Started November 2, 2004
The Horizontal Stabilizers are welded 4130N chromemolly steel tube with T-25 ribs made from 4130 steel sheet. The tail surfaces will later be covered with fabric and rib laced.
Starting with a 4'x8' flat table, the plywood top was painted white with some cheap house paint. This was done to be able to see the layout lines better. On the plans, the centerline of all tubes are shown. All measurements and lines are laid out with tube centerlines in mind.
First, a straight line was drawn vertically, along one end of the table, to represent the fuselage centerline. Many of the measurements are done from this line. Next, using a framing square, a second line was drawn perpendicular to the fuselage centerline. This line will represent the rear spar tube centerline. The remaining measurements are taken from this line.
Scaling to the drawing, all of the T-25 ribs and various tubes were drawn in their correct lengths and locations.
Using the T-25 tube lengths, the final line to be drawn was the curving leading edge tube centerline.
It is important that the first 3 inches or so, of the leading edge tube, be straight and perpendicular to the fuselage centerline. A framing square was used to draw this line.
With everything drawn out, its time to start placing some tubes. I started with the leading edge and rear spar tubes.
The leading edge tube is 7/8 x .035. However, the drawings show a stub of 7/8 x .049 tube about 3" long welded to the root end of this tube. This is to beef up where it bolts on the fuselage cross tube, to prevent the tube being crushed by the bolt/nut.
Here is the finish welded leading edge tube:
The leading edge and aft stabilizer spar tubes were then secured in place with some 3/4" x 1" blocks of wood, 2" long and nailed to the table top with small nails as shown below. This keeps them from moving during welding:
With the front and aft tubes located, I can now make the T-25 Ribs. I needed to locate these tubes first, so I could measure for the T-25 rib lengths as described in the section on "how to make the T-25 Ribs". Click here to see that
Click here to go to Making the T-25 Ribs
Click here to go to Horizontal Stabilizer page 2