Skybolt Fuselage

Page Index

-Accessory Trays
-Brackets
-Floor Tubes
-Fuselage Assembly
-Fuse Crosswires
-Fuse Finish Welding
-Fuselage Sides
-Fuselage Stand
-Internal Diagonals
-Longerons
-Passenger Handhold
-Side tubes 137-168

-Tailwheel Mount
-Tailpost
-Top Tubes

This page was updated on 10/04/2008
*New stuff!* 9/29/08- Seat brackets and accessory tray brackets are welded in. Accessory trays are fabbed and installed. New pictures. Click on the images to enlarge them. Supersize the image by clicking on the sizing icon that appears when you hold the mouse in the lower right corner of the picture.
12/30/04- This is the first step in building a fuselage. My 2- 8' tables were built from $150 worth of 2x4's, 1x4's, and MDF (medium density fiberboard), courtesy of Home Depot. First project on these tables will actually be the empennage. A wise old friend of mine who built 3 Pitts S-1's back in the 1970's advised me to start my welding of the 4130 on the small parts and tail-feathers first. If I really screw up a piece of tubing, at least it's a short piece and not as costly. Also, hopefully my welding skills will be improved by the time I start on the fuselage. Make sure your tables are flat and perfectly level.
1/15/05- While I wait for my tubing to arrive from Dillsburg Aero, I practiced notching and fitting scrap tubing. As you can see, using a tubing notcher and holesaw, the fit is perfect. Just what you want for TIG welding.
2/5/05- My tubing came in from Dillsburg. It came in an 18' cardboard tube and most of the pieces were about that long. I had it delivered to my work because the freight trucks charge so much extra to go into residential neighborhoods, so I had to cut the pieces in half to get them home.
Fuselage Sides	Return to top
2/20/06- Welded the splices in the 4 longerons for the fuselage sides. To hold the longerons straight while welding, I drew the top longeron line on the table and mounted the jig blocks. This light .035 tubing doesn't even take 30 amps to weld using the Lincoln TIG 185. Be sure to make your 30 degree splice.
2/27/06- For the last week I laid out the fuse side on the table and measured the tube lengths and notch angles. Here, the tubes are all cut, notched and fitted back to where the lowere longeron bends up.
2/27/06- I first mitered the longerons at 45 degrees and then fit the front vertical tube to it by sanding a little at a time on my 12" sander until I got a perfect fit. Here, I have pulled out the front tube and spun the longerons 90 degrees to drill the 1/8" oil holes at each cluster.
2/27/06- In the font half of the fuselage, this is the only notch that I could not do on my Accujigger. A lot of work on the bench grinder, hand grinder, and air file.
2/27/06- While I was notching and fitting, I had to remove the wood blocks from time to time to get a tube in location.
3/2/06- After I drilled the 1/8" oil holes in the longerons, I sanded each joint and tube with emery cloth to prepare for tack welding.
3/2/06- Here is the 4 tube cluster, all tacked.
3/2/06- Right after I tacked the tubes all the way back to station 57, I put some steel sheet under the longeron and heated the lower tube to easily bend the lower tube to match the plans drawn on the fuselage.
3/2/006- This is the mid-horizontal tube all tacked in place. Now that the lower tube is bent and blocks mounted, it's time to start cutting and notching tubing for the second half of the year.
3/14/06- Both fuselage sides are now tack welded and ready to stand up and assemble the top and bottom. The plans say that it should take you about 8 hours to do a side. I guess I'm real slow, because it took me 16 hours each. It took 79 blocks and 158 screws to jig the whole side.
3/14/06- These are the tubing joints in the forward half of the fuselage. I was able to notch all the joints using my notcher except for the bottom of this joint because of the extreme angle. Using my hand held grinder and the bench grinder, it turned out perfect. All it takes is patience and fitting the joint about 100 times.
3/14/06- This is the joint where the lower longeron bends upward. If you supersize this picture, you can see the small bump on the inside of the joint.
Fuselage Assembly	Return to top
3/15/06- When you layout your fuselage jigs, you should draw your perpendicular lines geometrically with a compass, not a square, it's much more accurate. I made this low-tech compass with a 1x2, pencil, and finish nail
3/15/06- If you've forgotten your geometry, here are the instructions for drawing perpendicular lines.	Click here to download the geometric instructions.
3/15/06- Finally, it's starting to look like something. Here the sides are clamped to each other with the 29 1/8" notched sticks on top and diagonal on the sides. Be sure to check for level and plumb on the sides.
3/15/06- I'm going to replace the stick diagonal with cables and turnbuckles so that the sides don't move around while I'm fitting the tubes.
3/15/06- I built the landing gear truss about 6 months ago and finally got to mount it. It fit perfect and just required some grinding on the top side of the notches. Be sure that you notch the truss ends so that it is flush with the bottom of the tube, rather than centered like the plans show. Return to top.
3/16/06- Today I rigged the crosswires and turnbuckles to help plumb and rigidly hold the fuselage sides in place. I use common bailing wire that I have had laying around the shop for years. Some people call it iron wire. With this setup, you can get the sides set perfectly. Just make sure that your table is level too.
3/16/06- I use a bubble level and a digital level and check them against each other. This looks right on to me.
3/16/06- This is the intricate notching required on both ends of the top and bottom tubes at 0-0, the firewall. Because the tube is 1.00 dia. instead of 7/8 and it has to be flush with the front of the fuse sides, you can't just chuck it in your joint jigger and cut it with the holesaw (at least I couldn't). I ruined a 30" piece of tubing by starting with the top tube (against the table) and came out with too big a gap along the top longeron. I finally figured out that I could notch both tubes on the bottom longerons where I have better visibility around the joints and just flip one over, do a little touch up grinding, and click it into position on the top (against the table since the fuse is upside down). This took a lot of patience and 100 trips to the bench grinder. Return to top.
3/17/06- Today I notched and tack welded 4 crosstubes and the landing gear truss in the stations from 57 1/8 forward to get ready to bend in the fuse sides to the tail.
3/17/06- I've done most of my notching using the AccuJigger you see here. I don't know if it's any better than a Joint Jigger because I haven't used one, but it's about double the price.
3/17/06- As soon as the tubes were tack welded, Bobbi and I bent the fuse sides into the tail by heating on the inside of the longerons and patiently pushing the sides toward the center of the table. I put a piece of steel plate under the longerons where I heated them so that I wouldn't burn up the table. It came out perfect. Return to top.
Tailpost	Return to top
3/20/06- Today I started on the vertical stabilizer spar and getting it ready to weld to the fuselage. Here is my rosette welds and 30 degree scarf joint.
3/20/06- I originally laid out the top fuselage planview with station 0-0 about 3" from the edge of the table. I had planned to drill a hole down through the table for the rudder post. These photos show the rudder post all spliced and welded, but I'm not going to weld in place like this. I decided that if I weld the full length post in now, it will get in the way as I rotate the fuselage later for finish welding. So I'm going to scrap this one and make another lower section only spar and weld that in and do the splice after the fuse is finish welded and the landing gear is mounted. Return to top.
3-21-06- I was able to get the post plumb and square with ease. Grinding and fitting the longerons to fit the post should be easy.
3-21-06- I used the same jig blocks to hold the rudder post as I used everywhere else. Return to top.
3/25/06- For the last 5 days I've been working on this crosstube at the lower 0-0 station and the passenger hand hold bar.
3/25/06- This level goes across the bottom of the fuselage. It's pretty level.
3/25/06- You also want the sides to be plumb as shown here. Using the crosswires and turnbuckles shown above, you can easily get this dialed in exact.
Passenger Hand Holds	Return to top
3/25/06- I laid out the passenger handhold on the table and notched all 6 tubes to fit.
3/25/06- Be sure to shim up the 3/4" tubing so that it is on center with the 7/8" tubing. Some 1/16" plywood from the rib gussets does the trick.
3/25/06- All fitted and jigged up and ready to tack weld. Return to top.
Floor Tubes	Return to top
3/30/06- Notched half the diagonals that go in the floor of the fuel tank and passenger compartments.
3/30/06- I still haven't welded the rudder post in yet. I want to finish all the cross bracing from 0-0 to the pilot compartment first.
4/1/06- Completed notching and fitting the floor tubes in the tank and passenger compartments and the V tubes at 0-0. Notice that the top tube at station 0-0 looks bowed up due to the camera lens. It really is straight.
4/1/06- Finished tack welding all the passenger floor tubes in place.
4/3/06- Yesterday, I spent the day laying out the pilot's floor tubes from 571/8 to 99 by drawing the lines on the table. Using the tube at 571/8 as a pivot, I raised the front up and clamped the rear of the fuse down to the table.
4/3/06- Only 2 more tubes to notch for the pilot's floor.
4/7/06- Notched the remaining tubes for the pilot's floor and tack welded them in.
Tailpost Jig	Return to top
4/8/06- After carefully jigging the fin spar vertically and marking the upper and lower longerons, I roughly notched the longerons with my grinder and then finish notched with my die grinder.
4/10/06- Today I made up this jig to hold the tail post perfectly plumb while I tack welded it. If you look closely, you'll see that I used playing cards for shims- a trick I learned in my model RC airplane building.
4/10/06- On the back side of the jig board, I screwed 1x2 boards and then screwed it to the table. Go to top
Top Diagonal Tubes	Return to top
4/12/06- While the fuse was upside down and the tailpost was still locked in the jig, I fit and tack welded the top tubes from 85 to 137. Be sure that the 2 diagonal tubes meet on the right side of the fuse when it is right side up like it is here. It's easy to get confused when the fuse is upside down so draw it correctly.
4/12/06- The fuse is right side up here and you can see the top tubes from 85 to 137. I've jigged the bottom longerons here and clamped down the rear half of the fuse to prepare for fitting the remainder of the bottom tubes. Go to top
Rear Bottom Tubes & Tailwheel Mount	Return to top
4/13/06- The job for today was the bottom tubes and tailwheel mount from 99 to 162. All the lines are laid out on the table and the jig blocks are ready. By now, I'm getting pretty fast with the bench grinder.
4/13/06- This is the view from the tailpost. You can see the tailwheel mount up close if you supersize the thumbnail picture by clicking on it and then clicking on the sizing logo that will appear in the lower right corner of the picture if you hold your cursor there.
4/13/06- Before I tacked the 3/4x11/2x.049 tailwheel mount in place, I drilled it out for the 1/2x.058 bushing but I didn't tack the bushing in place yet so that it wouldn't raise the rear of the fuse up off the table. Go to top.
Internal Diagonal Tubes	Return to top
4/17/06- For the past 4 days I notched and fitted the internal diagonals from 0-0 to 137. In this picture you can see the 0-24 diagonals. I hope they clear the fuel tank. I wanted to install the diagonals before fitting and tacking the 6 tubes on the aft sides from 137 to 168, hoping that the diagonals will prevent the tailpost from getting out of plumb. We'll see.
4/17/06- This picture shows the pilot seat diagonals. Notching and filing all these internal diagonals took a lot of time to get them to fit properly and not take off too much material.
4/17/06- The pilot seat back diagonals at 79-85. To avoid getting confused, I set the fuselage right side up and set welding rods in place before cutting the tubing.
4/17/06- This is the longest diagonal from 85-120. Also, before cutting the tubing, I sighted through the fuselage from the front and compared the welding rods to the diagrams in the plans.
4/17/06- The rear most diagonal from 120-137. I tacked all the diagonals and it's amazing how rigid the fuselage is, considering how floppy the the 2 sides were when I first set them up and started tacking in the cross members.
4/17/06- Now all I have to do is fill the hole from 137-168 with 4 more tubes on each side and keep that tailpost plumb. Go to top.
Rear Side Tubes 137-168	Return to top
4/19/06- Yesterday I actually notched, fitted and tacked the left side tubes from 137 to 168 but forgot to take a picture of the jig.
4/19/06- As you can see here, I laid the fuse on its side and set up the jig blocks on the table for the tubes from 137-168.
4/19/06- It's important to get these tubes in the proper positions since they support the tailwheel mount and stabilizer spar.
4/19/06- A side view of the tubes from 137-168.
All Fuselage Tubes Tacked in Place	Return to top
4/19/06- Finally, all the basic fuselage tubes are tacked in place.
4/19/06- The next step is to finish weld all the clusters. I figure that it will probably take me 60-80 hours since I'm not the fastest welder in the world.
4/19/06- This view shows all the internal tubes looking down the inside of the fuselage.
4/19/06- I tacked the completed landing gear truss in place when I first stood the fuselage sides up back on March 15. The basic fuselage took from Feb 20 to Apr 19. Almost exactly 2 months to complete.
4/19/06- This shot of the tailwheel mount shows that I should have welded the bushing in place before I welded the tubes in. Now I'm going to have to maneuver my TIG torch all around the tubes.
Finish Welding the Fuselage	Return to top
5/18/06- The first step in finish welding the fuselage is to build a rotating stand so that the fuselage can be turned to the best angles for welding each cluster. I took some scrap tubing and plate and welded them together. The front mount will have a 2x4 bolted to it and then clamped to the firewall tubes. The rear mount has a split tube of 1x.058 for clamping to the tail post. The 2 vertical 2x4's have holes sawed in them for the front and rear mounts as well as 10" long slots to enable clamping the mounts in any position.
5/25/06- Here is the fuselage mounted on the now completed rotating stand waiting to be finish welded. The clamps on the vertical posts, front and rear, provide the friction to hold the fuselage in an infinite number of positions for welding.
5/25/06- Here you can see all the parts for the front mount, including the clamping blocks that hold the tubes at 0-0.
5/25/06- The friction clamp does its job well in keeping the fuselage from spinning until you want it to.
5/25/06- To make the clamping blocks, I sawed a 7/8" hole for the tube and then ripped the block in half, taking 1/8" out with the cut so that the block would adequately clamp the tube. 2- 6" clamps keep the fuse from slipping.
5/25/06- I put duct tape inside the rear mounting tube so that the tailpost wouldn't slip and to protect it from scratches. 2- 2" clamps hold the tube mount together. Another clamp on the stand keeps the fuse from rotating. Return to top.
5/26/06- Now that the fuse is ready to finish weld, I decided to start at the tail post and work my way up to the firewall. The board is clamped in place for a hand rest while welding.
5/26/06- The first thing to do is to cover the ends of the longerons. While some builders elect to heat and bend the tubes down to the tailpost, I elected to cut them off tangent to the post and weld an end plate around the tailpost for a little extra strength.
5/26/06- After making a pattern with some file folder stock and cutting out the plates from .050" plate, I tack welded one end in place and then heated the plate to bend it around the tailpost and weld to the other longeron. Here, the end plate is partially welded. It was real easy to do. Return to top.
6/4/06- For the last several days I have been finish welding the fuselage clusters. Using the rotating stand, I can even get inside to get in a good position for each weld. I finally finished all the clusters on 6/11/06. It took a total of 49 hours of welding.
12/13/06- The fuselage is finally on it's own feet. Before I install the cabanes or upper tailpost, I'm going to weld in all the brackets, tabs, mounts, and belly formers.
Weld in the Seat Back Brackets	Return to top
9/27/08- I made up 24 brackets out of a piece of 6x12x.040x4130 and installed them on the front and rear seat back supports. The brackets are drilled for K1000 x 3/16" nutplates.
9/27/08- This is how I clamp each bracket in place so that it is tangent to the tube it is welded to.
9/27/08- Seat brackets tack welded in place. I don't know why they have the reddish tinge in the picture.
Accessory Trays	Return to top
9/28/08- Since my battery will be installed behind the pilot's seat, I decided that I would install 2 accessory trays for mounting the ELT, solenoids, and strobe power supplies. Each tray is supported by 4 brackets welded to the fuse structure.
9/28/08- I also installed a tray up front just behind the firewall for mounting my fuel and smoke pumps. I used 6061 T6 x .090 for the trays. This stuff is almost like steel, so I had to anneal it to get it to bend. These trays give me flexibility in mounting and servicing equipment since they can be removed and modified as needed.