hand strap.

The duplicator did its job and here is the result. The TC-2 tail cone neatly fits on top of the pre-fab skins.

Bede BD-4C tail cone

I wrote previously about the building the tail cone and posted more pictures in my tail cone photo gallery.

Three tail cone pieces, from largest to smallest: TC-3 (bottom of tail cone), TC-2 (top of tail cone), and TC-1 (back of tail cone).

Here is a picture of how it all fits together on the plane.

Test fitting the Bede BD-4C tail cone

Building the TC-1 (back of the tail cone) turned into yet another “learning opportunity” for me. The first one did not fit well at all. It was too wide, so it would not fit into the TC-3 (bottom of the tail cone). Since it would not fit into the TC-3, it would not slide all the way down. Between not sliding all the way down and being too tall, in addition to too wide, it stuck up about 0.10″ past the top of the tail cone sides.

TC-1 is too wide to fit all the way down into the TC-3

TC-1 sticks up past the top of the tail cone sides

Solving the problem involved making another, smaller piece. This time, I took into account the thickness of the material and the “bend radius”. These make the part about 0.05″ wider and taller. I drew the shape that I needed but made it 0.05″ narrower and 0.05″ shorter than the first time around. After bending the flanges, the new one fit perfectly.

Static skin on left end of horizontal stabilator

There are lots of pictures, with captions, in my photo gallery.

Having done this once, the second set of static skins (for the right end of the stabilator) should go much more quickly.

And… huge bonus… the new electric garage heater works!

Garage Heater

Son of a gun, it worked!

Rebuilt HS-7 ribs with the holes properly drilled

The TS-16 brackets are tricky, at least for a sheet metal novice like me, since all I have are drawings on paper but I have to fabricate the brackets out of 2″ x 2″ aluminum angle 0.063″ thick. This stuff is light and rigid so there is sure no way to flatten it out to cut it and then rebend it. Next time around, I will have a better idea what I am doing but this time I started by mocking up one of the parts by cutting up a cardboard box. In this photo, I am test fitting an HS-7 rib inside the HS-6 anti-servo tab skin and my mocked-up TS-16 bracket to the bottom.

Planning the TS-16 bracket installation with a cardboard mock-up of the TS-16 and an HS-7 rib in the end of the HS-6 anti-servo tab

My next step was to paste copies of the drawings onto the 2×2 angle so that I could transfer the shape to the metal so that I could do a rough cut.

Drawings for the TS-16 brackets rubber cemented to a piece of 2x2 angle

The two brackets need to be 0.44″ apart to properly hold the rod end. I took a piece of wood, sanded to be 0.44″ thick, and bolted it between the two rough cut brackets.

The TS-16 brackets roughed out and bolted to a 0.44" wide wooden spacer. I will sand all three pieced down to size while bolted together so that both TS-16 brackets are the same shape and size.

I sanded the brackets to their final shape and deburred and ended up with these:

Finished TS-16 brackets

Finally, it was time to fit the brackets, ribs, and skin together. I thought that I had a good method which would keep everything aligned properly.

Here are a couple of pictures so you have some idea what I am trying to build.

How the TS-16 and HS-7 fit onto the HS-6 anti-servo tab

How the TS-16 and HS-7 fit onto the HS-6 anti-servo tab

Unfortunately, my scheme did not work. I had the ribs misaligned and the holes in the ribs are messed up. I will be rebuilding the ribs and trying Plan B  for keeping everything aligned. If you have suggestions, I’d love to hear them.

Messed up HS-7 ribs with the holes too close to the edges

I started with this

Labeling a piece of aluminum stock which will become an HS-7 rib. The HS-7 appears on the plan just above the aluminum.

And ended up with this:

All of the HS-7 and HS-9 ribs. A good weekend's work.

I was feeling my way like a snow-blind Floridian in an Arctic snowstorm, since this was my first attempt to fabricate anything out of sheet metal (if you don’t count the speaker shelves in my freshman college dorm room which destroyed the dry wall when we removed them at the end of the year but that’s another story all together). This was also my first attempt to actually work in my new shop / airplane factory full of lots of new tools.

My first challenge was to transfer the pattern for the rib to each piece of 2024-T3 0.020″ aluminum stock. I ended up photocopying the section of the drawing with the rib pattern and sticking it to the piece of aluminum with a bit of rubber cement. I used a spring loaded center punch to mark the metal through the paper. Then I pulled the paper off and drew from dot to dot, er, from dent to dent, recreating the pattern on the metal.

I have transferred the rib pattern from the drawing onto the aluminum stock

I made the HS-7 ribs, which will go in the anti-server tab on the back edge of the horizontal stabilator, on Saturday. This entailed trips to Harbor Freight and Home Depot for a few tools which I still needed, most importantly, a Dremel tool and accessory kit. I tried cutting the HS-7 ribs out with the Dremel tool and a tiny cut-off wheel. It worked pretty well but boy was it slow!

Once I had the ribs cut out and the edges deburred, it was time to figure out how to bend them. My first thought was a sheet metal bending brake but I quickly discarded it because there are three bends and the brake could only have done one. Thanks to a phone conversation with my friend Karsten (I would never get through this project without advice from friends my EAA chapter), I decided to make a bending jig and hammer the flat metal over the top of the jig, forming the finished rib.

Since I could not figure a safe way to cut the jig on my table saw, I headed to Sears and picked up a small band saw. Quick as a wink, I had my jig cut and working. It had been so many years since I had used a band saw, I had forgotten what delightful tools they are.

After a bit of hammering, the rib comes out of the jig formed to shape.

I broke the top half of my jig after forming three ribs but realized that I could do quite nicely with just a straight piece of wood. That worked to fashion the fourth HS-7. When I built a jig for the HS-9 ribs, which will go into the non-moving trailing edges of the horizontal stabilator, I made only a lower portion shaped like a wedge and used another straight piece of wood for the top.

I learned that it is very important to properly center the flat aluminum stock in the jig before bending it when I messed up the first HS-9 rib. Since the stock was off-center, one flange ended up too wide and one too narrow near the pointed end of the rib. It might work but I think that the rivet hole will end up too close to the edge of the flange so I will rebuild the part. Better safe than sorry, particularly since this part will be difficult to inspect after the plane is flying and pretty difficult to replace if a flange cracks.

I spend a day and a half making just eight small parts but I feel like it was time very well spent. My shop is better set up, with a power strip securely fastened where I need it for the band saw and the Dremel tool. I have some real experience with a bunch of new tools: Dremel tool with a cut-off wheel and with a sanding disk, 12″ disk sander, band saw, a couple of files, drill with new 110° TiN #10 drill bit, and the Scotch-Brite deburring wheel on the bench grinder. I am learning a ton, too. I was much faster on Sunday than on Saturday.

Best of all, my friend Gale looked at the pictures of the parts, talked to me on the phone about how the ribs fit into the anti-server tab skin, and opined that it sounds like I built the ribs correctly!